(19)
(11)EP 2 899 874 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
26.06.2019 Bulletin 2019/26

(21)Application number: 15000220.2

(22)Date of filing:  26.01.2015
(51)International Patent Classification (IPC): 
H02P 6/16(2016.01)
H02P 7/00(2016.01)
H02P 6/00(2016.01)

(54)

Motor control device and correction data generation method in same

Motorsteuerungsvorrichtung und Korrekturdatenerzeugungsverfahren dafür

Dispositif de commande de moteur et procédé de génération de données de correction dans celui-ci


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 27.01.2014 JP 2014012319
27.01.2014 JP 2014012320

(43)Date of publication of application:
29.07.2015 Bulletin 2015/31

(73)Proprietor: Yamaha Hatsudoki Kabushiki Kaisha
Iwata-shi, Shizuoka-ken 438-8501 (JP)

(72)Inventor:
  • Furutani, Atsuo
    Iwata-shi Shizuoka-KEN, 438-8501 (JP)

(74)Representative: Müller-Boré & Partner Patentanwälte PartG mbB 
Friedenheimer Brücke 21
80639 München
80639 München (DE)


(56)References cited: : 
EP-A1- 0 997 341
DE-A1-102010 006 581
US-A1- 2008 298 784
EP-A1- 2 688 197
JP-A- 2005 295 721
US-B2- 7 800 321
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    CROSS REFERENCE TO RELATED APPLICATION



    [0001] This application claims benefit of priority to Japanese Patent Applications enumerated below:

    No.2014-012319 filed January 27, 2014; and

    No.2014-012320 filed January 27, 2014.


    TECHNICAL FIELD



    [0002] The technical field relates to a motor control device for controlling a motor by feeding back a corrected position signal. In the motor control device, a position detection signal of a rotary shaft of a motor is generated based on a signal output from a sensor such as a resolver or an encoder connected to the rotary shaft. The corrected position signal is obtained by correcting the position detection signal by correction data. The technical field also relates to a correction data generation method for generating the correction data used in the same device.

    BACKGROUND



    [0003] In a motor control technology, it is necessary to detect a rotational position of a rotary shaft of a motor in order to obtain a positional deviation between a position command and an actual rotational position of the rotary shaft. One of position detectors is a resolver. Here, in the case of using the resolver, a position correction technology in consideration of a position detection error of the resolver is necessary. Accordingly, in devices disclosed in Publications of Japanese Patents No. 2541169 and 5281102, correction data is stored in a memory in advance, a corrected position signal is generated by correcting a position detection signal generated based on a signal output from the resolver by the correction data and the motor is feedback-controlled using this corrected position signal during a motor control.

    SUMMARY



    [0004] Although the correction data is generated from the position detection signal detected by the resolver in Publications of Japanese Patents No. 2541169, 2005295721 and 5281102, this correction data is not necessarily highly accurate. Hence, it has been difficult to control the motor with high accuracy even if the position detection signal is corrected using the correction data.

    [0005] This disclosure was developed in view of the above problem and aims to enable the generation of correction data, used in a motor control device for controlling a motor based on a signal output from a sensor such as a resolver or an encoder, with a high degree of accuracy and improve the accuracy of a motor control.

    [0006] According to a first aspect of the disclosure, there is provided a correction data generation method for generating correction data in a motor control device that generates a position detection signal relating to a rotational position of a rotary shaft of a motor based on a signal output from a sensor in accordance with a rotational angle of the rotary shaft of the motor which rotates in response to a command signal and that controls the motor by feeding back a corrected position signal obtained by correcting the position detection signal with the correction data. The method comprises:

    obtaining in-forward-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in a forward direction in a constant speed region while the motor is driven in a forward drive pattern including the constant speed region where the rotary shaft rotates in the forward direction at a constant speed;

    obtaining in-reverse-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in a reverse direction in a constant speed region while the motor is driven in a return drive pattern including the constant speed region where the rotary shaft rotates in the reverse direction at the constant speed; and

    generating the correction data using the in-forward-rotation command information and the in-reverse-rotation command information.



    [0007] According to a second aspect of the disclosure, there is provided a motor control device for generating a position detection signal relating to a rotational position of a rotary shaft of a motor, which rotates in response to a command signal, based on a signal output from a sensor in accordance with a rotational angle of the rotary shaft and controlling the motor by feeding back a corrected position signal obtained by correcting the position detection signal with the correction data. The device comprises: a motor driver for driving the motor; and a correction data generator for generating the correction data, wherein, in generating the correction data: the motor driver performs forward drive for driving the motor in a forward drive pattern including a constant speed region where the rotary shaft rotates in a forward direction at a constant speed and return drive for driving the motor in a return drive pattern including a constant speed region where the rotary shaft rotates in a reverse direction at the constant speed; and the correction data generator obtains in-forward-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in the forward direction in the constant speed region during the forward drive, obtains in-reverse-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in the reverse direction in the constant speed region during the return drive and generates the correction data using the in-forward-rotation command information and the in-reverse-rotation command information.

    [0008] The above and further objects and novel features of the disclosure will more fully appear from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the disclosure.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0009] 

    FIG. 1A is a view showing a motor control device used for obtaining knowledge that forms foundations for the disclosure.

    FIG. 1B is a graph showing a relationship of a dynamic actual error and a current command when the resolver is used.

    FIG. 2 is a graph showing a relationship between a static actual error recognized in the device shown in FIG. 1A and actual dynamic errors during forward rotation.

    FIG. 3 is a graph showing a relationship between a static actual error recognized in the device shown in FIG. 1A and actual dynamic errors during reverse rotation.

    FIG. 4 is a graph showing a relationship of a dynamic actual error during forward rotation, a dynamic actual error during reverse rotation and a static actual error when the motor is reciprocally driven at the same constant speed in the device shown in FIG. 1A.

    FIG. 5A is a graph showing a relationship of a dynamic actual error and a current command when the resolver is used.

    FIG. 5B is a graph showing a static actual error.

    FIG. 6 is a diagram showing the electrical configuration of an embodiment of a motor control device according to the disclosure.

    FIG. 7 is a flow chart showing a correction data generating operation in the motor control device shown in FIG. 6.

    FIG. 8 is a view showing a speed pattern of the motor during a correction data generating process according to the embodiment.

    FIG. 9 is a graph showing examples of a forward-rotation current ripple and a reverse-rotation current ripple according to the embodiment.

    FIG. 10 is a graph showing an example of a phase matching operation according to the embodiment.

    FIG. 11 is a graph showing an example of a similarity ratio matching operation according to the embodiment.

    FIG. 12 is a graph showing an example of an offset matching operation according to the embodiment.

    FIG. 13 is a view showing an improvement of a static actual error by using the correction data.

    FIG. 14 is a diagram showing the electrical configuration of an example of the motor control device according to the disclosure.

    FIG. 15 is a flow chart showing a correction data generating operation in the motor control device shown in FIG. 14.

    FIG. 16 is a view showing a speed pattern of the motor during a correction data generating process according to the example.

    FIG. 17 is a graph showing an example of a forward-rotation current ripple according to the example.

    FIG. 18 is a graph showing an offset matching operation according to the example.

    FIG. 19 is a graph showing an example of a similarity ratio matching operation according to the example.


    DETAILED DESCRIPTION


    A. Similarity relationship between position detection error of resolver and current command



    [0010] The inventor of this application conducted various experiments using a motor control device having a configuration shown in FIG. 1A and obtained knowledge that there was a similarity relationship between a position detection error of a resolver and a current command. Here, a motor control device 100 used in the experiments is a robot controller and a motor M is driven to rotate by this motor control device 100. As shown in FIG. 1A, not only a resolver Re, but also a reference position detector E capable of detecting a position with higher accuracy than the resolver Re are mounted on a rotary shaft of this motor M, and detection signals by the resolver Re and the reference position detector E are respectively output to the motor control device 100. Note that PC in FIG. 1A denotes a personal computer connected to the motor control device 100 via a serial communication interface (RS232C).

    [0011] FIG. 1B is a graph showing a relationship of a dynamic actual error and a current command when the resolver is used. This experimental result is obtained by sampling while the motor M is rotated at a constant speed of 30 rps (="revolution per second" or "rotation per second"). The dynamic actual error in FIG. 1B means a difference between detection positions of the resolver and the reference position detector measured in a constant-speed operating state. In this embodiment, a value obtained by subtracting the detection position of the reference position detector E from that of the resolver Re at each rotational angle is used and the position detection error of the resolver Re is indicated by this actual dynamic error. Further, the current command indicates an AC component of a current command value in the constant-speed operating state, i.e. a current ripple. In this embodiment, the current ripple is calculated by calculating a section average (direct-current component) of current command signals sampled during one rotation section and subtracting the section average from the current command signal in this section. Note that a horizontal axis of FIG. 1B, i.e. rotational angle is a value obtained by converting the detection position of the reference position detector E into an angle.

    [0012] As is clear from FIG. 1B, the dynamic actual error that is the position detection error of the resolver Re has a similarity relationship with the AC component (current ripple) of the current command value. Thus, the inventor obtained knowledge that the dynamic actual error could be estimated from the current ripple and position accuracy could be improved by generating correction data from that estimated error and correcting the position detection signal of the resolver Re by this correction data. Further, the inventor measured actual dynamic errors while rotating the motor M in a forward direction at various constant speeds (15 rps, 30 rps, 60 rps) and compiled the measurement result together with a static actual error into FIG. 2. They also measured actual dynamic errors when the motor M was rotated in a reverse direction and compiled the measurement result together with a static actual error into FIG. 3. Note that this "static actual error" means a difference between a detection angle of the resolver Re and that of the reference position detector E measured in a stationary state.

    [0013] FIG. 2 is a graph showing a relationship between a static actual error recognized in the device shown in FIG. 1A and actual dynamic errors during forward rotation. Further, FIG. 3 is a graph showing a relationship between a static actual error recognized in the device shown in FIG. 1A and actual dynamic errors during reverse rotation. Furthermore, FIG. 4 is a graph showing a relationship of a dynamic actual error during forward rotation, a dynamic actual error during reverse rotation and a static actual error when the motor is reciprocally driven at the same constant speed in the device shown in FIG. 1A. Note that, in these figures, "stationary" indicates a static actual error which is a difference between a detection angle of the resolver Re and that of the reference position detector E measured in a stationary state.

    [0014] During forward rotation, as shown in FIG. 2, a phase is delayed and an error increases on a (-) side as the speed increases. Contrary to this, during reverse rotation, a phase is delayed and an error increases on a (+) side as the speed increases since the rotational angle on a horizontal axis is scanned in a direction from 360° to 0° as shown in FIG. 3. One of main reasons for this is thought to be due to an RD converter built in the motor control device 100. This "RD converter" is a resolver digital converter and has a function of converting an output signal of a resolver into digital angle data. Thus, the error is thought to increase and the phase is thought to tend to be delayed in the detection result of the resolver Re due to a delay system of the RD converter as compared with the detection result of the reference position detector E free from any delay.

    [0015] Further, if the dynamic actual error when the motor M is rotated in the forward direction at a constant speed of, e.g. 60 rps, the dynamic actual error when the motor M is rotated in the reverse direction at the same speed and the static actual error are plotted on the same graph, as shown in FIG. 4, error increasing directions and phase changing directions are directly opposite during forward rotation and during reverse rotation, and an average of the dynamic actual error during forward rotation and the dynamic actual error during reverse rotation is approximate to the static actual error. That is, the inventor obtained knowledge that the static actual error could be approximately calculated by obtaining the dynamic actual error during forward rotation and the dynamic actual error during reverse rotation while the motor M was driven to reciprocate at the same constant speed and averaging the values of the both at each rotational angle (hereinafter, referred to as "first knowledge"). Note that although only the measurement results of 15 to 60 rps are shown in FIGS. 2 to 4, similar measurement results are obtained also for 60 to 100 rps and the above first knowledge is satisfied.

    [0016] Based on such first knowledge, the inventor reached a conclusion that, after the dynamic actual error during forward rotation and the dynamic actual error during reverse rotation were obtained while the motor M was driven to reciprocate in a forward drive pattern including a constant speed region where the rotary shaft of the motor M rotated in the forward direction at a constant speed and a return drive pattern including a constant speed region where the rotary shaft rotated in the reverse direction at the same speed, correction data could be generated from these with high accuracy.

    [0017] Further, the inventor obtained the following knowledge by conducting a further experiment using the motor control device having the configuration shown in FIG. 1A.

    [0018] FIG. 5A is a graph showing a relationship of a dynamic actual error and a current command when the resolver is used. This experimental result is obtained by sampling while the motor M is rotated at a constant speed of 30 rps. The dynamic actual error in FIG. 5A means a difference between detection positions of the resolver and the reference position detector measured in a constant-speed operating state. In this embodiment, a value obtained by subtracting the detection position of the reference position detector E from that of the resolver Re at each rotational angle is used as the dynamic actual error that indicates a position detection error of the resolver Re. Further, the current command indicates an AC component of a current command value in the constant-speed operating state, i.e. a current ripple. In this embodiment, current command signals sampled during one rotation section are used as sampling data and the current ripple is calculated by calculating a section average (direct-current component) of the sampling data and subtracting the section average from the current command signal in this section. Note that a horizontal axis of FIG. 5A, i.e. rotational angle is a value obtained by converting the detection position of the reference position detector E into an angle.

    [0019] As is clear from FIG. 5A, the dynamic actual error that is the position detection error of the resolver Re has a similarity relationship with the AC component (current ripple) of the current command value. Thus, the inventor obtained knowledge that the dynamic actual error could be estimated from the current ripple and position accuracy could be improved by generating correction data from the estimated dynamic actual error and correcting the position detection signal of the resolver Re by this correction data (hereinafter, referred to as "second knowledge"). Although the above knowledge is obtained based on the result of sampling during the rotation of the motor M at the constant speed of 30 rps here, the inventor recognized that the same second knowledge as above was satisfied in a speed range including 30 rps, specifically a speed range of 15 rps to 100 rps.

    [0020] FIG. 5B is a graph showing a static actual error. This "static actual error" means a difference between detection angles of the resolver Re and the reference position detector E measured in a stationary state. Here, what should be noted in the static actual error shown in FIG. 5B is that the static actual error is zero when the rotational angle is zero. Thus, the inventor obtained knowledge that the accuracy of the correction data could be further enhanced by further considering a point that the static actual error was zero at a rotational angle of zero (hereinafter, referred to as "third knowledge").

    [0021] Based on such second and third knowledge, the inventor reached a conclusion that correction data could be generated with high accuracy by calculating a current ripple from sampling data obtained by sampling command signals while the rotary shaft of the motor M rotated at a constant speed and multiplying the current ripple by a suitable similarity ratio.

    [0022] Embodiments for generating correction data using the above knowledge will be described below with reference to the drawings.

    B. Embodiment



    [0023] FIG. 6 is a diagram showing the electrical configuration of an embodiment of a motor control device according to the disclosure. This motor control device 1 includes a motor driver 2 for driving a motor M based on a position command signal and a correction data generator 3 for generating correction data. The configuration of the correction data generator 3 will be described below after that of the motor driver 2 is described.

    [0024] In the motor driver 2, a speed command signal is output based on a difference between a position command signal given to a position controller 21 from outside and a corrected position signal to be described later. A speed controller 22 outputs a current command signal based on a difference between a driving speed of the motor M calculated by differentiating the corrected position signal by a differentiator 23 and the speed command signal. This current command signal is output to the correction data generator 3 to be described later and a current controller 24. This current controller 24 outputs a drive command signal to the motor M via a current sensor 25 based on the current command signal. More specifically, the current sensor 25 detects the drive command signal output from the current controller 24 and feeds a current detection signal indicating a current value of the drive command signal back to an input side of the current controller 24. Then, the current controller 24 outputs the drive command signal based on a difference between the current detection signal and the current command signal. The motor M having received the drive command signal then outputs a torque corresponding to this drive command signal.

    [0025] Further, a resolver Re is connected to a rotary shaft (not shown) of the motor M and detects a rotational position of the rotary shaft to output an analog signal indicating the rotational position. This analog signal is input to an RD converter 26, converted into a digital position detection signal and output. A signal, corrected by adding a correction signal generated in the correction data generator 3 to be described next to this position detection signal, is the above corrected position signal and given to the position controller 21 and the differentiator 23 as described above.

    [0026] Next, a correction data generation method is described after the configuration of the correction data generator 3 will be described. This correction data generator 3 includes an arithmetic processor 31 having an arithmetic function such as a CPU (Central Processing Unit) or the like and a storage 32 having four memories 321 to 324. The arithmetic processor 31 samples current command signals output from the speed controller 22 in accordance with a program stored in advance while the motor M is reciprocally driven in predetermined drive patterns by the motor driver 2 and generates the correction data by performing a phase matching process, a similarity ratio matching process and an offset matching process to be described in detail next. As just described, in this embodiment, the arithmetic processor 31 functions as a current command value sampling unit 311, a phase matching unit 312, a similarity ratio matching unit 313 and an offset matching unit 314.

    [0027] FIG. 7 is a flow chart showing a correction data generating operation in the motor control device shown in FIG. 6. In this embodiment, a correction data generating process described below is performed in a state where the motor M is incorporated in a device, e.g. in a state where a movable part (movable mechanism part such as a ball screw) of a robot is coupled to the rotary shaft of the motor M in the case of using the motor M as a drive source of the robot, when the motor M or the resolver Re is mounted or exchanged and when the generation of correction data is commanded by a user.

    [0028] In Step S101, a moving distance and speeds V0+, V0- (where |V0+|= |V0-|) in the constant speed regions of the robot actuated by the motor M under the control of the motor driver 2 are set. By these settings, an operation pattern in which the motor M drives the robot to operate the robot in performing the correction data generating process, i.e. a drive pattern of the motor M by the motor driver 2 is determined. Further, a plurality of operation modes are prepared in advance as operation modes of the motor driver 2. In the correction data generating process, a correction signal is not output to the motor driver 2 at first, i.e. a "correction-free operation" in which the motor M is driven without any correction by the correction data is selected (Step S102) and the phase matching process is performed (Steps S103 to S106).

    [0029] In the phase matching process, the robot is reciprocally moved by starting the drive of the motor M by the motor driver 2 and current sampling is performed during this movement (Step S103). Specifically, by starting the drive of the motor M, the motor M rotates in the forward direction to accelerate a moving speed of the robot up to the speed V0+ over a predetermined time and, after the constant speed V0+ is maintained for a time corresponding to the moving distance set in Step S101, deceleration is started to stop the forward rotation of the motor M, for example, as shown in FIG. 8. A movement of the robot by the forward rotation of the motor M in this way is called a "forward movement", the drive pattern of the motor M for making such a movement is called a "forward drive pattern" and a region where the constant speed V0+ is maintained in that forward drive pattern is called a "constant speed region". Further, current command signals output from the speed controller 22 of the motor driver 2 during one rotation of the motor M are sampled at fixed time intervals at substantially middle positions of the constant speed region during the forward movement and a current command value at each rotational angle is written as "sampling data of forward rotation" in the current sampling memory 321.

    [0030] When the forward movement of the robot is completed, the motor M rotates in the reverse direction and moves the robot in a drive pattern which is an inverse of the forward drive pattern. That is, the moving speed of the robot is accelerated up to the speed V0- and, after the constant speed V0- is maintained for a time corresponding to the moving distance set in Step S101, deceleration is started to stop the reverse rotation of the motor M. A movement of the robot by the reverse rotation of the motor M in this way is called a "return movement", the drive pattern of the motor M for making such a movement is called a "return drive pattern" and a region where the constant speed V0- is maintained in that return drive pattern is called a "constant speed region". Further, current command signals output from the speed controller 22 of the motor driver 2 during one rotation of the motor M are sampled at fixed time intervals at substantially middle positions of the constant speed region during the return movement and a current command value at each rotational angle is written as "sampling data of reverse rotation" in the current sampling memory 321.

    [0031] In next Step S104, the sampling data of forward rotation is read from the current sampling memory 321 and an average value (direct-current component) of the current command values of one rotation is calculated. Then, a forward-rotation current ripple is calculated by subtracting the above average value from the current command value at each rotational angle and overwritten in the current sampling memory 321. In this way, the forward-rotation current ripple that is an AC component of the current command value during the forward movement is obtained (solid line in FIG. 9).

    [0032] Also for a reverse rotation side, a reverse-rotation current ripple is calculated similarly to the forward rotation side (Step S105). Specifically, the sampling data of reverse rotation is read from the current sampling memory 321, an average value (direct-current component) of the current command values of one rotation is calculated, a reverse-rotation current ripple is calculated by subtracting the above average value from the current command value at each rotational angle and overwritten in the current sampling memory 321. In this way, the reverse-rotation current ripple that is an AC component of the current command value during the return movement is obtained (dotted line in FIG. 9).

    [0033] When the forward-rotation current ripple and the reverse-rotation current ripple are calculated, the current ripple of forward rotation and that of reverse rotation are respectively read for each rotational angle from the current sampling memory 321 and an average value of these values is calculated. Then, the average value (= (forward-rotation current ripple + reverse-rotation current ripple)/2) is written as an average current ripple in a correction base table in the memory 322 (Step S106). Note that an example of the average current ripple obtained as described above is shown in broken line in FIG. 10.

    [0034] When the above phase matching process is completed (timing T1 in FIG. 8), a "similarity ratio matching operation" is selected as the operation mode (Step S107) and the similarity ratio matching process described below is performed (Steps S108 to S116). In this similarity ratio matching process, various initial settings are made in Step S108. In this embodiment, a value obtained by subtracting a minimum value from a maximum value of the average current ripples of one rotation, i.e. a minimum value RWmin of a current ripple amplitude is set as a default value ("10000" in this embodiment) and "1" is set as an initial value of a count value n. A similarity ratio is set at a value (n/20) in next Step S109. For example, the similarity ratio is set at the initial value (1/20) when n= 1.

    [0035] After the similarity ratio (n/20) is set, the average current ripple is read from the correction base table memory 322 and a value obtained by multiplying the average current ripple at each rotational angle by the similarity ratio is output as a correction signal to the motor driver 2. Then, the robot is reciprocally moved and the current sampling is performed during this movement by starting the drive of the motor M by the motor driver 2 while performing a correction by the correction signal (Step S110). Note that the reciprocal movements and the current sampling operation are the same as those during the phase matching process (Step S103) except that the correction by the correction signal is performed, and the sampling data of one forward rotation and that of one reverse rotation are written in the current sampling memory 321. For example, when n = 1, the current sampling of one rotation substantially in the center of each constant speed region is performed while the motor M is driven in the successive forward and return drive patterns from timing T1 to timing T2 in FIG. 8.

    [0036] When the current sampling is completed, the current ripple is calculated and written in the similarity ratio matching memory 323 (Step Sill). Specifically, the forward-rotation current ripple is calculated as in Step S104 described above, the reverse-rotation current ripple is calculated as in Step S105 described above and the average current ripple is calculated as in Step S106 described above. Then, the average current ripple when the similarity ratio is set at (n/20) is written in the similarity ratio matching memory 323.

    [0037] In next Step S112, after the current ripple amplitude is calculated from the average current ripples of one rotation written in the similarity ratio matching memory 323, it is determined whether or not this current ripple amplitude is below the minimum value RWmin. If "YES" is determined in Step S112, i.e. the current ripple amplitude at the count value n is determined to be below the minimum value RWmin, a transition is made to Step S114 after the minimum value RWmin is updated to the current ripple amplitude and this count value n is written as an optimal value Kbest in the similarity ratio matching memory 323 (Step S113). Note that a storage destination of the optimal value Kbest is not limited to the similarity ratio matching memory 323 and the optimal value Kbest can be written in any arbitrary memory. On the other hand, if "NO" is determined in Step S112, a transition is directly made to Step S114 without updating the minimum value RWmin and the optimal value Kbest.

    [0038] After the count value n is incremented by "1" in this Step S114, it is determined whether or not the count value n is "21" (Step S115). If "NO" in Step S115, i.e. while the count value n is determined to be not larger than "20", a return is made to Step S119 and a process of deriving the similarity ratio at which the current ripple amplitude is minimized (Steps S109 to S115) is repeated. That is, in this embodiment, (1/20), (2/20), ..., (20/20) are prepared as candidates for the similarity ratio and the optimal value Kbest is determined after the similarity ratio deriving process is performed for each candidate for the similarity ratio.

    [0039] On the other hand, if "YES" is determined in Step S115, the optimal value Kbest is read from the similarity ratio matching memory 323 and an optimal similarity ratio (= Kbest/20) at which the current ripple amplitude is smallest is determined. Then, the average current ripple is read from the correction base table memory 322 and a value obtained by multiplying the average current ripple at each rotational angle by the optimal similarity ratio is written as similarity ratio matched data in the correction table memory 324 (Step S116).

    [0040] The similarity ratio matched data (solid line in FIG. 11) approximated to the static actual error (dotted line in FIG. 11) is obtained by adjusting the average current ripple using the optimal similarity ratio in this way. The similarity ratio matched data is offset from the static actual error, for example, as shown in FIG. 11 and the static actual error is zero at a rotational angle of 0° as shown in dotted line in FIG. 11. Thus, in this embodiment, offset matching is performed at the end (Step S117). Specifically, the similarity ratio matched data at a rotational angle of zero is subtracted from the similarity ratio matched data at each rotational angle and this offset matched data is overwritten as final correction data (e.g. solid line in FIG. 12) in the correction table memory 324. In this way, more accurate correction data is obtained.

    [0041] As described above, according to this embodiment, it is possible to generate the correction data with high accuracy and improve the control accuracy of the motor M since the correction data used in the motor control device 1 is generated based on the first to third knowledge described above. Further, in the embodiment, the average current ripple is calculated from the forward-rotation current ripple and the reverse-rotation current ripple and the similarity ratio matching process is performed on this average current ripple. Thus, "in-rotation command information" of the disclosure can be obtained with high accuracy and the accuracy of the correction data can be further enhanced. The reason for that is that the error increasing directions and the phase changing directions during forward rotation and during reverse rotation are directly opposite to each other and the dynamic actual error can be estimated with higher accuracy from the forward-rotation current ripple and the reverse-rotation current ripple as described in the above section "A. Similarity relationship between position detection error of resolver and current command".

    [0042] Further, although it has been conventionally proposed as a method for generating correction data to mount a reference position detector and use an error from a position measured by the reference position detector as correction data, a correction facility for generating the correction data is separately necessary in this case. Contrary to this, in the above embodiment, the correction data can be generated by a unique function of the motor control device 1 without using this correction facility at all and own performance can be improved. That is, the motor control device 1 according to the above embodiment has a self-correction function. Further, the correction data can be generated with the motor M mounted in the robot. Thus, even when the motor M is exchanged or repaired in a factory or the like where the robot is installed, correction data can be generated on the spot after the exchange or repair.

    [0043] Further, in the above embodiment, the correction data is generated utilizing the current command signals after the speed command signal is amplified by the speed controller 22, a sufficiently high resolution can be obtained and position accuracy after the correction can be set higher than the conventional technology. Here, the correction data may be generated using current detection signals instead of the current command signals and functions and effects similar to those of the above embodiment are obtained.

    [0044] As just described, in this embodiment, the resolver Re corresponds to an example of a "sensor" of the disclosure. Further, the "forward-rotation current ripple" corresponds to an example of "in-forward-rotation command information" of the disclosure and the "reverse-rotation current ripple" corresponds to an example of "in-reverse-rotation command information" of the disclosure. Further, the average current ripple calculated in Step S106 corresponds to an example of "phase matching information" of the disclosure. Further, the sampling of the current command signals performed during one forward movement corresponds to an example of "sampling during forward rotation" of the disclosure, the sampling of the current command signals performed during one return movement corresponds to an example of "sampling during reverse rotation" of the disclosure, and an operation of successively performing these corresponds to an example of "a pair of sampling operations" of the disclosure. In this embodiment, the correction data is generated by repeating this pair of sampling operations (n+1) times. Note that although the pair of sampling operations are repeated 20 times while switching the candidate for the similarity ratio during the similarity ratio matching process, the number of repetitions (number of candidates for the similarity ratio) is arbitrary without being limited to this.

    [0045] As just described, in the embodiment, the average current ripple calculated in Step S106 corresponds to an example of "in-rotation command information" of the disclosure. Here, an offset matched current ripple obtained by performing the offset matching process on the average current ripple as in an example described later may be used as the "in-rotation command information" of the disclosure. In this case, Step S117 becomes unnecessary and the similarity ratio matched data calculated in Step S116 can be used as the correction data.

    [0046] Further, in the embodiment, the phase matching process corresponds to an example of a "first step" of the disclosure. Further, the similarity ratio matching process corresponds to an example of a "second step" of the disclosure. The data obtained by multiplying the average current ripple by the similarity ratio (n/20) in this similarity ratio matching process corresponds to an example of a "correction data candidate" of the disclosure, an operation of obtaining this data corresponds to an example of a "correction data candidate generating step" of the disclosure and an operation of driving the motor M through a feedback control using this data corresponds to an example of a "motor driving step" of the disclosure.

    [0047] In the thus configured disclosure, the in-forward-rotation command information and the in-reverse-rotation command information are respectively obtained while the motor is driven in the forward drive pattern and the return drive pattern. This in-forward-rotation command information is obtained by sampling command signals during one or more rotations of the rotary shaft in the forward direction in the constant speed region. Further, the in-reverse-rotation command information is obtained by sampling command signals during one or more rotations of the rotary shaft in the reverse direction in the constant speed region. Thus, the error increasing directions and the phase changing directions included in the in-forward-rotation command information and the in-reverse-rotation command information are directly opposite to each other as described in detail later and the correction data can be generated with high accuracy from the in-forward-rotation command information and the in-reverse-rotation command information utilizing such a characteristic. Further, the accuracy of the motor control is improved by executing a feedback control using the correction data generated in this way.

    [0048] As described above, according to the disclosure, the correction data can be generated with high accuracy and the accuracy of the motor control can be improved since the correction data used in the motor control device is generated using the in-forward-rotation command information and the in-reverse-rotation command information.

    C. Example



    [0049] Based on the second and third knowledge, the inventor reached a conclusion that the correction data could be generated with high accuracy by obtaining the current ripple from the sampling data obtained by sampling the command signals while the rotary shaft of the motor M rotates at the constant speed and multiplying the current ripple by a proper similarity ratio. An example of the disclosure for generating correction data using the above second and third knowledge will be described below with reference to the drawings.

    [0050] FIG. 14 is a diagram showing the electrical configuration of the example of the motor control device according to the disclosure. This example largely differs from the embodiment in the configuration of the correction data generator 3 and the configuration of the motor driver 2 is the same. Accordingly, a correction data generation method will be described after the configuration of a correction data generator 3 in the example is described and the same components are denoted by the same reference signs and not described.

    [0051] This correction data generator 3 includes an arithmetic processor 31 having an arithmetic function such as a CPU (Central Processing Unit) or the like and a storage 32 having four memories 321 to 324. The arithmetic processor 31 samples current command signals output from a speed controller 22 in accordance with a program stored in advance while a motor M is reciprocally driven in predetermined drive patterns by a motor driver 2 and generates correction data by performing a current ripple obtaining process, an offset matching process and a similarity ratio matching process to be described in detail next. As just described, in this example, the arithmetic processor 31 functions as a current command value sampling unit 311, a current ripple obtaining unit 315, a similarity ratio matching unit 313 and an offset matching unit 314.

    [0052] FIG. 15 is a flow chart showing a correction data generating operation in the motor control device shown in FIG. 14. In this example, a correction data generating process described below is performed in a state where the motor M is incorporated in a device, e.g. in a state where a movable part (movable mechanism part such as a ball screw) of a robot is coupled to a rotary shaft of the motor M in the case of using the motor M as a drive source of the robot, when the motor M or a resolver Re is mounted or exchanged and when the generation of correction data is commanded by a user.

    [0053] In Step S201, a moving distance of the robot and speeds V0+, V0- in constant speed regions are set. By these settings, an operation pattern in which the motor M drives the robot to operate the robot in performing the correction data generating process, i.e. a drive pattern of the motor M by the motor driver 2 is determined. Further, a plurality of operation modes are prepared in advance as operation modes of the motor driver 2. In the correction data generating process, a correction signal is not output to the motor driver 2 at first, i.e. a "correction-free operation" in which the motor M is driven without any correction by the correction data is selected (Step S202) and the current ripple obtaining process is performed (Steps S203 to S205).

    [0054] In this current ripple obtaining process, the robot is reciprocally moved by starting the drive of the motor M by the motor driver 2 and current sampling is performed during a forward movement (Step S203). Specifically, by starting the drive of the motor M, the motor M rotates in the forward direction to accelerate a moving speed of the robot up to the speed V0+ over a predetermined time and, after the constant speed V0+ is maintained for a time corresponding to the moving distance set in Step S201, deceleration is started to stop the forward rotation of the motor M, for example, as shown in FIG. 16. A movement of the robot by the forward rotation of the motor M in this way is called a "forward movement", the drive pattern of the motor M for making such a movement is called a "forward drive pattern" and a region where the constant speed V0+ is maintained in that forward drive pattern is called a "constant speed region". Further, a current command value at each rotational angle, output from the speed controller 22 of the motor driver 2 during one rotation of the motor M and sampled at a fixed time interval, is written as "sampling data" in a current sampling memory 321.

    [0055] In next Step S204, the current command values of one rotation are read from the current sampling memory 321 and an average value (direct-current component) thereof is calculated. Then, a forward-rotation current ripple is calculated by subtracting the above average value from the current command value at each rotational angle and overwritten in the current sampling memory 321. In this way, the forward-rotation current ripple, that is an AC component of the current command value during the forward movement, is obtained (FIG. 17).

    [0056] Further, since a static actual error is zero at a rotational angle of zero, offset matching is performed (Step S205). That is, a value at a rotational angle of zero out of values at the respective rotational angles of the rotary shaft constituting the current ripple is set as offset data, and an offset matched current ripple (e.g. solid line in FIG. 18) is calculated by subtracting the offset data from the value at each rotational angle and written in a correction base table in the memory 322 (Step S206).

    [0057] When the above current ripple obtaining process is completed and a "similarity ratio matching operation" is selected as the operation mode (Step S207), the similarity ratio matching process described below is performed from timing T1 at which the next reciprocal drive is started (FIG. 16) (Steps S208 to S215). In this similarity ratio matching process, various initial settings are first made. In this example, "1" is set as an initial value of a count value n and a value obtained by subtracting a minimum value from a maximum value of the average current ripples of one rotation, i.e. a minimum value RWmin of a current ripple amplitude is set as a default value ("10000" in this example) as one initial setting (Step S208). The similarity ratio is set at a value (n/20) in next Step S209. For example, the similarity ratio is set at the initial value (1/20) when n = 1.

    [0058] After the similarity ratio (n/20) is set, the offset matched current ripple is read from the correction base table memory 322 and a value obtained by multiplying this offset matched current ripple by the similarity ratio is output as a correction signal to the motor driver 2. Then, the robot is reciprocally moved and the current sampling is performed during this movement by starting the drive of the motor M by the motor driver 2 while performing a correction by the correction signal (Step S210). Note that the reciprocal movements and the current sampling operation are the same as those during the current ripple obtaining process (Step S203) except that the correction by the correction signal is performed, and the sampling data of one rotation is written in the current sampling memory 321. For example, when n = 1, the current sampling of one rotation substantially in the center of the constant speed region of the forward drive pattern is performed while the motor M is driven from timing T1 to timing T2 in FIG. 16.

    [0059] When the current sampling is completed, the current ripple is calculated and written in the similarity ratio matching memory 323 (Step S211). Specifically, the current ripple is calculated as in Step S204 described above. Then, the current ripple when the similarity ratio is set at (n/20) is written in the similarity ratio matching memory 323.

    [0060] In next Step S212, after a current ripple amplitude is calculated from the current ripples of one rotation written in the similarity ratio matching memory 323, it is determined whether or not this current ripple amplitude is below the minimum value RWmin. If "YES" is determined in Step S212, i.e. the current ripple amplitude at the count value n is determined to be below the minimum value RWmin, a transition is made to Step S214 after the minimum value RWmin is updated to the current ripple amplitude and this count value n is written as an optimal value Kbest in the similarity ratio matching memory 323 (Step S213). Note that a storage destination of the optimal value Kbest is not limited to the similarity ratio matching memory 323 and the optimal value Kbest can be written in any arbitrary memory. On the other hand, if "NO" is determined in Step S212, a transition is directly made to Step S214 without updating the minimum value RWmin and the optimal value Kbest.

    [0061] After the count value n is incremented by "1" in this Step S214, it is determined whether or not the count value n is "21" (Step S215). If "NO" in Step S215, i.e. while the count value n is determined to be not larger than "20", a return is made to Step S209 and a process of deriving the similarity ratio at which the current ripple amplitude is minimized (Steps S209 to S214) is repeated. That is, in this example, (1/20), (2/20), ..., (20/20) are prepared as candidates for the similarity ratio and the optimal value Kbest is determined after performing the similarity ratio deriving process for each candidate for the similarity ratio.

    [0062] On the other hand, if "YES" is determined in Step S215, a transition is made to Step S209 of FIG. 15. In this Step S209, the optimal value Kbest is read from the similarity ratio matching memory 323 and an optimal similarity ratio (= Kbest/20) at which the current ripple amplitude is smallest is determined. Then, the offset matched current ripple is read from the correction base table memory 322, and similarity ratio matched data is generated by multiplying the value at each rotational angle constituting this offset matched current ripple by the optimal similarity ratio and written as correction data in the correction table memory 324 (Step S209). In this way, more accurate correction data is obtained.

    [0063] As described above, according to this example, it is possible to generate the correction data with high accuracy and improve the control accuracy of the motor M since the correction data used in the motor control device 1 is generated based on the knowledge described above.

    [0064] Further, although it has been conventionally proposed as a method for generating correction data to mount a reference position detector and use an error from a position measured by the reference position detector as correction data, a correction facility for generating the correction data is separately necessary in this case. Contrary to this, in the above example, the correction data can be generated by a unique function of the motor control device 1 without using this correction facility at all and own performance can be improved. That is, the motor control device 1 according to the above example has a self-correction function. Further, the correction data can be generated with the motor M mounted in the robot. Thus, even when the motor M is exchanged or repaired in a factory or the like where the robot is installed, correction data can be generated on the spot after the exchange or repair.

    [0065] Further, in the above example, the correction data is generated utilizing the current command signals after the speed command signal is amplified by the speed controller 22, a sufficiently high resolution can be obtained and position accuracy after the correction can be set higher than the conventional technology. Here, the correction data may be generated using current detection signals instead of the current command signals and functions and effects similar to those of the above example are obtained.

    [0066] As just described, in this example, the resolver Re corresponds to an example of the "sensor" of the disclosure. Further, in the above example, the offset matched current ripple is obtained by the current ripple obtaining process and the offset matching process and these processes correspond to an example of the "first step" of the disclosure. Further, the similarity ratio matching process corresponds to an example of the "second step" of the disclosure. Data obtained by multiplying the offset matched current ripple by the similarity ratio (n/20) in this similarity ratio matching process corresponds to an example of the "correction data candidate" of the disclosure, an operation of obtaining this data corresponds to an example of the "correction data candidate generating step" and an operation of driving the motor M through a feedback control using this data corresponds to an example of the "motor driving step" of the disclosure.

    [0067] Further, the offset matched current ripple calculated in Step S206 corresponds to an example of the "in-rotation command information" of the disclosure. Note that the forward-rotation current ripple may be used as the "in-rotation command information" of the disclosure. In this case, the current ripple obtaining process corresponds to an example of the "first step" of the disclosure. Further, since the offset matching process is not performed before the similarity ratio matching process is performed, it is desirable to use the offset matched data obtained by performing the offset matching process on the similarity ratio matched data as the correction data. Further, although the forward-rotation current ripple is obtained from the sampling data obtained by performing the current sampling during forward rotation and the offset matched current ripple, the similarity ratio matched data and the like are further calculated in the above example, sampling data obtained by performing the current sampling during reverse rotation may be used instead of the forward-rotation sampling data. That is, the correction data may be generated based on the reverse-rotation current ripple.

    [0068] In the thus configured disclosure, the command signals are sampled during one or more rotations of the rotary shaft in the constant speed region. Then, the in-rotation command information is obtained from the sampling data. This in-rotation command information has a similarity relationship with the dynamic actual error and the correction data can be generated with high accuracy by multiplying the in-rotation command information by the similarity ratio. Further, the accuracy of the motor control is improved by executing the feedback control using the correction data generated in this way.

    [0069] As described above, according to the disclosure, it is possible to generate correction data with high accuracy and improve the control accuracy of a motor control since the correction data used in a motor control device is generated by multiplying in-rotation command information by a similarity ratio.

    D. Miscellaneous



    [0070] Note that the disclosure is not limited to the above embodiments and example and various changes other than the aforementioned ones can be made without departing from the gist of the disclosure. For example, although the disclosure is applied to the motor control device 1 for controlling the motor M using the signals output from the resolver Re in the above embodiments and example, the disclosure is applicable also to a motor control device using a position detection sensor other than the resolver Re such as an encoder as the sensor of the disclosure.

    [0071] Further, the sampling period of the current command signals is one rotation of the motor M in the above embodiments and example, the current command signals may be sampled during more than one rotation. For example, if the current command signals are sampled during m rotations, the "forward-rotation current ripple" and the "reverse-rotation current ripple" may be derived by averaging m pieces of the sampling data at each rotational angle.

    [0072] Further, although the pair of sampling operations are repeated 20 times while the candidate for the similarity ratio is switched during the similarity ratio matching process as shown in FIGS. 7 and 15 in the above embodiments and example, this number of repetitions (number of the candidates for the similarity ratio) is arbitrary without being limited to this.

    [0073] Further, in the above embodiments and example, the average current ripple (phase matching information) is obtained by averaging the forward-rotation current ripple and the reverse-rotation current ripple. However, the average current ripple may be obtained by averaging sampling data during forward rotation and sampling data during reverse rotation. That is, a step of removing the direct current component may be omitted and the phase matching information may be obtained from both pieces of the sampling data, whereby signal processing can be simplified.

    [0074] Further, in the above embodiments and example, current sampling is performed in the phase matching process and the similarity ratio matching process while the motor is driven in the same drive pattern. However, it is not essential that the drive patterns coincide. In the phase matching process, the influence of rotational friction of a reduction gear (not shown) coupled to the rotary shaft of the motor is small and current sampling is desirably performed at a speed at which similarity to the position detection error of the resolver is high. Contrary to this, in the similarity ratio matching process, there is no influence of the above rotational friction and current sampling is desirably performed at a speed at which an effect by correction is largely exhibited. Accordingly, to satisfy such a demand, the drive patterns are preferably so set that the absolute values of the speeds V0+, V0- in the constant speed region in the phase matching process are larger than those in the similarity ratio matching process.

    [0075] Furthermore, although the motor M is used as the drive source of the robot in the above embodiments and example, an application object of the disclosure is not limited to a technology for controlling a motor mounted in a robot. That is, the disclosure can be, for example, applied also to motor control devices for controlling a motor mounted in devices including a movable part driven by a motor such as surface mounting machines, part inspection apparatuses, semiconductor manufacturing apparatuses and other industrial apparatuses.

    [0076] This disclosure is applicable to correction data generation technologies in general for generating correction data for correcting a signal output from a sensor connected to a rotary shaft of a motor and motor control technologies in general for controlling the motor using the correction data.


    Claims

    1. A correction data generation method for generating correction data in a motor control device that generates a position detection signal relating to a rotational position of a rotary shaft of a motor based on a signal output from a sensor in accordance with a rotational angle of the rotary shaft of the motor which rotates in response to a command signal and that controls the motor by feeding back a corrected position signal obtained by correcting the position detection signal with the correction data, the method characterized by:

    obtaining in-forward-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in a forward direction in a constant speed region while the motor is driven in a forward drive pattern including the constant speed region where the rotary shaft rotates in the forward direction at a constant speed;

    obtaining in-reverse-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in a reverse direction in a constant speed region while the motor is driven in a return drive pattern including the constant speed region where the rotary shaft rotates in the reverse direction at the constant speed; and

    generating the correction data using the in-forward-rotation command information and the in-reverse-rotation command information.


     
    2. The correction data generation method according to claim 1, wherein:
    the sampling during the forward rotation and the sampling during the reverse rotation are both performed N times, where N is a natural number not smaller than 2.
     
    3. The correction data generation method according to claim 2, wherein:
    a pair of sampling operations in which the sampling during the forward rotation and the sampling during the reverse rotation are respectively performed once are repeated the N times.
     
    4. The correction data generation method according to claim 3, wherein:
    the correction data is determined after the pair of sampling operations are repeated the N times.
     
    5. The correction data generation method according to any one of claims 1 to 4, wherein:

    the command signal is a signal relating to a current given to the motor; and

    the in-forward-rotation command information and the in-reverse-rotation command information are current command values at each rotational angle of the rotary shaft.


     
    6. The correction data generation method according to any one of claims 1 to 5, wherein:

    the command signal is a signal relating to a current given to the motor; and

    the in-forward-rotation command information and the in-reverse-rotation command information are current detection signals of the motor at each rotational angle of the rotary shaft.


     
    7. The correction data generation method according to any one of claims 1 to 6, wherein:
    sampling of the command signals is performed at each rotational angle of the rotary shaft.
     
    8. The correction data generation method according to any one of claims 1 to 7, comprising:

    a first step of obtaining phase matching information; and

    a second step of calculating the correction data from the phase matching information, wherein

    the first step includes:

    reciprocally driving the motor by feeding back the position detection signal without correcting the position detection signal with the correction data;

    obtaining a forward-rotation current ripple by removing a direct-current component from the in-forward-rotation command information;

    obtaining a reverse-rotation current ripple by removing a direct-current component from the in-reverse-rotation command information; and

    obtaining, as the phase matching information, an average current ripple at each rotational angle of the rotary shaft is obtained by averaging the forward-rotation current ripple and the reverse-rotation current ripple at each rotational angle.


     
    9. The correction data generation method according to any one of claims 1 to 8, comprising:

    a first step of obtaining phase matching information; and

    a second step of calculating the correction data from the phase matching information, wherein

    the first step includes:

    reciprocally driving the motor by feeding back the position detection signal without correcting the position detection signal with the correction data; and

    obtaining, as the phase matching information, an average current ripple at each rotational angle of the rotary shaft is obtained by averaging the in-forward-rotation command information obtained during the forward drive and the in-reverse-rotation command information obtained during the return drive at each rotational angle.


     
    10. The correction data generation method according to claim 8 or 9, wherein, in the second step:
    the correction data is calculated based on similarity ratio matched data at each rotational angle obtained by multiplying the phase matching information by a similarity ratio.
     
    11. The correction data generation method according to claim 10, wherein:

    a plurality of similarity ratio candidate values different from each other are prepared as candidates for the similarity ratio;

    for each similarity ratio candidate value, the motor is reciprocally driven by feeding back a corrected position signal obtained by correcting the position detection signal based on data obtained by multiplying the phase matched information by the similarity ratio candidate value, a forward-rotation current ripple is calculated by removing a direct-current component from the in-forward-rotation command information obtained during the forward drive, a reverse-rotation current ripple is calculated by removing a direct-current component from the in-reverse-rotation command information obtained during the return drive, and a difference between a maximum value and a minimum value out of average current ripples at the respective rotational angles of the rotary shaft obtained by averaging the forward-rotation current ripples and the reverse-rotation current ripples at each rotational angle is calculated as a current ripple amplitude; and

    the similarity ratio candidate value, at which the current ripple amplitude has a minimum value, out of the plurality of similarity ratio candidate values is set as the similarity ratio.


     
    12. The correction data generation method according to claim 10 or 11, wherein:

    a plurality of similarity ratio candidate values different from each other are prepared as candidates for the similarity ratio;

    for each similarity ratio candidate value, the motor is reciprocally driven by feeding back a corrected position signal obtained by correcting the position detection signal based on data obtained by multiplying the phase matched information by the similarity ratio candidate value, and a difference between a maximum value and a minimum value out of average current ripples at the respective rotational angles of the rotary shaft obtained by averaging the in-forward-rotation command information obtained during the forward drive and the in-reverse-rotation command information obtained during the return drive at each rotational angles is calculated as a current ripple amplitude; and

    the similarity ratio candidate value, at which the current ripple amplitude has a minimum value, out of the plurality of similarity ratio candidate values is set as the similarity ratio.


     
    13. The correction data generation method according to any one of claims 10 to 12, wherein, in the second step:

    similarity ratio matched data at a rotational angle of zero out of those at the respective rotational angles of the rotary shaft is set as offset data; and

    offset matched data obtained by subtracting the offset data from the similarity ratio matched data at each rotational angle is set as the correction data.


     
    14. The correction data generation method according to any one of claims 8 to 13, wherein:

    the motor is driven in the forward drive pattern and the reverse drive pattern in the second step; and

    absolute values of the constant speed in the first step are larger than those in the second step.


     
    15. A motor control device (1) generating a position detection signal relating to a rotational position of a rotary shaft of a motor (M), which rotates in response to a command signal, based on a signal output from a sensor in accordance with a rotational angle of the rotary shaft and controlling the motor (M) by feeding back a corrected position signal obtained by correcting the position detection signal with the correction data, the device comprising:

    a motor driver (2) driving the motor (M); and

    a correction data generator (3) generating the correction data,

    characterized in that,

    in generating the correction data:

    the motor driver performs forward drive for driving the motor (M) in a forward drive pattern including a constant speed region where the rotary shaft rotates in a forward direction at a constant speed and return drive for driving the motor (M) in a return drive pattern including a constant speed region where the rotary shaft rotates in a reverse direction at the constant speed; and

    the correction data generator obtains in-forward-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in the forward direction in the constant speed region during the forward drive, obtains in-reverse-rotation command information by sampling the command signals during one or more rotations of the rotary shaft in the reverse direction in the constant speed region during the return drive and generates the correction data using the in-forward-rotation command information and the in-reverse-rotation command information.


     


    Ansprüche

    1. Korrekturdaten-Erzeugungsverfahren zum Erzeugen von Korrekturdaten in einer Motorsteuervorrichtung, die ein Positionserfassungssignal erzeugt, das sich auf eine Drehposition einer Drehwelle eines Motors bezieht, basierend auf einem Signal, das von einem Sensor gemäß einem Drehwinkel der Drehwelle des Motors ausgegeben wird, die sich als Reaktion auf ein Steuersignal dreht, und den Motor steuert, indem ein korrigiertes Positionssignal zurückgeführt wird, das durch Korrigieren des Positionserfassungssignals durch die Korrekturdaten erhalten wird, wobei das Verfahren durch Folgendes gekennzeichnet ist:

    Erhalten von Vorwärtsdrehungs-Steuerungsinformationen durch Abtasten der Steuerungssignale während einer oder mehrerer Umdrehungen der Drehachse in einer Vorwärtsrichtung in einem konstanten Geschwindigkeitsbereich, während der Motor in einem Vorwärtsantriebsmuster angetrieben wird, das den konstanten Geschwindigkeitsbereich beinhaltet, in dem sich die Drehachse mit konstanter Geschwindigkeit in Vorwärtsrichtung dreht;

    Erhalten von Rückwärtsdrehungs-Steuerungsinformationen durch Abtasten der Steuerungssignale während einer oder mehrerer Umdrehungen der Drehachse in einer Rückwärtsrichtung in einem konstanten Geschwindigkeitsbereich, während der Motor in einem Rückwärtsantriebsmuster angetrieben wird, das den Bereich mit konstanter Geschwindigkeit beinhaltet, in dem sich die Drehachse mit konstanter Geschwindigkeit in der Rückwärtsrichtung dreht; und

    Erzeugen der Korrekturdaten unter Verwendung der Vorwärtsdrehungs-Steuerungsinformationen und der Rückwärtsdrehungs-Steuerungsinformationen.


     
    2. Das Verfahren zur Erzeugung von Korrekturdaten nach Anspruch 1, wobei:
    das Abtasten während der Vorwärtsdrehung und das Abtasten während der Rückwärtsdrehung jeweils N mal durchgeführt werden, wobei N eine natürliche Zahl nicht kleiner als 2 ist.
     
    3. Das Verfahren zur Erzeugung von Korrekturdaten nach Anspruch 2, wobei:
    ein Paar von Abtastoperationen, bei denen das Abtasten während der Vorwärtsdrehung und das Abtasten während der Rückwärtsdrehung jeweils einmal durchgeführt werden, N mal wiederholt werden.
     
    4. Das Verfahren zur Erzeugung von Korrekturdaten nach Anspruch 3, wobei:
    die Korrekturdaten bestimmt werden, nachdem das Paar von Abtastoperationen besagte N mal wiederholt wurde.
     
    5. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 1 bis 4, wobei:

    das Steuersignal ein Signal ist, das sich auf einen Strom bezieht, der dem Motor zugeführt wird; und wobei

    die Vorwärtsdrehungs-Steuerungsinformationen und die Rückwärtsdrehungs-Steuerungsinformationen Strom-Steuerwerte (current command values) bei jedem Drehwinkel der Drehachse sind.


     
    6. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 1 bis 5, wobei:

    das Steuersignal ein Signal ist, das sich auf einen Strom bezieht, der dem Motor zugeführt wird; und wobei

    die Vorwärtsdrehungs-Steuerungsinformationen und die Rückwärtsdrehungs-Steuerungsinformationen Stromerfassungssignale des Motors bei jedem Drehwinkel der Drehachse sind.


     
    7. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 1 bis 6, wobei:
    das Abtasten der Steuerungssignale erfolgt bei jedem Drehwinkel der Drehachse.
     
    8. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 1 bis 7, das Folgendes umfasst:

    einen ersten Schritt zum Erhalten von Phasenabgleichsinformationen; und

    einen zweiten Schritt zum Berechnen der Korrekturdaten aus den Phasenabgleichsinformationen, wobei

    der erste Schritt Folgendes beinhaltet:

    Hin- und Hergehendes Antreiben des Motors durch Rückführung des Positionserfassungssignals ohne Korrektur des Positionserfassungssignals mit den Korrekturdaten;

    Erhalten einer Vorwärtsdrehungs-Stromwelligkeit durch Entfernen einer Gleichstromkomponente aus den Vorwärtsdrehungs-Steuerungsinformationen;

    Erhalten einer Rückwärtsdrehungs-Stromwelligkeit durch Entfernen einer Gleichstromkomponente aus den Rückwärtsdrehungs-Steuerungsinformationen; und

    Erhalten, als Phasenabgleichsinformation, einer durchschnittlichen Stromwelligkeit bei jedem Drehwinkel der Drehachse durch Mittelung der Vorwärtsdrehungs-Stromwelligkeit und der Rückwärtsdrehungs-Stromwelligkeit bei jedem Drehwinkel.


     
    9. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 1 bis 8, das Folgendes umfasst:

    einen ersten Schritt zum Erhalten von Phasenabgleichsinformationen; und

    einen zweiten Schritt zum Berechnen der Korrekturdaten aus den Phasenabgleichsinformationen, wobei

    der erste Schritt Folgendes beinhaltet:

    Hin- und Hergehendes Antreiben des Motors durch Rückführung des Positionserfassungssignals ohne Korrektur des Positionserfassungssignals mit den Korrekturdaten; und

    Erhalten, als Phasenabgleichsinformation, einer durchschnittlichen Stromwelligkeit bei jedem Drehwinkel der Drehachse durch Mittelung der während des Vorwärtsantriebs erhaltenen Vorwärtsdrehungs-Steuerungsinformationen und der während des Rückwärtsantriebs erhaltenen Rückwärtsdrehungs-Steuerungsinformationen bei jedem Drehwinkel.


     
    10. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche 8 oder 9, wobei im zweiten Schritt:
    die Korrekturdaten berechnet werden basierend auf durch Ähnlichkeitsverhältnis abgeglichene Daten bei jedem Drehwinkel, die durch Multiplizieren der Phasenabgleichsinformationen mit einem Ähnlichkeitsverhältnis erhalten werden.
     
    11. Das Verfahren zur Erzeugung von Korrekturdaten nach Anspruch 10, wobei:

    eine Vielzahl von Ähnlichkeitsverhältnis-Kandidatenwerten, die sich voneinander unterscheiden, als Kandidaten für das Ähnlichkeitsverhältnis vorbereitet werden;

    für jeden Ähnlichkeitsverhältnis-Kandidatenwert: der Motor hin- und hergehend angetrieben wird, indem ein korrigiertes Positionssignal rückgeführt wird, das durch Korrektur des Positionserfassungssignals erhalten wird, basierend auf Daten, die durch Multiplikation der Phasenabgleichsinformationen mit dem Ähnlichkeitsverhältnis-Kandidatenwert erhalten werden, eine Vorwärtsdrehungs-Stromwelligkeit berechnet wird, indem eine Gleichstromkomponente aus den während des Vorwärtsantriebs erhaltenen Vorwärtsdrehungs-Steuerungsinformationen entfernt wird, eine Rückwärtsdrehungs-Stromwelligkeit berechnet wird, indem eine Gleichstromkomponente aus den während des Rückwärtsantriebs erhaltenen Rückwärtsdrehungs-Steuerungsinformationen entfernt wird, und eine Differenz zwischen einem Maximalwert und einem Minimalwert aus den durchschnittlichen Stromwelligkeiten bei den jeweiligen Drehwinkeln der Drehachse, die durch Mittelung der Vorwärtsdrehungs-Stromwelligkeiten und der Rückwärtsdrehungs-Stromwelligkeiten bei jedem Drehwinkel erhalten werden, als eine aktuelle Welligkeitsamplitude berechnet wird; und wobei

    der Ähnlichkeitsverhältnis-Kandidatenwert, bei dem die aktuelle Welligkeitsamplitude einen Minimalwert aufweist, aus der Vielzahl der Ähnlichkeitsverhältnis-Kandidatenwerte als Ähnlichkeitsverhältnis gesetzt wird.


     
    12. Das Verfahren zur Erzeugung von Korrekturdaten nach Anspruch 10 oder 11, wobei:

    vielzählige sich voneinander unterscheidende Ähnlichkeitsverhältnis-Kandidatenwerte als Kandidatenwerte für das Ähnlichkeitsverhältnis vorbereitet werden;

    für jeden Ähnlichkeitsverhältnis-Kandidatenwert: der Motor hin- und hergehend angetrieben wird durch Rückführung eines korrigierten Positionssignals, das durch Korrektur des Positionserfassungssignals erhalten wird, basierend auf Daten, die durch Multiplikation der Phasenabgleichsinformationen mit dem Ähnlichkeitsverhältnis-Kandidatenwert erhalten werden, und eine Differenz zwischen einem Maximalwert und einem Minimalwert aus den durchschnittlichen Stromwelligkeiten bei den jeweiligen Drehwinkeln der Drehachse, die durch Mittelung der während des Vorwärtsantriebs erhaltenen Vorwärtsdrehungs-Steuerungsinformationen und der während des Rückwärtsantriebs erhaltenen Rückwärtsdrehungs-Steuerungsinformationen bei jedem Drehwinkel als Stromwelligkeits-Amplitude berechnet wird; und wobei

    der Ähnlichkeitsverhältnis-Kandidatenwert, bei dem die Stromwelligkeits-Amplitude einen Minimalwert aufweist, aus der Vielzahl der Ähnlichkeitsverhältnis-Kandidatenwerte als Ähnlichkeitsverhältnis gesetzt wird.


     
    13. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 10 bis 12, wobei im zweiten Schritt:

    durch Ähnlichkeitsverhältnis abgeglichene Daten bei einem Drehwinkel von null aus denjenigen bei den jeweiligen Drehwinkeln der Drehachse als Offsetdaten gesetzt werden; und wobei

    durch Offset abgeglichene Daten, die durch Subtraktion der Offsetdaten von den durch Ähnlichkeitsverhältnis abgeglichenen Daten bei jedem Drehwinkel erhalten werden, als Korrekturdaten gesetzt werden.


     
    14. Das Verfahren zur Erzeugung von Korrekturdaten nach irgendeinem der Ansprüche von 8 bis 13, wobei:

    der Motor im zweiten Schritt im Vorwärtsantriebsmuster und im Rückwärtsantriebsmuster angetrieben wird; und wobei

    Absolutwerte der konstanten Geschwindigkeit im ersten Schritt größer sind als die im zweiten Schritt.


     
    15. Eine Motorsteuervorrichtung (1), die ein Positionserfassungssignal erzeugt, das sich auf eine Drehposition einer Drehwelle eines Motors (M) bezieht, der sich als Reaktion auf ein Steuersignal dreht, basierend auf einem Signal, das von einem Sensor gemäß einem Drehwinkel der Drehwelle ausgegeben wird, und die den Motor (M) steuert, indem sie ein korrigiertes Positionssignal zurückführt, das durch Korrigieren des Positionserfassungssignals mit den Korrekturdaten erhalten wird, wobei die Vorrichtung Folgendes umfasst:

    einen Motorantrieb (2), der den Motor (M) antreibt; und

    einen Korrekturdaten-Generator (3), der die Korrekturdaten erzeugt, dadurch gekennzeichnet, dass,

    beim Erzeugen der Korrekturdaten:

    der Motorantrieb Folgendes durchführt: einen Vorwärtsantrieb zum Antreiben des Motors (M) in einem Vorwärtsantriebsmuster mit einem Bereich konstanter Geschwindigkeit, in dem sich die Drehachse mit konstanter Geschwindigkeit in einer Vorwärtsrichtung dreht, und einen Rückwärtsantrieb zum Antreiben des Motors (M) in einem Rückwärtsantriebsmuster mit einem Bereich konstanter Geschwindigkeit, in dem sich die Drehachse mit konstanter Geschwindigkeit in einer Rückwärtsrichtung dreht; und dass

    der Korrekturdaten-Generator Folgendes erhält: Vorwärtsdrehungs-Steuerungsinformationen durch Abtasten der Steuerungssignale während einer oder mehrerer Umdrehungen der Drehachse in Vorwärtsrichtung im Bereich konstanter Geschwindigkeit während des Vorwärtstriebs, und Rückwärtsdrehungs-Steuerungsinformationen durch Abtasten der Steuerungssignale während einer oder mehrerer Umdrehungen der Drehachse in Rückwärtsrichtung im Bereich konstanter Geschwindigkeit während des Rückwärtstriebs, und die Korrekturdaten unter Verwendung der Vorwärtsdrehungs-Steuerungsinformationen und der Rückwärtsdrehungs-Steuerungsinformationen erzeugt.


     


    Revendications

    1. Un procédé de génération de données de correction pour générer des données de correction dans un dispositif de commande de moteur qui génère un signal de détection de position relatif à une position de rotation d'un arbre rotatif d'un moteur sur la base d'un signal délivré par un capteur selon un angle de rotation de l'arbre rotatif du moteur qui tourne en réponse à un signal de commande, et qui commande le moteur en renvoyant un signal de correction de position obtenu par correction du signal de détection de position avec les données de correction, le procédé étant caractérisé par le fait de :

    obtenir des informations de commande de rotation dans le sens avant en échantillonnant les signaux de commande pendant une ou plusieurs rotations de l'arbre rotatif dans une direction avant dans une région de vitesse constante alors que le moteur est entraîné dans une configuration d'entraînement dans le sens avant comprenant la région de vitesse constante où l'arbre rotatif tourne dans le sens avant à une vitesse constante ;

    obtenir des informations de commande de rotation dans le sens inverse en échantillonnant les signaux de commande pendant une ou plusieurs rotations de l'arbre rotatif dans un sens inverse dans une région de vitesse constante alors que le moteur est entraîné dans une configuration d'entraînement dans le sens inverse comprenant la région de vitesse constante où l'arbre rotatif tourne dans le sens inverse à la vitesse constante ; et de

    générer les données de correction en utilisant l'information de commande de rotation dans le sens avant et l'information de commande de rotation dans le sens inverse.


     
    2. Le procédé de génération de données de correction d'après la revendication 1, sachant que :
    l'échantillonnage pendant la rotation dans le sens avant et l'échantillonnage pendant la rotation dans le sens inverse sont tous deux effectués N fois, où N est un nombre naturel non inférieur à 2.
     
    3. Le procédé de génération de données de correction d'après la revendication 2, sachant que :
    une paire d'opérations d'échantillonnage, dans lesquelles l'échantillonnage pendant la rotation dans le sens avant et l'échantillonnage pendant la rotation dans le sens inverse sont respectivement effectués une fois, sont répétés lesdites N fois.
     
    4. Le procédé de génération de données de correction d'après la revendication 3, sachant que :
    les données de correction sont déterminées après que la paire d'opérations d'échantillonnage a été répétée lesdites N fois.
     
    5. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 1 à 4, sachant que :

    le signal de commande est un signal relatif à un courant donné au moteur ; et que

    l'information de commande de rotation dans le sens avant et l'information de commande de rotation dans le sens inverse sont des valeurs de commande de courant pour chaque angle de rotation de l'arbre rotatif.


     
    6. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 1 à 5, sachant que :

    le signal de commande est un signal relatif à un courant donné au moteur ; et que

    l'information de commande de rotation dans le sens avant et l'information de commande de rotation dans le sens inverse sont des signaux de détection de courant du moteur à chaque angle de rotation de l'arbre rotatif.


     
    7. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 1 à 6, sachant que :
    l'échantillonnage des signaux de commande est effectué à chaque angle de rotation de l'arbre rotatif.
     
    8. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 1 à 7, comprenant :

    une première étape consistant à obtenir de l'information sur l'accord de phase (phase matching information) ; et

    une deuxième étape consistant à calculer les données de correction à partir des informations sur l'accord de phase, sachant que

    la première étape comprend le fait de :

    entraîner le moteur en va-et-vient en renvoyant le signal de détection de position sans corriger le signal de détection de position avec les données de correction ;

    obtenir une ondulation du courant de rotation dans le sens avant en supprimant une composante de courant continu de l'information de commande de rotation dans le sens avant ;

    obtenir une ondulation du courant de rotation dans le sens inverse en supprimant une composante de courant continu de l'information de la commande de rotation dans le sens inverse ; et de

    obtenir, comme information sur l'accord de phase, une ondulation moyenne de courant à chaque angle de rotation de l'arbre rotatif obtenue en faisant la moyenne de l'ondulation du courant de rotation dans le sens avant et de l'ondulation du courant de rotation dans le sens inverse à chaque angle de rotation.


     
    9. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 1 à 8, comprenant :

    une première étape consistant à obtenir de l'information sur l'accord de phase ; et

    une deuxième étape consistant à calculer les données de correction à partir des informations sur l'accord de phase, sachant que

    la première étape comprend le fait de :

    entraîner le moteur en va-et-vient en renvoyant le signal de détection de position sans corriger le signal de détection de position avec les données de correction ; et de

    obtenir, en tant qu'information sur l'accord de phase, une ondulation moyenne de courant à chaque angle de rotation de l'arbre rotatif obtenue en faisant la moyenne de l'information de commande de rotation dans le sens avant obtenue pendant l'entraînement dans le sens avant et de l'information de commande de rotation dans le sens inverse obtenue pendant l'entraînement dans le sens inverse à chaque angle de rotation.


     
    10. Le procédé de génération de données de correction d'après la revendication 8 ou 9, sachant que, dans la deuxième étape :
    les données de correction sont calculées sur la base de données d'accord sur le rapport de similarité à chaque angle de rotation, obtenues en multipliant l'information sur l'accord de phase par un rapport de similarité.
     
    11. Le procédé de génération de données de correction d'après la revendication 10, sachant que :

    plusieurs valeurs candidates de rapport de similarité différentes les unes des autres sont préparées comme candidats pour le rapport de similarité ;

    pour chaque valeur candidate de rapport de similarité, le moteur est entraîné en va-et-vient en renvoyant un signal de position corrigé obtenu en corrigeant le signal de détection de position sur la base des données obtenues en multipliant l'information accordé en phase par la valeur candidate de rapport de similarité, une ondulation de courant de rotation dans le sens avant est calculée en retirant une composante de courant continu de l'information de commande de rotation dans le sens avant obtenue pendant la rotation dans le sens avant, une ondulation de courant de rotation dans le sens inverse est calculée en retirant une composante de courant continu de l'information de commande de rotation dans le sens inverse obtenue pendant l'entraînement dans le sens inverse, et qu'une différence entre une valeur maximale et une valeur minimale parmi les ondulations de courant moyen aux angles de rotation respectifs de l'arbre rotatif obtenues en calculant la moyenne des ondulations de courant de rotation dans le sens avant et des ondulations de courant de rotation dans le sens inverse à chaque angle de rotation, est calculée comme une amplitude d'ondulation de courant ; et que

    la valeur candidate de rapport de similarité, à laquelle l'amplitude d'ondulation de courant présente une valeur minimale, parmi la pluralité de valeurs candidates de rapport de similarité est établie comme le rapport de similarité.


     
    12. Le procédé de génération de données de correction d'après la revendication 10 ou 11, sachant que :

    une pluralité de valeurs candidates de rapport de similarité différentes les unes des autres sont préparées comme candidats pour le rapport de similarité ;

    pour chaque valeur candidate de rapport de similarité, le moteur est entraîné en va-et-vient en renvoyant un signal de position corrigé obtenu en corrigeant le signal de détection de position sur la base des données obtenues en multipliant l'information accordée en phase par la valeur candidate de rapport de similarité, et qu'une différence entre une valeur maximale et une valeur minimale parmi les ondulations de courant moyennes au niveau des angles de rotation respectifs de l'arbre rotatif obtenues en calculant la valeur moyenne des informations de commande en rotation dans le sens avant obtenues pendant l'entraînement dans le sens avant et des informations de commande de rotation dans le sens inverse obtenues pendant l'entraînement dans le sens inverse au niveau de chacun des angles de rotation est calculée comme une amplitude d'ondulation de courant ; et que

    la valeur candidate de rapport de similarité, à laquelle l'amplitude d'ondulation de courant présente une valeur minimale, parmi la pluralité de valeurs candidates de rapport de similarité est établie comme le rapport de similarité.


     
    13. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 10 à 12, sachant que, dans la deuxième étape :

    des données accordées en rapport de similarité à un angle de rotation zéro parmi celles à des angles de rotation respectifs de l'arbre rotatif sont définies comme données de décalage (offset data) ; et que

    des données accordées en décalage obtenues en soustrayant les données de décalage des données accordées en rapport de similarité à chaque angle de rotation sont définies comme données de correction.


     
    14. Le procédé de génération de données de correction d'après l'une quelconque des revendications de 8 à 13, sachant que :

    le moteur est entraîné selon le modèle d'entraînement dans le sens avant et le modèle d'entraînement dans le sens inverse dans la deuxième étape ; et que

    les valeurs absolues de la vitesse constante dans la première étape sont supérieures à celles de la deuxième étape.


     
    15. Un dispositif de commande de moteur (1) générant un signal de détection de position relatif à une position de rotation d'un arbre rotatif d'un moteur (M), qui tourne en réponse à un signal de commande, sur la base d'un signal émis par un capteur conformément à un angle de rotation de l'arbre rotatif, et commandant le moteur (M) en renvoyant un signal de position corrigé obtenu par correction du signal de détection de position avec les données de correction, le dispositif comprenant :

    un entraînement de moteur (2) entraînant le moteur (M) ; et

    un générateur de données de correction (3) générant les données de correction, caractérisé en ce que,

    en générant les données de correction :

    l'entraînement de moteur effectue un entraînement dans le sens avant pour entraîner le moteur (M) dans une configuration d'entraînement dans le sens avant incluant une région de vitesse constante où l'arbre rotatif tourne dans une direction avant à une vitesse constante et un entraînement dans le sens inverse pour entraîner le moteur (M) dans une configuration d'entraînement dans le sens inverse incluant une région de vitesse constante où l'arbre rotatif tourne dans une direction inverse à la vitesse constante ; et que

    le générateur de données de correction obtient des informations de commande de rotation dans le sens avant en échantillonnant les signaux de commande pendant une ou plusieurs rotations de l'arbre rotatif dans la direction avant dans la région de vitesse constante pendant l'entraînement dans le sens avant, qu'il obtient des informations de commande de rotation dans le sens inverse en échantillonnant les signaux de commande pendant une ou plusieurs rotations de l'arbre rotatif dans la direction inverse dans la région de vitesse constante pendant l'entraînement dans le sens inverse, et qu'il génère les données de correction en utilisant les informations de commande dans le sens avant et les informations de commande dans le sens inverse.


     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description