SYNCHRONOUS CONTROL METHOD BASED ON SYNCHRONOUS CONTROL SYSTEM FOR LIFTING HYDRAULIC CYLINDERS OF TUNDISH IN CONTINUOUS CASTING

Abstract

 The present disclosure is applicable to the hydraulic drive control field, and provides a synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish. According to the method, a master hydraulic cylinder synchronization position deviation velocity correction unit and a slave hydraulic cylinder synchronization position deviation velocity correction unit correct a position deviation exceeding a set range between a master hydraulic cylinder and a slave hydraulic cylinder. If the position deviation between the two exceeds a set maximum allowable position deviation, a master hydraulic cylinder synchronization position deviation out-of-range control unit and a slave hydraulic cylinder synchronization position deviation out-of-range control unit control a fast moving master hydraulic cylinder or slave hydraulic cylinder to stop moving, until the position deviation between the two is less than the set maximum allowable position deviation again. A master hydraulic cylinder automatic position holding control unit and a slave hydraulic cylinder automatic position holding control unit are used to avoid position deviation of the master hydraulic cylinder and the slave hydraulic cylinder without a manual instruction. Therefore, according to the synchronization control method, the master hydraulic cylinder and the slave hydraulic cylinder can be synchronously moved in cases of leakage of a hydraulic cylinder, different manufacturing accuracy of hydraulic elements, and uneven load.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the hydraulic drive control field, and in particular, to a synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish.

BACKGROUND

[0002] A continuous casting tundish is usually moved up or down synchronously by using four hydraulic cylinders (one master hydraulic cylinder and three slave hydraulic cylinders). At present, the lifting hydraulic cylinders of the continuous casting tundish are mainly synchronously controlled in a hydraulic cylinder synchronization control mode based on four hydraulic synchronous motors, or in a universal master/slave hydraulic cylinder synchronization control mode based on an independent PI regulator and proportion regulation valve. Synchronization control accuracy of the two multi-hydraulic cylinder synchronization control solutions is easily affected by factors such as leakage of a hydraulic system (such as internal leakage of a hydraulic cylinder), different manufacturing accuracy of hydraulic elements, and uneven load, especially the hydraulic cylinder synchronization control mode based on four hydraulic synchronous motors. The 1# and 2# continuous casting tundishes from the south section of Long Products Business Division of Masteel implement synchronous lifting of hydraulic cylinders by using four hydraulic synchronous motors. The 4# continuous casting tundish implements synchronization control of lifting hydraulic cylinders in the universal master/slave hydraulic cylinder synchronization control mode based on an independent PI regulator and proportion regulation valve. In actual production, for the 1# and 2# continuous casting tundishes, the lifting hydraulic cylinders are usually asynchronous because of abnormal working of the four hydraulic synchronous motors or internal leakage of the lifting hydraulic cylinders. For the 4# continuous casting tundish, the lifting hydraulic cylinders are also usually asynchronous because of factors such as internal leakage of the lifting hydraulic cylinders. Consequently, the continuous casting tundishes are askew or severely askew. Once a continuous casting tundish is severely askew, not only the molten steel in the tundish is very likely to overflow, causing safety accidents for human body and equipment, but also the tundish drain cannot be aligned with an inlet of a continuous casting mould, and the molten steel easily flows out of the continuous casting mould. Consequently, the continuous casting is interrupted, molten steel in a ladle is returned to a furnace, and the molten steel in the tundish is scrapped. In addition, it can be learned from the continuous casting process that if the continuous casting tundish is askew and the position of a submerged the tundish drain is not centered, molten steel in the mould is in an asymmetric flowing state, a heat center deviates, and a longitudinal crack easily occurs on a strand.

SUMMARY

[0003] The present disclosure provides a synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish, to resolve an existing problem that synchronization control accuracy of a hydraulic cylinder synchronization control mode based on four hydraulic synchronous motors or a universal master/slave hydraulic cylinder synchronization control mode based on an independent PI regulator and proportion regulation valve is easily affected by factors such as leakage of a hydraulic system (such as internal leakage of a hydraulic cylinder), different manufacturing accuracy of hydraulic elements, and uneven load.

[0004] The present disclosure provides a synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish, where the system includes a synchronization control subsystem for a master lifting hydraulic cylinder of a continuous casting tundish and a synchronization control subsystem for slave lifting hydraulic cylinders of a continuous casting tundish. The synchronization control subsystem for a master lifting hydraulic cylinder of a continuous casting tundish includes: a master hydraulic cylinder synchronization position deviation out-of-range control unit consisting of functional blocks LZSTC01-LZSTC11 and LZSTC24-LZSTC26; a master hydraulic cylinder synchronization position deviation velocity correction unit consisting of functional blocks LZSTC19-LZSTC23 and LZSTC51-LZSTC60; a master/slave hydraulic cylinder fault interruption control unit consisting of functional blocks LZSTC44-LZSTC46; a master hydraulic cylinder manual lifting synchronization control unit consisting of functional blocks LZSTC12-LZSTC15, LZSTC27-LZSTC30, LZSTC34-LZSTC38, and LZSTC43; a master hydraulic cylinder automatic position holding control unit consisting of functional blocks LZSTC16-LZSTC18, LZSTC31-LZSTC33, LZSTC39-LZSTC43, and LZSTC48-LZSTC50; and a master hydraulic cylinder lifting velocity closed-loop control unit consisting of functional blocks LZSTC47, LZSTC61-LZSTC63, and LZSTC67. The synchronization control subsystem for slave lifting hydraulic cylinders of a continuous casting tundish includes: a slave hydraulic cylinder synchronization position deviation out-of-range control unit consisting of functional blocks LZSTC100, LZSTC101, and LZSTC104; a slave hydraulic cylinder synchronization position deviation velocity correction unit consisting of functional blocks LZSTC116-LZSTC120 and LZSTC121-LZSTC130; a slave hydraulic cylinder manual lifting synchronization control unit consisting of functional blocks LZSTC102, LZSTC103, LZSTC105-LZSTC108, LZSTC134-LZSTC136, and LZSTC138; a slave hydraulic cylinder automatic position holding control unit consisting of functional blocks LZSTC110-LZSTC115, LZSTC131-LZSTC133, LZSTC137, and LZSTC138; and a slave hydraulic cylinder lifting velocity closed-loop control unit consisting of functional blocks LZSTC139-LZSTC142 and LZSTC146. To synchronously move the master hydraulic cylinder and the slave hydraulic cylinders up or down, the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish based on the synchronization control system for the lifting hydraulic cylinders of the continuous casting tundish includes: a synchronization control method for the master lifting hydraulic cylinder of the continuous casting tundish and a synchronization control method for the slave lifting hydraulic cylinders of the continuous casting tundish.

[0005] The synchronization control method for the master lifting hydraulic cylinder of the continuous casting tundish includes the following steps:

A1. When the continuous casting tundish moves down, the master hydraulic cylinder synchronization position deviation out-of-range control unit obtains a minimum value ΔSms.b.min of a difference between a position value of the master hydraulic cylinder and a position value of each slave hydraulic cylinder. If the value ΔSms.b.min is less than or equal to a set maximum allowable position deviation negative value, the master hydraulic cylinder stops moving down until a position deviation value between the master hydraulic cylinder and a slowest declining slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value. When the continuous casting tundish moves up, the master hydraulic cylinder synchronization position deviation out-of-range control unit obtains a maximum value ΔSms.f.max of a difference between an actual position value of the master hydraulic cylinder and an actual position value of each slave hydraulic cylinder. If the value ΔSms.f.max is greater than or equal to a set maximum allowable position deviation positive value, the master hydraulic cylinder stops moving up until a position deviation value between the master hydraulic cylinder and a slowest rising slave hydraulic cylinder is less than the set maximum allowable position deviation positive value.

A2. When the continuous casting tundish moves up or down, a synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a set range, and the master hydraulic cylinder synchronization position deviation velocity correction unit corrects a moving velocity of the master hydraulic cylinder until the position deviation value ΔSms between the master hydraulic cylinder and the slave hydraulic cylinders is within the set range again.
The master hydraulic cylinder synchronization position deviation velocity correction unit includes a master hydraulic cylinder velocity correction subunit and a master hydraulic cylinder synchronization deviation quick correction subunit.
When the continuous casting tundish moves down, and when the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a first set range, the master hydraulic cylinder velocity correction subunit multiplies a negative value of the synchronization position deviation value ΔSms of the master hydraulic cylinder by a velocity correction coefficient of a declining synchronization position deviation of the master hydraulic cylinder as a velocity correction value of the master hydraulic cylinder. When the continuous casting tundish moves up, and when the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds the first set range, the master hydraulic cylinder velocity correction subunit multiplies the negative value of the synchronization position deviation value ΔSms of the master hydraulic cylinder by a velocity correction coefficient of a rising synchronization position deviation of the master hydraulic cylinder as a velocity correction value of the master hydraulic cylinder.
When the continuous casting tundish moves up or down, and when the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a second set range, the master hydraulic cylinder synchronization deviation quick correction subunit uses a velocity correction value of the synchronization position deviation of the master hydraulic cylinder having a direction reverse to the synchronization position deviation value ΔSms of the master hydraulic cylinder, as the velocity correction value of the master hydraulic cylinder.

A3. For a lifting hydraulic control system of the continuous casting tundish, when a displacement sensor of the master lifting hydraulic cylinder or any slave lifting hydraulic cylinder of the tundish is faulty, a hydraulic system is faulty, or a lifting operation of the continuous casting tundish is prohibited or urgently stopped, the master/slave hydraulic cylinder fault interruption control unit controls an output of the master/slave hydraulic cylinder lifting velocity closed-loop control unit to be blocked, and a control voltage of the master/slave hydraulic cylinder proportion valve is always zero, that is, the lifting control of the master/slave hydraulic cylinder is blocked.

A4. When the lifting hydraulic control system of the continuous casting tundish is in a manual linkage mode of tundish lifting or in a manual/automatic linkage mode of tundish lifting, during a period in which a manual declining instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSms of the master hydraulic cylinder is greater than the set maximum allowable position deviation negative value and the master hydraulic cylinder is not at a declining end position, the master hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the master hydraulic cylinder lifting velocity closed-loop control unit in a released state. If the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder exceeds the set range, the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization position deviation velocity correction unit. If the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is less than or equal to a set maximum allowable position deviation negative value, the master hydraulic cylinder stops moving down until a position deviation value between the two is greater than the set maximum allowable position deviation negative value again. During a period in which a manual rising instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSms of the master hydraulic cylinder is less than the set maximum allowable position deviation positive value and the master hydraulic cylinder is not at a rising end position, the master hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual rising velocity of the master/slave hydraulic cylinder to the master hydraulic cylinder lifting velocity closed-loop control unit in a released state. If the position deviation between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder exceeds the set range, the position deviation between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization position deviation velocity correction unit. If the position deviation between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is greater than or equal to a set maximum allowable position deviation positive value, the master hydraulic cylinder stops moving up until a position deviation value between the two is less than the set maximum allowable position deviation positive value again.

A5. When a manual lifting instruction for the continuous casting tundish is terminated, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and an actual position value of the master hydraulic cylinder is greater than a set allowable position deviation positive value, a position regulator of the master hydraulic cylinder and the master hydraulic cylinder lifting velocity closed-loop control unit are in a released state. The position regulator of the master hydraulic cylinder outputs a corresponding position correction velocity reference value of the master hydraulic cylinder to reduce the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is less than or equal to the set allowable position deviation positive value. If the difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and the actual position value of the master hydraulic cylinder is less than the set allowable position deviation negative value, the position regulator of the master hydraulic cylinder and the master hydraulic cylinder lifting velocity closed-loop control unit are in a released state. The position regulator of the master hydraulic cylinder outputs a corresponding position correction velocity reference value of the master hydraulic cylinder to increase the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is greater than or equal to the set allowable position deviation negative value.

A6. When no fault interruption occurs in the master and slave hydraulic cylinders, and when the master hydraulic cylinder manual lifting synchronization control unit or the master hydraulic cylinder automatic position holding control unit sends a signal for releasing the master hydraulic cylinder lifting velocity control unit, the master hydraulic cylinder lifting velocity closed-loop control subunit converts a given input velocity into a corresponding control voltage output of the proportion regulation valve of the master hydraulic cylinder, until the master hydraulic cylinder reaches a desired position and is within an allowable position deviation range, and then a signal for enabling the master hydraulic cylinder lifting velocity control unit sent by the master hydraulic cylinder manual lifting synchronization control unit or the master hydraulic cylinder automatic position holding unit is blocked.

[0006] The control method for the slave lifting hydraulic cylinders of the continuous casting tundish includes the following steps:

B1. When the continuous casting tundish moves down, the slave hydraulic cylinder synchronization position deviation out-of-range control unit obtains a difference ΔSsnm between a position value of each slave hydraulic cylinder and a position value of the master hydraulic cylinder. If a value of ΔSsnm is less than or equal to a set maximum allowable position deviation negative value, the slave hydraulic cylinder stops moving down until the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value.
When the continuous casting tundish moves up, the slave hydraulic cylinder synchronization position deviation out-of-range control unit obtains a difference ΔSsnm between a position value of each slave hydraulic cylinder and a position value of the master hydraulic cylinder. If a value of ΔSsnm is greater than or equal to a set maximum allowable position deviation positive value, the slave hydraulic cylinder stops moving up until the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than the set maximum allowable position deviation positive value.

B2. When the continuous casting tundish moves up or down, if a synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a set range, the slave hydraulic cylinder synchronization position deviation velocity correction unit corrects a moving velocity of the slave hydraulic cylinder until the position deviation value ΔSsnm between the slave hydraulic cylinder and the master hydraulic cylinder is within the set range again.
The slave hydraulic cylinder synchronization position deviation velocity correction unit includes a slave hydraulic cylinder velocity correction subunit and a slave hydraulic cylinder synchronization deviation quick correction subunit.
When the continuous casting tundish moves down, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a first set range, the slave hydraulic cylinder velocity correction subunit multiplies a negative value of the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder by a velocity correction coefficient of a declining synchronization position deviation of the slave hydraulic cylinder as a velocity correction value of the slave hydraulic cylinder. When the continuous casting tundish moves up, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the first set range, the slave hydraulic cylinder velocity correction subunit multiplies the negative value of the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder by a velocity correction coefficient of a rising synchronization position deviation of the slave hydraulic cylinder as a velocity correction value of the slave hydraulic cylinder.
When the continuous casting tundish moves up or down, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a second set range, the slave hydraulic cylinder synchronization deviation quick correction subunit uses a velocity correction value of the synchronization position deviation of the slave hydraulic cylinder having a direction reverse to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder, as the velocity correction value of the slave hydraulic cylinder.

B3. When the lifting hydraulic control system of the continuous casting tundish is in a manual linkage mode of tundish lifting or in a manual/automatic linkage mode of tundish lifting, during a period in which a manual declining instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value and the master hydraulic cylinder is not at a declining end position, the slave hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the slave hydraulic cylinder lifting velocity closed-loop control unit in a released state. If the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the set range, the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization position deviation velocity correction unit. If the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than or equal to a set maximum allowable position deviation negative value, the slave hydraulic cylinder stops moving down until a position deviation value between the two is greater than the set maximum allowable position deviation negative value again. During a period in which a manual rising instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than the set maximum allowable position deviation positive value and the master hydraulic cylinder is not at a rising end position, the slave hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual rising velocity of the master/slave hydraulic cylinder to the slave hydraulic cylinder lifting velocity closed-loop control unit in a released state. If the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the set range, the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is corrected by the slave hydraulic cylinder synchronization position deviation velocity correction unit. If the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than or equal to a set maximum allowable position deviation positive value, the slave hydraulic cylinder stops moving up until a position deviation value between the two is less than the set maximum allowable position deviation positive value again.

B4. When a manual lifting instruction for the continuous casting tundish is terminated, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and an actual position value of the slave hydraulic cylinder is greater than a set allowable position deviation positive value, a position regulator of the slave hydraulic cylinder and the slave hydraulic cylinder lifting velocity closed-loop control unit are in a released state. The position regulator of the slave hydraulic cylinder outputs a corresponding position correction velocity reference value of the slave hydraulic cylinder to reduce the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is less than or equal to the set allowable position deviation positive value. If the difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and the actual position value of the slave hydraulic cylinder is less than the set allowable position deviation negative value, the position regulator of the slave hydraulic cylinder and the slave hydraulic cylinder lifting velocity closed-loop control unit are in a released state. The position regulator of the slave hydraulic cylinder outputs a corresponding position correction velocity reference value of the slave hydraulic cylinder to increase the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is greater than or equal to the set allowable position deviation negative value.

B5. When no fault interruption occurs in the master and slave hydraulic cylinders, and when the slave hydraulic cylinder manual lifting synchronization control unit or the slave hydraulic cylinder automatic position holding control unit sends a signal for releasing the slave hydraulic cylinder lifting velocity control unit, the slave hydraulic cylinder lifting velocity closed-loop control subunit converts a given input velocity into a corresponding control voltage output of the proportion regulation valve of the slave hydraulic cylinder, until the slave hydraulic cylinder reaches a desired position and is within an allowable position deviation range, and then a signal for enabling the slave hydraulic cylinder lifting velocity control unit sent by the slave hydraulic cylinder manual lifting synchronization control unit or the slave hydraulic cylinder automatic position holding unit is blocked.

[0007] According to the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish in the embodiments of the present disclosure, the master hydraulic cylinder synchronization position deviation velocity correction unit and the slave hydraulic cylinder synchronization position deviation velocity correction unit correct the position deviation exceeding the set range between the master hydraulic cylinder and the slave hydraulic cylinder in real time. If the deviation between the two continues to increase beyond the set maximum allowable position deviation, the master hydraulic cylinder synchronization position deviation out-of-range control unit and the slave hydraulic cylinder synchronization position deviation out-of-range control unit control the fast moving master hydraulic cylinder or slave hydraulic cylinder to stop moving, until the position deviation between the two is less than the set maximum allowable position deviation again. In addition, the master hydraulic cylinder automatic position holding control unit and the slave hydraulic cylinder automatic position holding control unit are used to avoid position deviation of the master hydraulic cylinder and the slave hydraulic cylinder without a manual instruction. Therefore, according to the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish, the lifting hydraulic cylinders of the continuous casting tundish can be synchronously moved, there is relatively high fault tolerance during operation of the lifting hydraulic cylinders of the continuous casting tundish, and the lifting hydraulic cylinders of the continuous casting tundish can be synchronously moved in cases of leakage of a hydraulic cylinder, different manufacturing accuracy of hydraulic elements, and uneven load.

BRIEF DESCRIPTION OF DRAWINGS

[0008] 

FIG. 1 is a diagram of a hydraulic system for a continuous casting tundish lifting mechanism according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a synchronization control subsystem for a master lifting hydraulic cylinder of a continuous casting tundish according to an embodiment of the present disclosure; and

FIG. 3 is a schematic structural diagram of a synchronization control subsystem for a slave lifting hydraulic cylinder of a continuous casting tundish according to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

[0009] To make the objects, technical solutions, and advantages of the present disclosure clearer, the following further describes the present disclosure in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present disclosure and are not intended to limit the present disclosure.

[0010] FIG. 1 is a diagram of a hydraulic system for a continuous casting tundish lifting mechanism according to an embodiment of the present disclosure. FIG. 2 is a schematic structural diagram of a synchronization control subsystem for a master lifting hydraulic cylinder of a continuous casting tundish according to an embodiment of the present disclosure. FIG. 3 is a schematic structural diagram of a synchronization control subsystem for a slave lifting hydraulic cylinder of a continuous casting tundish according to an embodiment of the present disclosure. For ease of description, only a part related to the embodiments of the present disclosure is shown.

[0011] In FIG. 2 and FIG. 3, SUB represents a subtractor; NSW represents a "digital input switch" functional block, where when I = '1', Y= X2 and when 1 = '0', Y= X1; NCM represents a "numeric comparison" functional block, where when X1 > X2, QU is '1', when X1 = X2, QE is '1', and when X1 < X2, QL is '1'; RSR represents an "RS trigger with a preferential reset end R" functional block, where when S is '1' and R is '0', Q is '1' and QN is '0', when S is '1' and R is '1', Q is '0' and QN is '1', when S is '0' and R is '0', Q and QN remain unchanged, and when S is '0' and R is '1', Q is '0' and QN is '1'; RGJ represents an "integrator" functional block; PIC represents a PI regulator functional block; ADD represents an adder; OR represents an "OR" gate; AND represents an "AND" gate; NOT represents a "NOT" gate; SZWBZ represents position holding values of master and slave lifting hydraulic cylinders of a continuous casting tundish; Sm.act represents an actual position value of the master hydraulic cylinder; Ss1.act, Ss2.act, and Ss3.act represent actual position values of a first, a second, and a third slave lifting hydraulic cylinders of the continuous casting tundish, respectively; ΔSms.b.min represents a minimum value of a difference between the actual position value of the master hydraulic cylinder and the actual position value of each slave hydraulic cylinder when the continuous casting tundish moves down (namely, a position deviation value between the master hydraulic cylinder and a slowest declining slave hydraulic cylinder when the continuous casting tundish moves down);

[0012] ΔSms.f.max represents a maximum value of a difference between the actual position value of the master hydraulic cylinder and the actual position value of each slave hydraulic cylinder when the continuous casting tundish moves up (namely, a position deviation value between the master hydraulic cylinder and a slowest rising slave hydraulic cylinder when the continuous casting tundish moves up); ΔSms represents a synchronization position deviation value of the master hydraulic cylinder (namely, a position deviation value between the master hydraulic cylinder and the slowest rising or declining slave hydraulic cylinder); and ΔSsnm represents a synchronization position deviation value of the slave hydraulic cylinder (Sn) (namely, a position deviation value between the slave hydraulic cylinder and the master hydraulic cylinder).

[0013] The synchronization control systems for the master and slave lifting hydraulic cylinders of the continuous casting tundish are shown in FIG. 2 and FIG. 3. In the control systems, declining end position values of the master and slave lifting hydraulic cylinders are all 0 mm, and position holding values and actual position values of the master and slave lifting hydraulic cylinders are all positive values or zero.

[0014] The synchronization control system for the lifting hydraulic cylinders of the continuous casting tundish includes: a synchronization control subsystem for the master lifting hydraulic cylinder of the continuous casting tundish and a synchronization control subsystem for the slave lifting hydraulic cylinders of the continuous casting tundish. The synchronization control subsystem for the master lifting hydraulic cylinder of the continuous casting tundish mainly includes six control units: a master hydraulic cylinder synchronization position deviation out-of-range control unit consisting of functional blocks LZSTC01-LZSTC11 and LZSTC24-LZSTC26; a master hydraulic cylinder synchronization position deviation velocity correction unit consisting of functional blocks LZSTC19-LZSTC23 and LZSTC51-LZSTC60; a master hydraulic cylinder manual lifting synchronization control unit consisting of functional blocks LZSTC12-LZSTC15, LZSTC27-LZSTC30, LZSTC34-LZSTC38, and LZSTC43; a master hydraulic cylinder automatic position holding control unit consisting of functional blocks LZSTC16-LZSTC18, LZSTC31-LZSTC33, LZSTC39-LZSTC43, and LZSTC48-LZSTC50; a master/slave hydraulic cylinder fault interruption control unit consisting of functional blocks LZSTC44-LZSTC46; and a master hydraulic cylinder lifting velocity closed-loop control unit consisting of functional blocks LZSTC47, LZSTC61-LZSTC63, and LZSTC67.

[0015] To synchronously move the master hydraulic cylinder and the slave hydraulic cylinders up or down, the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish based on the synchronization control system for the lifting hydraulic cylinders of the continuous casting tundish includes: a synchronization control method for the master lifting hydraulic cylinder of the continuous casting tundish and a synchronization control method for the slave lifting hydraulic cylinders of the continuous casting tundish. The synchronization control method for the master lifting hydraulic cylinder of the continuous casting tundish includes the following steps:

A1. When the master and slave hydraulic cylinders move up or down, if a position deviation between the master hydraulic cylinder and a slowest slave hydraulic cylinder in a desired moving direction during the rising movement is greater than or equal to a set maximum allowable position deviation positive value (for example, 6 mm), or a position deviation between the master hydraulic cylinder and a slowest slave hydraulic cylinder in a desired moving direction during the declining movement is less than or equal to a set maximum allowable position deviation negative value (for example, -6 mm), the master hydraulic cylinder is controlled to stop moving until the position deviation between the two is within the set maximum allowable position deviation again. Then, the master hydraulic cylinder increases, at a set acceleration, a velocity to a set velocity, and continues to move toward the desired direction, so that the position deviation between the master hydraulic cylinder and the slowest slave hydraulic cylinder in the desired moving direction is controlled to be within the maximum allowable position deviation. Based on this, a master hydraulic cylinder synchronization position deviation out-of-range control unit is designed in the synchronization control subsystem for the master hydraulic cylinder. In this unit, the functional blocks LZSTC01-LZSTC07 obtain a minimum value (namely, ΔSms.b.min) of a difference between a position value of the master hydraulic cylinder and a position value of each slave hydraulic cylinder during the declining movement of the continuous casting tundish; the functional blocks LZSTC01-LZSTC03 and LZSTC08-LZSTC11 obtain a maximum value (namely, ΔSms.f.max) of a difference between an actual position value of the master hydraulic cylinder and an actual position value of each slave hydraulic cylinder during the rising movement of the continuous casting tundish. In this way, when the continuous casting tundish moves down, if a value of ΔSms.b.min is less than or equal to the set maximum allowable position deviation negative value (for example, -6 mm), an output end QU of the functional block LZSTC26 is changed from the '1' state to the '0' state, so that the master hydraulic cylinder stops moving down until the position deviation value between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value (for example, -6 mm, that is, the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is less than 6 mm). When the continuous casting tundish moves up, if a value of ΔSms.f.max is greater than or equal to the set maximum allowable position deviation positive value (for example, 6 mm), an output end QL of the functional block LZSTC25 is changed from the '1' state to the '0' state, so that the master hydraulic cylinder stops moving up until the position deviation value between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is less than the set maximum allowable position deviation positive value (for example, 6 mm).

A2. When the master hydraulic cylinder moves synchronously with the slave hydraulic cylinder, if the master hydraulic cylinder urgently stops frequently because the position deviation exceeds the maximum allowable position deviation, the master hydraulic cylinder is prone to position oscillation during synchronous movement. This causes position oscillation of the slave hydraulic cylinder. For this reason, both the master hydraulic cylinder synchronization position deviation out-of-range control unit and the master hydraulic cylinder synchronization position deviation velocity correction unit are designed in the synchronization control subsystem for the master lifting hydraulic cylinder of the continuous casting tundish. During synchronous movement of the master and slave hydraulic cylinders, once a synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a set range, the master hydraulic cylinder synchronization position deviation velocity correction unit corrects a moving velocity of the master hydraulic cylinder in a timely manner, until the position deviation value between the master hydraulic cylinder and the slave hydraulic cylinder is within the set range again. This can significantly reduce a probability that the position deviation value ΔSms of the master hydraulic cylinder reaches or exceeds the maximum allowable position deviation. The master hydraulic cylinder synchronization position deviation velocity correction unit includes two subunits: a master hydraulic cylinder velocity correction subunit that consists of the functional blocks LZSTC19-LZSTC23 and LZSTC51-LZSTC56 and is inversely proportional to the synchronization position deviation value ΔSms of the master hydraulic cylinder; and a master hydraulic cylinder synchronization deviation quick correction subunit consisting of the functional blocks LZSTC57-LZSTC60. In the master hydraulic cylinder velocity correction subunit that is inversely proportional to the synchronization position deviation value ΔSms of the master hydraulic cylinder, an input end X2 of the functional block LZSTC56 is equal to a negative value of the synchronization position deviation value ΔSms of the master hydraulic cylinder multiplied by a set coefficient (which is also referred to as a velocity correction coefficient of a synchronization position deviation of the master hydraulic cylinder). Considering that there is a major difference between a rising velocity and a declining velocity of the continuous casting tundish (the rising velocity is usually approximately twice the declining velocity), in this case, to control both the rising synchronization position deviation and the declining synchronization position deviation of the master hydraulic cylinder to be within a set allowable range, different velocity correction coefficients of a synchronization position deviation are used for synchronization control of the rising and declining of the master hydraulic cylinder, that is, a velocity correction coefficient of a rising synchronization position deviation of the master hydraulic cylinder and a velocity correction coefficient of a declining synchronization position deviation of the master hydraulic cylinder. For this reason, a function of selecting a velocity correction coefficient of a synchronization position deviation of the master hydraulic cylinder consisting of the functional blocks LZSTC19-LZSTC23 and LZSTC54 is set in the master hydraulic cylinder velocity correction subunit that is inversely proportional to the synchronization position deviation value ΔSms of the master hydraulic cylinder. When the master hydraulic cylinder moves up, an output end Q of the functional block LZSTC23 in this phase is in the '1' state. In this case, a control end I of the "digital input switch" functional block LZSTC54 in this phase is also in the '1' state. Therefore, the velocity correction coefficient of a synchronization position deviation of the master hydraulic cylinder is the velocity correction coefficient (for example, 20) of a rising synchronization position deviation of the master hydraulic cylinder. When the master hydraulic cylinder moves down or stops moving, the output end Q of the functional block LZSTC23 in this phase is in the '0' state. In this case, the control end I of the "digital input switch" functional block LZSTC54 in this phase is also in the '0' state. Therefore, the velocity correction coefficient of a synchronization position deviation of the master hydraulic cylinder is the velocity correction coefficient (for example, 10) of a declining synchronization position deviation of the master hydraulic cylinder. In this way, when the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a first set range (for example, ±0.5 mm), a control end I of the functional block LZSTC56 is changed from the '0' state to the '1' state. Therefore, an output value of an output end Y of the functional block LZSTC56 is equal to an input value of an input end X2 of the functional block LZSTC56. In this way, the subunit outputs a velocity correction value that is inversely proportional to the synchronization position deviation value ΔSms of the master hydraulic cylinder. This portion of velocity correction value gradually decreases the synchronization position deviation between the master hydraulic cylinder and the slowest moving slave hydraulic cylinder, until the position deviation value ΔSms of the master hydraulic cylinder is within the first set range (for example, ±0.5 mm) again. When the continuous casting tundish moves up or down, if the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a second set range, the master hydraulic cylinder synchronization deviation quick correction subunit uses a velocity correction value of the synchronization position deviation of the master hydraulic cylinder having a direction reverse to the synchronization position deviation value ΔSms of the master hydraulic cylinder, as the velocity correction value of the master hydraulic cylinder. To be specific, when the synchronization position deviation value ΔSms of the master hydraulic cylinder is positive and is greater than a positive end value (for example, 2 mm) of the second set range, a control end I of the functional block LZSTC58 in the master hydraulic cylinder synchronization position deviation quick correction subunit is changed from the '0' state to the '1' state. Therefore, an output value of an output end Y of the functional block LZSTC58 is equal to an input value (for example, -2 V) of an input end X2 of the functional block LZSTC58. This portion of velocity correction value quickly decreases the synchronization position deviation value ΔSms (>0) of the master hydraulic cylinder, until the position deviation value ΔSms of the master hydraulic cylinder is less than the positive end value (for example, 2 mm) of the second set range. When the synchronization position deviation value ΔSms of the master hydraulic cylinder is negative and is less than a negative end value (for example, -2 mm) of the second set range, a control end I of the functional block LZSTC60 in the master hydraulic cylinder synchronization position deviation quick correction subunit is changed from the '0' state to the '1' state. Therefore, an output value of an output end Y of the functional block LZSTC60 is equal to an input value (for example, 2 V) of an input end X2 of the functional block LZSTC60. This portion of velocity correction value quickly increases the synchronization position deviation value ΔSms (<0) of the master hydraulic cylinder, until the position deviation value ΔSms of the master hydraulic cylinder is greater than the negative end value (for example, -2 mm) of the second set range. It can be learned from the foregoing description that the master hydraulic cylinder synchronization position deviation velocity correction unit can correct the velocity of the master hydraulic cylinder in a timely manner before the synchronization position deviation exceeds a limit (for example, ±6 mm). This can avoid urgent stop of the master hydraulic cylinder during synchronous movement because a position deviation between the master hydraulic cylinder and a slowest rising/declining slave hydraulic cylinder exceeds a set maximum allowable position deviation value.

A3. To prevent a lifting hydraulic control system of the continuous casting tundish from rising or declining the tundish in a faulty state, a master/slave hydraulic cylinder lifting fault interruption control unit is designed in the synchronization control subsystem for the master hydraulic cylinder. For a lifting hydraulic control system of the continuous casting tundish, when a displacement sensor of the master lifting hydraulic cylinder or any slave lifting hydraulic cylinder of the tundish is faulty, a hydraulic system is faulty, or a lifting operation of the continuous casting tundish is prohibited or urgently stopped, an output end Q of the functional block LZSTC46 in this unit is changed from the '1' state to the '0' state. In this way, an output of the master/slave hydraulic cylinder lifting velocity control unit is blocked, and a control voltage of the master/slave hydraulic cylinder proportion valve is always zero, that is, the lifting control of the master/slave hydraulic cylinder is blocked.

A4. For the master hydraulic cylinder manual lifting synchronization control unit, when the lifting hydraulic control system of the continuous casting tundish is in a manual linkage mode of tundish lifting or in a manual/automatic linkage mode of tundish lifting, during a period in which a manual declining instruction for the continuous casting tundish is delivered, a value of an output end Y (point A in FIG. 2) of the functional block LZSTC14 in this unit is equal to a set value (for example, -2 V) of a declining velocity of the master hydraulic cylinder, and an output end QL of the functional block LZSTC15 is in the '1' state. In this case, if the position deviation value (namely, ΔSms.b.min) between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value (for example, -6 mm) and the master hydraulic cylinder is not at the declining end position, output ends Q of the functional blocks LZSTC30, LZSTC37, and LZSTC43 in the master hydraulic cylinder manual lifting synchronization control unit are in the '1' state. Therefore, a value of an output end Y of the functional block LZSTC38 is equal to a value of an output end Y of the functional block LZSTC14 (namely, a set value of a declining velocity of the master/slave hydraulic cylinder, for example, -2 V). The master hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the master hydraulic cylinder lifting velocity closed-loop control unit. In addition, an output end Q of the functional block LZSTC43 in the master hydraulic cylinder manual lifting synchronization control unit is in the '1' state, so that the master hydraulic cylinder lifting velocity closed-loop control unit is in a released state. When the continuous casting tundish moves down, the position deviation value between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization deviation velocity correction unit. If the position deviation value between the two is less than or equal to the set maximum allowable position deviation negative value (for example, -6 mm), the master hydraulic cylinder stops moving down until the position deviation value between the two is greater than the set maximum allowable position deviation negative value (for example, -6 mm) again. During a period in which a manual rising instruction for the continuous casting tundish is delivered, a value of an output end Y (point A in FIG. 2) of the functional block LZSTC14 in this unit is equal to a set value (for example, 4 V) of a rising velocity of the master/slave hydraulic cylinder, and an output end QU of the functional block LZSTC15 is in the '1' state. In this case, if the position deviation value (namely, ΔSms.f.max) between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is less than the set maximum allowable position deviation positive value (for example, 6 mm) and the master hydraulic cylinder is not at the rising end position, output ends Q of the functional blocks LZSTC29, LZSTC37, and LZSTC43 in the master hydraulic cylinder manual lifting synchronization control unit are in the '1' state. Therefore, a value of an output end Y of the functional block LZSTC38 is equal to a value of an output end Y of the functional block LZSTC14 (namely, a set value of a rising velocity of the master/slave hydraulic cylinder, for example, 4 V). The master hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual rising velocity of the master/slave hydraulic cylinder to the master hydraulic cylinder lifting velocity closed-loop control unit. In addition, an output end Q of the functional block LZSTC43 in the master hydraulic cylinder manual lifting synchronization control unit is in the '1' state, so that the master hydraulic cylinder lifting velocity closed-loop control unit is in a released state. When the continuous casting tundish moves up, the position deviation value between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization deviation velocity correction unit. If the position deviation value between the two is greater than or equal to the set maximum allowable position deviation positive value (for example, 6 mm), the master hydraulic cylinder stops moving up until the position deviation value between the two is less than the set maximum allowable position deviation positive value (for example, 6 mm) again.

A5. After the continuous casting tundish moves up or down to a desired working position, the operator terminates the manual lifting instruction for the continuous casting tundish, and proportion valves for lifting control of the master and slave hydraulic cylinders are all in a neutral position self-locking state. In this case, if specific internal leakage occurs in the master hydraulic cylinder, the master hydraulic cylinder moves down to some extent after a specific period of time, causing an actual position of the master hydraulic cylinder to deviate from the desired working position. To avoid position deviation of the master hydraulic cylinder without a manual instruction, a master hydraulic cylinder automatic position holding control unit is designed in the synchronization control subsystem for the master hydraulic cylinder. When a manual lifting instruction for the continuous casting tundish is terminated, an output end Q of the functional block LZSTC17 in this unit is changed from the '0' state to the '1' state, and a value of an output end Y of the "digital input switch" functional block LZSTC18 (that is, a master/slave hydraulic cylinder position holding value SZWBZ) is always equal to a value entered at an input end X1 of the functional block at a moment at which the manual lifting instruction for the continuous casting tundish is terminated (that is, an actual position value of the master hydraulic cylinder corresponding to the moment at which the manual lifting instruction is terminated). In this way, when a lifting operation mode of the continuous casting tundish is the manual/automatic linkage mode, the manual lifting instruction for the continuous casting tundish is terminated, and no fault interruption occurs in the master and slave hydraulic cylinders, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is greater than the set allowable position deviation positive value (for example, 3 mm) after the manual lifting instruction for the continuous casting tundish is terminated, an output end Q of the functional block LZSTC49 in this unit is in the '1' state, so that an enabling control end (EN) of the "PI regulator" functional block LZSTC50 (namely, a position regulator of the master hydraulic cylinder) in this unit is in the '1' state and the position regulator of the master hydraulic cylinder is in a released state; and an output end Q of the functional block LZSTC43 in this unit is in the '1' state, so that the master hydraulic cylinder lifting velocity closed-loop control unit is also in a released state. Therefore, when there is a deviation between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder, the position regulator of the master hydraulic cylinder outputs a corresponding position correction velocity reference value of the master hydraulic cylinder to reduce the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder, until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is less than or equal to the set allowable position deviation positive value (for example, 3 mm). Similarly, when a lifting operation mode of the continuous casting tundish is the manual/automatic linkage mode, the manual lifting instruction for the continuous casting tundish is terminated, and no fault interruption occurs in the master and slave hydraulic cylinders, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is less than the set allowable position deviation negative value (for example, -3 mm) after the manual lifting instruction for the continuous casting tundish is terminated, an output end Q of the functional block LZSTC49 in this unit is in the '1' state, so that an enabling control end (EN) of the "PI regulator" functional block LZSTC50 (namely, a position regulator of the master hydraulic cylinder) in this unit is in the '1' state and the position regulator of the master hydraulic cylinder is in a released state; and an output end Q of the functional block LZSTC43 in this unit is in the '1' state, so that the master hydraulic cylinder lifting velocity closed-loop control unit is also in a released state. Therefore, when there is a deviation between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder, the position regulator of the master hydraulic cylinder outputs a corresponding position correction velocity reference value of the master hydraulic cylinder to increase the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder, until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is greater than or equal to the set allowable position deviation negative value (for example, -3 mm).

A6. When the master hydraulic cylinder manual lifting synchronization control unit or the master hydraulic cylinder automatic position holding control unit sends, by setting the output end Q of the functional block LZSTC43 to '1', a signal for releasing the master hydraulic cylinder lifting velocity closed-loop control unit (namely, a signal for enabling the master hydraulic cylinder lifting velocity control unit), a velocity-given integral functional block LZSTC62 and a velocity regulator functional block LZSTC63 in the master hydraulic cylinder lifting velocity closed-loop control unit are in a released state. Therefore, when a given velocity entered at an input end X of the velocity-given integral functional block LZSTC62 in this unit is not zero, this unit outputs, by using a functional block LZSTC67, a corresponding control voltage of the proportion regulation valve of the master hydraulic cylinder, until the master hydraulic cylinder reaches a desired position and is within an allowable position deviation range, and then a signal for enabling the master hydraulic cylinder lifting velocity control unit sent by the master hydraulic cylinder manual lifting synchronization control unit or the master hydraulic cylinder automatic position holding unit is blocked.

[0016] The synchronization control subsystem for the master lifting hydraulic cylinder of the continuous casting tundish includes a proportion regulation valve positive/negative dead zone compensation subunit of the master hydraulic cylinder consisting of functional blocks LZSTC64-LZSTC67. The synchronization control method for the master lifting hydraulic cylinder of the continuous casting tundish further includes:
A7. Usually, there is a specific dead zone between a control voltage of a proportion regulation valve of a hydraulic cylinder and an opening degree of the proportion valve, that is, when the control voltage of the proportion regulation valve reaches a specific value, the opening degree of the proportion regulation valve changes and is approximately proportional to the control voltage of the proportion regulation valve. Therefore, a proportion regulation valve positive/negative dead zone compensation unit of the master hydraulic cylinder is disposed to improve a control response of a proportion regulation valve of the master hydraulic cylinder. When the value of the output end Y of the velocity regulator functional block LZSTC63 (namely, the control voltage of the proportion regulation valve of the master hydraulic cylinder) in the master hydraulic cylinder lifting velocity control unit is greater than zero, a control end I of the functional block LZSTC65 in the proportion regulation valve positive/negative dead zone compensation subunit of the master hydraulic cylinder is in the '1' state, and an output end Y of the functional block LZSTC65 outputs a positive proportion regulation valve dead zone compensation voltage (for example, 1 V). In this way, a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the positive proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the master hydraulic cylinder, thereby speeding up regulation of a positive opening degree of the proportion regulation valve of the master hydraulic cylinder. When the value of the output end Y of the velocity regulator functional block LZSTC63 (namely, the control voltage of the proportion regulation valve of the master hydraulic cylinder) in the master hydraulic cylinder lifting velocity closed-loop control unit is less than zero, a control end I of the functional block LZSTC66 in the proportion regulation valve positive/negative dead zone compensation subunit of the master hydraulic cylinder is in the '1' state, and an output end Y of the functional block LZSTC66 outputs a negative proportion regulation valve dead zone compensation voltage (for example, -1 V). In this way, a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the negative proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the master hydraulic cylinder, thereby speeding up regulation of a negative opening degree of the proportion regulation valve of the master hydraulic cylinder.

[0017] The synchronization control subsystem for the slave lifting hydraulic cylinders of the continuous casting tundish mainly includes five control units: a slave hydraulic cylinder synchronization position deviation out-of-range control unit consisting of functional blocks LZSTC100, LZSTC101, and LZSTC104; a slave hydraulic cylinder synchronization position deviation velocity correction unit consisting of functional blocks LZSTC116-LZSTC120 and LZSTC121-LZSTC130; a slave hydraulic cylinder manual lifting synchronization control unit consisting of functional blocks LZSTC102, LZSTC103, LZSTC105-LZSTC108, LZSTC134-LZSTC136, and LZSTC138; a slave hydraulic cylinder automatic position holding control unit consisting of functional blocks LZSTC110-LZSTC115, LZSTC131-LZSTC133, LZSTC137, and LZSTC138; and a slave hydraulic cylinder lifting velocity closed-loop control unit consisting of functional blocks LZSTC139-LZSTC142 and LZSTC146.

[0018] The control method for the slave lifting hydraulic cylinders of the continuous casting tundish includes the following steps:

B1. When the master and slave hydraulic cylinders synchronously move up or down, if a position deviation between a slave hydraulic cylinder and the master hydraulic cylinder in a desired moving direction during the rising movement is greater than or equal to a set maximum allowable position deviation positive value (for example, 6 mm), or a position deviation between the slave hydraulic cylinder and the master hydraulic cylinder in a desired moving direction during the declining movement is less than or equal to a set maximum allowable position deviation negative value (for example, -6 mm), the slave hydraulic cylinder is controlled to stop moving until the position deviation between the two is less than the set maximum allowable position deviation again. Then, the slave hydraulic cylinder increases, at a set acceleration, a velocity to a set velocity, and continues to move toward the desired direction, so that the position deviation between the slave hydraulic cylinder and the master hydraulic cylinder in the desired moving direction is controlled to be within the maximum allowable position deviation. Based on this, a slave hydraulic cylinder synchronization position deviation out-of-range control unit is designed in the synchronization control subsystem for the slave hydraulic cylinder. When the continuous casting tundish moves down, if a synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than or equal to a set maximum allowable position deviation negative value (for example, -6 mm), an output end QU of the functional block LZSTC104 is changed from the '1' state to the '0' state, so that the slave hydraulic cylinder stops moving down until the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value (for example, -6 mm, that is, the position deviation between the slave hydraulic cylinder and the master hydraulic cylinder is less than 6 mm). When the continuous casting tundish moves up, if
a value of ΔSsnm is greater than or equal to a set maximum allowable position deviation positive value (for example, 6 mm), an output end QL of the functional block LZSTC101 is changed from the '1' state to the '0' state, so that the slave hydraulic cylinder stops moving up until the position deviation value between the slave hydraulic cylinder and the master hydraulic cylinder is less than the set maximum allowable position deviation positive value (for example, 6 mm).

B2. When the slave hydraulic cylinder moves synchronously with the master hydraulic cylinder, if the slave hydraulic cylinder urgently stops frequently because the position deviation exceeds the maximum allowable position deviation, the slave hydraulic cylinder is prone to position oscillation during synchronous movement. This causes position oscillation of the master hydraulic cylinder. For this reason, both the slave hydraulic cylinder synchronization position deviation out-of-range control unit and the slave hydraulic cylinder synchronization position deviation velocity correction unit are designed in the synchronization control subsystem for the slave lifting hydraulic cylinders of the continuous casting tundish. During synchronous movement of the master and slave hydraulic cylinders, once a synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a set range (for example, ±0.5 mm), the slave hydraulic cylinder synchronization position deviation velocity correction unit corrects a moving velocity of the slave hydraulic cylinder in a timely manner, until the position deviation value between the slave hydraulic cylinder and the master hydraulic cylinder is within the set range again. This can significantly reduce a probability that the position deviation between the slave hydraulic cylinder and the master hydraulic cylinder reaches or exceeds the maximum allowable position deviation. The slave hydraulic cylinder synchronization position deviation velocity correction unit includes two subunits: a slave hydraulic cylinder velocity correction subunit that consists of the functional blocks LZSTC116-LZSTC120 and LZSTC121-LZSTC126 and is inversely proportional to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder; and a slave hydraulic cylinder synchronization deviation quick correction subunit consisting of the functional blocks LZSTC127-LZSTC130. In the slave hydraulic cylinder velocity correction subunit that is inversely proportional to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder, an input end X2 of the functional block LZSTC126 is equal to a negative value of the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder multiplied by a set coefficient (which is also referred to as a velocity correction coefficient of a synchronization position deviation of the slave hydraulic cylinder). Considering that there is a major difference between a rising velocity and a declining velocity of the continuous casting tundish (the rising velocity is usually approximately twice the declining velocity), in this case, to control both the rising synchronization position deviation and the declining synchronization position deviation of the slave hydraulic cylinder to be within a set allowable range, different velocity correction coefficients of a synchronization position deviation are used for synchronization control of the rising and declining of the slave hydraulic cylinder, that is, a velocity correction coefficient of a rising synchronization position deviation of the slave hydraulic cylinder and a velocity correction coefficient of a declining synchronization position deviation of the slave hydraulic cylinder. For this reason, a function of selecting a velocity correction coefficient of a synchronization position deviation of the slave hydraulic cylinder consisting of the functional blocks LZSTC116-LZSTC120 and LZSTC124 is set in the slave hydraulic cylinder velocity correction subunit that is inversely proportional to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder. When the slave hydraulic cylinder moves up, an output end Q of the functional block LZSTC120 in this phase is in the '1' state. In this case, a control end I of the "digital input switch" functional block LZSTC124 in this phase is also in the '1' state. Therefore, the velocity correction coefficient of a synchronization position deviation of the slave hydraulic cylinder is the velocity correction coefficient (for example, 20) of a rising synchronization position deviation of the slave hydraulic cylinder. When the slave hydraulic cylinder moves down or stops moving, the output end Q of the functional block LZSTC120 in this phase is in the '0' state. In this case, the control end I of the "digital input switch" functional block LZSTC124 in this phase is also in the '0' state. Therefore, the velocity correction coefficient of a synchronization position deviation of the slave hydraulic cylinder is the velocity correction coefficient (for example, 10) of a declining synchronization position deviation of the slave hydraulic cylinder. In this way, when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a first set range (for example, ±0.5 mm), a control end I of the functional block LZSTC126 is changed from the '0' state to the '1' state. Therefore, an output value of an output end Y of the functional block LZSTC126 is equal to an input value of an input end X2 of the functional block LZSTC126. In this way, the subunit outputs a velocity correction value that is inversely proportional to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder. This portion of velocity correction value gradually decreases the synchronization position deviation between the slave hydraulic cylinder and the master hydraulic cylinder, until the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is within the first set range (for example, ±0.5 mm) again.
When the continuous casting tundish moves up or down, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a second set range, the slave hydraulic cylinder synchronization deviation quick correction subunit uses a velocity correction value of the synchronization position deviation of the slave hydraulic cylinder having a direction reverse to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder, as the velocity correction value of the slave hydraulic cylinder. To be specific, when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is positive and is greater than a positive end value (for example, 2 mm) of the second set range, a control end I of the functional block LZSTC128 in the slave hydraulic cylinder synchronization position deviation quick correction subunit is changed from the '0' state to the '1' state. Therefore, an output value of an output end Y of the functional block LZSTC128 is equal to an input value (for example, -2 V) of an input end X2 of the functional block LZSTC128. This portion of velocity correction value quickly decreases the synchronization position deviation value ΔSsnm (>0) of the slave hydraulic cylinder, until the position deviation value ΔSsnm of the slave hydraulic cylinder is less than the positive end value (for example, 2 mm) of the second set range. When the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is negative and is less than a negative end value (for example, -2 mm) of the second set range, a control end I of the functional block LZSTC130 in the slave hydraulic cylinder synchronization position deviation quick correction subunit is changed from the '0' state to the '1' state. Therefore, an output value of an output end Y of the functional block LZSTC130 is equal to an input value (for example, 2 V) of an input end X2 of the functional block LZSTC130. This portion of velocity correction value quickly increases the synchronization position deviation value ΔSsnm (<0) of the slave hydraulic cylinder, until the position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the negative end value (for example, -2 mm) of the second set range. It can be learned from the foregoing description that the slave hydraulic cylinder synchronization position deviation velocity correction unit can correct the velocity of the slave hydraulic cylinder in a timely manner before the synchronization position deviation exceeds a limit (for example, ±6 mm). This can avoid urgent stop of the slave hydraulic cylinder during synchronous movement because a position deviation between the slave hydraulic cylinder and the master hydraulic cylinder exceeds a maximum allowable position deviation value.

B3. For the slave hydraulic cylinder manual lifting synchronization control unit, when the lifting hydraulic control system of the continuous casting tundish is in a manual linkage mode of tundish lifting or in a manual/automatic linkage mode of tundish lifting, during a period in which a manual declining instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value (for example, -6 mm) and the slave hydraulic cylinder is not at the declining end position, output ends Q of the functional blocks LZSTC106, LZSTC135, and LZSTC138 in the slave hydraulic cylinder manual lifting synchronization control unit are in the '1' state. Therefore, a value of an output end Y of the functional block LZSTC136 is equal to a value of an output end Y of the functional block LZSTC14 in the synchronization control subsystem for the master hydraulic cylinder (namely, a set value of a declining velocity of the master/slave hydraulic cylinder, for example, -2 V). The slave hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the slave hydraulic cylinder lifting velocity closed-loop control unit. In addition, an output end Q of the functional block LZSTC138 in the slave hydraulic cylinder manual lifting synchronization control unit is in the '1' state, so that the slave hydraulic cylinder lifting velocity closed-loop control unit is in a released state. When the continuous casting tundish moves down, the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is corrected by the slave hydraulic cylinder synchronization deviation velocity correction unit. If a value of ΔSsnm is less than or equal to the set maximum allowable position deviation negative value (for example, -6 mm), the slave hydraulic cylinder stops moving down until the value of ΔSsnm is greater than the set maximum allowable position deviation negative value (for example, -6 mm) again. During a period in which a manual rising instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than the set maximum allowable position deviation positive value (for example, 6 mm) and the slave hydraulic cylinder is not at the end position, output ends Q of the functional blocks LZSTC103, LZSTC135, and LZSTC138 in the slave hydraulic cylinder manual lifting synchronization control unit are in the '1' state. Therefore, a value of an output end Y of the functional block LZSTC136 is equal to a value of an output end Y of the functional block LZSTC14 in the synchronization control subsystem for the master hydraulic cylinder (namely, a set value of a rising velocity of the master/slave hydraulic cylinder, for example, 4 V). The slave hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the slave hydraulic cylinder lifting velocity closed-loop control unit. In addition, an output end Q of the functional block LZSTC138 in the slave hydraulic cylinder manual lifting synchronization control unit is in the '1' state, so that the slave hydraulic cylinder lifting velocity closed-loop control unit is in a released state. When the continuous casting tundish moves up, the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is corrected by the slave hydraulic cylinder synchronization deviation velocity correction unit. If a value of ΔSsnm is greater than or equal to the set maximum allowable position deviation positive value (for example, 6 mm), the slave hydraulic cylinder stops moving up until the value of ΔSsnm is less than the set maximum allowable position deviation positive value (for example, 6 mm) again.

B4. After the continuous casting tundish moves up or down to a desired working position, the operator terminates the manual lifting instruction for the continuous casting tundish, and proportion valves for lifting control of the master and slave hydraulic cylinders are all in a neutral position self-locking state. In this case, if specific internal leakage occurs in the slave hydraulic cylinder, the slave hydraulic cylinder moves down to some extent after a specific period of time, causing an actual position of the slave hydraulic cylinder to deviate from the desired working position. To avoid position deviation of the slave hydraulic cylinder without a manual instruction, a slave hydraulic cylinder automatic position holding control unit is designed in the synchronization control subsystem for the slave hydraulic cylinder. When a lifting operation mode of the continuous casting tundish is the manual/automatic linkage mode, the manual lifting instruction for the continuous casting tundish is terminated, and no fault interruption occurs in the master and slave hydraulic cylinders, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is greater than the set allowable position deviation positive value (for example, 3 mm) after the manual lifting instruction for the continuous casting tundish is terminated, an output end Q of the functional block LZSTC114 in this unit is in the '1' state, so that an enabling control end (EN) of the "PI regulator" functional block LZSTC115 (namely, a position regulator of the slave hydraulic cylinder (Sn)) in this unit is in the '1' state and the position regulator of the slave hydraulic cylinder (Sn) is in a released state; and an output end Q of the functional block LZSTC138 in this unit is in the '1' state, so that the slave hydraulic cylinder lifting velocity closed-loop control unit is also in a released state. Therefore, when there is a deviation between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder, the position regulator of the slave hydraulic cylinder outputs a corresponding position correction velocity reference value of the slave hydraulic cylinder to reduce the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder, until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is less than or equal to the set allowable position deviation positive value (for example, 3 mm). Similarly, when a lifting operation mode of the continuous casting tundish is the manual/automatic linkage mode, the manual lifting instruction for the continuous casting tundish is terminated, and no fault interruption occurs in the master and slave hydraulic cylinders, if the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is less than the set allowable position deviation negative value (for example, -3 mm) after the manual lifting instruction for the continuous casting tundish is terminated, an output end Q of the functional block LZSTC114 in this unit is in the '1' state, so that an enabling control end (EN) of the "PI regulator" functional block LZSTC115 (namely, a position regulator of the slave hydraulic cylinder) in this unit is in the '1' state and the position regulator of the slave hydraulic cylinder is in a released state; and an output end Q of the functional block LZSTC138 in this unit is in the '1' state, so that the slave hydraulic cylinder lifting velocity closed-loop control unit is also in a released state. Therefore, when there is a deviation between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder, the position regulator of the slave hydraulic cylinder outputs a corresponding position correction velocity reference value of the slave hydraulic cylinder to increase the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder, until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is greater than or equal to the set allowable position deviation negative value (for example, -3 mm).

B5. When no fault interruption occurs in the master and slave hydraulic cylinders, and when the slave hydraulic cylinder manual lifting synchronization control unit or the slave hydraulic cylinder automatic position holding control unit sends, by setting the output end Q of the functional block LZSTC138 to '1', a signal for releasing the slave hydraulic cylinder lifting velocity control unit (namely, a signal for enabling the slave hydraulic cylinder lifting velocity control unit), a velocity-given integral functional block LZSTC141 and a velocity regulator functional block LZSTC142 in the slave hydraulic cylinder lifting velocity closed-loop control unit are in a released state. Therefore, when a given velocity entered at an input end X of the velocity-given integral functional block LZSTC142 in this unit is not zero, this unit outputs, by using a functional block LZSTC146, a corresponding control voltage of the proportion regulation valve of the slave hydraulic cylinder, until the slave hydraulic cylinder reaches a desired position and is within an allowable position deviation range, and then a signal for enabling the slave hydraulic cylinder lifting velocity control unit sent by the slave hydraulic cylinder manual lifting synchronization control unit or the slave hydraulic cylinder automatic position holding unit is blocked.

[0019] The synchronization control subsystem for the slave lifting hydraulic cylinder of the continuous casting tundish includes a proportion regulation valve positive/negative dead zone compensation unit of the slave hydraulic cylinder consisting of functional blocks LZSTC143-LZSTC146. The synchronization control method for the slave lifting hydraulic cylinders of the continuous casting tundish further includes:
B6. Usually, there is a specific dead zone between a control voltage of a proportion regulation valve of a hydraulic cylinder and an opening degree of the proportion valve, that is, when the control voltage of the proportion regulation valve reaches a specific value, the opening degree of the proportion regulation valve changes and is approximately proportional to the control voltage of the proportion regulation valve. Therefore, a proportion regulation valve positive/negative dead zone compensation unit is disposed in the slave hydraulic cylinder lifting velocity control unit to improve a control response of a proportion regulation valve of the slave hydraulic cylinder. When the value of the output end Y of the velocity regulator functional block LZSTC142 (namely, the control voltage of the proportion regulation valve of the slave hydraulic cylinder) in the slave hydraulic cylinder lifting velocity closed-loop control unit is greater than zero, a control end I of the functional block LZSTC144 in the proportion regulation valve positive/negative dead zone compensation unit of the slave hydraulic cylinder is in the '1' state, and an output end Y of the functional block LZSTC144 outputs a positive proportion regulation valve dead zone compensation voltage (for example, 1 V). In this way, a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the positive proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the slave hydraulic cylinder, thereby speeding up regulation of a positive opening degree of the proportion regulation valve of the slave hydraulic cylinder. When the value of the output end Y of the velocity regulator functional block LZSTC142 (namely, the control voltage of the proportion regulation valve of the slave hydraulic cylinder) in the slave hydraulic cylinder lifting velocity control unit is less than zero, a control end I of the functional block LZSTC145 in the proportion regulation valve positive/negative dead zone compensation subunit of the slave hydraulic cylinder is in the '1' state, and an output end Y of the functional block LZSTC145 outputs a negative proportion regulation valve dead zone compensation voltage (for example, -1 V). In this way, a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the negative proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the slave hydraulic cylinder, thereby speeding up regulation of a negative opening degree of the proportion regulation valve of the slave hydraulic cylinder.

[0020] According to the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish in the embodiments of the present disclosure, the master hydraulic cylinder synchronization position deviation velocity correction unit and the slave hydraulic cylinder synchronization position deviation velocity correction unit correct the position deviation exceeding the set range between the master hydraulic cylinder and the slave hydraulic cylinder in real time. If the deviation between the two continues to increase to the set maximum allowable position deviation, the master hydraulic cylinder synchronization position deviation out-of-range control unit and the slave hydraulic cylinder synchronization position deviation out-of-range control unit control the fast moving master hydraulic cylinder or slave hydraulic cylinder to stop moving, until the position deviation between the two is less than the set maximum allowable position deviation again. In addition, the master hydraulic cylinder automatic position holding control unit and the slave hydraulic cylinder automatic position holding control unit are used to avoid position deviation of the master hydraulic cylinder and the slave hydraulic cylinder without a manual instruction. Therefore, according to the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish, the lifting hydraulic cylinders of the continuous casting tundish can be synchronously moved, there is relatively high fault tolerance during operation of the lifting hydraulic cylinders of the continuous casting tundish, and the lifting hydraulic cylinders of the continuous casting tundish can be synchronously moved in cases of leakage of a hydraulic cylinder, different manufacturing accuracy of hydraulic elements, and uneven load.

[0021] What is described above is merely a preferred embodiment of the present disclosure, and is not intended to limit the present disclosure. Any modification, equivalent replacement, and improvement made within the spirit and principles of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

1. A synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish, wherein the synchronization control system for the hydraulic cylinders comprises a synchronization control subsystem for a master lifting hydraulic cylinder of the continuous casting tundish and a synchronization control subsystem for slave lifting hydraulic cylinders of the continuous casting tundish, wherein the synchronization control subsystem for the master lifting hydraulic cylinder of the continuous casting tundish comprises a master hydraulic cylinder synchronization position deviation out-of-range control unit and a master hydraulic cylinder synchronization position deviation velocity correction unit; the synchronization control subsystem for the slave lifting hydraulic cylinders of the continuous casting tundish comprises a slave hydraulic cylinder synchronization position deviation out-of-range control unit and a slave hydraulic cylinder synchronization position deviation velocity correction unit; and the synchronization control method for the lifting hydraulic cylinders of the continuous casting tundish based on the synchronization control system for the lifting hydraulic cylinders of the continuous casting tundish comprises:

1) when the continuous casting tundish moves down, the master hydraulic cylinder synchronization position deviation out-of-range control unit obtains a minimum value ΔSms.b.min of a difference between a position value of the master hydraulic cylinder and a position value of each slave hydraulic cylinder; if a value of ΔSms.b.min is less than or equal to a set maximum allowable position deviation negative value, the master hydraulic cylinder stops moving down until a position deviation value between the master hydraulic cylinder and a slowest declining slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value; when the continuous casting tundish moves down, the slave hydraulic cylinder synchronization position deviation out-of-range control unit obtains a difference ΔSsnm between a position value of each slave hydraulic cylinder and a position value of the master hydraulic cylinder; if a value of ΔSsnm is less than or equal to a set maximum allowable position deviation negative value, the slave hydraulic cylinder stops moving down until the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value;

2) when the continuous casting tundish moves up, the master hydraulic cylinder synchronization position deviation out-of-range control unit obtains a maximum value ΔSms.f.max of a difference between an actual position value of the master hydraulic cylinder and an actual position value of each slave hydraulic cylinder; if a value of ΔSms.f.max is greater than or equal to a set maximum allowable position deviation positive value, the master hydraulic cylinder stops moving up until a position deviation value between the master hydraulic cylinder and a slowest rising slave hydraulic cylinder is less than the set maximum allowable position deviation positive value; when the continuous casting tundish moves up, the slave hydraulic cylinder synchronization position deviation out-of-range control unit obtains a difference ΔSsnm between a position value of each slave hydraulic cylinder and a position value of the master hydraulic cylinder; if a value of ΔSsnm is greater than or equal to a set maximum allowable position deviation positive value, the slave hydraulic cylinder stops moving up until the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than the set maximum allowable position deviation positive value;

3) when the continuous casting tundish moves up or down, a synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a set range, and the master hydraulic cylinder synchronization position deviation velocity correction unit corrects a moving velocity of the master hydraulic cylinder until the position deviation value ΔSms between the master hydraulic cylinder and the slave hydraulic cylinder is within the set range again; and

4) when the continuous casting tundish moves up or down, if a synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds a set range, the slave hydraulic cylinder synchronization position deviation velocity correction unit corrects a moving velocity of the slave hydraulic cylinder until the position deviation value ΔSsnm between the slave hydraulic cylinder and the master hydraulic cylinder is within the set range again.

2. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claim 1, wherein

1) the master hydraulic cylinder synchronization position deviation velocity correction unit comprises a master hydraulic cylinder velocity correction subunit and a master hydraulic cylinder synchronization deviation quick correction subunit; when the continuous casting tundish moves down, and when the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a first set range, the master hydraulic cylinder velocity correction subunit multiplies a negative value of the synchronization position deviation value ΔSms of the master hydraulic cylinder by a velocity correction coefficient of a declining synchronization position deviation of the master hydraulic cylinder as a velocity correction value of the master hydraulic cylinder; when the continuous casting tundish moves up, and when the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds the first set range, the master hydraulic cylinder velocity correction subunit multiplies the negative value of the synchronization position deviation value ΔSms of the master hydraulic cylinder by a velocity correction coefficient of a rising synchronization position deviation of the master hydraulic cylinder as a velocity correction value of the master hydraulic cylinder; when the continuous casting tundish moves up or down, if the synchronization position deviation value ΔSms of the master hydraulic cylinder exceeds a second set range, the master hydraulic cylinder synchronization deviation quick correction subunit uses a velocity correction value of the synchronization position deviation of the master hydraulic cylinder having a direction reverse to the synchronization position deviation value ΔSms of the master hydraulic cylinder, as the velocity correction value of the master hydraulic cylinder;

2) the slave hydraulic cylinder synchronization position deviation velocity correction unit comprises a slave hydraulic cylinder velocity correction subunit and a slave hydraulic cylinder synchronization deviation quick correction subunit; when the continuous casting tundish moves down, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the first set range, the slave hydraulic cylinder velocity correction subunit multiplies a negative value of the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder by a velocity correction coefficient of a declining synchronization position deviation of the slave hydraulic cylinder as a velocity correction value of the slave hydraulic cylinder; when the continuous casting tundish moves up, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the first set range, the slave hydraulic cylinder velocity correction subunit multiplies the negative value of the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder by a velocity correction coefficient of a rising synchronization position deviation of the slave hydraulic cylinder as a velocity correction value of the slave hydraulic cylinder; and

3) when the continuous casting tundish moves up or down, and when the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the second set range, the slave hydraulic cylinder synchronization deviation quick correction subunit uses a velocity correction value of the synchronization position deviation of the slave hydraulic cylinder having a direction reverse to the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder, as the velocity correction value of the slave hydraulic cylinder.

3. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claim 1, wherein a master hydraulic cylinder fault interruption control unit, a slave hydraulic cylinder fault interruption control unit, a master hydraulic cylinder lifting velocity closed-loop control unit, and a slave hydraulic cylinder lifting velocity closed-loop control unit are additionally disposed in the synchronization control subsystem for a master lifting hydraulic cylinder of the continuous casting tundish and the synchronization control subsystem for slave lifting hydraulic cylinders of the continuous casting tundish in claim 1; for the lifting hydraulic control system of the continuous casting tundish, when a displacement sensor of the master lifting hydraulic cylinder or any slave lifting hydraulic cylinder of the tundish is faulty, a hydraulic system is faulty, or a lifting operation of the continuous casting tundish is prohibited or urgently stopped, the master hydraulic cylinder fault interruption control unit controls an output of the master hydraulic cylinder lifting velocity closed-loop control unit to be blocked, the slave hydraulic cylinder fault interruption control unit controls an output of the slave hydraulic cylinder lifting velocity closed-loop control unit to be blocked, and control voltages of proportion valves of the master and slave hydraulic cylinders are always zero, that is, the lifting control of the master and slave hydraulic cylinders is blocked.

4. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claim 1, wherein a master hydraulic cylinder manual lifting synchronization control unit, a slave hydraulic cylinder manual lifting synchronization control unit, a master hydraulic cylinder lifting velocity closed-loop control unit, and a slave hydraulic cylinder lifting velocity closed-loop control unit are additionally disposed in the synchronization control subsystem for a master lifting hydraulic cylinder of the continuous casting tundish and the synchronization control subsystem for slave lifting hydraulic cylinders of the continuous casting tundish in claim 1;

1) when the lifting hydraulic control system of the continuous casting tundish is in a manual linkage mode of tundish lifting or in a manual/automatic linkage mode of tundish lifting, during a period in which a manual declining instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSms of the master hydraulic cylinder is greater than the set maximum allowable position deviation negative value and the master hydraulic cylinder is not at a declining end position, the master hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the master hydraulic cylinder lifting velocity closed-loop control unit in a released state; if the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder exceeds the set range, the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization position deviation velocity correction unit; if the position deviation between the master hydraulic cylinder and the slowest declining slave hydraulic cylinder is less than or equal to a set maximum allowable position deviation negative value, the master hydraulic cylinder stops moving down until a position deviation value between the two is greater than the set maximum allowable position deviation negative value again; during a period in which a manual rising instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSms of the master hydraulic cylinder is less than the set maximum allowable position deviation positive value and the master hydraulic cylinder is not at a rising end position, the master hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual rising velocity of the master/slave hydraulic cylinder to the master hydraulic cylinder lifting velocity closed-loop control unit in a released state; if the position deviation between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder exceeds the set range, the position deviation between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization position deviation velocity correction unit; if the position deviation between the master hydraulic cylinder and the slowest rising slave hydraulic cylinder is greater than or equal to a set maximum allowable position deviation positive value, the master hydraulic cylinder stops moving up until a position deviation value between the two is less than the set maximum allowable position deviation positive value again; and

2) when the lifting hydraulic control system of the continuous casting tundish is in a manual linkage mode of tundish lifting or in a manual/automatic linkage mode of tundish lifting, during a period in which a manual declining instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than the set maximum allowable position deviation negative value and the master hydraulic cylinder is not at a declining end position, the slave hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual declining velocity of the master/slave hydraulic cylinder to the slave hydraulic cylinder lifting velocity closed-loop control unit in a released state; if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the set range, the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is corrected by the master hydraulic cylinder synchronization position deviation velocity correction unit; if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than or equal to a set maximum allowable position deviation negative value, the slave hydraulic cylinder stops moving down until a position deviation value between the two is greater than the set maximum allowable position deviation negative value again; during a period in which a manual rising instruction for the continuous casting tundish is delivered, if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is less than the set maximum allowable position deviation positive value and the master hydraulic cylinder is not at a rising end position, the slave hydraulic cylinder manual lifting synchronization control unit outputs a set value of a manual rising velocity of the master/slave hydraulic cylinder to the slave hydraulic cylinder lifting velocity closed-loop control unit in a released state; if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder exceeds the set range, the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is corrected by the slave hydraulic cylinder synchronization position deviation velocity correction unit; if the synchronization position deviation value ΔSsnm of the slave hydraulic cylinder is greater than or equal to a set maximum allowable position deviation positive value, the slave hydraulic cylinder stops moving up until a position deviation value between the two is less than the set maximum allowable position deviation positive value again.

5. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claim 1, wherein a master hydraulic cylinder automatic position holding control unit, a slave hydraulic cylinder automatic position holding control unit, a master hydraulic cylinder lifting velocity closed-loop control unit, and a slave hydraulic cylinder lifting velocity closed-loop control unit are additionally disposed in the synchronization control subsystem for a master lifting hydraulic cylinder of the continuous casting tundish and the synchronization control subsystem for slave lifting hydraulic cylinders of the continuous casting tundish in claim 1;

1) when a manual lifting instruction for the continuous casting tundish is terminated, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and an actual position value of the master hydraulic cylinder is greater than a set allowable position deviation positive value, a position regulator of the master hydraulic cylinder and the master hydraulic cylinder lifting velocity closed-loop control unit are in a released state; the position regulator of the master hydraulic cylinder outputs a corresponding position correction velocity reference value of the master hydraulic cylinder to reduce the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is less than or equal to the set allowable position deviation positive value; if the difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and the actual position value of the master hydraulic cylinder is less than the set allowable position deviation negative value, the position regulator of the master hydraulic cylinder and the master hydraulic cylinder lifting velocity closed-loop control unit are in a released state; the position regulator of the master hydraulic cylinder outputs a corresponding position correction velocity reference value of the master hydraulic cylinder to increase the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the master hydraulic cylinder is greater than or equal to the set allowable position deviation negative value; and

2) when a manual lifting instruction for the continuous casting tundish is terminated, if a difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and an actual position value of the slave hydraulic cylinder is greater than a set allowable position deviation positive value, a position regulator of the slave hydraulic cylinder and the slave hydraulic cylinder lifting velocity closed-loop control unit are in a released state; the position regulator of the slave hydraulic cylinder outputs a corresponding position correction velocity reference value of the slave hydraulic cylinder to reduce the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is less than or equal to the set allowable position deviation positive value; if the difference between the master/slave hydraulic cylinder position holding value SZWBZ after the termination of the manual lifting instruction for the continuous casting tundish and the actual position value of the slave hydraulic cylinder is less than the set allowable position deviation negative value, the position regulator of the slave hydraulic cylinder and the slave hydraulic cylinder lifting velocity closed-loop control unit are in a released state; the position regulator of the slave hydraulic cylinder outputs a corresponding position correction velocity reference value of the slave hydraulic cylinder to increase the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder until the difference between the master/slave hydraulic cylinder position holding value SZWBZ and the actual position value of the slave hydraulic cylinder is greater than or equal to the set allowable position deviation negative value.

6. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claim 1, wherein a master hydraulic cylinder automatic position holding control unit, a slave hydraulic cylinder automatic position holding control unit, a master hydraulic cylinder lifting velocity closed-loop control unit, a slave hydraulic cylinder lifting velocity closed-loop control unit, a master hydraulic cylinder manual lifting synchronization control unit, and a slave hydraulic cylinder manual lifting synchronization control unit are additionally disposed in the synchronization control subsystem for a master lifting hydraulic cylinder of the continuous casting tundish and the synchronization control subsystem for slave lifting hydraulic cylinders of the continuous casting tundish in claim 1;

1) when no fault interruption occurs in the master and slave hydraulic cylinders, and when the master hydraulic cylinder manual lifting synchronization control unit or the master hydraulic cylinder automatic position holding control unit sends a signal for releasing the master hydraulic cylinder lifting velocity control unit, the master hydraulic cylinder lifting velocity closed-loop control subunit converts a given input velocity into a corresponding control voltage output of the proportion regulation valve of the master hydraulic cylinder, until the master hydraulic cylinder reaches a desired position and is within an allowable position deviation range, and then a signal for enabling the master hydraulic cylinder lifting velocity control unit sent by the master hydraulic cylinder manual lifting synchronization control unit or the master hydraulic cylinder automatic position holding unit is blocked; and

2) when no fault interruption occurs in the master and slave hydraulic cylinders, and when the slave hydraulic cylinder manual lifting synchronization control unit or the slave hydraulic cylinder automatic position holding control unit sends a signal for releasing the slave hydraulic cylinder lifting velocity control unit, the slave hydraulic cylinder lifting velocity closed-loop control subunit converts a given input velocity into a corresponding control voltage output of the proportion regulation valve of the slave hydraulic cylinder, until the slave hydraulic cylinder reaches a desired position and is within an allowable position deviation range, and then a signal for enabling the slave hydraulic cylinder lifting velocity control unit sent by the slave hydraulic cylinder manual lifting synchronization control unit or the slave hydraulic cylinder automatic position holding unit is blocked.

7. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claim 1, wherein the synchronization control subsystem for the master lifting hydraulic cylinder of the continuous casting tundish comprises a proportion regulation valve positive/negative dead zone compensation unit of the master hydraulic cylinder consisting of functional blocks LZSTC64-LZSTC67, the synchronization control subsystem for slave lifting hydraulic cylinders of the continuous casting tundish comprises a proportion regulation valve positive/negative dead zone compensation unit of the slave hydraulic cylinder consisting of functional blocks LZSTC143-LZSTC146, and the synchronization control method for the master lifting hydraulic cylinder of the continuous casting tundish further comprises:

1) when no fault interruption occurs in the master and slave hydraulic cylinders, and when the control voltage of the proportion regulation valve of the master hydraulic cylinder is greater than zero, the proportion regulation valve positive/negative dead zone compensation unit of the master hydraulic cylinder outputs a positive proportion regulation valve dead zone compensation voltage, and a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the positive proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the master hydraulic cylinder, thereby speeding up regulation of a positive opening degree of the proportion regulation valve of the master hydraulic cylinder; when the control voltage of the proportion regulation valve of the master hydraulic cylinder is less than zero, the proportion regulation valve positive/negative dead zone compensation subunit of the master hydraulic cylinder outputs a negative proportion regulation valve dead zone compensation voltage, and a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the negative proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the master hydraulic cylinder, thereby speeding up regulation of a negative opening degree of the proportion regulation valve of the master hydraulic cylinder; and

2) when the control voltage of the proportion regulation valve of the slave hydraulic cylinder is greater than zero, the proportion regulation valve positive/negative dead zone compensation unit of the slave hydraulic cylinder outputs a positive proportion regulation valve dead zone compensation voltage, and a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the positive proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the slave hydraulic cylinder, thereby speeding up regulation of a positive opening degree of the proportion regulation valve of the slave hydraulic cylinder; when the control voltage of the proportion regulation valve of the slave hydraulic cylinder is less than zero, the proportion regulation valve positive/negative dead zone compensation subunit of the slave hydraulic cylinder outputs a negative proportion regulation valve dead zone compensation voltage, and a control voltage of the proportion regulation valve that is output by the velocity regulator functional block is added to the negative proportion regulation valve dead zone compensation voltage to serve as the control voltage of the proportion regulation valve of the slave hydraulic cylinder, thereby speeding up regulation of a negative opening degree of the proportion regulation valve of the slave hydraulic cylinder.

8. The synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish according to claims 1, 3, 4, 5, and 6, wherein the master hydraulic cylinder synchronization position deviation out-of-range control unit consists of functional blocks LZSTC01-LZSTC11 and LZSTC24-LZSTC26; the master hydraulic cylinder synchronization position deviation velocity correction unit consists of functional blocks LZSTC19-LZSTC23 and LZSTC51-LZSTC60; the master/slave hydraulic cylinder fault interruption control unit consists of functional blocks LZSTC44-LZSTC46; the master hydraulic cylinder manual lifting synchronization control unit consists of functional blocks LZSTC12-LZSTC15, LZSTC27-LZSTC30, LZSTC34-LZSTC38, and LZSTC43; the master hydraulic cylinder automatic position holding control unit consists of functional blocks LZSTC16-LZSTC18, LZSTC31-LZSTC33, LZSTC39-LZSTC43, and LZSTC48-LZSTC50; the master hydraulic cylinder lifting velocity closed-loop control unit consists of functional blocks LZSTC47, LZSTC61-LZSTC63, and LZSTC67; the slave hydraulic cylinder synchronization position deviation out-of-range control unit consists of functional blocks LZSTC100, LZSTC101, and LZSTC104; the slave hydraulic cylinder synchronization position deviation velocity correction unit consists of functional blocks LZSTC116-LZSTC120 and LZSTC121-LZSTC130; the slave hydraulic cylinder manual lifting synchronization control unit consists of functional blocks LZSTC102, LZSTC103, LZSTC105-LZSTC108, LZSTC134-LZSTC136, and LZSTC138; the slave hydraulic cylinder automatic position holding control unit consists of functional blocks LZSTC110-LZSTC115, LZSTC131-LZSTC133, LZSTC137, and LZSTC138; and the slave hydraulic cylinder lifting velocity closed-loop control unit consists of functional blocks LZSTC139-LZSTC142 and LZSTC146.

Drawing