DOOR PINCH DETECTION DEVICE, RAILWAY DOOR DEVICE AND PROGRAM

Abstract

 A door pinch detection device (1), for detecting door pinch when a door (3R, 3L) is driven in a closing direction by a driving force from a motor (11), includes a first obtaining unit (31) for obtaining a first current value indicating current flowing through the motor (11) in a first period while the door (3R, 3L) is closed, a threshold setting unit (32) for, based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred, a second obtaining unit (33) for obtaining a second current value indicating current flowing through the motor (11) in a second period following the first period while the door (3R, 3L) is closed, and a determining unit (34) for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

Description

TECHNICAL FIELD

[0001] Embodiments of the present invention relate to a door pinch detection device, a railway door device, and a program.

BACKGROUND

[0002] Electric door devices include door pinch detection devices for detecting whether persons or objects touch the leading edge of the door leaves. Conventional door pinch detection devices are classified into two types, one of which is configured to consult the moving speed of the door leaves to detect door pinch, and the other is configured to refer to the current flowing through the motor (hereinafter, referred to as the motor current) for generating a driving force intended for moving the door leaves in order to detect door pinch.

[0003] In a case where the moving speed of the door leaves is referred to in order to detect door pinch, the conventional door pinch detection devices determine that door pinch has occurred if the moving speed of the door leaves becomes zero. In another case where the motor current is referred to in order to detect door pinch, the conventional door pinch detection devices determine that door pinch has occurred if the motor current exceeds a predetermined threshold value. This is because the motor current suddenly increases following the occurrence of door pinch.

[0004] The leading edge of the door leaf has a rubber material attached thereto in order to mitigate the impact on the persons and objects. Accordingly, if persons or objects touch the rubber material, the moving speed of the door leaf does not instantly reach zero and, instead, the door leaf moves at a low speed as long as the rubber material can contract. Similarly, when left and right door leaves are fully closed, the door leaves keep moving at a low speed for a while after the rubber materials of the door leaves touch each other. For the above reasons, whether door pinch has occurred may not be accurately determined only based on the moving speed of the door.

[0005] The motor current, on the other hand, may be also subject to change for various factors. The motor current may be compared against a threshold value in an attempt to detect door pinch. If the motor current significantly changes, however, it cannot be accurately detected whether door pinch has occurred. For example, the motor current may depend on the sliding friction of the door leaves and the driving force produced by the motor, but the sliding friction of the door leaves and the driving force produced by the motor do not necessarily remain unchanged but may change over time. Accordingly, if the motor current is referred to in order to detect door pinch, it should be noted that the motor current may change due to aging deterioration.

[0006] To address the above problems, embodiments of the present invention are designed to provide a door pinch detection device, a railway door device, and a program capable of detecting whether door pinch has occurred in a simple and accurate manner.

SUMMARY

[0007] To solve the above problems, one embodiment of the present invention provides a door pinch detection device for detecting door pinch when a door is driven in a closing direction by a driving force from a motor. The door pinch detection device includes a first obtaining unit for obtaining a first current value indicating current flowing through the motor in a first period while the door is closed, a threshold setting unit for, based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred, a second obtaining unit for obtaining a second current value indicating current flowing through the motor in a second period following the first period while the door is closed, and a determining unit for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

[0008] The first period may include a period in which the door moves at constant speed after the door starts moving in the closing direction.

[0009] The first period may be included in a period in which a moving speed of the door is increasing after the door starts moving in the closing direction, or in a period in which the moving speed remains constant after increasing.

[0010] The threshold setting unit may set the threshold value based on at least one selected from the group consisting of an average value, a median value, a most frequent value, and an integrated value of values indicating the current flowing through the motor in the first period.

[0011] The door pinch detection device may include a storage unit for storing association between (i) at least one measured value of an average value, a median value, a most frequent value, or an integrated value of values indicating the current flowing through the motor when no door pinch occurs while the door is driven in a closing direction and (ii) a reference threshold value determined by the measured value. The threshold setting unit may set the threshold value based on (i) the association stored in the storage unit and (ii) at least one selected from the group consisting of an average value, a median value, a most frequent value, and an integrated value of values indicating the current flowing through the motor in the first period.

[0012] The threshold setting unit may set the threshold value based on voltage used to drive the motor in the first period.

[0013] The door pinch detection device may include a period specifying unit for specifying the first and second periods based on at least one selected from the group consisting of a speed, a distance and a duration of the movement made by the door while the door is closed.

[0014] The first obtaining unit may obtain the first current value in the first period every time the door is moved in the closing direction from a fully open position, and the threshold setting unit may set a new threshold value every time the door is moved in the closing direction from the fully open position, based on the first current value obtained by the first obtaining unit.

[0015] The first obtaining unit may obtain the first current value in the first period when the door is driven in the closing direction immediately following power-on of the door, and the threshold setting unit may set the threshold value based on the first current value obtained by the first obtaining unit when the door is moved in the closing direction immediately following the power-on of the door.

[0016] The determining unit may determine that the door pinch has occurred in at least one of (i) a case where the door pinch is determined to have occurred based on the current flowing through the motor in the second period or (ii) a case where the door pinch is determined to have occurred based on a speed of the door.

[0017] Another aspect of the present invention provides a door pinch detection device for detecting door pinch when a door is driven in a closing direction by a driving force from a motor. The door pinch detection device includes a storage unit for storing a first current value indicating current flowing through the motor when the door is closed previously, a threshold setting unit for setting a threshold value based on the first current value stored in the storage unit, an obtaining unit for obtaining a second current value indicating current flowing through the motor when the door is closed, and a determining unit for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

[0018] Another aspect of the present invention provides a railway door device including a door provided in a railway vehicle, a motor for opening or closing the door, a door opening-closing control unit for controlling the motor, and a door pinch detecting unit for detecting door pinch when the door is driven by a driving force from the motor in a closing direction. The door pinch detecting unit includes a first obtaining unit for obtaining a first current value indicating current flowing through the motor in a first period while the door is closed, a threshold setting unit for, based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred, a second obtaining unit for obtaining a second current value indicating current flowing through the motor in a second period following the first period while the door is closed, and a determining unit for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

[0019] Yet another aspect of the present invention provides a program for causing a computer to detect door pinch when a door is driven in a closing direction by a driving force from a motor. The program causes the computer to execute procedures of obtaining a first current value indicating current flowing through the motor in a first period while the door is closed, based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred, obtaining a second current value indicating current flowing through the motor in a second period following the first period while the door is closed, and determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

[0020] If the door restarts moving in the closing direction after the door pinch is determined to have occurred, the first current value may be prevented from being obtained again and the threshold value is prevented from being set again until the door moves to the fully closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 

Fig. 1 is an external view showing an electric door device having a door pinch detection device relating to a first embodiment built therein.

Fig. 2 more specifically shows constituent components in the vicinity of a motor.

Fig. 3 is a block diagram schematically showing the configuration of a control system of the electric door device of Fig. 1.

Fig. 4 is a graph showing how a stroke amount, a moving speed and motor current change.

Fig. 5 is a block diagram showing the configuration of a door pinch detection device relating to the embodiment.

Fig. 6 is a flow chart showing the series of steps in the procedure performed by the door pinch detection device relating to the embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The following describes embodiments or a door pinch detection device, a railway door device, and a program with reference to the attached drawings. The following description focuses on the main constituent parts of the door pinch detection device, railway door device and program, and the door pinch detection device, railway door device and program may include more constituent parts and functions not shown or described. The following description by no means excludes such constituent parts and functions not shown or described.

<First Embodiment

[0023] Fig. 1 is an external view showing an electric door device 2 having a door pinch detection device 1 relating to a first embodiment built therein. The electric door device 2 shown in Fig. 1 is designed to be installed in railway vehicles. The electric door device 2 according to the present embodiment can be used in a wide range of applications in addition to railway vehicles. For example, the electric door device 2 relating to the present embodiment is applicable to automatic door devices installed in vehicles, buildings, and facilities, and also to doors of private residences. The electric door device 2 described herein is installed mainly in railway vehicles.

[0024] The electric door device 2 shown in Fig. 1 includes a pair of door leaves 3R and 3L constituting a sliding door. The door leaves 3R and 3L are movable in the left-right direction in the drawing. Above the door leaves 3R and 3L, a guide rail 4, a suspension device 5R supporting the right door leaf 3R and a suspension device 5L supporting the left door leaf 3L are provided.

[0025] The suspension device 5R and door leaf 3R are integrally movable along the guide rail 4. Likewise, the suspension device 5L and door leaf 3L are integrally movable along the guide rail 4. At least one of the door leaf 3R or the door leaf 3L may be herein simply referred to as a door.

[0026] In the suspension devices 5R and 5L, a plurality of rollers 6 are provided, as shown by the dotted lines in Fig. 1. The rollers 6 roll while remaining in contact with the upper or lower surface of the guide rail 4.

[0027] The leading edge of the door leaves 3R and 3L has a rubber material 7 attached thereto, which is made of a soft synthetic rubber material. When the door leaves 3R and 3L are fully closed, their respective rubber materials 7 touch each other and contract to a certain extent while touching each other. After this, the door leaves 3R and 3L stop moving.

[0028] Above the guide rail 4, a right rack gear 8R and a left rack gear 8L are provided and extend in the direction in which the guide rail 4 extends. The right rack gear 8R is coupled with a right bracket 9R. As the right rack gear 8R moves in the left-right direction, the movement causes the right bracket 9R to move in the left-right direction. Similarly, the left rack gear 8L is coupled with a left bracket 9L. As the left rack gear 8L moves in the left-right direction, the movement causes the left bracket 9L to move in the left-right direction. The right bracket 9R is coupled with the suspension device 5R. As the right bracket 9R moves in the left-right direction, the suspension device 5R and door leaf 3R integrally move in the left-right direction. Similarly, the left bracket 9L is coupled with the suspension device 5L. As the left bracket 9L moves in the left-right direction, the suspension device 5L and door leaf 3L integrally move in the left-right direction.

[0029] The right and left rack gears 8R and 8L mesh with a pinion gear 10, so that they are configured to convert the rotation of the pinion gear 10 into linear movement. The pinion gear 10 is rotated when acted upon by a driving force from a motor 11.

[0030] Fig. 2 more specifically shows the constituent parts in the vicinity of the motor 11. The motor 11 has a rotational shaft 12, to which a sun gear 13 is attached, a plurality of planetary gears 14 surround and mesh with the sun gear 13, and the pinion gear 10 serves as an outer gear that is positioned outside the planetary gears 14 and meshes with the planetary gears 14.

[0031] With the above-described configuration, as the motor 11 rotates, the resulting rotational force is transmitted to the rack gears 8R and 8L via the pinion gear 10. As the rack gears 8R and 8L move in the left-right direction as a result of the rotation of the motor 11, the door leaves 3R and 3L move in the left-right direction along the guide rail 4 via the right and left brackets 9R and 9L. The motor 11 is controlled by a controller 15 shown in Fig. 3, which will be described below.

[0032] In the above description, the electric door device 2 may be opened or closed using the rack and pinion system, but the present disclosure is not necessarily limited to such. Any other systems (for example, belt, screw, and linear motor systems) may be employed.

[0033] Fig. 3 is a block diagram schematically showing the configuration of a control system of the electric door device 2 of Fig. 1. The control system of the electric door device 2 relating to the present embodiment includes a controller 15 having the door pinch detection device 1 built therein, a power supply unit 16 and a motor monitoring unit 17.

[0034] The power supply unit 16 includes a power unit for converting an alternating-current voltage fed from an overhead line to a direct-current voltage. The controller 15 includes a door opening-closing control unit 18 and an instructing unit 19. The instructing unit 19 outputs, to the door opening-closing control unit 18, an instruction signal for opening or closing the door leaves 3R and 3L. The door opening-closing control unit 18 controls the opening or closing of the door leaves 3R and 3L based on the instruction signal.

[0035] The door opening-closing control unit 18 includes a power-supply voltage detecting unit 21, a PWM control unit 22, a motor driving unit 23 and a Hall signal detector 24.

[0036] The power-supply voltage detecting unit 21 is configured to detect the level of the DC voltage output from the power supply unit 16. The PWM control unit 22 is configured to generate a PWM signal for driving the motor 11 based on the level of the DC voltage detected by the power-supply voltage detecting unit 21 and the instruction signal from the instructing unit 19. More specifically, the PWM control unit 22 generates the PWM signal for controlling the duty ratio of the voltage to be fed to the motor 11, based on a reference voltage instruction pattern indicated by the instruction signal and the voltage level of the DC signal detected by the power-supply voltage detecting unit 21.

[0037] The motor driving unit 23 is configured to turn on or off the transistors configured to drive the motor 11, based on the PWM signal. For example, when the motor 11 is a three-phase motor, the motor driving unit 23 generates gate signals for turning on or off the U-phase, V-phase and W-phase transistors.

[0038] A Hall element 25 is provided in the vicinity of the rotational shaft 12 of the motor 11. The Hall element 25 detects the number of rotations of the motor 11. In the vicinity of the motor 11, the motor monitoring unit 17 is provided. The motor monitoring unit 17 includes, in addition to the above-mentioned Hall element 25, a motor current detector 26 for detecting the motor current and a motor voltage detector 27 for detecting the voltage applied to the motor 11.

[0039] The Hall signal detector 24 is configured to detect the number of rotations of the motor 11 based on the detection signal from the Hall element 25. The motor driving unit 23 can refer to the number of rotations of the motor 11 detected by the Hall signal detector 24 to feedback control the timing of turning on or off the transistors for driving the motor 11.

[0040] The door pinch detection device 1 is configured to detect occurrence of door pinch between the leading edges of the door leaves 3R and 3L when the driving force from the motor 11 drives the door leaves 3R and 3L in the closing direction.

[0041] The electrical door device 2 relating to the present embodiment may include a sending unit 28. The sending unit 28 is configured to, if the door pinch detection device 1 detects that door pinch has occurred, notify a managing device, a mobile terminal owned by a maintenance worker or the like (not shown) of the fact that door pinch has occurred.

[0042] Fig. 4 is a graph showing how the stroke amount w1, moving speed w2, and motor current w3a, w3b, w3c of the door leaves 3R and 3L change while the door leaves 3R and 3L move from the fully open position to the fully closed position. In Fig. 4, the horizontal axis represents the position of the leading edge of the door leaves 3R and 3L, and the vertical axis represents the stroke amount by the waveform w1, the moving speed by the waveform w2 and the motor current by the waveforms w3a, w3b and w3c. The stroke amount indicates the distance by which the door leaves 3R and 3L have moved. The motor current changes in the manner indicated by the waveforms w3a, w3b and w3c when the sliding friction of the door leaves 3R and 3L exhibits a first friction value, second friction value and a third friction value, respectively.

[0043] As indicated by the waveform w2, the moving speed of the door leaves 3R and 3L is increasing immediately after the door leaves 3R and 3L start moving, in other words, rises linearly as the time elapses. Once the moving speed reaches a certain level, the moving speed of the door leaves 3R and 3L remains constant at the level for a predetermined period of time. The moving speed then decreases as the time elapses. While decreasing, the moving speed drops in a stepwise manner. As the moving speed changes, the stroke amount of the door leaves 3R and 3L changes to draw a non-linear line or curved line, as indicated by the waveform w1.

[0044] The waveforms w3a, w3b, w3c shown in Fig. 4 show how the motor current changes when the electric door device 2 is closed with the sliding friction exhibiting different values. The sliding friction depends on the cant at railway stations and the level of passenger crowdedness.

[0045] The motor current significantly changes as influenced by external disturbances immediately after the door leaves 3R and 3L start moving in the closing direction from the fully open position. After this, the motor current decreases in a stepwise manner. Once the moving speed of the door leaves 3R and 3L start decreasing, the motor current changes drastically temporarily and then decreases in a stepwise manner. Once the door leaves 3R and 3L reach a position near the fully closed position, the rubber materials of the door leaves 3R and 3L touch each other, so that the motor current suddenly increases. As can be seen from the shape of the waveforms w3a, w3b and w3c, the motor current exhibits different values determined by the sliding friction but changes in the same manner. Specifically, irrespective of the sliding friction, the motor current suddenly increases immediately before the door leaves 3R and 3L are fully closed.

[0046] Although not shown in the graph of Fig. 4, the motor current increases even more if door pinch occurs when the door leaves 3R and 3L are positioned near the fully closed position. Considering this, the door pinch detection device 1 relating to the present embodiment sets a threshold value used to detect door pinch when the door leaves 3R and 3L are positioned near the fully closed position. The threshold value is set greater than the value exhibited by the motor current when no door pinch occurs. As can be seen from the waveforms w3a, w3b, w3c, however, the motor current depends on the sliding friction of the door leaves 3R and 3L. Therefore, the threshold value is set taking into consideration the sliding friction of the door leaves 3R and 3L.

[0047] Fig. 4 shows a threshold value w4a corresponding to the waveform w3a, a threshold value w4b corresponding to the waveform w3b and a threshold value w4c corresponding to the waveform w3c. The door pinch detection device 1 relating to the present embodiment determines that door pinch has occurred if the motor current observed when the door leaves 3R and 3L are positioned near the fully closed position exceeds the threshold value.

[0048] Fig. 5 is a block diagram showing the configuration of the door pinch detection device 1 relating to the present embodiment. As shown in Fig. 5, the door pinch detection device 1 includes a first obtaining unit 31, a threshold setting unit 32, a second obtaining unit 34 and a determining unit 34.

[0049] The first obtaining unit 31 is configured to obtain a first current value indicating current flowing through the motor 11 in a first period while the door leaves 3R and 3L are closed. The first period overlaps, for example, the entire period in which the moving speed of the door leaves 3R and 3L remains constant, as shown in Fig. 4, and may be herein referred to as a current collecting domain. As shown in Fig. 4, the motor current relatively stably change in the period in which the moving speed of the door leaves 3R and 3L remains constant. As being configured to obtain the motor current value in the constant speed period, the first obtaining unit 31 can obtain a motor current value less influenced by external disturbances.

[0050] The first period may alternatively overlap part of the period in which the moving speed is increasing after the door starts moving in the closing direction, or part of the period in which the moving speed remains constant after increasing. As shown in Fig. 4, the motor current significantly changes immediately after the moving speed starts increasing. For this reason, it should be avoided to obtain the motor current value immediately after the moving speed starts increasing, but the motor current changes less dramatically in the middle and final stages of the period in which the moving speed increases. Accordingly, the first period may overlap the period in which the moving speed increases. Similarly, when the moving speed starts decreasing after remaining constant, the motor current is stabilized after a while and changes less dramatically, as shown in Fig. 4. For this reason, the first period may overlap part of the period in which the moving speed of the door leaves 3R and 3L is decreasing.

[0051] The first obtaining unit 31 may obtain the first current value in the first period every time the door leaves 3R and 3L are moved from the fully open position in the closing direction. In this case, the threshold setting unit 32 may set a new threshold value every time the door leaves 3R and 3L are moved from the fully open position in the closing direction, based on the first current value obtained by the first obtaining unit 31. Since a new threshold value is set every time the door leaves 3R and 3L are closed, the threshold value can be optimally set without being influenced by aging deterioration of the electric door device 2.

[0052] The first obtaining unit 31 may obtain the first current value in the first period in a case where the door leaves 3R and 3L are driven in the closing direction immediately following the power-on of the door leaves 3R and 3L (the electric door device 2). The threshold setting unit 32 may set the threshold value based on the first current value obtained by the first obtaining unit 31 in the case where the door leaves 3R and 3L are driven in the closing direction immediately following the power-on of the door leaves 3R and 3L. In a case where the electric door device 2 is used in railways, some passengers lean on the door leaves 3R and 3L or are pushed against the door leaves 3R and 3L due to the crowded situation. This changes the sliding friction. Accordingly, with passengers on board, the motor current is likely to change as affected by the varying sliding friction. In addition, the cant, which may vary among railway stations, may also cause a change in the sliding friction of the door leaves 3R and 3L. To address this issue, the first obtaining unit 31 obtains the motor current while the motor current is still less influenced by the varying sliding friction, for example, immediately following the power-on of the door leaves 3R and 3L. In this way, the first obtaining unit 31 can obtain the motor current without being affected by the varying sliding friction.

[0053] The threshold setting unit 32 is configured to, based on the first current value obtained by the first obtaining unit 31, set a threshold value used to determine whether door pinch has occurred. The threshold value set by the threshold setting unit 32 is to be compared against the motor current when the door leaves 3R and 3L are positioned near the fully closed position. In other words, the threshold setting unit 32 uses the actual value of the motor current observed when the door leaves 3R and 3L have not reached a position close to the fully closed position to set the threshold value to be compared against the motor current observed when the door leaves 3R and 3L are positioned close to the fully closed position.

[0054] The threshold setting unit 32 is provided for the following reasons. While the electric door device 2 is in operation, the sliding friction may gradually change or the driving force produced by the motor 11 may drop. This means that the motor current is not necessarily the same even if the moving speed of the door leaves 3R and 3L is the same. To address this issue, the actually measured present value of the motor current is considered to set the threshold value for the motor current.

[0055] The threshold setting unit 32 sets the threshold value based on at least one selected from the group consisting of the average value, median value, most frequent value, and integrated value of the values indicating the current flowing through the motor 11 in the first period. The motor current depends on the sliding friction of the door leaves 3R and 3L or the driving force produced by the motor 11, and also depends on an environmental condition such as temperature and power-supply voltage. Accordingly, the threshold setting unit 32 may determine which type of value of the motor current is to be compared against the threshold value, considering that the motor current may change in the first period. For example, if the motor current does not change significantly temporarily in the first period, the average value may be calculated. On the other hand, if the motor current changes significantly temporarily in the first period, the average value may inadvertently incorporate the influence of the temporary change of the motor current. In this case, the median or most frequent value is desirable. If the motor current exhibits a small value, the integrated value may be selected.

[0056] The power-supply voltage fed to the motor 11 may change, and this may affect the motor current. The threshold setting unit 32 thus may consider the power-supply voltage detected by the voltage detector to set the threshold value. In other words, the threshold setting unit 32 may set the threshold value based on the voltage used to drive the motor 11 in the first period. As the driving voltage for the motor 11 increases, the motor current generally increases. Accordingly, the threshold setting unit 32 may desirably increase the threshold value as the driving voltage increases.

[0057] The second obtaining unit 33 is configured to obtain a second current value indicating the current flowing through the motor 11 in a second period following the first period while the door leaves 3R and 3L are closed. In the second period, the door leaves 3R and 3L are positioned close to the fully closed position and the motor current suddenly increases, for example, as shown in Fig. 4. The motor current suddenly increases when the door leaves 3R and 3L are at a certain position before the fully closed position, but the certain position differs among individual electric door devices 2. Accordingly, the second period is preferably set for each individual electric door device 2. In the second period, the door leaves 3R and 3L are at a position within a range of several dozen millimeters to several millimeters before the fully closed position, for example.

[0058] The determining unit 34 is configured to determine whether door pinch has occurred based on comparing the obtained second current value against the set threshold value. More specifically, the determining unit 34 determines that door pinch has occurred in at least one of (i) a case where door pinch is determined to have occurred based on the current flowing through the motor 11 in the second period or (ii) a case where door pinch is determined to have occurred based on the speed of the door.

[0059] The door pinch detection device 1 relating to the present embodiment may include a period specifying unit 35. The period specifying unit 35 is configured to specify the first and second periods based on at least one selected from the group consisting of a speed, a distance and a duration of the movement made by the door leaves 3R and 3L while the door leaves 3R and 3L are closed. For example, the period specifying unit 35 may specify the first and second periods based on the stroke amount of the door leaves 3R and 3L detected by a stroke detector, not shown. The stroke detector is configured to detect the stroke amount based on, for example, the number of rotations of the motor 11 detected by the Hall signal detector 24. Alternatively, the period specifying unit 35 may specify the first and second periods based on the duration of the movement made by the door leaves 3R and 3L from the fully open position. Alternatively, the period specifying unit 35 may specify the first and second periods based on the speed of the movement made by the door leaves 3R and 3L.

[0060] The door pinch detection device 1 relating to the present embodiment may include a storage unit 36. The storage unit 36 stores, in association with each other, (i) at least one measured value of the average value, median value, most frequent value and integrated value of the values indicating the current flowing through the motor 11 when the door is driven in the closing direction without causing door pinch and (ii) a reference threshold value determined by the measured value. The current flowing through the motor 11 depends on the sliding friction of the door leaves 3R and 3L. Accordingly, for example, a plurality of heavy objects having different weights are by turns attached to the suspension devices 5R and 5L, so that the sliding friction is artificially changed. In this way, the association between the motor current and the reference threshold is obtained in advance and stored in the storage unit 36. In this case, the threshold setting unit 32 sets the threshold value based on (i) at least one selected from the group consisting of the average value, median value, most frequent value, and integrated value of the values indicating the current flowing through the motor 11 in the first period and (ii) the association stored in the storage unit 36. The storage unit 36 thus can store the previous threshold values set by the threshold setting unit 32, so that the previous threshold values can be used again.

[0061] As described above, the door pinch detection device 1 relating to the present embodiment is configured to set the threshold value based on the motor current obtained in the first period after the door leaves 3R and 3L start moving in the closing direction and compare the set threshold value against the motor current in the subsequent second period. The electric door device 2, however, must bear great processing load if it is required to set a new threshold value every time the door leaves 3R and 3L are moved in the closing direction from the fully open position. Accordingly, the threshold setting unit 32 may be alternatively set a new threshold value once every n times the door leaves 3R and 3L are closed (n is an integer equal to or greater than two). In this case, the threshold value set by the threshold setting unit 32 is stored in the storage unit 36 and read out as required to be compared against the motor current. As noted, the storage unit 36 spares the burden of setting a new threshold value every time the door leaves 3R and 3L are closed, thereby reducing the processing load on the door pinch detection device 1.

[0062] Furthermore, the storage unit 36 may store the value indicative of the current flowing through the motor 11 when door pinch occurred in the past (hereinafter, referred to as "the first current value"). In this case, the threshold setting unit 32 sets the threshold value based on the first current value stored in the storage unit 36. For example, the threshold setting unit 32 may multiply the first current value with a coefficient greater than zero and less than one and use the resulting value as the threshold value. When the electric door device 2 is actually used, the second obtaining unit 33 obtains a value indicative of the current flowing through the motor 11 when the door is closed (hereinafter, referred to as "the second current value"). The determining unit 34 determines whether door pinch has occurred based on comparing the obtained second current value against the threshold value set by the threshold setting unit 32. This eliminates the need of setting a new threshold value every time the door leaves 3R and 3L are moved in the closing direction from the fully open position, thereby providing a simpler procedure of detecting door pinch.

[0063] Fig. 6 is a flow chart showing the series of steps in the procedure performed by the door pinch detection device 1 relating to the present embodiment. The series of steps shown in the flow chart of Fig. 6 starts when the door leaves 3R and 3L start moving from the fully open position in the closing direction. More specifically, the electric door device 2 starts closing the door leaves 3R and 3L, and the door pinch detection device 1 starts the procedure shown in Fig. 6, on reception of a closure instruction from a superior device to the railway vehicle.

[0064] In the first step, the first obtaining unit 31 determines whether the door leaves 3R and 3L have reached a start position of the first period (the step S1 ).Until the door leaves 3R and 3L reach the start position of the first period, the step S1 is repeatedly performed. Once the door leaves 3R and 3L reach the start position of the first period, the door pinch detection device 1 starts obtaining the motor current and obtains the motor current continuously in the first period (the step S2). The step S2 is performed by the first obtaining unit 31.

[0065] Subsequently, the door pinch detection device 1 determines whether or not the first period ends (the step S3). If the first period is determined to have ended, the first obtaining unit 31 stops obtaining the motor current (the step S4).

[0066] Following this, the threshold setting unit 32 sets the threshold value based on the motor current obtained by the first obtaining unit 31 (the step S5). For example, the threshold setting unit 32 may set the threshold value based on at least one selected from the group consisting of the average value, median value, most frequent value, and integrated value of the values indicating the motor current in the first period. For example, the threshold value may be defined as the value obtained by cumulatively adding together the values of the motor current in the first period, calculating the average value based on the result of the cumulative addition, and multiplying the average value with a predetermined coefficient. The predetermined coefficient is greater than zero and less than one and determined, for example, based on the past operational performance of the electric door device 2. Alternatively, the threshold value may be defined as the value obtained by multiplying the median value of the values indicating the motor current in the first period with a predetermined coefficient. As a further alternative example, the threshold value may be defined as the value obtained by sorting by frequency the values of the motor current in the first period, specifying the most frequent value, and multiplying the most frequent value with a predetermined coefficient. As a yet another alternative example, the threshold value may be defined as the value obtained by cumulatively adding together the values of the motor current in the first period to calculate the integrated value, and multiplying the integrated value with a predetermined coefficient. In this case, the coefficient is less than the coefficient used to calculate the threshold value based on the average value.

[0067] Subsequently, the door pinch detection device 1 determines whether the door leaves 3R and 3L have reached a start position of the second period (the step S6). Until the door leaves 3R and 3L reach the start position of the second period, the step S6 is repeatedly performed. Once the door leaves 3R and 3L reach the start position of the second period, the second obtaining unit 33 detects the motor current. The determining unit 34 compares the detected motor current against the threshold value set in the step S5 (the step S7). If the motor current is greater than the threshold value, the door pinch detection device 1 detects that door pinch has occurred (the step S8). If such is the case, the door pinch detection device 1 performs a predetermined notification procedure of notifying a managing device or maintenance worker (not shown) of the occurrence of the door pinch.

[0068] If the step S7 determines that the motor current is not greater than the threshold value, the door pinch detection device 1 determines that no door pinch has occurred and determines whether the second period has ended (the step S9). If the second period has not ended, the procedure goes back to the step S7. If the second period ends, the procedure shown in Fig. 6 ends.

[0069] As described above, the present embodiment is configured to obtain the motor current in the first period and sets the threshold value, after the door leaves 3R and 3L start moving in the closing direction. Following this, in the second period before the door leaves 3R and 3L reach the fully closed position, the door pinch detection device 1 obtains the motor current again and compares the obtained current value against the threshold value. If the motor current exceeds the threshold value, the door pinch detection device 1 determines that door pinch has occurred. According to the present embodiment, the threshold value used to detect whether door pinch has occurred is set based on the value of the motor current obtained in the first period that starts soon after the door leaves 3R and 3L start closing. The motor current may change due to aging, environmental conditions, and other factors, but the threshold value can be set based on the present value of the motor current. This allows the door pinch detection device 1 to set a threshold value such that door pinch can be accurately determined.

[0070] At least some of the constituent parts of the door pinch detection device 1 and railway door device described in the above embodiments may be implemented through hardware or software. If the software is used, at least some of the functions of the door pinch detection device 1 and railway door device are implemented by a program, and the program may be stored on a storage medium such as a flexible disc and a CD-ROM and executed when read by a computer. The storage medium is not limited to detachable ones such as magnetic and optical discs, and may be stationary storage media such as hard disk devices and memory devices.

[0071] Alternatively, at least some of the functions of the door pinch detection device 1 and railway door device may be implemented by a program, and the program may be distributed through communication lines (including wireless communication) such as the Internet. Furthermore, the program may be encrypted, modulated or compressed to be distributed through wired or wireless connections such as the Internet or in the state of being stored on storage media.

[0072] Aspects of the present invention are not limited to the foregoing embodiments and embrace various modifications conceivable to those skilled in the art. Effects of the present invention are also not limited to the above-mentioned contents. That is, various additions, changes, and partial deletions are possible in a range not departing from the conceptual ideas and spirit of the present invention derived from contents defined in the claims and equivalents thereof.

Claims

1. A door pinch detection device (1) for detecting door pinch when a door (3R, 3L) is driven in a closing direction by a driving force from a motor (11), the door pinch detection device (1) comprising:

a first obtaining unit (31) for obtaining a first current value indicating current flowing through the motor (11) in a first period while the door (3R, 3L) is closed;

a threshold setting unit (32) for, based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred;

a second obtaining unit (33) for obtaining a second current value indicating current flowing through the motor (11) in a second period following the first period while the door (3R, 3L) is closed; and

a determining unit (34) for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

2. The door pinch detection device (1) of claim 1, wherein the first period includes a period in which the door (3R, 3L) moves at constant speed after the door (3R, 3L) starts moving in the closing direction.

3. The door pinch detection device (1) of claim 2, wherein the first period is included in a period in which a moving speed of the door (3R, 3L) is increasing after the door (3R, 3L) starts moving in the closing direction, or in a period in which the moving speed remains constant after increasing.

4. The door pinch detection device (1) of any one of claims 1 to 3, wherein the threshold setting unit (32) sets the threshold value based on at least one selected from the group consisting of an average value, a median value, a most frequent value, and an integrated value of values indicating the current flowing through the motor (11) in the first period.

5. The door pinch detection device (1) of any one of claims 1 to 4, comprising

a storage unit (36) for storing association between (i) at least one measured value of an average value, a median value, a most frequent value, or an integrated value of values indicating the current flowing through the motor (11) when no door pinch occurs while the door (3R, 3L) is driven in the closing direction and (ii) a reference threshold value determined by the measured value,

wherein the threshold setting unit (32) sets the threshold value based on (I) the association stored in the storage unit (36) and (II) at least one selected from the group consisting of an average value, a median value, a most frequent value, and an integrated value of values indicating the current flowing through the motor (11) in the first period.

6. The door pinch detection device (1) of any one of claims 1 to 5, wherein the threshold setting unit (32) sets the threshold value based on voltage used to drive the motor (11) in the first period.

7. The door pinch detection device (1) of any one of claims 1 to 6, comprising
a period specifying unit (35) for specifying the first and second periods based on at least one selected from the group consisting of a speed, a distance and a duration of the movement made by the door (3R, 3L) while the door (3R, 3L) is closed.

8. The door pinch detection device (1) of any one of claims 1 to 7,

wherein the first obtaining unit (31) obtains the first current value in the first period every time the door (3R, 3L) is moved in the closing direction from a fully open position, and

wherein the threshold setting unit (32) sets a new threshold value every time the door (3R, 3L) is moved in the closing direction from the fully open position, based on the first current value obtained by the first obtaining unit (31).

9. The door pinch detection device (1) of any one of claims 1 to 7,

wherein the first obtaining unit (31) obtains the first current value in the first period when the door (3R, 3L) is driven in the closing direction immediately following power-on of the door (3R, 3L), and

wherein the threshold setting unit (32) sets the threshold value based on the first current value obtained by the first obtaining unit (31) when the door (3R, 3L) is moved in the closing direction immediately following the power-on of the door (3R, 3L).

10. The door pinch detection device (1) of any one of claims 1 to 9, wherein the determining unit (34) determines that the door pinch has occurred in at least one of (i) a case where the door pinch is determined to have occurred based on the current flowing through the motor (11) in the second period or (ii) a case where the door pinch is determined to have occurred based on a speed of the door (3R, 3L).

11. A door pinch detection device (1) for detecting door pinch when a door (3R, 3L) is driven in a closing direction by a driving force from a motor (11), the door pinch detection device comprising:

a storage unit (36) for storing a first current value indicating current flowing through the motor (11) when the door (3R, 3L) is closed previously;

a threshold setting unit (32) for setting a threshold value based on the first current value stored in the storage unit (36);

an obtaining unit (33) for obtaining a second current value indicating current flowing through the motor (11) when the door (3R, 3L) is closed; and

a determining unit (34) for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

12. A railway door device (2) comprising:

a door (3R, 3L) provided in a railway vehicle;

a motor (11) for opening or closing the door (3R, 3L);

a door opening-closing control unit (18) for controlling the motor (11); and

a door pinch detecting unit (1) for detecting door pinch when the door (3R, 3L) is driven by a driving force from the motor (11) in a closing direction,

wherein the door pinch detecting unit (1) includes:

a first obtaining unit (31) for obtaining a first current value indicating current flowing through the motor (11) in a first period while the door (3R, 3L) is closed;

a threshold setting unit (32) for, based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred;

a second obtaining unit (33) for obtaining a second current value indicating current flowing through the motor (11) in a second period following the first period while the door (3R, 3L) is closed; and

a determining unit (34) for determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

13. A program for causing a computer to detect door pinch when a door (3R, 3L) is driven in a closing direction by a driving force from a motor (11), the program causing the computer to execute procedures of:

obtaining a first current value indicating current flowing through the motor (11) in a first period while the door (3R, 3L) is closed;

based on the obtained first current value, setting a threshold value used to determine whether the door pinch has occurred;

obtaining a second current value indicating current flowing through the motor (11) in a second period following the first period while the door (3R, 3L) is closed; and

determining whether the door pinch has occurred based on comparing the obtained second current value against the set threshold value.

14. The program of claim 13, wherein if the door (3R, 3L) restarts moving in the closing direction after the door pinch is determined to have occurred, the first current value is prevented from being obtained again and the threshold value is prevented from being set again until the door (3R, 3L) moves to the fully closed position.

Drawing