Robot control method and robot control device

Abstract

A robot includes a swing arm that rotates, a common arm attached to the swing arm, and hands attached to both ends of the common arm via a tip arm, thereby shortening the time until the movement of the robot between access points is completed. When a swing arm (21) is rotated about an axis (T) to move a robot from a starting point access point in which hands (25, 26) overlap each other and face a first direction to an end point access point in which the hands (25, 26) overlap each other and face a second direction, control is performed to move the hands (26) by a continuous path (CP) operation in which the tips of the hands (26) are positioned on a path (L) and in which a change in the orientation of the hands (26) is designated. The other hand (25) is also controlled so that the tip is positioned on the path (L).

Description

Technical Field

[0001] The present invention relates to the control of an industrial robot (hereinafter referred to as a robot) suitable for carrying workpieces, and particularly relates to a control method and a control device that can prevent interference with wall surfaces and the like arranged around the robot and enable the robot to operate at high speed. Background Art

[0002] In the manufacture of liquid crystal display panels and organic EL (electroluminescence) display panels, it is necessary to carry a glass substrate as a workpiece between processing chambers that perform various processes via a transfer chamber. In a robot used for such a purpose, for example, as described in Patent Document 1, it has: a swing arm whose one end is connected to a main body part (i.e., a base) and swings in a horizontal plane; an arm group that is installed at the other end of the swing arm, i.e., the front end of the swing arm; and a hand that is installed at the front end of each arm to hold the workpiece. In particular, in Patent Documents 2 and 3, a robot is disclosed that mounts a common arm bent in an L shape or a V shape at the center part of the front end of the swing arm, and hands are respectively installed at both ends of the common arm via front arms. The workpiece is placed on the hand and carried between the processing chambers. In addition, these robots are configured such that regardless of the orientation of the swing arm, the hand moves on a straight line connecting the center of the hand and the front end of the swing arm. Therefore, by driving the arm group, with respect to the position of the front end of the swing arm, the hand expands and contracts so as to move away from or approach this position. The loading / unloading ports of the processing chambers are adjacent to the transfer chamber so as to open into the transfer chamber. The robot first moves the hand to a position in front of the processing chamber, i.e., an access point, and then makes the hand enter and exit the loading / unloading port of the processing chamber from the access point, thereby enabling the workpiece to be placed in the processing chamber or taken out from the processing chamber.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-207938

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2023-54397

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 2023-54938 Summary of the Invention

[0008] Technical Problem to be Solved by the Invention

[0009] When using the robots for transportation described in Patent Documents 1 to 3 to transport workpieces between processing chambers, the swing arms of the robots also rotate according to the positions of the respective processing chambers that serve as the starting point and the ending point. On the other hand, in order to reduce the moving distance of the hand when entering and exiting the processing chamber, the size of the transfer chamber is also reduced as much as possible. Therefore, when moving the robot from one posture to another posture, the hand or the workpiece placed on the hand may collide with the wall surface of the transfer chamber. In order to prevent the hand or the workpiece from colliding with the surrounding objects of the robot, such as the wall surface, that is, interference during the movement of the robot, conventionally, during the movement of the robot, first, in order to prevent the hand from protruding significantly in the outer direction of the rotation of the swing arm, the common arm is rotated while the swing arm is fixed to change the position and orientation of the hand. Then, while keeping the orientation of the hand relative to the surrounding space, that is, the transfer chamber unchanged, the swing arm is rotated by a desired angle. After the rotation of the swing arm is completed, the robot is controlled so that the position and orientation of the hand become the desired position and orientation. However, when controlling the robot in this way, since the operation of relatively changing the orientation of the hand with respect to the transfer chamber and the operation of rotating the swing arm itself are performed in different periods, as a whole, there is a problem that the time until the movement is completed becomes long.

[0010] An object of the present invention is to provide a robot control method and a robot control device that can prevent collisions and the like, and at the same time execute the operation of rotating the swing arm itself and the operation of relatively moving the orientation of the hand with respect to the surrounding space, so as to be able to shorten the time until the movement of the robot between the access points is completed.

[0011] Technical solutions for solving the technical problems

[0012] For example, a robot that is the object of the robot control method and control device according to the present invention has: a swing arm whose proximal end is connected to a first axis and can rotate around the first axis; a common arm whose proximal end is connected to the front end of the swing arm via a second axis and can rotate around the second axis; a first front arm whose proximal end is connected to one front end of the common arm via a third axis and can rotate around the third axis; a second front arm whose proximal end is connected to the other front end of the common arm via a fourth axis and can rotate around the fourth axis; a first hand whose proximal end is connected to the front end of the first front arm via a fifth axis and rotates around the fifth axis in a manner linked to the rotation of the first front arm around the third axis with respect to the common arm, and a second hand whose proximal end is connected to the front end of the second front arm via a sixth axis and rotates around the sixth axis in a manner linked to the rotation of the second front arm around the fourth axis with respect to the common arm, and the first axis to the sixth axis are parallel to each other.

[0013] In the robot control method of the first mode, when rotating the swing arm around the first axis to move the robot from the starting access point where the first hand and the second hand overlap each other and face the first direction to the ending access point where the first hand and the second hand overlap each other and face the second direction, the control of moving the first hand is performed by continuous path (CP) motion, and at the same time, the control is performed to make the control target point of the second hand located on a specified path, where the continuous path (CP) motion is that the control target point of the first hand is located on the specified path and the change of the orientation of the first hand is specified.

[0014] By performing such control, since the first hand and the second hand move along a specified path during the rotation of the swing arm, it is possible to prevent the hand or the workpiece on the hand from colliding with surrounding objects such as the wall surface, and at the same time, it is possible to quickly move the entire robot from the starting access point to the ending access point. When the first direction and the second direction are the same direction, it is preferable not to change the orientation of the first hand during the CP motion. When the first direction is different from the second direction, the orientation of the first hand can be changed from the first direction to the second direction at the same speed during the CP motion, or the swing arm can be rotated at the same speed, and the orientation of the first hand can also be changed according to the change of the rotation angle of the swing arm.

[0015] In the robot control method of the second mode, when rotating the swing arm around the first axis to move the robot from the starting access point where the first hand and the second hand overlap each other and face the first direction to the ending access point where the first hand and the second hand overlap each other and face the second direction, one or more via points are determined in such a way that the control target point of the first hand and the control target point of the second hand are located on a specified path, and the robot is moved from the starting access point to the ending access point via the one or more via points by point-to-point (PTP) motion.

[0016] When such control is performed, since one or more points where it is known that no collision occurs are used as via points and the robot is moved by PTP motion, it is possible to prevent the hand or the workpiece from colliding with the wall surface around the robot, and it is possible to quickly move the robot from the starting access point to the ending access point.

[0017] When performing the PTP motion, preferably, the PTP motion is executed under the first constraint condition and the second constraint condition. The first constraint condition is that according to the angular difference of the orientation of the common arm between the starting access point and the ending access point, the common arm rotates relative to the rotation amount of the swing arm around the first axis in proportion to the rotation around the second axis. The second constraint condition is that the change of the rotation angle of the swing arm around the first axis, the change of the rotation angle of the first front arm around the third axis, and the change of the rotation angle of the second front arm around the fourth axis form a linkage. By introducing such constraint conditions, the degree of freedom of control is reduced, so it is possible to more reliably prevent the robot from moving on an orbit where a collision occurs.

[0018] In the robot control methods of the above-described various modes, preferably, for each of the first hand and the second hand, the control target point is determined as a point on the hand or an object loaded on the hand that may potentially collide with an object around the robot as the robot moves from the start access point to the end access point, and a specified path is determined as a path along which the control target point does not collide with an object around the robot. By determining the control target point and the specified path in this way, it is possible to more reliably prevent the occurrence of collisions in the robot. Further, when the first direction and the second direction are in the same orientation, a straight line is preferably used as the specified path, and when the second direction is orthogonal to the first direction, a curve such as an arc is preferably used as the specified path. By using such a specified path, the amount of computation required for controlling the robot can be reduced.

[0019] In a robot to which the robot control method of the above-described various modes is applied, the common arm is, for example, an arm that bends at a position held by the swing arm via the second axis. Further, in this robot, the distance between the second axis and the third axis is equal to the distance between the third axis and the fifth axis, and the distance between the second axis and the fourth axis is equal to the distance between the fourth axis and the sixth axis. Such a robot is suitable for carrying workpieces in a relatively narrow transfer chamber, but by applying the robot control method of the above-described various modes, it is possible to avoid the occurrence of collisions and further narrow the transfer chamber.

[0020] The robot control device of the first mode includes: a storage unit that stores parameters required for controlling the robot; and an arithmetic unit that, when rotating the swing arm around the first axis to move the robot from a start access point where the first hand and the second hand overlap and face the first direction to an end access point where the first hand and the second hand overlap and face the second direction, performs arithmetic operations with reference to the parameters in the storage unit, and thereby controls the first axis to the fourth axis in such a manner that while moving the first hand by a CP operation, the control target point of the second hand is located on the specified path, where the CP operation is a change in the orientation of the first hand specified with the control target point of the first hand located on the specified path. By using such a control device, in the robot, the first hand and the second hand move along the specified path during the rotation of the swing arm, and thus it is possible to prevent the hand or a workpiece on the hand from colliding with an object such as a surrounding wall surface, and it is possible to move the entire robot from the start access point to the end access point quickly.

[0021] The robot control device of the second method includes: a storage unit that stores parameters required for controlling the robot; and an arithmetic unit that, when rotating the swing arm around the first axis to move the robot from a starting access point where the first hand and the second hand overlap and face the first direction to an ending access point where the first hand and the second hand overlap and face the second direction, performs arithmetic operations with reference to the parameters in the storage unit. Thus, one or more via points are determined in such a way that the control target points of the first hand and the second hand are on a specified path, and the first axis to the fourth axis are controlled in such a way that the robot moves from the starting access point to the ending access point via one or more via points by PTP operation.

[0022] Advantages of the Invention

[0023] According to the present invention, when moving the robot between access points, collisions and the like can be prevented, and the operation of rotating the swing arm itself and the operation of relatively moving the hand with respect to the surrounding space can be performed simultaneously. Therefore, the time until the movement of the robot is completed can be shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a diagram showing an example of a robot to which a control method according to an embodiment is applied.

[0025] Figure 2 (a) to (c) of FIG. are schematic top views showing examples of the postures of the robot.

[0026] Figure 3 (a) to (c) of FIG. are schematic top views for explaining the control of the robot.

[0027] Figure 4 (a) and (b) of FIG. are schematic top views for explaining the control of the robot in a state where a workpiece is loaded.

[0028] Figure 5 (a) to (c) of FIG. are schematic top views for explaining another example of the control of the robot.

[0029] Figure 6 (a) to (c) of FIG. are schematic top views for explaining another example of the control of the robot.

[0030] REFERENCE SIGNS LIST

[0031] 10... Robot; 20... Base; 21... Swing arm; 22... Common arm; 23, 24... Front-end arms; 25, 26... Hands; 31, 32... Workpieces; 41... Wall surface; 42, 43... Loading / unloading ports; 50... Control device; 51... Storage unit; 52... Arithmetic unit. DETAILED DESCRIPTION OF THE INVENTION

[0032] Next, a mode for carrying out the present invention will be described with reference to the accompanying drawings. Figure 1 FIG. is a view showing an example of a robot for a control method according to an embodiment of the present invention. (a) is a front view, (b) is a top view, and (c) is a schematic perspective view. Further, in Figure 1 , (a), (b), and (c) respectively correspond to different postures of the robot 10. In the figure, arrows indicated by X, Y, and Z represent the directions of the X-axis, Y-axis, and Z-axis in a three-dimensional orthogonal coordinate system defined for the robot 10 as a world coordinate system. The Z-axis is a vertical axis. Therefore, the XY plane is a horizontal plane.

[0033] Figure 1 The shown robot 10 is a horizontal multi-joint robot also called a translation type, and is the same as the robots described in Patent Documents 2 and 3. The robot 10 is used for carrying plate-shaped workpieces such as glass substrates. The robot 10 includes: a base 20; a swing arm 21 having a base end connected to the base 20; a common arm 22 connected to the front end of the swing arm 21; two front arms 23 and 24 respectively connected to the common arm 22; and two hands 25 and 26 respectively connected to the front arms 23 and 24. The hands 25 and 26 are elongated in shape. The swing arm 21 can move up and down in the Z-axis direction, i.e., the height direction, by a lifting mechanism 27 provided in the base 20, and is driven by a motor (not shown) provided in the lifting mechanism 27 to be able to rotate in a horizontal plane about the base end of the swing arm 21, i.e., the position where the swing arm 21 is connected to the base 20. The rotation center of the swing arm 21 in the horizontal plane is set as the T-axis. The T-axis corresponds to the first axis.

[0034] The common arm 22 is an arm bent in an L-shape or a V-shape (i.e., a boomerang shape), and is connected to the other end of the swing arm 21 at its bent position, and is driven by a motor (not shown) built in the swing arm 21 to be able to rotate in a horizontal plane. The axis of this rotation is set as the TH-axis. The TH-axis corresponds to the second axis. The L-shaped common arm 22 has two ends, one end of which is connected to the front arm 23 and the other end of which is connected to the front arm 24.

[0035] A front end arm 23 is connected to a common arm 22 at its proximal end side and can be rotated in a horizontal plane by a motor (not shown) built in the common arm 22. The axis of this rotation of the front end arm 23 is defined as the RR axis. A hand 25 is connected to the front end of one front end arm 23 and can be rotated in a horizontal plane by a motor (not shown) that drives the rotation of the front end arm 23 via a transmission mechanism (not shown). The transmission mechanism includes, for example, a pair of pulleys and a belt stretched over these pulleys, and is configured such that when the front end arm 23 rotates by an angle θ relative to the common arm 22, the hand 25 rotates by an angle 2θ relative to the front end arm 23. The axis of this rotation of one hand 25 is defined as the AR axis. In the horizontal plane, the distance between the TH axis and the RR axis is equal to the distance between the RR axis and the AR axis (i.e., the length of one front end arm 23), forming an isosceles triangle. Since the relationship between the rotation angle of the front end arm 23 relative to the common arm 22 and the rotation angle of the hand 25 relative to the front end arm 23 is defined as above and an isosceles triangle is formed, a certain reference line fixed to the hand 25 always passes through the TH axis regardless of the rotation driving angle of the front end arm 23. Usually, this reference line is the center line in the length direction of the hand 25. That is, the hand 25 expands and contracts while satisfying the condition that its center line in the length direction passes through the TH axis. As long as the movement of such a hand 25 can be achieved, a motor (not shown) provided in the front end arm 23 can also be used to rotationally drive the hand 25 instead of the transmission mechanism.

[0036] Similarly, another front end arm 24 is connected to the common arm 22 at its proximal end side and can be rotated in a horizontal plane about the RL axis by a motor (not shown) built in the common arm 22. Another hand 26 is connected to the front end of the other front end arm 24 and can be rotated in a horizontal plane about the AL axis by a motor (not shown) that drives the rotation of the front end arm 24 via a transmission mechanism (not shown). The same mechanism as described above is used as the transmission mechanism, and a motor (not shown) that drives the rotation of the hand 26 can also be provided in the front end arm 24 instead of the transmission mechanism. In the horizontal plane, the distance between the TH axis and the RL axis is equal to the distance between the RL axis and the AL axis, forming an isosceles triangle. The distance between the RL axis and the AL axis, which is the length of the other front end arm 24, can be different from the distance between the RR axis and the AR axis, which is the length of one front end arm 23. Regarding the other hand 26, a certain reference line fixed to this hand 26 always passes through the TH axis regardless of the rotation driving angle of the front end arm 24. Usually, this reference line is the center line in the length direction of the hand 26. That is, the other hand 26 also expands and contracts while satisfying the condition that its center line in the length direction passes through the TH axis. One of the RR axis and the RL axis corresponds to the third axis, and the other corresponds to the fourth axis. Similarly, one of the AR axis and the AL axis corresponds to the fifth axis, and the other corresponds to the sixth axis.

[0037] In Figure 1In the shown robot 10, in order to prevent interference between the front arms 23 and 24 and interference between the hands 25 and 26, the rotation planes formed by the respective rotations of the front arms 23 and 24 and the hands 25 and 26 are arranged in the order of the rotation plane of one front arm 23, the rotation plane of one hand 25, the rotation plane of the other front arm 24, and the rotation plane of the other hand 26 from the lower side in the height direction. These rotation planes are all horizontal. In addition, in this robot 10, when the front arms 23 and 24 and the hands 25 and 26 are in the folded state, the swing arm 21 extends in the Y direction, and the two hands 25 and 26 extend in the Y direction so as to overlap the swing arm 21. Moreover, the posture in which the AR axis and the AL axis are located near the T axis on the straight line connecting the T axis and the TH axis is the posture of the origin position. Hereinafter, the direction in which the hands 25 and 26 extend from the AR axis and the AL axis will be simply referred to as the direction or orientation of the hands 25 and 26.

[0038] As Figure 1 As shown in (a) of FIG. , a control device (robot controller) 50 for controlling and driving the respective axes of the robot 10 is connected to the robot 10. The control device 50 includes: a storage unit 51 that stores various parameters required for controlling the robot 10; and an arithmetic unit 52 that refers to the parameters stored in the storage unit 51 and performs arithmetic operations required for controlling each motor. In particular, the arithmetic unit 52 performs arithmetic operations by referring to the parameters in the storage unit 51, and drives the motors of the T axis, the TH axis, the RR axis, and the RL axis in such a manner as to implement the control described later.

[0039] Figure 1 The shown robot 10 is arranged in the transfer chamber for transporting workpieces. Figure 2 (a) to (c) of FIG. are schematic top views showing examples of the posture of the robot 10, showing the arrangement of the robot 10 in the transfer chamber, the positions of the access points, the entry into the processing chamber, etc. Consider a case where the robot 10 is arranged in the transfer chamber, which is a space surrounded by a pair of side walls extending in the X direction, and the robot 10 is used to transport workpieces between two processing chambers. In the robot 10 of the present embodiment, the TH axis exists on the center line in the length direction of the hands 25 and 26. However, in Figure 2 FIG. , for the sake of illustration, the hands 25 and 26 are depicted such that the center line in the length direction of the hands 25 and 26 deviates from the position of the TH axis.

[0040] As Figure 2 As shown in FIG. , on one wall surface 41 extending in the X direction of the transfer chamber, carry-in / carry-out ports 42 and 43 for the two processing chambers are respectively provided. When the robot 10 enters each processing chamber, it moves to the access point that is directly opposite to the carry-in / carry-out port 42 or 43 corresponding to the processing chamber, and makes one of the hands 25 and 26 enter linearly from the position of this access point with respect to the carry-in / carry-out port 42 or 43. Figure 2FIG. (a) shows the state where the robot 10 moves to an access point. Figure 2 FIG. (b) shows the state where the robot moves to another access point. As shown in these figures, in this robot 10, as an example, in the state where the robot moves to an access point, the angle α formed by the extending direction of the swing arm 21 and the Y direction is +45°, and in the state where the robot moves to another access point, the angle α is -45°. At the access point, both hands 25 and 26 extend parallel to the direction (in this example, the +Y direction) passing through the carry-in / carry-out ports 42 and 43 and into the processing chamber, and are arranged to overlap each other so that either of the hands 25 and 26 can enter the processing chamber through the carry-in / carry-out ports 42 and 43. In addition, in order for the hands 25 and 26 to enter the processing chamber, the common arm 22 needs to rotate around the TH axis, so the hands 25 and 26 do not extend into the processing chamber simultaneously. Figure 2 FIG. (c) shows the state where the hand 25 enters the processing chamber through the carry-out port 42. At this time, the other hand 26 is in a folded state.

[0041] Next, the control of the robot 10 in this embodiment will be described. The control method of the robot based on the present invention is a method of moving the robot 10 between two access points, so that the hands 25 and 26 of the robot 10 do not collide with surrounding objects, such as the wall surface 41, and the robot 10 can be moved quickly. Figure 3 FIGS. (a) to (c) are schematic top views for explaining the control of the robot 10 in this embodiment, showing the appearance of the movement of the robot when the angle α formed by the extending direction of the swing arm 21 and the Y direction changes. In Figure 3 the figures, the changes in the posture of the robot 10 accompanying the change of the angle α are shown offset in the figure, but it should be noted that actually the position of the T axis in the horizontal plane in the transfer chamber itself does not change. In addition, in Figure 3 the figures, for the purpose of explanation, the hands 25 and 26 are depicted in such a way that the center lines in the length directions of the hands 25 and 26 deviate from the position of the TH axis. Here, considering the access point shown in Figure 2 FIG. (a) as the starting access point and the access point shown in Figure 2 FIG. (b) as the ending access point, the case where the robot 10 moves from the starting access point to the ending access point is considered.

[0042] Figure 3The (a) of shows the change in the posture of the robot when the robot 10 is moved while maintaining the orientations of the hands 25 and 26 at the starting access point, that is, while maintaining the posture in which the hands 25 and 26 are oriented in the Y direction. In this case, during the process in which the swing arm 21 rotates about the T axis so that the angle α changes from +45° to -45°, as depicted in the figure in such a way that the hands 25 and 26 are inserted into the wall surface 41, the front end portions of the hands 25 and 26 collide with the wall surface 41 of the transfer chamber. That is, it is not possible to move from the starting access point to the ending access point while maintaining the directions of the two hands 25 and 26. Conventionally, for example, the direction of the hands 25 and 26 is set to the -X direction by rotating the common arm 22 about the TH axis, and then the swing arm 21 is moved about the T axis while the hands 25 and 26 are oriented in the -X direction. Since the directions of the hands 25 and 26 do not change, the common arm 22 also rotates about the TH axis relative to the swing arm 21 at this time. If the swing arm 21 rotates to the desired angle, finally the common arm 22 is rotated about the TH axis so that the directions of the hands 25 and 26 become the Y direction. Thus, the movement from the starting access point to the ending access point is completed without colliding with the wall surface 41, but since the operation of changing the directions of the hands 25 and 26 and the operation of rotating the swing arm 21 are performed at different time periods, the time required until the movement is completed becomes long.

[0043] Figure 3Part (b) of [description] shows the change in the posture of the robot 10 when it is controlled by the control method based on the present invention. Generally, as the operation mode when the robot 10 is operated by specifying the target position, there are well-known PTP (point-to-point) operation and CP (continuous path) operation. The PTP operation is generally an operation that moves the tool or the hand by only specifying the start point and the end point of the trajectory that the front end of the tool or hand installed on the robot should take. The CP operation is generally an operation that specifies a straight line or a curved path in a three-dimensional space and makes the front end of the tool or hand move along this path. In the PTP operation, the start point and the end point are specified, but the trajectory of the robot between the start point and the end point is not specified. Especially in a robot with two or more axes, after determining how much each axis should move between the start point and the end point for each axis, each axis moves independently according to the movement amount of each axis. In the control based on the PTP operation, an intermediate point can also be determined between the start point and the end point. In the case where an intermediate point is determined, the robot is moved from the start point to the intermediate point by the PTP operation, and the robot is also moved from the intermediate point to the end point by the PTP operation. In the case where multiple intermediate points are set, the robot is also moved between the intermediate points by the PTP operation. In contrast, the CP operation is an operation that controls each axis at each moment so as not to deviate from the specified path. For example, it is used when interpolating the movement between the teaching points represented by the teaching data using a straight line or an arc. It is known that the PTP operation can move the robot at a higher speed than the CP operation. In Figure 3 In the example shown in part (b) of [description], by controlling the movement of the hand 26 from the start access point to the end access point using the CP operation, the orientations of the hands 25 and 26 are changed in a manner that avoids collision with the wall surface 41, and at the same time, the swing arm 21 is rotated around the T axis to shorten the time until the movement between the access points is completed.

[0044] The goal of the control in the CP motion is to prevent the front end of the hand 26 from colliding with the wall surface 41. Therefore, the control performed by the CP motion is executed with the front end of the hand 26 as the control target point. Considering the degrees of freedom of the mechanism of the robot 10, among the control parameters when the hand 26 performs the CP motion, in addition to the coordinates of the front end of the hand 26, i.e., the coordinates of the control target point, it also includes the orientation of the hand 26. In the example shown here, at the two access points, the direction of the hand 26 is the Y direction, so the direction of the moving hand 26 also remains the Y direction. To avoid collision with the wall surface 41, a straight path L is set parallel to the wall surface 41 while slightly departing from the wall surface 41. Then, the robot 10 is driven and controlled in such a way that the front end of the hand 26, i.e., the control target point, moves on the path L. If the position (XY coordinate values) of the front end of the hand 26 and the extending direction of the hand 26 are determined, then the rotation angle of the front end arm 24 around the RL axis, the rotation angle of the common arm 22 around the TH axis, and the rotation angle of the swing arm 21 around the T axis (angle α) are determined. Therefore, in the control device 50, the arithmetic unit 52 determines the driving amount of the motors of each axis by referring to the values of the respective parameters stored in the storage unit 51 and the like. Thus, the robot 10 is controlled in such a way that the hand 26 moves in the CP motion. Since the position of the RR axis on the common arm 22 is determined by the control of the hand 26 in the CP motion, at this time, only the degree of freedom of the rotation angle on the RR axis remains in the robot 10. That is, only one degree of freedom remains related to the other hand 25. Therefore, regarding the hand 25, the control is performed such that the control target point of its front end, i.e., the hand 25, is located on the path L, that is, the control is performed by only specifying the Y coordinate of the front end of the hand 25. In addition, when the hand 26 always faces the Y direction, the relationship between the X direction position of the hand 26 controlled by the CP motion and the angle α of the swing arm 21 is determined one-to-one. Therefore, when the robot 10 is moved by the CP motion, the control can also be performed to rotate the swing arm 21 around the T axis at a constant rotational speed.

[0045] If the control described above is performed, as shown in (b) of Figure 3 , while the direction of the hand 26 remains in the Y direction, the hand 25 rotates in the XY plane, and at the same time, it is possible to avoid the hands 25 and 26 from colliding with the wall surface 41 and quickly move the robot 10 from the starting access point to the ending access point. Additionally, according to the structure of the processing chamber, sometimes it is also necessary to enter the processing chamber at an inclined angle from the Y direction. That is, the two access points are arranged along the X direction, but the directions in which the hands 25 and 26 should face at the access points deviate from the Y direction, and sometimes it is necessary to change the directions of the hands 25 and 26 between the access points. In this case, regarding the hand 26, only the control based on the CP motion needs to be performed, which means that the front end of the hand 26 moves on the path L from the starting access point to the ending access point and the direction of the hand 26 gradually changes. Even when such control is performed on the hand 26, the direction of the other hand 25 at the two access points is the same as the direction of the hand 26.

[0046] In the control described above, the hand 26 is moved by the CP action so that it moves along the path L, and the other hand 25 moves naturally with its tip located on the path L. However, the roles of the hands 25 and 26 can be exchanged, and the following control can be performed: The hand 25 is moved by the CP action so that it moves along the path L, and the hand 26 moves naturally.

[0047] The movement of the robot 10 from the start access point to the end access point can also be controlled by the PTP action. Figure 3 (c) of shows the change in the posture of the robot 10 when controlling the robot 10 by the PTP action. When performing the PTP action by only specifying the start access point and the end access point, since the intermediate trajectory is not specified, the possibility of the hands 25 and 26 colliding with the wall surface 41 cannot be excluded. Therefore, via points are determined to avoid collisions. The via points are determined as positions where no collision occurs in the robot 10. Since the swing arm 21 is closest to the wall surface 41 at α = 0°, it is preferable to determine that the tips of the hands 25 and 26, that is, the control object points of the hands 25 and 26, are located on the above-mentioned path L at α = 0° as the via points. In addition to the via points at α = 0°, other via points can also be determined.

[0048] Furthermore, in the present embodiment, in order to reduce the degree of freedom in control and more reliably avoid collisions, constraint conditions are added to perform control based on the PTP action. The first constraint condition is that the orientation of the common arm 22 in the XY plane changes in proportion to the angle difference between the orientation of the common arm 22 at the start access point and the orientation of the common arm 22 at the end access point in the world coordinate, that is, in the XY plane, and the rotation amount of the swing arm 21 around the T axis. The orientation of the common arm 22 can be defined, for example, as the angle formed by the direction from the TH axis to the RR axis in the XY plane and the X direction. In Figure 3 (c) shown in the example, at the start access point and the end access point, the orientation of the common arm 22 in the XY plane is the same and the angle difference between the two is 0. Therefore, even during the movement of the robot 10, the orientation of the common arm 22 in the XY plane does not change. In addition, a second constraint condition is added, which is that the change in the rotation angle of the swing arm 21 around the T axis is linked to the change in the rotation angles of the front end arms 23 and 24 around the RR axis and the RL axis, respectively. In addition, the control based on the first constraint condition and the second constraint condition is not necessary.

[0049] According to the first constraint condition, compared with the position of the TH axis, the positions of the RR axis and the RL axis are farther from the wall surface 41, and the Y coordinate value of the RR axis is always equal to the Y coordinate value of the RL axis. The second constraint condition is that the angles formed by the common arm 22 and the front arm 23 with the RR axis and the angles formed by the common arm 22 and the front arm 24 with the RL axis are both such that if the absolute value |α| of the angle α formed by the swing arm 21 and the Y direction becomes larger, it becomes smaller, and if the absolute value |α| becomes smaller, it becomes larger. Since the swing arm 21 is closest to the wall surface 41 when α = 0°, as the passing point, it is preferably determined that the front ends of the hands 25 and 26, that is, the control target points of the hands 25 and 26, are located on the above-mentioned path L when α = 0°. In addition to the passing point at α = 0°, other passing points can also be determined. Moreover, the robot 10 is controlled to move in a PTP motion from the start access point to the end access point via each passing point under the first constraint condition and the second constraint condition.

[0050] In the case of controlling by such a PTP motion, as shown in Fig. 3(c), the hands 25 and 26 move in a manner symmetric with respect to the straight line passing through the TH axis and extending in the Y direction. Moreover, the front ends of the hands 25 and 26 are approximately located on the path L, and the robot 10 moves from the start access point to the end access point.

[0051] The above describes the control for preventing the front ends of the hands 25 and 26 from colliding with the wall surface 41 when the robot 10 moves between the start access point and the end access point shown in (a) and (b) of Figure 2 by means of a CP motion or a PTP motion. By executing these controls, it is possible to avoid collisions at the front ends of the hands 25 and 26 and shorten the time until the robot 10 completes the movement from the start access point to the end access point.

[0052] Next, the control when workpieces 31 and 32 are loaded on the hands 25 and 26 will be described. In fact, the robot 10 is a handling robot, and in many cases, a plate-shaped workpiece is placed on at least one of the hands 25 and 26. Therefore, when the robot 10 is loaded with a workpiece, control is required to prevent the workpiece from colliding with the wall surface 41. The control of the robot 10 when loading a workpiece will be described with reference to Figure 4 (a) and (b) of

[0053] Figure 4 (a) of Figure 3 shows the change in the posture of the robot 10 when the robot 10 moves from the start access point to the end access point by controlling with a CP motion in the same manner as (b) of Figure 3is different from the situation shown in (b). Regarding the hand 26 which is actually the object of the CP operation, since it moves while maintaining its direction in the Y direction, the workpiece 32 on the hand 26 also moves accordingly. As a result, there is no need to consider the collision of the workpiece 32 with the wall surface 41. For the hand 26, the same control as that described in (b) using Figure 3 can be performed. On the other hand, the direction of the hand 25 changes as the robot 10 moves. Therefore, even if the front end of the hand 25 does not collide with the wall surface 41, the workpiece 31 placed on the hand 25 may collide with the wall surface 41. Among the workpieces 31, the vertex S that is close to the end access point among the two vertices at both ends of the edge on the front end side of the workpiece 31 may collide with the wall surface 41. Therefore, regarding the hand 25, as long as the control is performed under the condition that neither the front end of the hand 25 nor the vertex S is closer to the wall surface 41 than the path L, so that either the front end of the hand 25 or the vertex S is located on the path L. That is, the one of the front end of the hand 25 and the vertex S that is closer to the wall surface 41 is used as the control object point, and the control is performed in such a way that the control object point is located on the path L. The front end of the hand 25 and the vertex S can be collectively referred to as the potential collision positions related to the hand 25. If the term potential collision position is used, in other words, the control condition in the CP operation is that under the condition that no potential collision position is closer to the wall surface 41 than the path L, at least one potential collision position is located on the path L. In addition, for the hand 26 that always moves in the Y direction, its front end position is the only potential collision position and is the control object point.

[0054] In Figure 4 In the example shown in (a), during a short period after starting to move from the start access point, the front end of the hand 25 moves on the path L. Among them, since the front end of the hand 25 and the vertex S are both located on the path L at the same time, the vertex S then moves on the path L. At this time, as shown when α = 0°, the front end of the hand 25 is farther from the wall surface 41 than the path L. Then, since the front end of the hand 25 and the vertex S are both located on the path L at the same time, the front end of the hand 25 then moves on the path L and reaches the end access point. When the directions of the hands 25 and 26 are also inclined with respect to the Y direction at each access point, regarding the hand 26 whose position and orientation are controlled by the CP operation, as long as the control is performed under the condition that no potential collision position is closer to the wall surface 41 than the path L, so that at least one potential collision position is located on the path L.

[0055] Figure 4 (b) shows the change in the posture of the robot 10 when the PTP operation is controlled in the same way as in Figure 3 (c) to move the robot 10 from the start access point to the end access point. However, the same as above, workpieces 31 and 32 are placed on the hands 25 and 26 respectively, which is different from Figure 3The difference is shown in (c) below. When controlling the PTP motion, under the condition that the above-mentioned respective constraint conditions are satisfied and no potential collision position is closer to the wall surface 41 than the path L, the passing points are determined such that at least one potential collision position lies on the path L, and the robot 10 is moved by the PTP motion so that the robot 10 moves from the start access point via the respective passing points to the end access point. In Figure 4 In the example shown in (b) below, α = 0° is taken as the passing point. However, at this time, the vertex S of the workpiece 31 lies on the path L, and the same applies to the workpiece 32.

[0056] In Figure 4 In the cases shown in (a) and (b) below, if the protruding amounts of the hands 25 and 26 from the workpieces 31 and 32 are small and collisions between the workpieces 31 and 32 and the wall surface 41 can be avoided, then when the possibility of collisions between the hands 25 and 26 and the wall surface 41 can be substantially ignored, the vertex of the workpiece 31, etc., that is, the vertex close to the end access point among the two vertices at both ends of the leading-edge side of the workpiece 31 and 32 can be used as the control target point and control can be started from the beginning. In addition, when the possibility of collisions between the workpieces 31 and 32 and the wall surface 41 can be ignored according to the sizes of the workpieces 31 and 32 and the mounting states of the workpieces 31 and 32 on the hands 25 and 26, the front-end positions of the hands 25 and 26 can be used as the control target points.

[0057] According to the control described using Figure 4 (a) and (b) below, collisions of the hands 25 and 26 or the workpieces 31 and 32 can be avoided, and the time required for the robot 10 to complete the movement from the start access point to the end access point can be shortened.

[0058] According to the configuration of the robot 10 in the transfer chamber, sometimes the hands 25 and 26 collide with the wall surface 41 at the base ends of the hands 25 and 26, that is, at the positions of the AR axis and the AL axis. Figure 5 (a) to (c) below are the same as Figure 3 (a) to (c) below, and show the appearance of the movement of the robot when the angle α formed by the extending direction of the swing arm 21 and the Y direction is changed. Here, at the start access point, α = +45° and the orientations of the hands 25 and 26 are in the -Y direction. That is, at the start access point, starting from the state shown in Figure 2 (a) below, the relative positional relationships of the front-end arms 23 and 24 and the hands 25 and 26 with respect to the common arm 22 do not change, and the common arm 22 rotates 180° about the TH axis. Similarly, at the end access point, α = -45° and the orientations of the hands 25 and 26 are in the -Y direction.

[0059] Figure 5FIG. (a) shows the change in the posture of the robot 10 when the robot 10 is moved while maintaining the orientations of the hands 25 and 26 at the starting access point, that is, while maintaining the posture in which the hands 25 and 26 are oriented in the -Y direction. In this case, during the movement, the proximal ends of the hands 25 and 26 collide with the wall surface 41 of the transfer chamber. In contrast, Figure 5 FIG. (b) shows Figure 3 FIG. (b) shows the change in the posture of the robot 10 when the path L is set in the same manner as in the case shown in FIG. (b) and the robot 10 is moved along the path L by the CP operation. In the example shown here, the hand 25 is controlled by the CP operation so that its proximal end moves along the path L while the hand 25 is oriented in the -Y direction. In this case, the proximal end of the hand 25 is the only potential collision position related to the hand 25 and becomes the control target point. The other hand 26 also moves along the path L with its proximal end as the control target point. In the hands 25 and 26, since no workpiece is loaded on the proximal end side, in Figure 5 the cases shown in FIGS. (a) to (c), it is not necessary to consider the collision between the workpiece and the wall surface 41.

[0060] Figure 5 FIG. (c) shows Figure 3 FIG. (c) shows the change in the posture of the robot 10 when the path L is set in the same manner as in the case shown in FIG. (c) and the robot 10 is moved by the PTP operation. The constraint conditions during the PTP operation are the same as those described in the case using Figure 3 FIG. (c). The robot 10 moves from the starting access point via each via point to the ending access point in the same manner as in the case described in FIG. (c) using Figure 3 FIG. (c), except that the robot 10 uses the via points where the proximal ends of the hands 25 and 26 are located on the path L as the via points.

[0061] According to the control described using Figure 5 FIGS. (a) to (c), it is possible to avoid collisions on the proximal end sides of the hands 25 and 26 and to shorten the time until the movement of the robot 10 from the starting access point to the ending access point is completed.

[0062] The control of the movement of the robot 10 has been described above in the case where the directions of the hands 25 and 26 (i.e., the first direction) at the starting access point are the same as the directions of the hands 25 and 26 (i.e., the second direction) at the ending access point. However, the control method of the present invention can also be applied in the case where the orientations of the hands 25 and 26 are different between the starting access point and the ending access point. Here, consider the case where the hands 25 and 26 are oriented in the -X direction at the starting access point and the angle α representing the orientation of the swing arm 21 is +45°, and the hands 25 and 26 are oriented in the Y direction at the ending access point and the angle α of the swing arm 21 is -45°. The starting access point in this case is at Figure 2The access point after rotating the common arm 22, the front end arms 23, 24, and the hands 25, 26 by +90° around the TH axis in the starting access point shown in (a). The end access point is the same as the Figure 2 end access point shown in (b). Figure 6 Figures (a) to (c) are schematic top views for explaining the control of the robot 10 when such access points are determined. In particular, Figure 6 figures (a) and (c) show the movement of the robot when changing the angle α formed by the extending direction of the swing arm 21 and the Y direction. Workpieces 31 and 32 are placed on the hands 25 and 26 respectively.

[0063] Regardless of whether it is the starting access point or the end access point, the hands 25, 26 overlap with each other facing the same direction. In addition, between the starting access point and the end access point, the swing arm 21 rotates -90° around the T axis, and the orientations of the hands 25, 26 also rotate -90°. Therefore, if the swing arm 21 is rotated -90° with the common arm 22, the front end arms 23, 24, and the hands 25, 26 relatively fixed with respect to the swing arm 21, the robot 10 should move from the starting access point to the end access point. However, in this case, as Figure 6 shown in (a), since the front ends of the hands 25, 26, the workpieces 31, 32 collide with the wall surface 41, the movement from the starting access point to the end access point cannot be completed. Therefore, as described above, consider controlling the robot 10 by CP motion or PTP motion to avoid collision and move the robot 10 from the starting access point to the end access point.

[0064] When performing CP motion, it is necessary to determine the path that the control object point should follow. When performing PTP motion, a path is also required to determine the via point. In this example, since the orientations of the hands 25, 26 are different between the access points and the Y coordinates of the front ends of the hands 25, 26 are also different, it is not appropriate to use a straight path. Instead, a curved path C is set. If the protrusion amounts of the front ends of the hands 25, 26 from the workpieces 31, 32 in the horizontal plane are very small and can be ignored, the vertices at both ends of the edges on the front end side of the workpieces 31, 32 that are located on the front side in the rotation direction of the swing arm 21 can be considered as potential collision positions for the hands 25, 26 respectively, and this point is used as the control object point. Then, consider a path C starting from the control object point P when the hands 25, 26 are at the starting access point and ending at the control object point Q when the hands 25, 26 are at the end access point. The path C is, for example, an arc or an elliptical arc, but it can also be a spline curve or a Bezier curve. During the movement of the robot 10, the XY coordinate values of the position of the T axis in the world coordinate system do not change, so Figure 6Figure (b) overlaps and shows the postures of the robot 10 at the start access point and the end access point in such a way that the T-axis positions are the same in the XY plane, and shows the path C in the XY plane. In the example described here, the path C is a circular arc.

[0065] Figure 6 Figure (c) shows the change in the posture of the robot 10 when performing CP motion control to move the robot 10 from the start access point to the end access point. At the start access point and the end access point, the orientations of the hands 25 and 26 differ by -90°. Therefore, in the example shown here, for the control object point of the hand 25, it moves from the position P to the position Q, and according to the moving distance of the control object point, the orientation of the hand 25 (or the angle α of the swing arm 21) changes at a constant speed, and the hand 25 is controlled under CP motion. For the other hand 26, it is controlled on the condition that its control object point is located on the path C.

[0066] When the robot 10 starts to move from the start access point, the hand 25 starts to move along the path C towards the end access point, but the hand 26 moves ahead of the hand 25, that is, starts to move towards the end access point at a speed greater than that of the hand 25. Then, when the hand 26 approaches the end access point, its speed is smaller than that of the hand 25, and finally the hands 25 and 26 reach the end access point simultaneously. When approaching the end access point, among the vertices at both ends of the front side edge of the workpiece 32, the vertex located on the rear side in the rotation direction of the swing arm 21 protrudes slightly outward from the path C, but this vertex also protrudes from the path C when the hand 26 is at the end access point. Through this protrusion of the vertex from the path C, the workpiece 32 does not collide with surrounding objects. In order to alleviate the rapid movement of the hand 26 when starting to move from the start access point, as the path C, a curve other than a circular arc can be considered, for example. Or, the hand 26 can be moved by CP motion instead of the hand 25, and the hand 25 can be controlled to only follow the path C.

[0067] When performing PTP motion-based control, at the start access point and the end access point, the orientation of the common arm 22 in the XY plane of the world coordinate system is different, and like the swing arm 21, it only rotates -90°. Therefore, the first constraint condition is that when the swing arm 21 only rotates -90°, even in the XY plane, the common arm 22 also rotates -90°. In this case, since there is no rotational difference between the swing arm 21 and the common arm 22, the common arm 22 does not move relative to the swing arm 21. Regarding the second constraint condition, the same conditions as those described when using Figure 3 Figure (c) are used. On this basis, via points that satisfy the condition that the control object points of the hands 25 and 26 are respectively located on the path C are set, and the robot 10 is controlled to move from the start access point via the via points to the end access point.

[0068] According to the use of Figure 6The control described in (a) to (c) can avoid collisions between the hands 25, 26 or the workpieces 31, 32 even when the orientations of the hands 25, 26 at the start access point are different from the orientations of the hands 25, 26 at the end access point, and can shorten the time until the movement of the robot 10 from the start access point to the end access point is completed.

Claims

1. A robot control method, controlling a robot, the robot comprising: a swing arm, a base end of which is connected to a first axis and can rotate around the first axis; a common arm, which is connected to the front end of the swing arm via a second axis and can rotate around the second axis; a first front end arm, a base end of which is connected to one front end of the common arm via a third axis and can rotate around the third axis; a second front end arm, a base end of which is connected to the other front end of the common arm via a fourth axis and can rotate around the fourth axis; a first hand, a base end of which is connected to the front end of the first front end arm via a fifth axis and rotates around the fifth axis in a manner linked to the rotation of the first front end arm relative to the common arm around the third axis; and a second hand, a base end of which is connected to the front end of the second front end arm via a sixth axis and rotates around the sixth axis in a manner linked to the rotation of the second front end arm relative to the common arm around the fourth axis, the first axis to the sixth axis are parallel to each other, In the robot control method, When the swing arm is rotated about the first axis to move the robot from a starting access point where the first hand and the second hand overlap each other and face the first direction to an end access point where the first hand and the second hand overlap each other and face the second direction, The control of moving the first hand is performed by continuous path action, and the control of placing the control object point of the second hand on a predetermined path is performed at the same time. The continuous path motion is a motion in which a control target point of the first hand is located on the prescribed path and a change in the orientation of the first hand is specified.

2. A robot control method, controlling a robot, the robot comprising: a swing arm, a base end of which is connected to a first axis and can rotate around the first axis; a common arm, which is connected to the front end of the swing arm via a second axis and can rotate around the second axis; a first front end arm, a base end of which is connected to one front end of the common arm via a third axis and can rotate around the third axis; a second front end arm, a base end of which is connected to the other front end of the common arm via a fourth axis and can rotate around the fourth axis; a first hand, a base end of which is connected to the front end of the first front end arm via a fifth axis and rotates around the fifth axis in a manner linked to the rotation of the first front end arm relative to the common arm around the third axis; and a second hand, a base end of which is connected to the front end of the second front end arm via a sixth axis and rotates around the sixth axis in a manner linked to the rotation of the second front end arm relative to the common arm around the fourth axis, the first axis to the sixth axis are parallel to each other, In the robot control method, When the swing arm is rotated about the first axis to move the robot from a starting access point where the first hand and the second hand overlap each other and face the first direction to an end access point where the first hand and the second hand overlap each other and face the second direction, One or more transit points are determined in such a way that the control object point of the first hand and the control object point of the second hand are present on a specified path, and the robot moves from the starting access point to the ending access point via the one or more transit points through point-to-point action.

3. The robot control method according to claim 2, wherein: The point-to-point action is performed under a first constraint and a second constraint, wherein the first constraint is that the common arm rotates relative to the swing arm around the second axis in proportion to the rotation amount of the swing arm around the first axis based on the angular difference in the orientation of the common arm between the starting access point and the ending access point, and the second constraint is that the change in the rotation angle of the swing arm around the first axis, the change in the rotation angle of the first front arm around the third axis, and the change in the rotation angle of the second front arm around the fourth axis form a linkage.

4. The robot control method according to any one of claims 1 to 3, wherein: The control object point is determined, for each of the first hand and the second hand, as a point on the hand or on an object carried by the hand, which may potentially collide with an object around the robot as the robot moves from the starting access point to the ending access point, The predetermined path is determined as a path in which the control target point does not collide with an object around the robot.

5. The robot control method according to claim 4, wherein: The first direction and the second direction are in the same direction, and the prescribed path is a straight line.

6. The robot control method according to claim 4, wherein: The second direction is orthogonal to the first direction, and the prescribed path is a curve.

7. The robot control method according to any one of claims 1 to 3, wherein: In the robot, the common arm is an arm bent at a position maintained at the swing arm via the second axis, and the distance between the second axis and the third axis is equal to the distance between the second axis and the fifth axis, and the distance between the second axis and the fourth axis is equal to the distance between the fourth axis and the sixth axis.

8. A robot control device for controlling a robot, the robot comprising: a swing arm, a base end of which is connected to a first axis and can rotate around the first axis; a common arm, which is connected to the front end of the swing arm via a second axis and can rotate around the second axis; a first front end arm, a base end of which is connected to one front end of the common arm via a third axis and can rotate around the third axis; a second front end arm, a base end of which is connected to the other front end of the common arm via a fourth axis and can rotate around the fourth axis; a first hand, a base end of which is connected to the front end of the first front end arm via a fifth axis and rotates around the fifth axis in a manner linked to the rotation of the first front end arm relative to the common arm around the third axis; and a second hand, a base end of which is connected to the front end of the second front end arm via a sixth axis and rotates around the sixth axis in a manner linked to the rotation of the second front end arm relative to the common arm around the fourth axis, the first to sixth axes are parallel to each other, wherein The robot control device has: a storage unit that stores parameters required for controlling the robot; and A calculation unit, which refers to the parameters in the storage unit for calculation when rotating the swing arm around the first axis to move the robot from a starting access point where the first hand and the second hand overlap each other and face the first direction to an end access point where the first hand and the second hand overlap each other and face the second direction, thereby controlling the first axis to the fourth axis in such a manner that the control object point of the second hand is located on a prescribed path while the first hand is moved through a continuous path action, wherein the continuous path action is a change in the direction of the first hand where the control object point of the first hand is located on the prescribed path and is specified.

9. A robot control device for controlling a robot, the robot comprising: a swing arm, a base end of which is connected to a first axis and can rotate around the first axis; a common arm, which is connected to the front end of the swing arm via a second axis and can rotate around the second axis; a first front end arm, a base end of which is connected to one front end of the common arm via a third axis and can rotate around the third axis; a second front end arm, a base end of which is connected to the other front end of the common arm via a fourth axis and can rotate around the fourth axis; a first hand, a base end of which is connected to the front end of the first front end arm via a fifth axis and rotates around the fifth axis in a manner linked to the rotation of the first front end arm relative to the common arm around the third axis; and a second hand, a base end of which is connected to the front end of the second front end arm via a sixth axis and rotates around the sixth axis in a manner linked to the rotation of the second front end arm relative to the common arm around the fourth axis, the first to sixth axes are parallel to each other, wherein The robot control device has: a storage unit that stores parameters required for controlling the robot; and A calculation unit, which refers to the parameters in the storage unit for calculation when the swing arm is rotated around the first axis to move the robot from a starting access point where the first hand and the second hand overlap each other and face the first direction to an end access point where the first hand and the second hand overlap each other and face the second direction, thereby determining one or more transit points in a manner such that the control object point of the first hand and the control object point of the second hand exist on a prescribed path, and controlling the first to fourth axes in a manner such that the robot moves from the starting access point to the end access point via the one or more transit points through a point-to-point action.

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