Transfer device

Abstract

A transfer device (100) equipped with a hook (110) and a forward / backward movement device (120) for moving the hook (110) forward and backward, the transfer device (100) comprising: a hook drive device (130) serving as a drive source that moves the hook (110) between an engaged position and a retracted position; a forward / backward drive device (140) that moves the forward / backward movement device (120) forward and backward; and a drive control device (150) that controls the hook drive device (130) and the forward / backward drive device (140). The drive control device (150) is equipped with: a hook position determination unit (151) that determines a hook position on the basis of a position threshold value; a hook (110) control unit that stops the hook (110) upon detecting an overload of the hook drive device (130); and a forward / backward drive device control unit (153) that moves the hook (110) forward and / or backward when the hook (110) control unit has stopped the hook drive device (130) and the acquired hook position is equal to or greater than the position threshold value.

Description

Technical Field

[0001] The present invention relates to a transfer device that moves a load from a predetermined holding part for holding the load to another holding part.

Background Art

[0002] Conventionally, as described in Patent Document 1 for example, there is a transfer device that transfers a load by moving a hook engaged with the load forward and backward. When the hook is not properly engaged with the load, such a transfer device detects an overload of a drive motor that drives the hook and treats it as an error. When an overload error is output, the transfer device is stopped to check the situation, and maintenance is performed as necessary.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the inventor has found that even when an overload error occurs, the hook may be sufficiently engaged with the load and the load can be transferred.

[0005] The present invention has been made based on the above findings of the inventor, and an object thereof is to provide a transfer device that can continue the transfer operation even when an overload error occurs.

Means for Solving the Problems

[0006] In order to achieve the above object, a transfer device, which is one of the present inventions, is a transfer device including a hook that engages with a load and a reciprocating device that moves the hook forward or backward, and includes a hook drive device that is a drive source for moving the hook between an engagement position and a retracted position, a reciprocating drive device that is a drive source of the reciprocating device, and a drive control device that controls the hook drive device and the reciprocating drive device. The drive control device includes a hook position determination unit that acquires a hook position, which is the position of the hook, and determines the hook position based on a position threshold value, a hook control unit that controls the hook drive device so that the hook stops when an overload of the hook drive device is detected, and a reciprocating drive device control unit that controls the reciprocating drive device so that the hook moves forward or backward when the acquired hook position is equal to or greater than the position threshold value when the hook control unit stops the hook drive device.

Advantages of the Invention

[0007] According to the present invention, even when an overload error occurs, the drive control device can determine the position of the hook and continue the transfer operation.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the transfer device according to the present invention will be described with reference to the drawings. Note that the following embodiments are examples for explaining the present invention and are not intended to limit the present invention. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, mathematical formulas, the content of each step in the method, the order of each step, etc. shown in the following embodiments are examples, and may include content not described below. In addition, although geometric expressions such as parallel and orthogonal may be used, these expressions do not indicate mathematical precision and include substantially allowable errors, deviations, etc. Also, expressions such as simultaneous and identical include a substantially allowable range.

[0010] Also, the drawings are schematic diagrams that are appropriately emphasized, omitted, or adjusted in ratio for explaining the present invention, and are different from the actual shapes, positional relationships, and ratios.

[0011] Also, in the following, a plurality of inventions may be comprehensively described as one embodiment. In addition, a part of the content described below is explained as an arbitrary component related to the present invention.

[0012] FIG. 1 is a perspective view showing the transfer device together with the holding part and the load. FIG. 2 is a block diagram showing the functional configuration of the transfer device. The transfer device 100 is a device that transfers the load 200 between the first holding part 300 and the second holding part 101, and includes a hook 110, a reciprocating device 120, a hook drive device 130, a reciprocating drive device 140, a drive control device 150, and a position sensor 160. In the case of this embodiment, the transfer device 100 is a device that transfers the load 200 while sliding on the first holding part 300 and the second holding part 101. The transfer device 100 is attached to, for example, a transport device (not shown) such as a stacker crane or a traveling vehicle that can transport the load 200.

[0013] The package 200 is held by the first holding part 300 which is a part for holding the package 200 of a device different from the transfer device 100, or a part for holding the package 200 of equipment such as a rack, and is an object to be transferred between the second holding part 101. The package 200 is provided with an engaged part 210 that fits the hook 110 provided in the transfer device 100.

[0014] The engaged part 210 is a part provided on the package 200 at a predetermined distance away from the outer side surface part 220 on a surface intersecting the transfer direction (Y-axis direction in the figure) of the package 200 toward the outside in the transfer direction (Y-side in the figure). It is a part with which the hook 110 provided in the transfer device 100 engages in the transfer direction and to which a force for transferring the package 200 from the hook 110 is applied. In the case of the present embodiment, the engaged part 210 is integrally attached to the outer side surface part 220 of the package 200, and two engaged parts 210 are arranged symmetrically with respect to the plane. Note that the package 200 may not be provided with an engaged part 210 having a special shape, and the front end surface, the rear end surface, etc. may function as the engaged part 210.

[0015] The second holding part 101 is provided in the transfer device 100 and is a part for holding the package 200. In the case of the present embodiment, the second holding part 101 corresponds to the first holding part 300 and is a plate-like part for holding the package 200 in a placed state, and holds both end parts in the width direction of the package 200 from below.

[0016] The hook 110 is a member that engages with the engaged part 210 of the package 200 and moves between an engagement position where it engages with the engaged part 210 and a retracted position where it does not engage with the engaged part 210. In the case of the present embodiment, the hook 110 is inserted between the engaged part 210 of the package 200 by rotating around a rotation axis along the transfer direction (Y-axis direction in the figure), and applies a force for transferring the package 200 to the engaged part 210. The transfer device 100 includes two hooks 110 that are symmetric with respect to the YZ plane in the figure, and each rotates in the opposite direction. Further, the transfer device 100 includes two symmetric hooks 110 arranged side by side in the transfer direction. Thereby, it is possible to transfer the package 200 regardless of which side in the transfer direction it is arranged on.

[0017] The advancing and retracting device 120 is a device that moves the hook 110 forward or backward in the transfer direction, and is a device that can reciprocate the load 200 in the transfer direction via the engaged portion 210 of the load 200 or the hook 110 that engages with the outer side surface portion 220. In the case of this embodiment, the advancing and retracting device 120 simultaneously reciprocates the four hooks 110 in the transfer direction. The advancing and retracting device 120 also reciprocates the hook driving device 130 together with the hook 110. Specifically, for example, the advancing and retracting device 120 includes a rail that guides the hook 110 in the transfer direction and a linear motion unit that reciprocates these.

[0018] The hook driving device 130 is a device that moves the hook 110 between an engaged position where it engages with the engaged portion 210 and a retracted position, and includes a motor. In the case of this embodiment, the hook driving device 130 and the four hooks 110 are connected via a conversion mechanism in which mechanical elements are combined, and one hook driving device 130 can rotate and swing the four hooks 110 symmetrically in the plane at the same time.

[0019] The type of the hook driving device 130 is not particularly limited, but in the case of this embodiment, the hook driving device 130 includes a servo amplifier, a servo motor driven by the servo amplifier, a speed reducer, and the like.

[0020] The advancing and retracting driving device 140 is a driving means for advancing or retracting the advancing and retracting device 120. The type of the advancing and retracting driving device 140 is not particularly limited, but in the case of this embodiment, similar to the hook driving device 130, the advancing and retracting driving device 140 includes a servo amplifier, a servo motor driven by the servo amplifier, a speed reducer, and the like.

[0021] The position sensor 160 is a sensor that detects the hook position, which is the position of the hook 110 between the engagement position and the retracted position, including the engagement position and the retracted position. The type of the position sensor 160 is not particularly limited, but in the case of this embodiment, an optical encoder is adopted. The position sensor 160 is attached to a shaft connected to two hooks 110 arranged in the transfer direction. Note that the position sensor 160 may be a potentiometer, a resolver, etc., or may be a sensor included in the hook drive device 130 that is a servo motor.

[0022] The drive control device 150 is a device that controls the hook drive device 130 and the forward and backward drive device 140 to cause the hook 110 and the forward and backward device 120 to perform predetermined operations. As a processing unit realized by causing a processor to execute a program, the drive control device 150 includes a hook position determination unit 151, a hook control unit 152, and a forward and backward drive device control unit 153. In the case of this embodiment, the drive control device 150 includes an abnormality notification unit 154.

[0023] The hook position determination unit 151 is a processing unit that acquires the hook position, which is the position of the hook 110, from the position sensor 160 and determines whether the hook position is equal to or greater than a position threshold value. Here, being equal to or greater than the position threshold value means that the hook 110 is located at the engagement position, and being less than the position threshold value means that the hook 110 is located at the retracted position. In the case of this embodiment, based on the information obtained from the position sensor 160, for example, when the hook is located on the most retracted position side, the hook position is set to 0, and when it is located on the most engagement position side, the hook position is set to 255, and the hook position is acquired with a predetermined resolution, and it is determined whether the hook position is equal to or greater than the position threshold value. When the hook position is equal to or greater than the position threshold value, the hook position determination unit 151 determines that the hook 110 is present at the engagement position, and when the hook position is less than the position threshold value, it determines that the hook 110 is present at the retracted position. The position threshold value that serves as the criterion for the hook position determination unit 151 is not limited, but it is a value empirically derived, for example, when the hook 110 is not at the engagement position but a considerable amount is engaged with the engaged portion 210 and transfer is possible. Even when the value output by the position sensor 160 is reversed, for example, when the case where it is present on the most retracted position side is set to 255 and the case where it is present on the most engagement position side is set to 0, if the hook position is numerically less than the position threshold value, the hook position determination unit 151 determines that the hook 110 is located at the engagement position and thus is equal to or greater than the position threshold value, and if the hook position is numerically equal to or greater than the position threshold value, it determines that the hook 110 is located at the retracted position and thus is less than the position threshold value.

[0024] When the hook control unit 152 detects an overload of the hook drive device 130 when the hook 110 moves from the retracted position to the engaged position, the hook control unit 152 controls the hook drive device 130 so that the hook 110 stops. In the case of this embodiment, when the servo amplifier included in the hook drive device 130 exceeds the first load threshold, it outputs overload information and abnormally stops the servo motor to stop the hook 110. The hook control unit 152 acquires load information regarding the load from the hook drive device 130, and based on the second load threshold lower than the first load threshold and the acquired load information, detects an overload and controls the hook drive device 130 so that the hook 110 stops before acquiring the overload information. Specifically, the hook control unit 152 stops the hook 110 by stopping the instruction for the servo motor to operate in that direction. As described above, the hook control unit 152 can stop the operation of the hook 110 before a large load is applied to the hook drive device 130. The load information is information related to the torque of the servo motor, and is, for example, information based on the current value of the current supplied by the servo amplifier to the servo motor.

[0025] Further, when the hook control unit 152 stops the hook drive device 130, if the hook position determination unit 151 determines that the hook position is less than the position threshold, the hook control unit 152 controls the hook drive device 130 to move the hook 110 to the retracted position.

[0026] Note that when the load information continuously exceeds the second load threshold for a time threshold or more, it is preferable that the hook control unit 152 controls the hook drive device 130 so that the hook 110 stops. Thereby, it is possible to exclude the stop due to the momentary increase in the load information, and the hook 110 can be stably controlled.

[0027] When the hook control unit 152 stops the hook drive device 130, if the hook position acquired by the hook position determination unit 151 is equal to or greater than the position threshold value, the forward and reverse drive device control unit 153 controls the forward and reverse drive device 140 so that the hook 110 moves forward or backward based on the transfer information while maintaining the state of the stopped hook 110. Thereby, even in the state of the hook 110 that has not reached the engagement position, the load 200 can be transferred.

[0028] Also, when the hook position determination unit 151 determines that the hook position acquired when the hook control unit 152 stops the hook drive device 130 is less than the position threshold value, after controlling the hook drive device 130 to move the hook 110 to the retracted position, the forward and reverse drive device control unit 153 controls the forward and reverse drive device 140 so that the hook 110 moves forward or backward based on the transfer information. Thereby, the load 200 remains without being transferred, and the hook 110 retreats and exits from the first holding unit 300.

[0029] When the hook position determination unit 151 determines that the hook position acquired when the hook control unit 152 stops the hook drive device 130 is less than the position threshold value, the abnormality notification unit 154 notifies abnormality information. The method of notifying the abnormality information is not particularly limited. For example, the abnormality information may be output to a host computer. Also, the abnormality information may be notified to the user by sound, light, characters, images, or the like.

[0030] Next, the processing flow of the drive control device 150 will be described. FIG. 3 is a flowchart showing the processing flow of the drive control device. Note that the flowchart shown in FIG. 3 is an example, and the embodiments of the present invention may include cases where the processing order is different, a plurality of processes are integrated, or one process is separated, etc., and the processing flow is different. The forward and reverse drive device control unit 153 controls the forward and reverse drive device 140 so that the hook 110 is arranged at the retracted position with respect to the engaged portion 210 of the load 200 based on the acquired transfer information (S101). When the hook 110 is arranged at the retracted position, the hook control unit 152 controls the hook drive device 130 so that the hook 110 moves to the engagement position.

[0031] Based on the information from the position sensor 160, the hook position determination unit 151 acquires the position of the hook 110. When it is determined that the hook 110 has not reached the engagement position (S103, No), the hook control unit 152 acquires the load information regarding torque from the hook drive device 130 and determines whether it exceeds the second load threshold (S104). When the load information is less than the second load threshold (S104, No), the process returns to the confirmation of the position of the hook 110 (S103). When the load information is equal to or greater than the second load threshold (S104, Yes), the hook position determination unit 151 determines whether the load information continues to exceed the second load threshold for a time threshold or more (S105). When the load information does not continue to exceed the second load threshold for a time threshold or more (S105, No), the process returns to the confirmation of the position of the hook 110 (S103).

[0032] When the load information continues to exceed the second load threshold for a time threshold or more (S105, Yes), the hook control unit 152 controls the hook drive device 130 so that the operation of the hook 110 stops (S106). In this state, the hook control unit 152 performs control to stop, for example, an instruction for the servo motor to operate in that direction, but it is in a state where the hook drive device 130 can be further controlled to move the hook 110. Also, the hook control unit 152 stores an overload stop log (S107). The content of the overload stop log is not limited, but for example, the value (torque) of the finally detected additional information, the stop position of the hook 110, etc. can be exemplified.

[0033] Next, the hook position determination unit 151 determines whether the hook position acquired from the position sensor 160 is equal to or greater than the position threshold value (S108). When the hook position is equal to or greater than the position threshold value (S108, Yes), while maintaining the position of the hook 110 stopped by the hook control unit 152, the forward and backward drive device control unit 153 drives the forward and backward drive device 140 based on the transfer information to transfer the load 200 (S109). On the other hand, when the hook position is less than the position threshold value (S108, No), the hook control unit 152 controls the hook drive device 130 so that the hook 110 moves to the retracted position (S110). When the hook 110 reaches the retracted position, the forward and backward drive device control unit 153 controls the forward and backward drive device 140 to arrange the hook 110 and the forward and backward device 120 at positions where maintenance is possible (S111). The abnormality notification unit 154 notifies abnormality information (S112). The abnormality information may include the content of the log saved in step S107).

[0034] Note that when the abnormality information is notified, the facility equipped with the transfer device 100 may stop operation and perform maintenance. Alternatively, only the transfer of the load 200 to be transferred may be aborted, and the transfer of other loads 200 may be continued.

[0035] According to the transfer device 100 according to the embodiment, even when the hook 110 stops due to an overload, based on the position where the hook 110 stops, it is determined whether to transfer the load 200. Therefore, the number of stops of the transfer device 100 and the facility equipped with the transfer device 100 can be suppressed, and the transfer efficiency of the load 200 can be increased.

[0036] In addition, before a device such as a servo amplifier provided in the hook drive device 130 detects an overload based on the first load threshold value and abnormally stops the operation of the hook 110, the hook control unit 152 detects the overload software-wise based on a second load threshold value lower than the first load threshold value. Therefore, the forced stop time of the hook 110 by a device such as a servo amplifier can be reduced, and the time required for recovery can be shortened.

[0037] In addition, by moving the advancing / retreating device 120 to a position where maintenance is possible and notifying abnormal information, the time required for maintenance for recovery can be shortened.

[0038] Note that the present invention is not limited to the above-described embodiments. For example, another embodiment realized by arbitrarily combining the constituent elements described in this specification and excluding some of the constituent elements may also be an embodiment of the present invention. Further, various modifications conceived by those skilled in the art without departing from the gist of the present invention, that is, the meaning indicated by the language described in the claims, with respect to the above-described embodiments are also included in the present invention.

[0039] For example, the advancing / retreating device 120 may include an extendable and retractable arm, and the hook 110 may be attached to the end of the arm. The arm is inserted laterally to the load 200, the hook 110 is hooked on the rear end face of the load 200, and the load 200 is transferred from the first holding portion 300 to the second holding portion 101 by retracting the arm. Then, the hook 110 may be hooked on the front end face of the load 200, and the load 200 may be transferred from the second holding portion 101 to the first holding portion 300 by advancing the arm.

[0040] In addition, the hook 110 is not limited to rotating around a rotation axis along the transfer direction (Y-axis direction in the figure), and as shown in FIG. 4, it may rotate around a rotation axis 139 extending in the vertical direction. Further, the hook 110 may move linearly without rotating.

[0041] In addition, the load 200 is applicable not only to a load 200 in an arbitrary holding state such as being held in a placed state but also being held in a suspended state.

Industrial Applicability

[0042] The present invention is applicable to a transfer device for transferring loads in an automated warehouse, a station at a logistics base, a picking system, and the like.

Explanation of Reference Numerals

[0043] 100 Transfer device 101 Second holding part 110 Hook 120 Advancing and retracting device 130 Hook drive device 139 Rotating shaft 140 Advancing and retracting drive device 150 Drive control device 151 Hook position determination part 152 Hook control part 153 Advancing and retracting drive device control part 154 Abnormality notification part 160 Position sensor 200 Load 210 Engaged part 220 Outer surface part 300 First holding part

Claims

1. A transfer device comprising a hook that engages with a load and a forward / backward movement device that moves the hook forward or backward, a hook drive device that is a drive source for moving the hook between an engagement position and a retracted position, a forward / backward drive device that is a drive source for the forward / backward movement device, and a drive control device that controls the hook drive device and the forward / backward drive device, wherein the drive control device includes a hook position determination unit that acquires the hook position, which is the position of the hook, and determines the hook position based on a position threshold value, a hook control unit that controls the hook drive device so that the hook stops when an overload of the hook drive device is detected, and a forward / backward drive device control unit that controls the forward / backward drive device so that the hook moves forward or backward when the acquired hook position is equal to or greater than the position threshold value when the hook control unit stops the hook drive device. Transfer device.

2. wherein the hook control unit controls the hook drive device so that the hook moves to the retracted position when the acquired hook position when the hook drive device is stopped is less than the position threshold value, and the forward / backward drive device control unit controls the forward / backward drive device so that the hook moves forward or backward after the hook has moved to the retracted position, and the drive control device includes an abnormality notification unit that notifies abnormality information when the acquired hook position when the hook drive device is stopped is less than the position threshold value. The transfer device according to claim 1.

3. The hook drive device outputs overload information based on a first load threshold value, and the hook control unit Obtain load information regarding the load from the hook drive device, detect an overload based on a second load threshold lower than the first load threshold and the load information, and control the hook drive device so that the hook stops. The transfer device according to claim 1 or 2.

4. The hook control unit When the load information continuously exceeds the second load threshold for a time threshold or more, control the hook drive device so that the hook stops. The transfer device according to claim 3.

Images