Control device for a material handling device

Abstract

A control device of a material handling device capable of conveying and assembling a plurality of workpieces having different shapes. A control device of a material handling device, the material handling device including: a frame held by a robot arm in a manner capable of changing a position and an attitude; and at least two holding portions provided on the frame, wherein the frame has a support portion and is held by the robot arm in a manner of rotating around a central axis of the support portion, the two holding portions are provided on both sides across the central axis of the support portion, and in a case where the frame is opposed to a workpiece with the position of the frame moved to a predetermined initial position and the attitude of the frame controlled to a predetermined initial attitude (step S1), in a case where a length of the workpiece in a direction intersecting a virtual line connecting the two holding portions is longer than a distance between the two holding portions (NO in step S3), the frame is rotated (step S4).

Description

Technical Field

[0001] This invention relates to a control device for a material handling apparatus that holds multiple parts of a workpiece for conveying or installing the workpiece. Background Technology

[0002] Patent Document 1 describes a glass mounting system for attaching a vehicle's windshield, rear windshield, and quarter-windshield to the vehicle body. This glass mounting system includes: a conveying device for conveying large glass panes such as the windshield or rear windshield and small glass panes such as the quarter-windshield; a large glass mounting robot for mounting the large glass panes conveyed by the conveying device onto the vehicle body; and a small mounting robot for mounting the small glass panes onto the vehicle body. These large and small glass mounting robots consist of a holding device that adsorbs and holds the glass, and a robotic arm that can change the position or orientation of the holding device.

[0003] Patent Document 2 describes a material handling device mounted on the front end of a robot arm. This material handling device is configured to allow a workpiece held by a holding part to move horizontally relative to the front end of the robot arm while maintaining the workpiece's horizontal posture, without the need for a sliding mechanism. Specifically, the material handling device comprises a handle held by the robot arm, a holding part that holds the workpiece, a rotating body that rotatably supports the holding part, and an electric motor located on the side opposite to the rotating body, separated from it by the handle, and supplying torque to the rotating body via a transmission mechanism.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2009-220733

[0005] Patent Document 2: Japanese Patent Application Publication No. 2024-093982 Summary of the Invention

[0006] As described in Patent Document 1 or Patent Document 2, when holding a workpiece, it is preferable to hold the workpiece near its outer periphery using multiple holding parts. Therefore, conventional material handling devices are structured based on the shape of the workpiece being transported and assembled. Thus, for example, in the design where a workpiece larger than intended is being held, the distance between the holding part and the outer periphery of the large workpiece becomes longer. The outer periphery of the large workpiece has low rigidity, and vibration at the outer periphery may lead to a decrease in the assembly accuracy of the workpiece. In other words, a material handling device for transporting and assembling a predetermined workpiece is sometimes unsuitable for transporting and assembling workpieces with shapes different from the intended workpiece. Furthermore, if a separate dedicated material handling device is prepared for transporting and assembling workpieces with different shapes, in addition to increased system costs, manufacturing time may also increase due to the need to replace the material handling device.

[0007] This invention was made in view of the above-mentioned technical problems. The purpose of this invention is to provide a control device for a material handling device that can transport and assemble multiple workpieces of different shapes.

[0008] To achieve the above objectives, the present invention provides a control device for a material handling apparatus, the material handling apparatus comprising: a frame held by a robotic arm in a manner capable of changing position and posture; and at least two holding portions disposed on the frame, wherein the material handling apparatus holds a workpiece for conveying and assembling via the holding portions, wherein the frame has a support portion and is held by the robotic arm in a manner rotatable about a central axis of the support portion, the two holding portions being disposed on both sides of the central axis of the support portion, and the control device for the material handling apparatus comprising a controller for controlling the position and posture of the frame, wherein the controller moves the position of the frame to a predetermined initial position and controls the posture of the frame to a predetermined initial posture so that the frame is facing the workpiece, and if the length of the workpiece in the direction intersecting with the virtual line connecting the two holding portions is longer than the distance between the two holding portions, the controller rotates the frame to hold the workpiece.

[0009] Furthermore, in this invention, the workpiece can be as follows: the workpiece includes a first workpiece whose length in the width direction is longer than its length in the height direction; and a second workpiece whose length in the height direction is longer than that of the first workpiece; the initial position includes a position in which the support portion is opposite to the center of gravity of the first workpiece; and the initial posture includes the posture of the virtual line connecting the two holding portions along the width direction of the first workpiece.

[0010] Furthermore, in this invention, the frame may be configured such that, when the first workpiece is held, it is opposed to the outer periphery of the first workpiece and detects the gap between the first workpiece and the portion assembling the first workpiece, and at least one of the plurality of sensors is disposed at a position that, when the second workpiece is held, is opposed to the outer periphery of the second workpiece and is capable of detecting the gap between the second workpiece and the portion assembling the second workpiece.

[0011] Invention Effects

[0012] The material handling device of this invention has at least two holding parts on a frame held by a robotic arm in a manner that allows for changes in position and orientation. These holding parts are positioned on both sides, separated by the central axis of the support held by the robotic arm. That is, when holding a workpiece by the material handling device, the rigidity in the direction where the holding parts are formed is increased. The control device for this material handling device is configured such that, when the frame is moved to an initial position and its orientation is controlled to the initial orientation so that the frame is positioned opposite the workpiece, and the length of the workpiece in the direction intersecting the virtual line connecting the two holding parts is longer than the distance between the two holding parts, the frame is rotated to hold the workpiece. In other words, when holding a workpiece corresponding to the initial position and initial orientation, it is not necessary to rotate the frame to hold the workpiece. Therefore, the rotation angle of the frame can be controlled to an orientation suitable for the shape of the workpiece to hold it. In other words, by holding the workpiece near its outer edge by the holding parts, workpiece deflection or vibration caused by loads acting on the workpiece can be suppressed, and a decrease in the assembly accuracy of the workpiece can be suppressed. As a result, a material handling device configured for a specified workpiece can be used as a material handling device for conveying and assembling workpieces of other shapes. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating an example of a material handling device according to an embodiment of the present invention.

[0014] Figure 2 This is a flowchart illustrating an example of control performed by the control device of a material handling device.

[0015] Figure 3 This diagram illustrates the operation of a material handling device when holding a large windshield. Figure 3 (a) is a diagram showing the initial position and initial posture of the material handling device. Figure 3 (b) is a diagram showing the state in which the material handling device is rotating. Figure 3 (c) is a diagram showing the state of maintaining a large windshield. Detailed Implementation

[0016] The present invention will be described based on the embodiments shown in the figures. Furthermore, the embodiments described below are merely examples embodying the present invention and do not limit the scope of the invention.

[0017] exist Figure 1 An example of a material handling device according to an embodiment of the present invention is shown. Figure 1The material handling device 1 shown is configured to transport the windshield of a vehicle and embed it into a window frame formed on the vehicle body. The material handling device 1 is held by a robotic arm A, configured such that by controlling the robotic arm A, the material handling device 1 is moved to a position holding the windshield 2, and the windshield 2 is embedded into a window frame (not shown) by moving the material handling device 1 holding the windshield 2. Therefore, the robotic arm A is configured to be able to move the material handling device 1 in the vehicle width direction, the vehicle longitudinal direction, and the vehicle height direction, and to rotate the material handling device 1 about axes along the vehicle width direction, the vehicle longitudinal direction, and the vehicle height direction, respectively.

[0018] Figure 1 The material handling device 1 shown is configured to transport a conventional windshield 2a, which is shorter in the width direction than the height direction of a car-type vehicle, and assemble it into the window frame of the vehicle body. Furthermore, the conventional windshield 2a is formed in a trapezoidal diameter shape with the upper end shorter than the lower end, and is symmetrically shaped on both sides of the central portion in the width direction. This conventional windshield 2a corresponds to the "first workpiece" in the embodiment of the present invention.

[0019] like Figure 1 As shown, the material handling device 1 includes a frame 3, a holding part 4, and a sensor 5. The frame 3 has a rectangular base part 3a, and a cylindrical tool flange part 3b protruding from the upper surface of the base part 3a is formed in the central part of the base part 3a. The tool flange part 3b is held by a robot arm A, etc. That is, in order to change the position or posture of the frame 3 by the robot arm A, the tool flange part 3b is held by the robot arm A. Furthermore, the material handling device 1 is configured to rotate around the central axis of the tool flange part 3b by rotating the part of the robot arm A that holds the tool flange part 3b, etc. In addition, the tool flange part 3b corresponds to the "support part" in the embodiment of the present invention.

[0020] The base portion 3a is provided with a first retaining arm 3c protruding from above in the left direction, a second retaining arm 3d protruding from above in the right direction, a third retaining arm 3e protruding from below in the left direction and arranged parallel to the first retaining arm 3c, and a fourth retaining arm 3f protruding from below in the right direction and arranged parallel to the second retaining arm 3d. That is, each retaining arm 3c, 3d, 3e, and 3f extends toward the vicinity of the four corners of the windshield 2a. Alternatively, the first retaining arm 3c and the third retaining arm 3e may be constructed as an integral shaft member, and the second retaining arm 3d and the fourth retaining arm 3f may be constructed as an integral shaft member, and the base portion 3a may be mounted by connecting these shaft members.

[0021] In addition, when the windshield 2a is held in a predetermined position by the material handling device 1, the front ends of the first retaining arm 3c and the third retaining arm 3e are formed to overlap with the left edge of the windshield 2a, and their front ends are connected to each other by the reinforcing part 3g.

[0022] Furthermore, a [feature] is provided on the base portion 3a. Figure 1 The first sensor is mounted on the left-hand side extending upwards along the 3h axis. Figure 1 The second sensor mounting shaft 3i extends upward from the right side of the windshield. These first sensor mounting shafts 3h and second sensor mounting shafts 3i are formed to protrude from the upper edge of the normal windshield 2a when held by the material handling device 1. Furthermore, the material handling device 1 is configured to transport and assemble the large windshield 2b (described later), and when the large windshield 2b is held as described later, the front end of the first sensor mounting shaft 3h is formed to protrude from the right edge of the large windshield 2b. Additionally, in... Figure 1 In the example shown, the second sensor mounting shaft 3i is formed to be shorter than the first sensor mounting shaft 3h, but it can also be formed to be the same length as the first sensor mounting shaft 3h.

[0023] Furthermore, the material handling device 1 is configured to hold the normal windshield 2a in a state opposite to it. Therefore, holding portions 4 for holding the normal windshield 2a are provided on the surfaces of each holding arm 3c, 3d, 3e, and 3f facing the normal windshield 2a. Specifically, a first holding portion 4a is provided on the first holding arm 3c, a second holding portion 4b is provided on the second holding arm 3d, a third holding portion 4c is provided on the third holding arm 3e, and a fourth holding portion 4d is provided on the fourth holding arm 3f. Thus, each holding portion 4a, 4b, 4c, and 4d is provided such that the imaginary surface connecting adjacent holding portions is rectangular. In other words, a pair of first retaining portions 4a and third retaining portions 4c are provided to retain the tool flange portion 3b on the side closer to the vehicle width direction (e.g., the left side), and a pair of second retaining portions 4b and fourth retaining portions 4d are provided to retain the tool flange portion 3b on the other side closer to the vehicle width direction (e.g., the right side).

[0024] These retaining parts 4a, 4b, 4c, and 4d are composed of suction pads, and suction devices (not shown) are connected to these suction pads. Therefore, the windshield 2a can be retained by the suction device drawing air from the suction pad while the suction pad is pressed against the windshield 2a, thereby generating a retaining force between the windshield 2a and the suction pad. Conversely, the suction pad can be removed from the windshield 2a by supplying air into the suction pad through the suction device.

[0025] Furthermore, a typical left sensor 5a and a large lateral sensor 5b are provided on the aforementioned first sensor mounting shaft 3h. Specifically, when the material handling device 1 holds the typical windshield 2a, the typical left sensor 5a is provided at the position where the first sensor mounting shaft 3h intersects with the upper edge of the typical windshield 2a, and as described later, when the material handling device 1 holds the large windshield 2b, the large lateral sensor 5b is provided at the position where the first sensor mounting shaft 3h intersects with the right edge of the large windshield 2b.

[0026] Furthermore, a normally right sensor 5c is provided on the second sensor mounting shaft 3i. Specifically, when the material handling device 1 holds the normally windshield 2a, the normally right sensor 5c is provided at the position where the second sensor mounting shaft 3i intersects with the upper edge of the normally windshield 2a.

[0027] Furthermore, a general lateral sensor 5d is provided on the first holding arm 3c. Specifically, when the material handling device 1 holds the general windshield 2a, and when the material handling device 1 is rotated to hold the large windshield 2b at the position where the first holding arm 3c intersects with the left edge of the general windshield 2a, as described later, a general lateral sensor 5d is provided at the position where the first holding arm 3c intersects with the upper edge of the large windshield 2b.

[0028] Furthermore, a large left sensor 5e is provided on the third holding arm 3e. Specifically, when the large windshield 2b is held by the material handling device 1 as described later, the large left sensor 5e is provided at the position where the third holding arm 3e intersects with the upper edge of the large windshield 2b.

[0029] The aforementioned sensors 5a, 5b, 5c, 5d, and 5e (hereinafter, sometimes collectively referred to as sensor 5) are capable of measuring, for example,... Figure 1The sensor 5 is a conventional linear optical sensor that measures the depth (distance from sensor 5) of a defined length range centered on sensor 5 and the distances between objects within that range, as shown by dashed lines. Therefore, when the windshield 2 is mounted on a window frame, it is possible to measure the distance (gap) between the periphery of the windshield 2 and the inner edge of the window frame, or the distance (distance in the depth direction) between the periphery of the windshield 2 and the inner edge of the window frame in the direction in which the windshield 2 is embedded in the window frame. These sensors 5 are connected to a controller 6 for controlling the robotic arm A.

[0030] Therefore, when the windshield 2a is embedded in the window frame, the positional relationship between the windshield 2a and the window frame can be determined based on the signals detected by the left sensor 5a, the right sensor 5c, and the lateral sensor 5d, and the position of the windshield 2a can be corrected based on the determined positional relationship. For example, in addition to the vertical or horizontal position of the windshield 2a, the roll angle or yaw angle of the windshield 2a can also be corrected.

[0031] In the material handling device 1 configured as described above, in order to suppress the torque acting on the robot arm A or the tool flange 3b based on the load acting on the holding part 4, the tool flange 3b is provided at the center of gravity of the material handling device 1. Furthermore, the device is configured to hold the workpiece by adjusting the relative position between the workpiece and the material handling device 1 such that the center of gravity of the held object (workpiece) is located within a predetermined radius from the center of gravity of the material handling device 1. Additionally, in Figure 1 In the figure, the center of gravity of the workpiece (usually the windshield 2a) is exaggeratedly represented by a dashed line, and the allowable range of the center of gravity of the tool flange 3b and the workpiece (a circle with the specified radius) is represented by a single-dot dashed line.

[0032] Therefore, in Figure 1 In the example shown, the position of the material handling device 1 is controlled such that the center of gravity of the tool flange 3b overlaps with that of the normal windshield 2a; that is, the position where the tool flange 3b is located is opposite to the center of gravity of the normal windshield 2a. Furthermore, the center of gravity position of the normal windshield 2a in the coordinate system of the robot arm A when the material handling device 1 holds the normal windshield 2a is pre-stored in the controller 6.

[0033] The controller 6 is primarily composed of a microcomputer and is configured to output command signals to multiple actuators (electric motors) (not shown) mounted on the robot arm A based on signals input from the sensor 5 and pre-stored formulas. Specifically, it calculates the correction amount for the position of the material handling device 1 in the vertical, horizontal, or forward / backward directions (usually the assembly direction of the windshield 2a) or the correction angle for the roll or pitch angle of the material handling device 1 based on the gap between the windshield 2a and the window frame detected by the sensor 5, and outputs command signals to each actuator based on the calculated correction amount or correction angle.

[0034] On the other hand, the windshield 2 (hereinafter referred to as the large windshield 2b) for a station wagon type vehicle is longer in the vehicle height direction than the normal windshield 2a. Therefore, the center of gravity of the large windshield 2b is higher in the vehicle height direction than that of the normal windshield 2a. Therefore, when the large windshield 2b is held by the material handling device 1, the center of gravity of the large windshield 2b can be maintained by shifting the material handling device 1 in the vehicle height direction compared to the case of holding the normal windshield 2a. This large windshield 2b corresponds to the "second workpiece" in the embodiment of the present invention.

[0035] However, in the posture of the material handling device 1 when the windshield 2a is held normally, the long dimension direction of the imaginary rectangular surface connecting the adjacent holding parts becomes horizontal. Therefore, the distance between the upper edge of the large windshield 2b and the first holding part 4a or the third holding part 4c becomes longer, and the distance between the lower edge of the large windshield 2b and the second holding part 4b or the fourth holding part 4d becomes longer.

[0036] Furthermore, when assembling the windshield 2 onto the vehicle body, typically with the windshield 2 tilted relative to the window frame, one end of the windshield 2 (top or bottom) is inserted into the window frame before the other end, and then the other end is inserted into the window frame. Therefore, there are times when the torque based on the load acting on the top of the windshield 2 and the torque based on the load acting on the bottom of the windshield 2 do not cancel each other out. Additionally, since the left and right ends of the windshield 2 are assembled into the window frame almost simultaneously, the torque based on the load acting on the left edge and the torque based on the load acting on the right edge are opposing forces and generated almost simultaneously, thus these torques cancel each other out.

[0037] Therefore, in the embodiments of the present invention, the control device is configured such that, while holding the large windshield 2b, the material handling device 1 is rotated so that the longitudinal direction of the imaginary rectangular surface connecting adjacent holding portions is along the vertical direction of the large windshield 2b; in other words, the large windshield 2b is held in such a way that the virtual line connecting the holding portions provided on both sides across the tool flange portion 3b is in the vertical direction of the large windshield 2b. Figure 2 The diagram shows a flowchart illustrating an example of this control.

[0038] exist Figure 2 In the control example shown, firstly, the material handling device 1 is moved to a predetermined position (step S1). Specifically, while maintaining the ordinary windshield 2a that was previously mounted on the vehicle body, the position and orientation of the frame 3 are controlled so that the frame 3 is aligned with the ordinary windshield 2a, and the center of gravity of the ordinary windshield 2a is within a predetermined range of the tool flange 3b. In this step S1, the center of gravity position of the mounted ordinary windshield 2a in the coordinate system of the robot arm A can be pre-stored in the controller 6, and the material handling device 1 is moved to this center of gravity position as the target position. Furthermore, the position of the frame 3 moved by this step S1 corresponds to the "initial position" in the embodiment of the present invention, and the orientation of the frame 3 aligned with the ordinary windshield 2a corresponds to the "initial orientation" in the embodiment of the present invention.

[0039] Next, the distance between the workpiece's center of gravity and the tool flange 3b is calculated (step S2). Specifically, information about whether the workpiece held by the material handling device 1 is a regular windshield 2a or a large windshield 2b, and its center of gravity coordinates, is read from the controller controlling the assembly line of the windshield 2. Then, the distance between the workpiece's center of gravity and the position of the tool flange 3b of the material handling device 1, which moved in step S1, is calculated.

[0040] Additionally, in step S2, the workpiece can be photographed using a camera (not shown), and its center of gravity position can be determined based on the image data. Furthermore, in step S2, for example, a sensor capable of detecting the magnitude and orientation of the load exerted by the portion of the tool flange 3b held by the robot arm A can be installed. The workpiece is temporarily held at the position where the material handling device 1 was moved in step S1, and its center of gravity position is determined based on the magnitude or orientation of the load detected by the aforementioned sensor.

[0041] After step S2, it is determined whether the distance between the center of gravity of the workpiece and the tool flange 3b is within a predetermined range (step S3). Specifically, it is determined whether the center of gravity of the workpiece is within a predetermined radius of the center of gravity of the material handling device 1 (i.e., the position of the tool flange 3b) predetermined based on the structure (rigidity) of the material handling device 1.

[0042] If the judgment is rejected in step S3 because the distance between the workpiece's center of gravity and the tool flange 3b is not within the specified range, it is assumed that the length of the workpiece in the vertical direction—in other words, the length of the workpiece in the direction intersecting the virtual line connecting the first holding part 4a and the second holding part 4b or the virtual line connecting the third holding part 4c and the fourth holding part 4d—is longer than the distance to these holding parts 4a, 4b (4c, 4d). In this case, even if the material handling device 1 is moved so that the tool flange 3b is near the workpiece's center of gravity, the torque acting on the material handling device 1 increases during workpiece transport or assembly, which may lead to a decrease in the workpiece's assembly accuracy.

[0043] Therefore, if the judgment is negative in step S3, the material handling device 1 is rotated by a predetermined angle (step S4), returning to step S1. Furthermore, upon returning to step S1, the predetermined position in step S1 is rewritten as the coordinates of the material handling device 1 opposite the center of gravity of the workpiece to the tool flange 3b. As a result, the judgment is positive when step S3 is executed again.

[0044] Conversely, if the distance between the workpiece's center of gravity and the tool flange 3b is within a specified range and is confirmed in step S3, the workpiece is held (step S5), and the routine is temporarily terminated.

[0045] exist Figure 3 The diagram shows the operation of the material handling device 1 used to illustrate the holding of the large windshield 2b. (See diagram below.) Figure 3 As shown in (a), firstly, the material handling device 1 is moved to the position where the windshield 2a is normally maintained. Additionally, in Figure 3 In (a), the standby position of the windshield 2a is indicated by a dashed line, that is, the position in which the windshield 2a is normally placed while the windshield 2a is in normal condition.

[0046] like Figure 3 As shown in (a), while maintaining the normal windshield 2a, the large windshield 2b is mounted such that its upper edge is aligned with the upper edge of the large windshield 2b. Therefore, the center of gravity of the large windshield 2b is lower than that of the normal windshield 2a, resulting in a negative judgment in step S3 of the control example described above.

[0047] Therefore, by performing step S4 above, as Figure 3 As shown in (b), the material handling device 1 rotates 90 degrees clockwise. Furthermore, by rewriting the specified position in step S1 as the coordinates of the material handling device 1 with the center of gravity of the tool flange 3b opposite to that of the large windshield 2b, as follows... Figure 3 As shown in (c), the material handling device 1 moves downward to maintain the large windshield 2b.

[0048] In addition, Figure 1 The material handling device 1 shown is equipped with a sensor 5 for detecting the positional relationship such as the gap between the outer periphery of the windshield 2 and the inner periphery of the window frame. Therefore, as described above, when the material handling device 1 is moved to the center of gravity position of the windshield 2, the position of the material handling device 1 can be corrected so that the outer periphery of the windshield 2 and the inner periphery of the window frame become the detection range of the sensor 5.

[0049] As described above, a tool flange portion 3b held by the robot arm A is formed on the frame 3, and holding portions 4a, 4b (4c, 4d) are provided on both sides of the central axis of the tool flange portion 3b. Furthermore, in order to hold the general windshield 2a in the vehicle width direction which is longer than the vehicle height direction, the material handling device 1 equipped with this frame 3 provides a holding portion 4 according to the length of the general windshield 2a in the vehicle width direction.

[0050] Then, while maintaining a large windshield 2b that is longer than the usual windshield 2a in the vehicle height direction, the frame 3 is rotated with the holding part 4 along the vehicle height direction (the vertical direction of the large windshield). Therefore, the area near the upper edge of the large windshield 2b can be held by the first holding part 4a and the third holding part 4c, and the area near the lower edge of the large windshield 2b can be held by the second holding part 4b and the fourth holding part 4d. That is, the rigidity in the vertical direction of the large windshield 2b can be improved. As a result, while holding the large windshield 2b, it is possible to suppress the deflection or vibration of the large windshield 2b due to the weight of the portion further outward than the holding part 4 or loads acting on the upper or lower edge of the large windshield 2b, and to suppress the decrease in the assembly accuracy of the large windshield 2b. In other words, the material handling device 1 configured for a typical windshield 2a can be used as a material handling device 1 for conveying and assembling a large windshield 2b.

[0051] Furthermore, the general lateral sensor 5d installed in the aforementioned material handling device 1 is positioned at the upper edge of the large windshield 2b when the material handling device 1 (frame 3) is rotated to hold the large windshield 2b. In other words, the general lateral sensor 5d also functions as a sensor for measuring the gap or distance between the upper edge of the large windshield 2b and the window frame. As a result, the number of dedicated sensors used to assemble the large windshield 2b to the window frame can be reduced, thus reducing the rigidity required for the frame 3. In other words, the frame 3 can be miniaturized.

[0052] Furthermore, the workpiece in the embodiments of the present invention is not limited to a front windshield, but may also be other glass such as a rear windshield or a quarter windshield, and may also be a workpiece other than glass such as a door. Moreover, it is not limited to having four holding parts as in the material handling device described above; two or more holding parts can be provided on both sides with the support part as the center.

[0053] Symbol Explanation

[0054] 1-Material handling device, 2-Windshield, 2a-Standard windshield, 2b-Large windshield, 3-Frame, 3a-Base section, 3b-Tool flange section, 3c, 3d, 3e, 3f-Holding arm section, 3g-Reinforcing section, 3h, 3i-Sensor mounting shaft, 4, 4a, 4b, 4c, 4d-Holding section, 5, 5a, 5b, 5c, 5d, 5e-Each sensor, 6-Controller, A-Robot arm.

Claims

1. A control device for a material handling apparatus, the material handling apparatus comprising: a frame held by a robotic arm in a manner capable of changing position and orientation; and at least two holding portions disposed on the frame, wherein the material handling apparatus holds workpieces for conveying and assembling via the holding portions, the frame having a support portion and being held by the robotic arm in a manner rotatable about a central axis of the support portion, the two holding portions being disposed on opposite sides of the central axis of the support portion, the control device for the material handling apparatus being characterized in that... A controller is provided to control the position and orientation of the frame. When the controller moves the frame to a predetermined initial position and controls the frame's posture to a predetermined initial posture so that the frame is opposite the workpiece, and the length of the workpiece in the direction intersecting the virtual line connecting the two holding parts is longer than the distance between the two holding parts, the controller rotates the frame to hold the workpiece.

2. The control device for the material handling apparatus according to claim 1, characterized in that, The workpiece includes: a first workpiece whose length in the width direction is longer than its length in the height direction; and a second workpiece whose length in the height direction is longer than that of the first workpiece. The initial position includes the position where the support portion is opposite to the center of gravity of the first workpiece. The initial posture includes the posture of the virtual line connecting the two holding parts along the width direction of the first workpiece.

3. The control device for the material handling apparatus according to claim 2, characterized in that, The frame has multiple sensors that, while holding the first workpiece, are positioned opposite the outer periphery of the first workpiece and detect the gap between the first workpiece and the portion assembling the first workpiece. At least one of the plurality of sensors is positioned opposite the outer periphery of the second workpiece while the second workpiece is held, and is capable of detecting the gap between the second workpiece and the portion assembling the second workpiece.

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