Article transfer device

Abstract

To realize a technique that can easily reduce vibrations of a holding part and an article held by the holding part that occur when the holding part moves in and out.SOLUTION: An article transfer device 1 includes: a holding part 21 that holds an article 2; a projection and retraction drive part M3 that moves the holding part 21 projecting and retracting; and a control part that controls the projection and retraction drive part M3. In a projection and retraction operation which is an operation projecting or retracting the holding part 21 by the projection and retraction drive part M3, based on a reference command pattern which is a time-varying pattern of command values for a position, a speed or a time-varying pattern of an acceleration command value such that an acceleration changes stepwise over time, a moving average of a setting period of the command value shown in the reference command pattern is set as an output command value, the control part controls the projection and retraction drive part M3 in accordance with the output command value.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an article transfer device including a holding section that holds an article, an extension / retraction drive section that moves the holding section forward and backward, and a control section that controls the extension / retraction drive section. [Background technology]

[0002] An example of such an article transfer device is disclosed in Japanese Patent Laid-Open Publication No. 2007-119136 (Patent Document 1). In the following description of the background art, the reference symbols in Patent Document 1 will be cited in parentheses. The article transfer device (13) in Patent Document 1 includes a fork (24) that holds an article (9), an extension / retraction drive device (25) that moves the fork (24) to and from a retracted position and an extended position, and an extension / retraction control unit (31c) that controls the extension / retraction drive device (25). When the fork (24) is extended from the retracted position to the extended position or when the fork (24) is retracted from the extended position to the retracted position, the extension / retraction control unit (31c) controls the extension / retraction speed of the fork (24) in accordance with an extension / retraction speed curve as shown in FIG. 6 of Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-119136 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when the holding part (the fork in Patent Document 1) is moved forward or backward, a change in the acceleration of the holding part may cause vibrations in the holding part or the article held by the holding part. Vibrations in the holding part or the article held by the holding part may cause delays in subsequent operations (e.g., raising and lowering the holding part) due to waiting until the vibrations subside, or may adversely affect the article. For this reason, it is desirable to keep such vibrations as small as possible.

[0005] It is therefore desirable to realize a technology that can easily reduce vibrations of the holding parts and the articles held by the holding parts that accompany the extending and retracting movements of the holding parts. [Means for solving the problem]

[0006] The item transfer device of the present disclosure is an item transfer device comprising a holding section for holding an item, an extension / retraction drive section for causing the holding section to extend or retract, and a control section for controlling the extension / retraction drive section, wherein in an extension / retraction operation in which the holding section is extended or retracted by the extension / retraction drive section, the control section uses a moving average of a set period of command values ​​indicated in the reference command pattern as an output command value based on a reference command pattern which is a time-varying pattern of command values ​​for position, speed, or acceleration such that acceleration changes in a step-like manner over time, and controls the extension / retraction drive section in accordance with the output command value.

[0007] According to this configuration, the change in acceleration (jerk) of the holding part during the extension / retraction movement of the holding part can be kept small compared to the case where the extension / retraction drive part is controlled according to the command value shown in the reference command pattern, and therefore the change in acceleration acting on the article held by the holding part can also be kept small. Therefore, according to this configuration, it is easy to keep vibrations of the holding part and the article held by the holding part caused by the extension / retraction movement of the holding part small.

[0008] Further features and advantages of the article transfer device will become apparent from the following description of the embodiments, which are given with reference to the drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a transport vehicle according to an embodiment; [Diagram 2] FIG. 1 is a side view showing a transport vehicle according to an embodiment; [Diagram 3] FIG. 1 is a front view showing a transport vehicle according to an embodiment; [Figure 4] Control block diagram according to an embodiment [Diagram 5] FIG. 13 is a diagram showing an example of a reference command pattern and a pattern after sine wave processing. [Figure 6]FIG. 13 is a diagram showing an example of a reference command pattern and a pattern after moving average processing; [Figure 7] FIG. 13 is a perspective view showing a transport vehicle according to another embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of an article transfer device will be described with reference to the drawings. In this embodiment, as shown in Fig. 2 and Fig. 3, an article transfer device 1 is provided on a transport vehicle 100 (here, an automated transport vehicle) that transports an article 2. The article 2 is, for example, a FOUP (Front Opening Unified Pod) that accommodates a semiconductor wafer.

[0011] The transport vehicle 100 of this embodiment shown in Figs. 1 to 3 is configured as follows. The transport vehicle 100 includes a running section 10 that runs along a travel path 40, and a main body section 20 connected to the running section 10. Here, the main body section 20 is supported by the running section 10 while being disposed on a lower side Z2 relative to the running section 10. The article 2 is stored in the main body section 20 and transported by the transport vehicle 100.

[0012] The travel path 40 is formed by travel rails 41 (here, a pair of travel rails 41 arranged at an interval in the width direction Y). The direction along the travel path 40 is the travel direction X, and the width direction Y is a direction perpendicular to the travel direction X when viewed in the up-down direction Z (vertical direction) (here, a horizontal direction perpendicular to the travel direction X). The travel unit 10 includes travel wheels 11 that roll on the travel surface (here, the upper surface) of the travel rail 41, and the travel wheels 11 are rotationally driven by a travel drive unit M1 (for example, an electric motor such as a servo motor), so that the travel unit 10 travels along the travel rail 41. Here, the travel rail 41 is supported by being suspended from the ceiling 3, and the travel path 40 is formed along the ceiling 3. That is, the transport vehicle 100 of this embodiment is a ceiling transport vehicle.

[0013] As shown in Fig. 2 and Fig. 3, the article transfer device 1 includes a holding unit 21 that holds the article 2. In this embodiment, the holding unit 21 holds the article 2 from the upper side Z1. In the example shown in Fig. 3, the holding unit 21 holds the article 2 by supporting a supported portion 2a (here, a flange portion) formed on the upper portion of the article 2 with a support member 21a. The manner in which the article 2 is held by the holding unit 21 is not limited to this, and may be, for example, as in the example shown in Fig. 7 to be referred to later, in which the holding unit 21 supports the article 2 from the lower side Z2, or in which the holding unit 21 clamps the article 2 from both sides in the horizontal direction.

[0014] In this embodiment, the holder 21 is configured to perform a holding operation for holding the article 2 and a holding release operation for releasing the holding of the article 2. In the example shown in Fig. 3, in the holding operation by the holder 21, at least a part of the support member 21a is moved to the lower side Z2 of the supported portion 2a. This makes the holder 21 capable of holding the article 2 (specifically, makes the support member 21a capable of supporting the supported portion 2a). In addition, in the holding release operation by the holder 21, the support member 21a is retracted from the lower side Z2 of the supported portion 2a.

[0015] The article transfer device 1 includes a holding drive unit M4 (e.g., an electric motor such as a servo motor) that drives the holding unit 21 (specifically, the support member 21a), and the holding operation by the holding unit 21 and the holding release operation by the holding unit 21 are performed by driving the holding drive unit M4. In the example shown in FIG. 3, the holding unit 21 includes a pair of support members 21a, and the holding drive unit M4 is configured to move the pair of support members 21a toward and away from each other. In the holding operation by the holding unit 21, at least a part of each of the pair of support members 21a is moved to the lower side Z2 of the supported portion 2a. In the holding release operation by the holding unit 21, each of the pair of support members 21a is retracted from the lower side Z2 of the supported portion 2a.

[0016] 3, the holding operation by the holding unit 21 is performed by bringing the pair of support members 21a closer to each other, and the holding release operation by the holding unit 21 is performed by moving the pair of support members 21a away from each other. In addition to this configuration, a configuration may also be used in which the holding operation by the holding unit 21 is performed by moving the pair of support members 21a away from each other, and the holding release operation by the holding unit 21 is performed by bringing the pair of support members 21a closer to each other.

[0017] In this embodiment, the article transfer apparatus 1 is equipped with a lifting drive unit M2 (e.g., an electric motor such as a servo motor) that lifts and lowers the holding unit 21. Here, "lifting" means lifting and lowering relative to a reference portion of the article transfer apparatus 1 (hereinafter referred to as "reference portion"). In this embodiment, the reference portion of the article transfer apparatus 1 is a portion fixed to the main body portion 20 of the article transfer apparatus 1. Therefore, the lifting drive unit M2 lifts and lowers the holding unit 21 relative to the main body portion 20.

[0018] The article transfer device 1 includes a lifting device 22 that lifts and lowers the holding part 21, and the lifting drive unit M2 operates the lifting device 22 to lift and lower the holding part 21. In the example shown in FIG. 2, the lifting device 22 is configured to lift the holding part 21 by winding up a rope 23 (such as a belt or wire) that suspends the holding part 21, and to lower the holding part 21 by unwinding the rope 23. One end of the rope 23 is connected to the holding part 21, and the other end of the rope 23 is fixed to a drum (not shown). The lifting drive unit M2 winds up the rope 23 around the drum by rotating the drum in one rotation direction, and unwinds the rope 23 from the drum by rotating the drum in the other rotation direction.

[0019] When the transport vehicle 100 performs a traveling operation to travel along the travel route 40, the holding unit 21 is disposed at a reference height H1 (see FIG. 2). The reference height H1 is set to, for example, the upper limit position of the lifting range of the holding unit 21 by the lifting device 22 (in other words, the height when the cord body 23 is wound to the maximum). In the example shown in FIG. 2, the reference height H1 is the height at which the holding unit 21 and the article 2 held by the holding unit 21 are accommodated in the main body 20.

[0020] When the transport vehicle 100 (specifically, the article transfer device 1) transfers the article 2 between the holding unit 21 and the transfer target location 4, the holding unit 21 is disposed at a transfer height H2 (see FIG. 2) corresponding to the transfer target location 4. The transfer target location 4 may be, for example, a load port of a processing device that processes the article 2 (or the contents contained in the article 2), an in / out port of a storage device that stores the article 2, or a storage shelf that temporarily stores the article 2. The holding operation of the article 2 by the holding unit 21 and the holding release operation of the article 2 by the holding unit 21 are performed in a state where the holding unit 21 is disposed at the transfer height H2. The transfer height H2 is set according to the height of the transfer target location 4. In the example shown in FIG. 2, the transfer height H2 is set to a height lower than the reference height H1.

[0021] 3 and 4, the article transfer device 1 includes an extension / retraction drive unit M3 (for example, an electric motor such as a servo motor) that causes the holding unit 21 to extend and retract. Here, "extend and retract" means to cause the holding unit 21 to extend and retract relative to the above-mentioned reference portion of the article transfer device 1. Thus, the extension / retraction drive unit M3 causes the holding unit 21 to extend and retract relative to the main body unit 20.

[0022] The article transfer device 1 includes an advance / retract device 24 for advancing and retracting the holding part 21, and the advance / retract drive unit M3 operates the advance / retract device 24 to advancing and retract the holding part 21. The advance / retract device 24 is configured, for example, to advancing and retract the holding part 21 while maintaining the attitude of the holding part 21 (in other words, to move the holding part 21 in parallel between the retracted position and the protruding position). The retracted position and the protruding position will be described later. Such an advance / retract device 24 can be configured, for example, using a slide mechanism (linear mechanism). In this embodiment, the lifting device 22 supports the holding part 21 so that it can be raised and lowered, and the advance / retract device 24 supports the lifting device 22 so that it can be raised and lowered. The advance / retract device 24 is configured to advancing and retract the holding part 21 supported by the lifting device 22 by advancing and retracting the lifting device 22. In the example shown in FIG. 3, the moving-out device 24 is configured to move the lifting device 22 out and back while maintaining the attitude of the lifting device 22 (in other words, to translate the lifting device 22).

[0023] The extension / retraction direction D of the holding part 21 by the extension / retraction drive part M3 may be a direction along a horizontal plane or a direction inclined relative to the horizontal plane. In this embodiment, the extension / retraction direction D is a direction along a horizontal plane. In this specification, "along a plane" is not limited to a state parallel to the plane, but also includes a state slightly inclined relative to the plane. Therefore, the extension / retraction direction D is not limited to a direction parallel to the horizontal plane, but may be a direction slightly inclined relative to the horizontal plane. In the example shown in Figs. 1 to 3, the extension / retraction direction D is parallel to the width direction Y.

[0024] When the transport vehicle 100 performs a traveling operation to travel along the travel path 40, the holding unit 21 is disposed in a retracted position. The retracted position is a position retracted to the side of the above-mentioned reference portion of the article transfer device 1. In this embodiment, the retracted position is a position where the holding unit 21 overlaps with the traveling unit 10 when viewed in the up-down direction along the up-down direction Z. Although the holding unit 21 is not shown in Fig. 1, Fig. 1 shows a state in which the holding unit 21, which holds the article 2, is disposed in the retracted position.

[0025] When the transport vehicle 100 (specifically, the article transfer device 1) transfers the article 2 between the holding unit 21 and the transfer target location 4, and the transfer target location 4 to which the article 2 is to be transferred is located at a position overlapping the travel path 40 in a vertical view, the holding unit 21 is located at the retracted position. On the other hand, when the transfer target location 4 to which the article 2 is to be transferred is located at a position shifted in the width direction Y from the travel path 40 in a vertical view, the holding unit 21 is located at the protruding position. The protruding position is a position protruding on the opposite side to the side of the above-mentioned reference portion in the article transfer device 1. In this embodiment, the protruding position is a position where the holding unit 21 overlaps the transfer target location 4 in a vertical view. FIG. 3 shows a state where the holding unit 21 is located at the protruding position.

[0026] The article transfer device 1 includes a control unit 30 (see FIG. 4) that controls the outgoing / retracting drive unit M3. In this embodiment, the control unit 30 further controls the traveling drive unit M1, the lifting drive unit M2, and the holding drive unit M4. The control unit 30 includes, for example, a processor such as a CPU (Central Processing Unit) and peripheral circuits such as a memory. Each function of the control unit 30 is realized, for example, by cooperation between hardware such as the processor and a program executed on the hardware. The control unit 30 is configured to control at least the outgoing / retracting drive unit M3. A control unit separate from the control unit 30 may be configured to control at least one of the traveling drive unit M1, the lifting drive unit M2, and the holding drive unit M4.

[0027] The control unit 30 may be divided into a plurality of control units capable of communicating with each other. The control unit 30 may be entirely provided in a device (hereinafter referred to as a "main device") in which the control target such as the entry / exit drive unit M3 is provided, or entirely provided in a device (hereinafter referred to as an "external device") that is provided outside the main device and capable of communicating with the main device. Alternatively, the control unit 30 may be partially provided in the main device and partially provided in the external device. In this embodiment, the main device is the transport vehicle 100.

[0028] Various technical features of the control unit 30 described below are also applicable to an operation method of the control unit 30 and a program for causing a computer to function as the control unit 30, and such operation methods and programs, as well as a recording medium (a computer-readable recording medium such as an optical disk or a flash memory) on which such a program is recorded, are also disclosed in this specification. The program for causing a computer to function as the control unit 30 is provided, for example, by a recording medium on which the program is recorded, or is provided via a communication network, and the provided program is stored in a storage device that can be referenced by the computer.

[0029] The control unit 30 controls the travel drive unit M1 to make the travel unit 10 perform a travel operation to travel along the travel path 40. The control unit 30 controls the lift drive unit M2 to make the lift device 22 perform a lift operation to lift the holding unit 21. The lift operation includes an ascending operation to raise the holding unit 21 and a descending operation to lower the holding unit 21. In this embodiment, the control unit 30 controls the lift drive unit M2 to gradually increase the lift speed of the holding unit 21 toward a target speed in the lift operation of the holding unit 21, and then to perform a constant-speed lift operation to maintain the lift speed of the holding unit 21 at the target speed, and then to gradually decrease the lift speed of the holding unit 21 from the target speed to stop the holding unit 21. The control unit 30 controls the exit drive unit M3 to make the exit device 24 perform an exit operation to exit the holding unit 21. The extending / retracting operation includes a protruding operation for protruding the holding portion 21, and a retracting operation for retracting the holding portion 21. The control unit 30 controls the holding drive unit M4 to cause the holding portion 21 to perform the holding operation and the holding release operation.

[0030] When the transport vehicle 100 (specifically, the item transfer device 1) is caused to perform the transfer operation of the item 2 between the holding unit 21 and the transfer target location 4, and the transfer target location 4 is positioned at a position shifted in the width direction Y relative to the travel path 40 when viewed in the vertical direction, the control unit 30 controls the travel drive unit M1, the lift drive unit M2, the entry / exit drive unit M3, and the holding drive unit M4 to operate the transport vehicle 100 as follows.

[0031] When transferring the article 2 from the holding unit 21 to the transfer target location 4, the control unit 30 causes the traveling unit 10 to perform a traveling operation to travel the transport vehicle 100 to the same position in the traveling direction X as the transfer target location 4, with the holding unit 21 holding the article 2 being located at the retracted position at the reference height H1. Thereafter, the control unit 30 causes the exit / entrance device 24 to perform a protruding operation to move the holding unit 21 holding the article 2 from the retracted position to the protruding position, and then causes the lifting device 22 to perform a lifting operation (here, a lowering operation) to raise and lower the holding unit 21 from the reference height H1 to the transfer height H2, and then causes the holding unit 21 to perform an operation to release the holding of the article 2. Then, the control unit 30 causes the lifting device 22 to perform a lifting operation (here, a raising operation) to raise and lower the holding section 21, which is not holding an item 2, from the transfer height H2 to the reference height H1, and then causes the exit / entrance device 24 to perform a retraction operation to retract the holding section 21 from the protruding position to the retracted position.

[0032] When transferring the article 2 from the transfer target location 4 to the holding unit 21, the control unit 30 causes the traveling unit 10 to perform a traveling operation to travel the transport vehicle 100 to the same position in the traveling direction X as the transfer target location 4, with the holding unit 21 not holding the article 2 being located at the retracted position at the reference height H1. Thereafter, the control unit 30 causes the exit / entrance device 24 to perform a protruding operation to move the holding unit 21 not holding the article 2 from the retracted position to the protruding position, and then causes the lifting device 22 to perform a lifting operation (here, a lowering operation) to raise and lower the holding unit 21 from the reference height H1 to the transfer height H2, and then causes the holding unit 21 to hold the article 2. Then, the control unit 30 causes the lifting device 22 to perform a lifting operation (here, a raising operation) to raise and lower the holding part 21 holding the item 2 from the transfer height H2 to the reference height H1, and then causes the exit / entrance device 24 to perform a retraction operation to retract the holding part 21 from the protruding position to the retracted position.

[0033] Details will be omitted, but when the transport vehicle 100 (specifically, the item transfer device 1) is caused to perform the transfer operation of the item 2 between the holding section 21 and the transfer target location 4, and the transfer target location 4 is located at a position that overlaps with the travel path 40 when viewed in the vertical direction, the control unit 30 operates the transport vehicle 100 in the same manner as described above, except that it does not cause the exit / entrance device 24 to perform the protruding operation of the holding section 21 and the retracting operation of the holding section 21.

[0034] In this way, when transferring the article 2 between the holding part 21 and the transfer target location 4, the control part 30 causes the exit / entrance device 24 to perform an exit / entrance operation for exiting and retracting the holding part 21. Then, in order to reduce vibration of the holding part 21 and the article 2 held by the holding part 21 caused by the exit / entrance operation of the holding part 21, the control part 30 controls the exit / entrance drive part M3 as described below in the exit / entrance operation, which is an operation for extending or retracting the holding part 21 by the exit / entrance drive part M3. Note that the control part 30 may be configured to control the exit / entrance drive part M3 as described below for only one of the operations, rather than for both the protruding operation for protruding the holding part 21 and the retracting operation for retracting the holding part 21.

[0035] In the extension / retraction operation, which is an operation of protruding or retracting the holding unit 21 by the extension / retraction drive unit M3, the control unit 30 sets the moving average of the command value indicated in the reference command pattern for a set period as the output command value, based on the reference command pattern, which is a time-varying pattern of the command value of the position, speed, or acceleration such that the acceleration changes stepwise with the passage of time. Here, the acceleration also includes deceleration (negative acceleration). Then, the control unit 30 controls the extension / retraction drive unit M3 according to the output command value. This makes it possible to change the speed of the holding unit 21 so that the change in the acceleration of the holding unit 21 becomes smooth while using the reference command pattern in which the acceleration changes stepwise. In other words, it is possible to change the speed of the holding unit 21 so that the change in the acceleration of the holding unit 21 becomes smooth, even without deriving a time-varying pattern of the command value in which the acceleration changes smoothly by a calculation taking into account the jerk (rate of change in acceleration).

[0036] The control unit 30 sets the command value obtained by performing moving average processing on the reference command pattern as the output command value. Specifically, the control unit 30 sets the command value obtained by performing moving average processing on the time series data of the reference command pattern in a set period (moving average time) as the output command value. The moving average processing is, for example, a simple moving average processing without weighting. The control unit 30 acquires the reference command pattern from another control unit such as a higher-level control unit, or acquires the reference command pattern by referring to a storage unit.

[0037] The reference command pattern may be any one of a time change pattern of a position command value in which the acceleration changes in a step-like manner over time (hereinafter referred to as a "reference position command pattern"), a time change pattern of a velocity command value in which the acceleration changes in a step-like manner over time (hereinafter referred to as a "reference velocity command pattern"), and a time change pattern of an acceleration command value in which the acceleration changes in a step-like manner over time (hereinafter referred to as a "reference acceleration command pattern"). When the reference command pattern is the reference position command pattern, the output command value is set to a position command value, when the reference command pattern is the reference velocity command pattern, the output command value is set to a velocity command value, and when the reference command pattern is the reference acceleration command pattern, the output command value is set to an acceleration command value.

[0038] When the output command value is a position command value, the control unit 30 controls the protruding / retracting drive unit M3 by position control based on the output command value. When the output command value is a speed command value, the control unit 30 controls the protruding / retracting drive unit M3 by speed control based on the output command value. When the output command value is an acceleration command value, the control unit 30 controls the protruding / retracting drive unit M3 by acceleration control based on the output command value. Note that the control of the protruding / retracting drive unit M3 by the control unit 30 according to the output command value may be control of the protruding / retracting drive unit M3 based on a command value obtained by differentiating or integrating the output command value. For example, when the output command value is a speed command value, the control unit 30 may be configured to control the protruding / retracting drive unit M3 by position control based on a position command value generated by integrating the output command value.

[0039] The control unit 30 controls the retraction driving unit M3 according to the output command value, for example, by feedback control. In the feedback control, the control unit 30 generates a drive command based on the deviation between a feedback value and a command value (an output command value, or a command value obtained by differentiating or integrating the output command value), and controls the retraction driving unit M3 to output a drive force (for example, torque) according to the drive command. The feedback value is detected, for example, by a detector (for example, an encoder) provided in the retraction driving unit M3. The control unit 30 may be configured to control the retraction driving unit M3 according to the output command value, by feedforward control or a combination of feedback control and feedforward control.

[0040] The control unit 30 may be configured to control the retraction drive unit M3 according to the command value indicated in the reference command pattern under certain conditions. The control content when the control unit 30 controls the retraction drive unit M3 according to the command value indicated in the reference command pattern is the same as that described above for the case where the control unit 30 controls the retraction drive unit M3 according to the output command value that is the moving average of the reference command pattern, except that the "output command value" is read as the "command value indicated in the reference command pattern," and therefore a detailed description will be omitted.

[0041] In this embodiment, the control unit 30 controls the advance / retract drive unit M3 so that, in the advance / retract operation of the holding unit 21, the speed of the holding unit 21 is gradually increased toward the target speed Vt (see FIG. 5 and FIG. 6), the speed of the holding unit 21 is maintained at the target speed Vt, and then the speed of the holding unit 21 is gradually decreased from the target speed Vt to stop the holding unit 21. In the example shown in FIG. 5, the period from time t1 to time t2 is the period during which the speed of the holding unit 21 is gradually increased toward the target speed Vt, the period from time t2 to time t3 is the period during which the speed of the holding unit 21 is maintained at the target speed Vt, and the period from time t3 to time t4 is the period during which the speed of the holding unit 21 is gradually decreased from the target speed Vt. In this embodiment, the reference command pattern is the reference speed command pattern, and the speeds shown by the dashed lines in FIG. 5 and FIG. 6 represent the reference command pattern (reference speed command pattern) when the speed of the holding unit 21 is changed as described above. The acceleration indicated by the dashed dotted line in FIG. 5 and FIG. 6 represents the change over time in acceleration corresponding to the reference speed command pattern (specifically, the first-order differential value of the speed indicated in the reference speed command pattern).

[0042] The velocity and acceleration shown by the solid lines in Fig. 5 represent the time changes of the velocity and acceleration when sine wave processing is performed to convert step-like changes in acceleration into sine wave changes in acceleration. By performing sine wave processing in this way, the velocity of the holding unit 21 can be changed so that the change in acceleration of the holding unit 21 becomes smooth, but as shown in Fig. 5, the maximum value (absolute value, the same applies below) of the acceleration of the holding unit 21 exceeds the maximum value of the acceleration corresponding to the reference speed command pattern shown by the dashed line in Fig. 5, specifically, it becomes π / 2 times larger. Such an increase in the maximum value of the acceleration of the holding unit 21 may cause adverse effects on the article 2 held by the holding unit 21, for example, and therefore the scope of application of such a technology may be limited.

[0043] In response to this, the control unit 30 controls the retraction driving unit M3 according to an output command value which is a moving average of command values ​​shown in a reference command pattern (a reference speed command pattern in this embodiment). As a result, as shown in Fig. 6, it is possible to change the speed of the holding unit 21 so that the change in the acceleration of the holding unit 21 is smooth while preventing the maximum value of the acceleration of the holding unit 21 from exceeding the maximum value of the acceleration corresponding to the reference speed command pattern shown by the dashed line in Fig. 6. Note that in Fig. 6, the speed shown by the solid line represents the time change in the output command value (here, the speed command value) which is the moving average of the reference command pattern, and the acceleration shown by the solid line represents the time change in the acceleration corresponding to the speed shown by the solid line.

[0044] 6 correspond to time t1, time t2, time t3, and time t4 in FIG. 4, respectively. In FIG. 6, the length of the period from time t11 to time t12, the length of the period from time t13 to time t14, the length of the period from time t15 to time t6, and the length of the period from time t17 to time t18 are consistent with the length of the set period (moving average time) related to the moving average. As shown in FIG. 6, when the extension / retraction driving unit M3 is controlled according to the output command value which is the moving average of the reference command pattern, the time until the holding unit 21 reaches the target position (retracted position or projected position) (i.e., the time required for the extension / retraction operation of the holding unit 21) is longer by the length of the set period than when the extension / retraction driving unit M3 is controlled according to the command value shown in the reference command pattern. 6, the time required for the extension / retraction movement of the holding unit 21 is extended from the time from time t11 to time t17 to the time from time t11 to time t18. If the set period is extended, the change in acceleration of the holding unit 21 can be made smoother, but the time required for the extension / retraction movement of the holding unit 21 is correspondingly longer.

[0045] Although the control unit 30 may be configured not to change the length of the set period, taking into consideration that the time required for the extension / retraction operation of the holding unit 21 is lengthened by the length of the set period as described above, the control unit 30 may be configured to change the length of the set period as described below. Note that changing the length of the set period includes setting the length of the set period to zero (in other words, controlling the extension / retraction drive unit M3 according to the command value indicated in the reference command pattern).

[0046] For example, the control unit 30 may be configured to lengthen the set period when the holding unit 21 holds the article 2 compared to when the holding unit 21 does not hold the article 2. In this case, as shown in FIG. 4, it is preferable that the article transfer device 1 includes a determination unit 31 that determines whether the holding unit 21 holds the article 2 or not, and the control unit 30 changes the length of the set period as described above based on the determination result by the determination unit 31. The determination unit 31 and a weight determination unit 32 described later are realized, for example, by the control unit 30 (specifically, an arithmetic processing device) executing a program. Note that the control unit 30, the determination unit 31, and the weight determination unit 32 described later shown in FIG. 4 are at least logically or conceptually distinct, and do not necessarily need to be physically distinct. For example, the determination unit 31 and the weight determination unit 32 may be a common determination unit.

[0047] When transferring the article 2 from the holding unit 21 to the transfer target location 4 (hereinafter referred to as "unloading transfer"), the protruding operation of protruding the holding unit 21 is performed in a state where the holding unit 21 is holding the article 2, and the retracting operation of retracting the holding unit 21 is performed in a state where the holding unit 21 is not holding the article 2. When transferring the article 2 from the transfer target location 4 to the holding unit 21 (hereinafter referred to as "scooping transfer"), the protruding operation of protruding the holding unit 21 is performed in a state where the holding unit 21 is not holding the article 2, and the retracting operation of retracting the holding unit 21 is performed in a state where the holding unit 21 is holding the article 2. Therefore, for example, the determination unit 31 can be configured to determine whether the holding unit 21 is holding the article 2 in the entry / exit operation (protruding operation or retracting operation) based on whether the transfer is unloading transfer or scooping transfer. When the control unit 30 is configured to cause the transport vehicle 100 to transport the item 2 in response to an instruction from another control unit, such as a higher-level control unit, the judgment unit 31 can be configured to judge whether the transfer is a unloading transfer or a scooping transfer based on the instruction.

[0048] The determination method of the determination unit 31 is not limited to the above method, and for example, the determination unit 31 may be configured to determine whether or not the holding unit 21 is holding the article 2 based on an index related to the driving force of the lift drive unit M2 during lifting and lowering operation (for example, an output torque or a current value when the lift drive unit M2 is a motor). Also, the determination unit 31 may be configured to determine whether or not the holding unit 21 is holding the article 2 based on detection information of a sensor provided in the holding unit 21 (such as a presence sensor that detects the presence or absence of the article 2 or a weight sensor that detects the weight of the article 2).

[0049] As described above, in the configuration in which the control unit 30 lengthens the set period when the holding unit 21 holds the article 2 compared to when the holding unit 21 does not hold the article 2, the control unit 30 may be configured to set the length of the set period to zero when the holding unit 21 does not hold the article 2. In this case, the control unit 30 is configured to control the extension / retraction drive unit M3 according to the output command value in the extension / retraction operation in a state in which the holding unit 21 holds the article 2, and to control the extension / retraction drive unit M3 according to the command value indicated in the reference command pattern in the extension / retraction operation in a state in which the holding unit 21 does not hold the article 2.

[0050] Incidentally, the vibration form of the holding unit 21 and the article 2 held by the holding unit 21 may differ depending on the weight of the article 2. Therefore, the length of the set period for effectively reducing the vibration may differ depending on the weight of the article 2. In consideration of this point, the control unit 30 may be configured to change the set period depending on the weight of the article 2 held by the holding unit 21 (specifically, the length of the set period may be changed, the same below). In this case, as shown in FIG. 4, it is preferable that the article transfer device 1 includes a weight determination unit 32 that determines the weight of the article 2 held by the holding unit 21, and the control unit 30 changes the set period as described above based on the determination result by the weight determination unit 32. Note that, when the article 2 is a container that contains substrates such as semiconductor wafers, the weight of the article 2 changes depending on the number of substrates contained therein. For example, the weight determination unit 32 may be configured to determine the weight of the article 2 held by the holding unit 21 during the lifting and lowering operation of the holding unit 21 by the lifting and lowering drive unit M2.

[0051] In the case where the control unit 30 is configured to cause the transport vehicle 100 to transport the article 2 in response to a command from another control unit such as a higher-level control unit, and where information on the weight of the article 2 can be obtained based on the command, the weight determination unit 32 can be configured to determine the weight of the article 2 held by the holding unit 21 based on the command. Also, similar to the determination method of the determination unit 31 described above, the weight determination unit 32 can be configured to determine the weight of the article 2 held by the holding unit 21 based on an index related to the driving force of the lifting / lowering drive unit M2 during the lifting / lowering operation, or based on detection information of a weight sensor provided in the holding unit 21.

[0052] For example, a weight-based set period that is an appropriate set period according to the weight of the article 2 may be obtained in advance by testing or the like, and the control unit 30 may change the set period to the weight-based set period according to the weight of the article 2 held by the holding unit 21. Alternatively, the control unit 30 may simply lengthen the set period stepwise or continuously as the weight of the article 2 held by the holding unit 21 increases. Note that the characteristic of the article 2 that is the basis for changing the set period is not limited to the weight of the article 2, and for example, the control unit 30 may change the set period according to a characteristic other than the weight of the article 2 held by the holding unit 21 (for example, vibration tolerance).

[0053] However, if the set period is changed during the moving-out operation of the holding unit 21, the moving-out operation of the holding unit 21 may become unstable due to the output command value being discontinuous before and after the change in the length of the set period. In view of this point, it is preferable to configure the control unit 30 to change the set period during a period other than the moving-out operation. In this embodiment, the period other than the moving-out operation includes a period during the moving-up and moving-down operation of the holding unit 21 by the lifting and lowering drive unit M2, a period during the holding operation by the holding unit 21, and a period during the holding release operation by the holding unit 21. Therefore, the control unit 30 can be configured to change the set period during the moving-up and moving-down operation of the holding unit 21 by the lifting and lowering drive unit M2, during the holding operation by the holding unit 21, or during the holding release operation by the holding unit 21. The control unit 30 can also be configured to change the set period during the moving-up and moving-down operation of the holding unit 21 by the lifting and lowering drive unit M2. That is, the control unit 30 may be configured not to change the set period while the holding unit 21 is performing a holding operation or while the holding unit 21 is performing a holding release operation.

[0054] In this embodiment, when unloading and transferring, the protruding operation of the holding part 21, the descending operation of the holding part 21, the holding release operation by the holding part 21, the ascending operation of the holding part 21, and the retracting operation of the holding part 21 are executed in this order. In this case, by shortening the set period during the descending operation of the holding part 21, the holding release operation by the holding part 21, or the ascending operation of the holding part 21, it is possible to lengthen the set period when the holding part 21 is holding the item 2 compared to when the holding part 21 is not holding the item 2. When changing the set period during the descending operation of the holding part 21 in unloading and transferring, for example, a configuration can be adopted in which the set period is changed while the holding part 21 is descending by the constant speed elevation operation described above.

[0055] In addition, in this embodiment, when scooping transfer is performed, the protruding operation of the holding part 21, the descending operation of the holding part 21, the holding operation by the holding part 21, the ascending operation of the holding part 21, and the retracting operation of the holding part 21 are executed in this order. In this case, by changing the set period to be longer during the descending operation of the holding part 21, during the holding operation by the holding part 21, or during the ascending operation of the holding part 21, it is possible to make the set period longer when the holding part 21 is holding the article 2 than when the holding part 21 is not holding the article 2. When changing the set period during the ascending operation of the holding part 21 in scooping transfer, for example, the set period can be changed during the ascending of the holding part 21 by the constant speed ascending and descending operation described above after the article 2 is separated from the transfer target location 4 by the ascending of the holding part 21.

[0056] Other embodiments (1) In the above embodiment, a configuration has been described as an example in which the lifting device 22 supports the holding unit 21 so as to be freely raised and lowered, and the entrance / exit device 24 supports the lifting device 22 so as to be freely raised and lowered. However, the present disclosure is not limited to such a configuration, and a configuration is also possible in which the entrance / exit device 24 supports the holding unit 21 so as to be freely raised and lowered, and the lifting device 22 supports the entrance / exit device 24 so as to be freely raised and lowered. In this case, the lifting device 22 is configured to raise and lower the holding unit 21 supported by the entrance / exit device 24 by raising and lowering the entrance / exit device 24.

[0057] (2) In the above embodiment, an example has been described in which the article transfer device 1 includes a lifting / lowering drive unit M2 that raises and lowers the holder 21. However, the present disclosure is not limited to such a configuration, and the article transfer device 1 may also be configured not to include the lifting / lowering drive unit M2. In other words, the article transfer device 1 may also be configured not to include the lifting device 22. In this case, for example, a device provided at the transfer target location 4 for the article 2 includes a device that raises and lowers the article 2.

[0058] (3) In the above embodiment, the transport vehicle 100 on which the article transfer device 1 is provided is an overhead transport vehicle that travels along a travel path 40 formed along the ceiling 3. However, the present disclosure is not limited to such a configuration, and the article transfer device 1 may be provided on a transport vehicle 100 of another type. FIG. 7 shows a case where the transport vehicle 100 on which the article transfer device 1 is provided is a stacker crane. In FIG. 7, parts having the same functions as the transport vehicle 100 of the above embodiment are denoted by the same reference numerals as those in the above embodiment.

[0059] The transport vehicle 100 shown in Fig. 7 includes a traveling section 10 that travels along a traveling rail 41 provided on a floor surface, a mast 12 erected on the traveling section 10, and a lifting platform 13 that rises and falls along the mast 12. The holding section 21 is supported by the lifting platform 13. Driven by a traveling drive section M1, the traveling section 10 travels along a travel path 40 while an upper end of the mast 12 is guided by a guide rail 42 provided on the ceiling side. The lifting device 22 is configured to raise and lower the lifting platform 13 along the mast 12, and the lifting drive section M2 operates the lifting device 22 to raise and lower the lifting platform 13 and the holding section 21 supported by the lifting platform 13.

[0060] In the example shown in FIG. 7, the holding unit 21 holds the article 2 from the lower side Z2. Specifically, the holding unit 21 holds the article 2 by supporting the bottom of the article 2 from the lower side Z2. The advance / retract device 24 is configured to advance / retract the holding unit 21 relative to the lifting platform 13, and an advance / retract drive unit M3 not shown in FIG. 7 operates the advance / retract device 24 to advance / retract the holding unit 21 relative to the lifting platform 13. Note that in the example shown in FIG. 7, a drive unit equivalent to the holding drive unit M4 in the above embodiment is not provided. Also, in the example shown in FIG. 7, for example, a shelf unit in a storage shelf having multiple shelves in the vertical direction Z for storing the article 2 is set as the transfer target location 4.

[0061] When unloading and transferring, the protruding operation of the holding unit 21, the descending operation of the holding unit 21, and the retracting operation of the holding unit 21 are executed in this order. In this case, by shortening the set period during the descending operation of the holding unit 21, the set period can be lengthened when the holding unit 21 is holding an item 2 compared to when the holding unit 21 is not holding an item 2. Also, when scooping and transferring, the protruding operation of the holding unit 21, the ascending operation of the holding unit 21, and the retracting operation of the holding unit 21 are executed in this order. In this case, by lengthening the set period during the ascending operation of the holding unit 21, the set period can be lengthened when the holding unit 21 is holding an item 2 compared to when the holding unit 21 is not holding an item 2.

[0062] The transport vehicle 100 on which the article transfer device 1 is provided is not limited to a type that travels along a travel rail 41, such as an overhead transport vehicle, a stacker crane, or other rail-guided transport vehicle, but may be a non-rail transport vehicle, such as an AGV (Automated Guided Vehicle) or an AMR (Autonomous Mobile Robot). When the transport vehicle 100 is a non-rail transport vehicle, the transport vehicle 100 travels along a virtually formed travel path 40, not a physically formed travel path 40 using a travel rail or the like. For example, a plurality of detectable objects, such as two-dimensional codes or RF (Radio Frequency) tags, are placed on the floor, and the travel path 40 is virtually formed so as to connect the plurality of detectable objects. It is also possible to configure the transport vehicle 100 such that the detectable objects are not placed on the floor, and the travel path 40 is virtually formed by a route calculated based on the recognition result of the surrounding environment.

[0063] (4) In the above embodiment, the article transfer device 1 is provided on the transport vehicle 100. However, the present disclosure is not limited to such a configuration, and the article transfer device 1 may be fixed to a floor or the like.

[0064] (5) Note that the configurations disclosed in the above-described embodiments can be applied in combination with configurations disclosed in other embodiments (including combinations of the embodiments described as other embodiments) as long as no contradiction occurs. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate within the scope of the present disclosure.

[0065] [Summary of this embodiment] The above-described embodiment of the article transfer device will be summarized below.

[0066] The item transfer device is an item transfer device comprising a holding section for holding items, an extension / retraction drive section for extending and retracting the holding section, and a control section for controlling the extension / retraction drive section, wherein in an extension / retraction operation in which the holding section is extended or retracted by the extension / retraction drive section, the control section sets an output command value to a moving average of a set period of command values ​​indicated in the reference command pattern, which is a time-varying pattern of command values ​​for position, speed, or acceleration such that acceleration changes in a step-like manner over time, and controls the extension / retraction drive section in accordance with the output command value.

[0067] According to this configuration, the change in acceleration (jerk) of the holding part during the extension / retraction movement of the holding part can be kept small compared to the case where the extension / retraction drive part is controlled according to the command value shown in the reference command pattern, and therefore the change in acceleration acting on the article held by the holding part can also be kept small. Therefore, according to this configuration, it is easy to keep vibrations of the holding part and the article held by the holding part caused by the extension / retraction movement of the holding part small.

[0068] Here, it is preferable that the device further includes a judgment unit that judges whether the holding unit is holding the item or not, and that the control unit extends the set period when the holding unit is holding the item compared to when the holding unit is not holding the item.

[0069] According to this configuration, when the holding unit holds an article, the set period is lengthened so that the change in acceleration acting on the article is small, thereby making it possible to suppress vibration of the article to a small extent. On the other hand, when the holding unit does not hold an article, the set period can be shortened so that the time required for the holding unit to move in and out is not lengthened. Therefore, according to this configuration, it is possible to suppress an increase in the time required for the holding unit to move in and out while suppressing vibration of the article held in the holding unit to a small extent.

[0070] It is also preferable that the device further includes a judgment unit which judges whether the holding unit is holding the item or not, and the control unit controls the outgoing / outgoing drive unit in accordance with the output command value during the outgoing / outgoing operation when the holding unit is holding the item, and controls the outgoing / outgoing drive unit in accordance with the command value indicated in the reference command pattern during the outgoing / outgoing operation when the holding unit is not holding the item.

[0071] According to this configuration, when the holding unit holds an article, the change in acceleration acting on the article can be kept small by controlling the protruding / retracting drive unit according to the output command value, which is the moving average of the command value shown in the reference command pattern, and the vibration of the article can be kept small. On the other hand, when the holding unit does not hold an article, the protruding / retracting drive unit is controlled according to the command value shown in the reference command pattern without taking the moving average, thereby making it possible to shorten the time required for the protruding / retracting operation of the holding unit compared to the case where the moving average is taken. Therefore, according to this configuration, it is possible to suppress the time required for the protruding / retracting operation of the holding unit from becoming long while keeping the vibration of the article held in the holding unit small.

[0072] It is also preferable that the device further includes a weight determination unit that determines the weight of the item held by the holding unit, and the control unit changes the set period depending on the weight of the item held by the holding unit.

[0073] According to this configuration, it is possible to set an appropriate set period depending on the weight of the item held by the holding section.

[0074] In addition, it is preferable that the device further includes a lifting / lowering drive unit for raising and lowering the holding unit, wherein the direction in which the holding unit is moved forward and backward by the lifting / lowering drive unit is along a horizontal plane, and the control unit changes the set period while the holding unit is being raised and lowered by the lifting / lowering drive unit.

[0075] According to this configuration, the set period can be changed by utilizing the period during which the lift drive unit is lifting and lowering the holding unit. By changing the set period during the lift drive unit's lift operation, the set period can be prevented from being changed during the holding unit's retraction and retraction operation, which makes it easier to stably perform the retraction and retraction operation of the holding unit.

[0076] It is sufficient for the article transfer device according to the present disclosure to achieve at least one of the above-mentioned effects. [Explanation of symbols]

[0077] 1: Goods transfer device 2: Goods 21: Holding part 30: Control unit 31: Judgment part 32: Weight determination section D: Direction of exit / exit M2: Lifting drive unit M3: Ingress / egress drive section

Claims

1. An article transfer device including a holding unit that holds an article, an extension / retraction drive unit that causes the holding unit to extend and retract, and a control unit that controls the extension / retraction drive unit, In an article transfer device, during an extension / retraction operation, which is an operation of extending or retracting the holding part by the extension / retraction drive part, the control part sets an output command value as a moving average of a set period of the command values ​​indicated in a reference command pattern, which is a time-varying pattern of command values ​​for position, speed, or acceleration, such that acceleration changes in steps over time, and controls the extension / retraction drive part in accordance with the output command value.

2. A determination unit that determines whether the holding unit is holding the item, The article transfer device according to claim 1 , wherein the control unit extends the set period when the holding unit is holding the article, compared to when the holding unit is not holding the article.

3. A determination unit that determines whether the holding unit is holding the item, The item transfer device described in claim 1, wherein the control unit controls the outgoing / retracting drive unit in accordance with the output command value during the outgoing / retracting operation when the holding unit is holding the item, and controls the outgoing / retracting drive unit in accordance with the command value indicated in the standard command pattern during the outgoing / retracting operation when the holding unit is not holding the item.

4. A weight determination unit that determines a weight of the item held by the holding unit, The article transfer device according to claim 1 , wherein the control unit changes the set period in accordance with a weight of the article held by the holding unit.

5. Further, a lifting drive unit that lifts and lowers the holding unit is provided, The extension / retraction direction of the holding part by the extension / retraction drive part is a direction along a horizontal plane, The article transfer device according to claim 2 , wherein the control unit changes the set period while the lift drive unit is lifting and lowering the holding unit.

Images