JP2016002626A - Parallel link robot, control method for parallel link robot, and control method for robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which can easily detect a position of an output member using an inexpensive configuration.SOLUTION: A CPU, in a position specification mode for specifying a position of an output member, executes rotation area specification processing for specifying whether first to third rotation arms are positioned in any of a plurality of rotation areas in which a plurality of detection sensors have different ON/OFF signals respectively. The CPU executes drive processing for moving an edge part by driving first to third motors up to a boundary position between a rotation area where the first to third rotation arms are positioned and its neighboring rotation area, among boundary positions where the ON/OFF signal of any one of the plurality of detection sensors changes over. The CPU executes the rotation area specification processing and the drive processing with respect to all of the first to third motors, and then executes position specification processing for specifying a position of the output member.

Description

  The present invention relates to a parallel link robot, a parallel link robot, and a robot control method, which are configured by combining a plurality of actuators and a link mechanism, and are used for operations such as processing and assembly of articles.

  The parallel link robot is provided with a link mechanism as an arm between a plurality of actuators supported by a fixed member serving as a base and an output member. A plurality of actuators are driven to control the position and posture of the output member connected to the tip of each link and the end effector attached to the output member.

  Here, if the parallel link robot is stopped for some reason during the work by the parallel link robot and the stop position does not exist on the original work route, the parallel link robot may come into contact with surrounding interference objects when the operation is restarted from the stop position. is there. In order to avoid contact with an interfering object, a parallel link robot generally has a configuration in which an origin return operation is automatically executed when restarting from a stopped state. As the return to origin operation, for example, first, an area composed of a movable area of the robot and an interference area where the robot and a jig interfere with each other is divided into a matrix. Then, a configuration has been proposed in which the robot can be returned to the original position regardless of the stop position of the robot by moving the robot based on the information on the movement direction of the robot set for each divided area ( Patent Document 1).

JP 2009-090383 A

  In the case of the configuration described in Patent Document 1, it is necessary to detect the absolute position of the stop position of the robot, and the absolute position of the robot is detected using an encoder capable of detecting the absolute position, a so-called absolute encoder. However, the parallel link robot has a plurality of actuators, and in order to detect the absolute position of the output member of the parallel link robot, it is necessary to provide each actuator with an absolute encoder. In the case of such a configuration, there is a problem that the manufacturing cost increases because the absolute encoder itself is expensive. Further, even in a robot that drives a plurality of actuators other than the parallel link robot to control the position of the output member, the use of an absolute encoder may similarly increase the cost.

  In view of such circumstances, the present invention provides a parallel link robot, a parallel link robot control method, and a robot control method that realize a structure that can easily detect the absolute position of an output member with an inexpensive configuration. It is the purpose.

  The present invention provides an output member having an output shaft, a plurality of actuators supported by a fixed member and moving the output member, and provided between the output shaft and the plurality of actuators, respectively, and interlocked with the actuators. A drive link member that is driven by the drive link member, and a driven link member that is connected to the output shaft and driven by the drive link member. When the drive link member is driven, A link mechanism that positions the output member, a rotating member that has a detected portion and whose rotational position moves in conjunction with the drive link member, and a plurality of detections in which an on / off signal is switched depending on the rotational position of the detected portion And a control unit having a position specifying mode for specifying the position of the output member, the control unit in the position specifying mode A rotation region specifying process for specifying in which rotation region the drive link member is located among a plurality of rotation regions having different on / off signals of the plurality of detection units, and any of the detection units The actuator is driven to the boundary position between the rotation area where the drive link member is located and the rotation area adjacent to the rotation area among the boundary positions of each rotation area where the on / off signal is switched. A drive process for moving a detection unit, and a position specifying process for executing the rotation region specifying process and the drive process for all of the plurality of actuators to specify the position of the output member are performed. It is a parallel link robot.

  Further, the present invention provides an output member having an output shaft, a plurality of actuators supported by a fixed member to move the output member, and provided between the output shaft and the plurality of actuators, A drive link member that is driven in conjunction, and a driven link member that is connected to the output shaft and driven by the drive link member, and each of the driven link members is connected when the drive link member is driven. A link mechanism that positions the output member according to a relationship, a rotating member that has a detected portion and whose rotational position moves in conjunction with the drive link member, and a plurality of on / off signals that are switched depending on the rotational position of the detected portion And a control unit having a position specifying mode for specifying the position of the output member. The control unit executes a rotation region specifying process for specifying in which rotation region the drive link member is located among a plurality of rotation regions having different on / off signals of the plurality of detection units. A rotation region specifying process step, and the control unit includes a rotation region in which the drive link member is located and a rotation of the rotation region where the ON / OFF signal of any one of the plurality of detection units is switched. A drive processing step of executing a driving process of moving the detected part by driving the actuator to a boundary position with a rotation area adjacent to the area; and the control unit performs the rotation area specifying process and the driving process. And a position specifying process step for executing a position specifying process for specifying the position of the output member, which is executed on all of the plurality of actuators. It is a method of controlling the link robot.

  Further, the present invention provides a plurality of actuators that move the position of the output member, and a rotation region that is provided in each of the plurality of actuators and that is driven in each rotation region that divides the drive region into a plurality of regions A plurality of actuator position detection sensors for detecting, and a control unit that controls the position of the output member by dividing the movable region of the output member into a plurality of divided spaces by combining the rotation regions of the plurality of actuators. In the robot control method, the control unit executes a rotation region specifying process in which the actuator position detection sensor detects a rotation region driven by each of the plurality of actuators at the time of starting or after the robot is started. The rotation area specifying process step, and the control unit outputs the output from a combination of the rotation areas. A drive process step of determining a divided space including a material position and executing a drive process of driving the plurality of actuators; and the control unit that the plurality of actuators have reached the boundary position of the rotation region A position specifying process for executing a position specifying process for specifying the positions of the plurality of actuators and the output member from the origin when detected by an actuator position detection sensor. It is.

  According to the present invention, the absolute position of the output member is driven by driving each actuator and moving the drive link member to the boundary position where the on / off signal of any one of the plurality of detection units provided in each actuator is switched. Is identified. Thereby, the absolute position of the output member can be specified with an inexpensive configuration. Further, the driving amount of each actuator can be suppressed, and the absolute position of the output member can be easily specified.

(A) is a front view of the parallel link robot which concerns on this embodiment, (b) is a side view of a parallel link robot. (A) is a perspective view of the parallel link robot which concerns on this embodiment, (b) is an enlarged front view of the output member in a parallel link robot. The front view which shows the structure of the detection part which detects the rotation position of the rotation member of the parallel link robot which concerns on this embodiment. The schematic front view which shows the rotation area | region of the parallel link robot which concerns on this embodiment. The schematic front view which shows the division | segmentation space which divides | segments the movable area | region of the output member of the parallel link robot which concerns on this embodiment. (A) is a schematic perspective view which shows the division | segmentation space which divides | segments the movable area | region of the output member of the parallel link robot which concerns on this embodiment, and the origin position of an output member, (b) moves in the division | segmentation space by a drive process. Explanatory drawing explaining the movement method of an output member. The block diagram of the control part of the parallel link robot which concerns on this embodiment. The flowchart which shows each process in the absolute position specific mode of the parallel link robot which concerns on this embodiment. The flowchart which shows each process in the case where there exists an interfering object in division space in the absolute position specific mode of the parallel link robot which concerns on this embodiment. (A)-(d) is explanatory drawing which shows the movement method of an output member in the case where there exists an interference object in division space in the absolute position specific mode of the parallel link robot which concerns on this embodiment.

  An embodiment of the present invention will be described with reference to FIGS.

[Parallel link robot overview]
As shown in FIGS. 1A and 1B, the parallel link robot 100 includes a base portion 100A as a fixed member, an output member 103 that moves within a predetermined space, and a plurality of motors 107, 108, and 111. And a plurality of arms 109, 110, and 112. Here, the motor 107 corresponds to a first actuator, the motor 108 corresponds to a second actuator, and the motor 111 corresponds to a third actuator. The motors 107, 108, and 111 constitute a plurality of actuators in the present embodiment. The arm 109 corresponds to the first arm, the arm 110 corresponds to the second arm, and the arm 112 corresponds to the third arm. In the following description, the motor 107 is also referred to as a first motor 107, the motor 108 is also referred to as a second motor 108, and the motor 111 is also referred to as a third motor 111.

  The base portion 100A includes a horizontal plate 101 disposed in a substantially horizontal direction and a vertical plate 102 provided in a substantially vertical direction from the horizontal plate 101, and supports the first to third motors 107, 108, and 111. To do. The first to third motors 107, 108, and 111 are fixed to predetermined positions on the vertical plate 102, respectively. In the present embodiment, the parallel link robot 100 includes the third motor 111 on the upper side in the center of the vertical direction of the vertical plate 102 and the third motor 111 on both sides of the vertical direction intermediate portion of the vertical plate 102 with the width direction center interposed therebetween. 1 motor 107 and 2nd motor 108 are arranged. On the horizontal plate 101, a workpiece, an assembly jig, and the like are arranged.

  The output member 103 is a manipulator for mounting an end effector 104 such as a robot hand that holds and moves a workpiece. The output member 103 has an output shaft 105 to which link mechanisms constituting a plurality of arms to be described later are coupled on the same axis as the end effector 104 that is detachably provided.

[Positioning of output member]
A configuration for positioning the output member 103 by the parallel link robot 100 will be described with reference to FIGS. 1 and 2. The first arm 109 and the second arm 110 are disposed between the output member 103 and the first motor 107 and between the output member 103 and the second motor 108, respectively. The first arm 109 and the second arm 110 hold the output member 103 from both sides. The output member 103 is moved in a direction (substantially horizontal direction) intersecting the output shaft 105 by driving the first motor 107 and the second motor 108. Strictly speaking, when the third motor 111 is stopped, the output member 103 is moved on a virtual spherical surface by the first motor 107 and the second motor 108.

  The third arm 112 is provided between the output member 103 and the third motor 111. The third arm 112 holds the output member 103 from above in the vertical direction. Then, the output member 103 is moved in a direction substantially parallel to the output shaft 105 by driving the third motor 111. Strictly speaking, when the first motor 107 and the second motor 108 are stopped, the output member 103 moves on a virtual arc by driving the third motor 111. When the first to third motors 107, 108, and 111 are driven, the output member 103 can be positioned in a predetermined space by the connection relationship of the first to third arms 109, 110, and 112. Yes. The first arm 109, the second arm 110, and the third arm 112 constitute a holding unit that holds the posture of the output member 103. Further, the holding means and the output member 103 constitute a parallel link structure. More specific description will be given below.

  The first motor 107 is a rotary actuator that positions the first link shaft 107b by rotating the first rotating arm 107a in a substantially horizontal direction. The second motor 108 is a rotary actuator that positions the second link shaft 108b by rotating the second rotary arm 108a in a substantially horizontal direction. In this embodiment, the length of the 1st rotation arm 107a and the length of the 2nd rotation arm 108a are made the same. The positions of the first rotating arm 107a and the second rotating arm 108a in the direction parallel to the output shaft 105 are also the same.

  The first and second link shafts 107b and 108b are tips of the first and second rotating arms 107a and 108a so as to be substantially parallel to the rotation shafts of the first and second motors 107 and 108, respectively, and not tiltable. Is provided. In the present embodiment, since the rotation shafts of the first and second motors 107 and 108 are arranged substantially parallel to the output shaft 105, the first and second link shafts 107b and 108b are also substantially the same as the output shaft 105, respectively. Arranged in parallel.

  The first arm 109 includes a plurality of first links 109 a that are spaced apart in a direction parallel to the output shaft 105 and arranged in parallel with each other. In the present embodiment, the first arm 109 is constituted by two first links 109a having the same length. Such a first arm 109 has one end rotated with respect to the output member 103 around the axis (first axis 132) parallel to the output shaft 105, and the arrangement of the first axis 132 and the first arm 109. It is connected in a state having two degrees of freedom capable of rotating around an axis orthogonal to the installation direction. Further, the other end is connected to a first link shaft 107 b provided in a non-tiltable manner on a first rotating arm 107 a serving as a drive unit of the first motor 107. Thereby, the 1st arm 109 comprises the parallel link mechanism.

  Specifically, one end of each of the two first links 109a is connected to a first shaft 132 parallel to the output shaft 105 that supports the end effector 104 by a joint portion 109b having two degrees of freedom. The other ends of the two first links 109a are respectively connected to the first link shaft 107b by joint portions 109c having two degrees of freedom. Here, the joint portion 109c can rotate around the first link shaft 107b and rotate around an axis orthogonal to the arrangement direction of the first link shaft 107b and the first link 109a. That is, the two first links 109a have both ends connected to the first shaft 132 and the first link shaft 107b with two degrees of freedom, respectively. The first shaft 132, the first link shaft 107b, and the two first links 109a constitute a parallel link mechanism.

  The second arm 110 is composed of a plurality of second links 110 a that are spaced apart in a direction parallel to the output shaft 105 and arranged in parallel to each other. In the present embodiment, the second arm 110 is constituted by two second links 110a having the same length. The length of the two second links 110a is the same as the length of the two first links 109a of the first arm 109. The second arm 110 is configured such that one end of the second arm 110 rotates around the axis parallel to the output shaft 105 (second shaft 133) with respect to the output member 103 and the second shaft 133 and the second arm 110 are disposed. They are connected in a state having two degrees of freedom that allows rotation about an axis orthogonal to the direction. Further, the other end is connected to a second link shaft 108b provided in a non-tiltable manner on a second rotating arm 108a as a drive unit of the second motor 108.

  Specifically, one end of each of the two second links 110 a is connected to a second shaft 133 parallel to the output shaft 105 that supports the end effector 104 by a joint portion 110 b with two degrees of freedom. The other ends of the two second links 110a are respectively connected to the second link shaft 108b by joint portions 110c having two degrees of freedom. Here, the joint portion 110c is capable of rotating about the second link shaft 108b and rotating about an axis orthogonal to the arrangement direction of the second link shaft 108b and the second link 110a. That is, the two second links 110a are connected at both ends to the second shaft 133 and the second link shaft 108b with two degrees of freedom. The second shaft 133, the second link shaft 108b, and the two second links 110a constitute a parallel link mechanism. In addition, the joint portion 110b that connects the two second links 110a to the second shaft 133 includes the joint portion 109b that connects the two first links 109a of the first arm 109 to the first shaft 132, and the output shaft 105. Are arranged at the same position in the direction parallel to the.

  With this configuration, the output shaft 105 that supports the end effector 104 and the first link shaft 107b and the second link shaft 108b that are provided so as not to tilt are always kept parallel. The posture (tilt) of the end effector 104 is held constant (substantially in the vertical direction) regardless of the position of each of the first and second rotating arms 107a and 108a.

  The third motor 111 as the third actuator is a rotary actuator that positions the third link shaft 111b by rotating the third rotating arm 111a in a substantially vertical direction. The third link shaft 111b is provided at the tip of the third rotating arm 111a so as to be substantially parallel to the rotating shaft of the third motor 111 and not tiltable. In the present embodiment, since the rotation shaft of the third motor 111 is disposed substantially parallel to the third shaft 106, the third link shaft 111 b is also disposed substantially parallel to the third shaft 106.

  The third arm 112 includes a plurality of third links 112a that are spaced apart from each other in a direction parallel to the third shaft 106 and arranged in parallel with each other. In the present embodiment, the third arm 112 is constituted by two third links 112a having the same length. The third arm 112 has one end centered on an axis perpendicular to the rotation direction of the third shaft 106 and the arrangement direction of the third shaft 106 and the third arm 112 with respect to the output member 103. It is connected in a state having two degrees of freedom capable of rotating. Further, the other end is connected to a third link shaft 111 b provided in a non-tiltable manner on a third rotating arm 111 a as a drive unit of the third motor 111. Thereby, the 3rd arm 112 comprises the parallel link mechanism.

  Specifically, one end of each of the two third links 112a is connected to the third shaft 106 by a joint portion 112b having two degrees of freedom. The other ends of the two third links 112a are respectively connected to the third link shaft 111b by joint portions 112c having two degrees of freedom. Here, the joint portion 112c can rotate around the third link shaft 111b and can rotate around an axis orthogonal to the arrangement direction of the third link shaft 111b and the third link 112a. The pair of third links 112a of the third arm 112 are connected at symmetrical positions in the horizontal direction from the portion where the output shaft 105 of the third shaft 106 is joined. That is, the two third links 112a are connected at both ends to the third shaft 106 and the third link shaft 111b with two degrees of freedom. The third shaft 106, the third link shaft 111b, and the two third links 112a constitute a parallel link mechanism. As a result, the third shaft 106 that supports the end effector 104 and the third link shaft 111b provided so as not to tilt are always kept parallel. Then, no matter which position the third rotating arm 111a rotates, the rotation of the end effector 104 around the output shaft 105 is constrained and the orientation is kept constant.

  As described above, the first to third rotating arms 107a, 108a driven in conjunction with the first to third motors 107, 108, 111 among the first to third arms 109, 110, 112 constituting the link mechanism, 111a comprises the drive link member in this embodiment. The first to third links 109a, 110a, and 112a connected to the output shaft 105 and driven by the first to third rotating arms 107a, 108a, and 111a constitute a driven link member in the present embodiment. As described above, when the first to third rotating arms 107a, 108a, and 111a are driven, the output member within a predetermined space due to the connection relationship between the first to third links 109a, 110a, and 112a. 103 is positioned.

  In the present embodiment, the angle formed between the output shaft 105 and the third shaft 106 is 90 degrees and is orthogonal to each other, but may be three-dimensionally orthogonal or limited to 90 degrees. Instead, they may be arranged at a predetermined angle.

  Thus, in the parallel link robot 100 according to the present embodiment, the end effector 104 attached to the output member 103 maintains a constant posture by the parallel link mechanism formed by the first to third arms 109, 110, and 112. To be supported. Here, the attitude of the end effector 104 means both inclination and direction.

  In the parallel link robot 100 according to the present embodiment, the output member 103 is substantially omitted by driving the first rotating arm 107a by the first motor 107 and driving the second rotating arm 108a by the second motor 108. Move horizontally. In addition, when the output member 103 is moved in the vertical direction by driving the third rotating arm 111a by the third motor 111, the first arm 109 and the second arm 110 are displaced from the horizontal. For this reason, the position of the output member 103 in the three-dimensional space (predetermined space) is determined in consideration of the inclination of the first arm 109 and the second arm 110, and the first to third rotating arms 107a, 108a, 111a. It is possible to calculate geometrically from the driving amount. Further, it is possible to calculate the driving amounts of the first to third motors 107, 108, and 111 from the spatial position coordinates of the output member 103 by calculation of inverse kinematics.

[Configuration to divide motor operating area]
Next, a configuration for detecting the absolute positions of the first to third motors 107, 108, and 111 in the present embodiment will be described. Note that the configurations for detecting the absolute positions of the first to third motors 107, 108, and 111 are all the same, and the configuration for detecting the absolute position of the first motor 107 will be described below as a representative. . Regarding the configuration for detecting the absolute position of other motors, the same subscript is given to the same configuration and member as the configuration for detecting the absolute position of the first motor 107, and the numbers indicating the respective motors are changed.

  As shown in FIG. 3, the first motor 107 includes a plate 107d as a rotating member whose rotational position moves in conjunction with the first rotating arm 107a, and detection sensors 107i to 107k as a plurality of detection units. Is provided. The plate 107d has a first arc portion 107e having a first radius and a second arc portion 107f having a second radius longer than the first radius. The detection sensors 107i to 107k are composed of photo interrupters and are arranged on the outer peripheral side of the first arc portion 107e, and detect the presence or absence of the second arc portion 107f. In the present embodiment, the on / off signals of the detection sensors 107i to 107k are switched by the edges 107g and 107h of the second arc portion 107f of the plate 107d that is driven in conjunction with the first motor 107 and the first rotating arm 107a. It is configured. Here, the rotational position of the plate 107 d is the position of the plate 107 d in the circumferential direction around the drive shaft of the first motor 107. Further, the edges 107g and 107h for switching the on / off signals of the detection sensors 107i to 107k depending on the rotation position constitute a detected portion in the present embodiment. In the present embodiment, the detection sensors 107i to 107k are configured by photo interrupters, but are not limited thereto. For example, the detection sensors 107i to 107k are turned on when pressed by the second arc portion 107f when facing the second arc portion 107f, and are turned off when not facing the second arc portion 107f. A push-type switch may be used.

  A CPU 401 (described later) of the parallel link robot 100 divides an operation area as an area where the first rotary arm 107a can be positioned for each on / off signal of the detection sensors 107i to 107k. That is, the CPU 401 divides the operating area of the first motor 107 for each rotation angle. As shown in FIG. 4, the operating area of the first motor 107 according to this embodiment is divided into first to sixth rotation areas A to F corresponding to the operation area of the first rotating arm 107a. Here, among the first to sixth rotation areas A to F, the first to fourth rotation areas A to D are movable areas that are areas where the first rotation arm 107a can be moved, and have the same size. Yes. The first to fourth rotation areas A to D have different patterns of on / off signals of the detection sensors 107i to 107k, respectively. For example, when the first rotation arm 107a is located in the first rotation area A, the detection sensors 107i and 107j are off and the detection sensor 107k is on. Further, when the first rotation arm 107a is located in the second rotation region B, the detection sensors 107i to 107k are turned off. In addition, the 1st-4th rotation area | region AD in this embodiment and the pattern of the ON / OFF signal of each detection sensor 107i-107k are illustrations, and this invention is not limited to this.

  The CPU 401 drives the first motor 107 and moves the rotational positions of the edges 107g and 107h to the position where the on / off signal of any one of the detection sensors 107i to 107k is switched, whereby the absolute position ( Rotation angle) can be specified. At this time, the first rotation arm 107a is located at a boundary position that is a boundary between the rotation area located before the movement and the rotation area adjacent to the rotation area. That is, the CPU 401 can specify the absolute position of the first motor 107 by driving the first motor 107 and moving the first rotating arm 107a to the boundary position. Here, the position at which the on / off signal of any one of the detection sensors 107i to 107k switches forms the boundary position of each rotation region.

  The fifth and sixth rotation areas E and F are immovable areas of the first rotation arm 107a. Here, the non-movable area is an area where the first rotating arm 107a cannot physically move and an arbitrarily set area which does not allow movement. In the present embodiment, the fifth and sixth rotation regions E and F are set in consideration of the interference between the first rotation arm 107a and the vertical plate 102. In order to prevent the first rotating arm 107a from interfering with the vertical plate 102 at the time of abnormality, the first motor 107 contacts the first rotating arm 107a and stops the rotation of the first rotating arm 107a. A stopper 107l is provided. With this configuration, the first motor 107 can take a rotation angle within a range in which the first rotation arm 107a does not contact the stopper 107l in each of the fifth and sixth rotation regions E and F.

Note that the number and size of the rotation regions are determined by the positions of the edges 107g and 107h of the plate 107d and the positions and number of detection sensors. Since the operation area of the first motor 107 can be divided into two rotation areas for each detection sensor, the maximum division number of the rotation area is represented by 2 ⁿ where n is the number of detection sensors. In the present embodiment, three detection sensors 107i to 107k are provided in order to divide the operation area of the first motor 107 into first to sixth rotation areas A to F.

[Division of movable area of output member]
FIG. 5 shows a state in which a predetermined space (movable region) in which the output member 103 is movable is divided for each of the first to fourth rotation regions A to D of the first to third motors 107, 108, and 111. FIG. In the present embodiment, the movable region of the output member 103 is divided into four movable regions of the first to third motors 107, 108, and 111, and each of the movable regions of the rotary arms is divided into first to fourth rotational regions A to D, respectively. Therefore, it is divided into 64 divided spaces. In FIG. 5 and FIG. 6 to be described later, in order to clarify the explanation, illustration of some parts such as arms and links constituting the parallel link robot 100 is omitted. Further, for example, when the rotation angles of the first to third motors 107, 108, and 111 are included in the fourth rotation area D, the first rotation area A, and the third rotation area C, respectively, the position of the output member 103 is 5 is included in the divided space hatched. The position of this divided space is described as “DAC”. Hereinafter, when the regions including the rotation angles of the first to third motors 107, 108, and 111 are 107x, 108y, and 111z, respectively, the divided space including the position of the output member 103 is described as “xyz”. In the following description, one point representing the position of the output member 103 in the movable region is referred to as an output member position 103a.

  Here, the surface shape of the divided space depends on the movement path of the output member 103 when any one of the first to third motors 107, 108, and 111 is moved independently. In this embodiment, when each rotary arm connected to the first to third motors 107, 108, 111 is rotationally driven, the movement path of the output member 103 takes a substantially arc shape via each link mechanism. The surface shape of the divided space is a curved surface. The surface of each divided space is a boundary between the divided space and the adjacent divided space. When the output member position 103a is on the surface of the divided space, the output member 103 moves along the surface of the divided space when any one of the first to third motors 107, 108, and 111 is driven alone. . Further, when the output member position 103a is inside the divided space, when the first to third motors 107, 108, and 111 are driven independently, the movement path of the output member 103 is substantially the same track as the ridgeline of the divided space. Become. The size of each divided space depends on the arrangement position of each actuator, the size of the rotation area of each actuator, and the like.

  In the present embodiment, the region where the output member 103 can be positioned can be set wider than the range where there is a divided space where the absolute position can be specified by including the fifth and sixth rotation regions E and F. . In the parallel link robot 100, in the space outside the divided space, since the parallel link robot 100 does not execute each operation, there is no interference such as a workpiece or a part. Therefore, by setting the origin position to the outside of the divided space and closer to the third motor 111 than the first and second motors 107 and 108, the parallel link robot 100 contacts an interference object in the origin return process described later. Less likely. Thereby, the parallel link robot 100 can return the output member 103 to the origin stably and promptly.

[Control unit of parallel link robot]
Next, the control unit of the parallel link robot 100 according to the present embodiment will be described with reference to FIG. The parallel link robot 100 includes a CPU 401 that functions as a control unit, and a ROM 402 and a RAM 403 that function as storable storage units.

  A ROM 402, a RAM 403, first to third motors 107, 108, 111, detection sensors 107 i to 107 k, 108 i to 108 k, 111 i to 111 k and an external network 420 are connected to the CPU 401 via a bus 410. The CPU 401 controls the operations of the first to third motors 107, 108, and 111, moves the output member 103 within the rotation region, and executes work by the end effector 104. In addition, the CPU 401 determines the rotation region where the first to third rotation arms 107a, 108a, and 111a are located from the on / off signals of all the detection sensors. Then, in the absolute position specifying mode for specifying the absolute position of the output member 103 described later, the absolute position of the output member 103 in the movable region is specified. The CPU 401 is configured to be able to input various control information from the outside via the external network 420.

[Specify absolute position of output member]
Next, each process of the CPU 401 when the parallel link robot 100 according to the present embodiment specifies the absolute position of the output member 103 will be described with reference to FIGS. 6 and 8. In the control method of the parallel link robot 100 according to the present embodiment, firstly, the parallel link robot 100 performs a rotation area specifying process step of executing a rotation area specifying process for specifying the rotation area where the first rotation arm 107a is located. Run. Next, the parallel link robot 100 executes a driving process step of driving the first motor 107 to move the edges 107g and 107h to the boundary position of the rotation region where the first rotating arm 107a is located. Next, the absolute position specifying process for executing the rotation position specifying process and the driving process for all of the second and third motors 108 and 111 and executing the absolute position specifying process for specifying the absolute position of the output member 103 is performed as a parallel link robot. Run at 100.

  In the present embodiment, when the output member 103 is stopped at a predetermined position due to an abnormal stop or the like, the parallel link robot 100 generates an ON / OFF signal for each detection sensor of the first to third motors 107, 108, and 111. refer. The parallel link robot 100 can determine in which divided space the stop position is included from the on / off signals of the respective detection sensors referred to. However, the absolute position of the output member 103 cannot be specified from the on / off signals of the detection sensors of the first to third motors 107, 108, and 111. As described above, the absolute positions of the first to third motors 107, 108, and 111 are the positions at which the edge portions of the plates 107d, 108d, and 111d switch the on / off signal of any one of the detection sensors, respectively. Identified. That is, the absolute positions of the first to third motors 107, 108, and 111 are specified when the first to third arms 107a, 108a, and 111a are located at the boundary positions of the rotation region. Therefore, the first to third motors 107, 108, 111 are driven, and the first to third rotating arms 107a, 108a, 111a are driven to the boundary position, so that the first to third motors 107, 108, 111 are driven. Specify the absolute position. Then, the absolute position of the output member 103 is specified by specifying all the absolute positions of the first to third motors 107, 108, and 111.

  FIGS. 6A and 6B are diagrams for explaining until the absolute position of the output member 103 is specified when the output member position 103a is located in the divided space “DAC”. FIG. 8 is a flowchart for describing each process executed when the CPU 401 specifies the absolute position of the output member 103. When executing the absolute position specifying mode for specifying the absolute position of the output member 103, the CPU 401 executes each process shown in FIG.

  As shown in FIG. 8, in the absolute position specifying mode, the CPU 401 first sets a variable i corresponding to the number of actuators that move the output member of the robot as a loop 1 (step S1). In the parallel link robot 100 according to the present embodiment, since the actuator includes the first to third motors 107, 108, and 111, the CPU 401 sets the upper limit value n of the variable i to “3”. When this process is first executed, the CPU 401 sets “1” as the initial value of the variable i.

  Next, the CPU 401 executes a rotation area specifying process for the actuator i (step S2). In this process, the CPU 401 first selects an actuator of the parallel link robot corresponding to the actuator i using the variable i set in step S1. Then, the CPU 401 specifies a rotation region where the rotation arm connected to the actuator is located from each on / off signal of the detection sensor provided in the selected actuator. Here, in the present embodiment, since the variable i takes a value of “1” to “3”, three of the actuator 1, the actuator 2, and the actuator 3 are set by the CPU 401. In step S2, the CPU 401 does not know in which divided space the output member position 103a is located. Therefore, the CPU 401 sets the first motor 107 for the actuator 1, the second motor 108 for the actuator 2, and the third motor 111 for the actuator 3. That is, when the variable i is “1”, the CPU 401 executes the rotation area specifying process for the first motor 107 corresponding to the actuator 1. In addition, when performing the process of step S2, the setting of the actuator corresponding to each actuator i is not limited to this.

  Next, the CPU 401 adds “1” to the variable i (step S3), and determines whether or not the variable i is a value larger than n (step S4). If it is determined in step S4 that the variable i is n or less, the CPU 401 returns the process to step S1 of loop 1. And CPU401 performs the process of step S2 and step S3 again. In the process of step S3, the CPU 401 can execute the rotation region specifying process for all the actuators by executing the processes of step S2 and step S3 until the variable i becomes n + 1. Thereby, the CPU 401 can specify the divided cooking position where the output member position 103a is located.

  If it is determined in step S4 that the variable i is larger than n, the CPU 401 sets the variable i again as the loop 2 (step S5). In this process, the CPU 401 resets the variable i in order to execute the processes after step S6 on each actuator. When this process is first executed, the CPU 401 sets “1” as the initial value of the variable i.

  Next, the CPU 401 drives the actuator i in a predetermined direction (step S6). Next, the CPU 401 drives the actuator i to move to the boundary position between the rotation area where the rotation arm connected to the actuator i is located and the rotation area adjacent to the rotation area (step S7). In these processes, the CPU 401 moves the actuator i to the boundary position between the rotation area where the rotation arm is located and the rotation area adjacent to the boundary position where the on / off signal of any one of the detection sensors of the actuator i is switched. Drive in a predetermined direction. These processes constitute the driving process in the present embodiment. Here, the CPU 401 sets the first to third motors 107, 108, and 111 corresponding to the actuators 1 to 3 for each divided space. In the divided space “DAC”, the CPU 401 sets the third motor 111 for the actuator 1, the first motor 107 for the actuator 2, and the second motor 108 for the actuator 3. That is, when the variable i is “1”, the CPU 401 executes a driving process on the third motor 111 corresponding to the actuator 1. Further, the CPU 401 sets the direction in which the actuator i is driven for each divided space. The driving direction of the actuator 1 in the divided space “DAC” is set to a direction of moving from the third rotation region C to the fourth rotation region D. As a result, the output member position 103a at the first position moves to the second position in the divided space “DAC” shown in FIG.

  Next, the CPU 401 specifies the absolute position of the actuator i (step S8). In this process, the CPU 401 specifies the absolute position of the actuator i because the rotary arm has moved to the boundary position.

  Next, the CPU 401 adds “1” to the variable i (step S9), and determines whether or not the variable i is larger than n (step S10). If it is determined in step S10 that the variable i is n or less, the CPU 401 returns the process to step S5 of the loop 2. And CPU401 performs the process of step S6-step S9 again. As shown in FIG. 7B, the output member position 103a at the second position is moved to the third position by the processing of steps S6 to S9 by the CPU 401. Then, the output member position 103a at the third position is moved to the fourth position that is the intersection of the three surfaces along the ridgeline of the divided space “DAC” by the processing of step S6 to step S9 by the CPU 401.

  On the other hand, if it is determined in step S10 that the variable i is greater than n, the CPU 401 determines that the absolute positions of all actuators have been specified. Then, the CPU 401 executes an absolute position specifying process for specifying the absolute position of the output member 103 from the specified absolute position of each actuator (step S11), and ends the absolute position specifying mode. The first to third rotating arms 107a, 108a, and 111a are all located at the boundary positions by the processing of step S5 to step S10. That is, the output member position 103a is located at the intersection of each divided space, as is the position 4 in FIG. Therefore, in the absolute position specifying process, the CPU 401 specifies the position of the intersection as the absolute position of the output member 103.

[Return to origin of output member]
By specifying the absolute position of the output member 103, the parallel link robot 100 takes an arbitrary path in the return operation to the origin position that is executed after execution of the absolute position specifying process of the output member 103, as in normal operation. be able to. Here, the origin position of the output member 103 is preferably set on the vertical plate 102 side in the movable region. When the robot stops abnormally, it is often interrupted in the middle of a series of operations. In such a case, the operator directly confirms whether or not the part was attached to the work or whether the part held by the robot has fallen on the work, and the work such as collection of the work or parts is performed. There is a need to. When the origin position of the output member 103 is set to the vertical plate 102 side, the parallel link robot 100 is in a standby state at the origin position, and a jig installed in the work area when the worker stands with the vertical plate 102 facing the front. Visibility and workability with respect to and workpieces are improved.

  The origin position of the output member 103 may be set to a position higher than the maximum height of the jig installed in the movable region of the output member 103. In this case, the parallel link robot 100 can move the output member 103 vertically upward after specifying the absolute position of the output member 103, and move it to the origin position by the shortest path after reaching the jig maximum height. Specifically, the origin position may be set at the position of the point O shown in FIG. In this case, the parallel link robot 100 can return to the origin in a stable posture by opening the first and second rotating arms 107a and 108a outward when returning to the origin. With this configuration, the parallel link robot 100 can easily control the return to the origin position because the output member 103 and the jig do not interfere when returning to the origin position. .

[Absolute position specification processing of output member when there is an interference]
Next, each process executed when the CPU 401 specifies the absolute position of the output member 103 when there is an interference in the movable region of the output member 103 will be described. In parallel link robots, interference objects such as work jigs are usually installed in the movable region of the output member. For this reason, when the parallel link robot is restarted from the stopped state and specifies the absolute position, the output member, the end effector, and the interfering object may contact each other unless the movement path of the output member is correctly selected. Therefore, the parallel link robot 100 according to the present embodiment can specify the absolute position without the output member 103 and the end effector 104 coming into contact with the interference object in a situation where the interference object exists in the movable region of the output member 103. It is configured. Note that the position and shape of the interfering object existing in the movable region of the output member 103 are known in advance. In addition, by setting the shape of the end effector 104 in advance, information on the position and shape of the interferer is offset in the horizontal and vertical directions by the distance from the position of the end effector 104 to the surface of the end effector 104. .

  FIG. 9 is a flowchart showing each process when the CPU 401 executes an origin return process for returning the output member 103 to the origin position. As shown in FIG. 9, the CPU 401 first determines which position in the divided space the output member position 103a is in (step S20). In this process, the CPU 401 executes the rotation area specifying process on the first to third motors 107, 108, and 111 (see step S1 to step S4 in FIG. 8), and in which divided space the output member position 103a is included. Judging.

  Next, the CPU 401 determines whether there is an interfering object in the divided space determined in step S20 (step S21). In this process, the CPU 401 refers to preset information on the shape and position of the interferer, and determines whether there is an interferer in the divided space specified in step S20.

  If it is determined in the process of step S21 that there is an interfering object in the divided space (YES), the CPU 401 executes a retreat process for moving the output member 103 to the adjacent divided space (step S22), and step S21. Return to the process. In this process, the CPU 401 drives the first to third motors 107, 108, and 111 to move the output member 103 in a direction that avoids contact with the interference existing in the divided space, and adjacent divided spaces. The evacuation process for moving the output member 103 is executed. Here, the driving order and the driving direction of the first to third motors 107, 108, and 111 executed in the evacuation process are preset for each divided space by the CPU 401 based on the position and shape information of the interferer in the divided space. Has been. Details of the saving process will be described later.

  If it is determined in step S21 that there is no interfering object in the divided space (NO), the CPU 401 executes the absolute position specifying mode shown in FIG. 8 and specifies the absolute position of the output member 103 (step). S23). In this process, since the divided space in which the output member position 103a is already determined has been determined, the CPU 401 executes the processes in steps S5 to S11 among the processes in the absolute position specifying mode shown in FIG.

  Next, the CPU 401 executes an origin return process for moving the output member 103 to the origin position (step S24), and ends the origin return process. In this process, the CPU 401 returns the origin of the output member 103 by inverse kinematics calculation as in the normal operation. That is, the CPU 401 calculates the driving amounts of the first to third motors 107, 108, and 111 necessary for moving from the position of the output member 103 to the origin position. Then, by performing driving of the first to third motors 107, 108, and 111 with the calculated drive amount, an origin return process for returning to the origin is executed.

  Here, the saving process executed in step S22 will be specifically described with reference to FIG. In FIG. 10, in order to simplify the description, the divided space and the interference are shown in two dimensions. FIG. 10 shows the output member position 103a as one point, but the CPU 401 does not specify the absolute position of the output member position 103a when executing the process of step S22. Any position can be used as long as no exists.

  FIGS. 10A and 10B show a case where there is only one ridge line of the interferers W1 and W2 existing in the divided space. As described above, the parallel link robot 100 is configured such that when the first to third motors 107, 108, and 111 are driven independently, the output member 103 moves along the ridgeline of each divided space. In the evacuation process, the CPU 401 moves the output member 103 in the direction away from the interfering object W (one of the directions indicated by two arrows in FIGS. 10A and 10B). A driving order and a driving direction are determined so as to drive the motors 107, 108, and 111. Here, the driving order and the driving direction of the actuator are determined from the position of the divided space where the interference exists, and the position of the adjacent divided space of the movement destination. For example, when the output member 103 is located in the divided space “DDB”, there is an interferer on the divided space “DDA” side, and moves to the adjacent divided space “DDC”, the CPU 401 sets the third motor as the driving order of the actuator. 111 is determined as the actuator to be driven first. Then, the CPU 401 determines the driving direction in the direction in which the output member 103 moves to the divided space “DDC” as the driving direction of the third motor 111.

  FIG. 10C shows a case where there are a plurality of ridge lines of the interference W3 in the divided space. In such a case, the CPU 401 executes a save process that is executed when the interferent W1 is present and a save process that is executed when the interferer W2 is present. That is, the CPU 401 treats the position and shape information of the interference object W3 as the sum of the position and shape information of the interference object W1 and the position and shape information of the interference object W2. The CPU 401 drives the actuators so as to drive the first to third motors 107, 108, and 111 that move the output member 103 in the direction indicated by the arrow in FIG. 10C as the direction away from the interference W3. And the driving direction is determined. Here, the direction indicated by the arrow in FIG. 10C is a common direction among the directions indicated by the arrows shown in FIGS. Further, as shown in FIG. 10C, when the ridgeline of the interference object W3 exists in the adjacent divided space, the CPU 401 executes the evacuation process in the direction away from the interference object W3 again.

  In FIG. 10 (d), the CPU 401 configures the position and shape information of the interferent W4 in the divided space from portions common to the position and shape information of the interferent W1 and the position and shape information of the interferer W2. Shows the case. That is, the case where the position and shape information of the interference object W4 is treated as a product of the position and shape information of the interference objects W1 and W2 is shown. Also in this case, the CPU 401 operates as an actuator so as to drive the first to third motors 107, 108, and 111 that move the output member 103 in the direction indicated by the arrow in FIG. The driving order and driving direction are determined. Here, the direction indicated by the arrow in FIG. 10 (d) is a common direction among the directions indicated by the arrows shown in FIGS. 10 (a) and 10 (b).

  With this configuration, the parallel link robot 100 can easily determine the driving order and the driving direction of the first to third motors 107, 108, and 111 even for the divided space including the interference. . Then, by driving the first to third motors 107, 108, and 111 according to the determined driving order and driving direction, the parallel link robot 100 does not contact the output member 103 with the interfering object. The position can be specified.

  As described above, the parallel link robot 100 according to the present embodiment drives the first to third motors 107, 108, and 111 and moves the first to third rotating arms 107a, 108a, and 111a to the boundary positions. The absolute position of the output member 103 is specified. That is, the parallel link robot 100 can specify the absolute position of the output member 103 by using a plurality of inexpensive detection sensors that transmit an on / off signal without using an expensive absolute encoder. Further, when the absolute position of the output member 103 is specified, the parallel link robot 100 can specify the absolute position simply by moving the output member 103 in the divided space. The position can be easily specified.

  In the present embodiment, the CPU 401 specifies the absolute position of the output member 103 by driving the first to third motors 107, 108, and 111 one by one in the absolute position specifying mode. However, the present invention is not limited to this. The CPU 401 may specify the absolute position of the output member 103 by simultaneously driving a plurality of first to third motors 107, 108, and 111. Further, the driving directions and driving order of the first to third motors 107, 108, 111 are not particularly limited.

  In the present embodiment, the CPU 401 presets the driving order and driving direction of the actuator for each divided space in the absolute position specifying mode, but the present invention is not limited to this. For example, the CPU 401 may be configured to execute a driving process based on a preset driving order and driving direction of actuators in any divided space.

  In the present embodiment, the CPU 401 determines the driving order and driving direction of the first to third motors 107, 108, and 111 in the case of specifying the absolute position of the output member 103 from the position and shape information of the interferer before driving. However, it is not limited to this. For example, the CPU 401 may determine the driving order and driving direction of the first to third motors 107, 108, and 111 at the time of returning to the origin before driving for each divided space using the position and shape information of the interference object. . By configuring in this way, the parallel link robot 100 can reliably prevent the output member 103 and the interfering object from contacting each other when the output member 103 is returned to the origin.

  In this embodiment, the method for specifying the absolute position of the output member 103 is used in the parallel link robot 100. However, the method is not limited to the parallel link robot having the above-described link configuration, and is not limited to the conventional delta type parallel link robot. May also be applied. Furthermore, the present invention may be applied to a serial type robot.

  In this embodiment, the absolute position specifying method of the output member 103 is used for the parallel link robot 100 having a link mechanism. However, the method is not limited to this, and the position of the output member is determined by driving a plurality of actuators. You may use for the control part of the robot to control. In this configuration, the robot includes a plurality of actuators that move the position of the output member, and a plurality of actuator position detection sensors provided in each of the plurality of actuators. The actuator position detection sensor detects in which rotation region the actuator is driven in each rotation region that divides the drive region of the actuator into a plurality of regions. In addition, the robot includes a control unit that divides the movable region of the output member into a plurality of divided spaces and controls the position of the output member by combining the rotation regions of the plurality of actuators. In such a robot control method, first, at the time of starting or after starting the robot, a rotation region specifying process is executed in which a rotation region specifying process is performed in which a rotation region driven by each of a plurality of actuators is detected by an actuator position detection sensor. The processing process is executed by a robot. Next, a robot performs a driving process step of determining a divided space including the position of the output member from a combination of rotation regions driven by the actuators and executing a driving process for driving the plurality of actuators. Next, when the actuator position detection sensor detects that each actuator has reached the boundary position of the rotation region, the robot performs a position specifying process step for executing a position specifying process for specifying the position from the origin of each actuator and output member. Run with. With this configuration, the robot can specify the absolute position of the output member by using a plurality of inexpensive detection sensors without using an expensive absolute encoder. Further, when specifying the absolute position of the output member, the robot can specify the absolute position simply by moving the output member in the divided space, and easily specify the absolute position of the output member without greatly moving the output member. be able to.

DESCRIPTION OF SYMBOLS 100 ... Parallel link robot: 100A ... Base part (fixing member): 103 ... Output member (manipulator): 104 ... End effector: 105 ... Output shaft: 107 ... 1st motor (actuator): 107a ... 1st rotation arm (drive) Link member): 107d, 108d, 111d ... Plate (rotating member): 107g, 107h, 108g, 108h, 111g, 111h ... Edge (detected portion): 107i, 107j, 107k, 108i, 108j, 108k, 111i, 111j , 111k ... detection sensor (detection unit): 108 ... second motor (actuator): 108a ... second rotating arm (drive link member): 109 ... first arm (link mechanism): 109a ... first link (following link member) ): 110... Second arm (link mechanism): 110a 2nd link (driven link member): 111 ... 3rd motor (actuator): 111a ... 3rd rotation arm (drive link member): 112 ... 3rd arm (link mechanism): 112a ... 3rd link (driven link member) : 401... CPU (control unit)

Claims (6)

An output member having an output shaft;
A plurality of actuators supported by a fixed member to move the output member;
A drive link member provided between each of the output shaft and the plurality of actuators and driven in conjunction with the actuator; and a driven link member connected to the output shaft and driven by the drive link member; A link mechanism for positioning the output member according to the connection relationship of the driven link member when the drive link member is driven;
A rotating member having a detected portion and whose rotational position moves in conjunction with the drive link member;
A plurality of detection units in which the on and off signals are switched according to the rotational position of the detected unit;
A control unit having a position specifying mode for specifying the position of the output member,
The control unit, in the position specifying mode,
A rotation region specifying process for specifying in which rotation region the drive link member is located among a plurality of rotation regions in which the on / off signals of the plurality of detection units are different from each other;
Among the boundary positions of each rotation region where the on / off signal of any one of the plurality of detection units is switched, to the boundary position between the rotation region where the drive link member is located and the rotation region adjacent to the rotation region, Drive processing for moving the detected portion by driving an actuator;
Performing the rotation area specifying process and the driving process for all of the plurality of actuators, and performing a position specifying process for specifying the position of the output member;
A parallel link robot characterized by that. The control unit includes a drive direction of the actuator in the drive process and a plurality of actuators in each of a plurality of divided spaces obtained by dividing the movable region of the output member for each rotation region where the plurality of drive link members are located. A driving order for executing the driving process is set for
The control unit is configured to drive the plurality of actuators set in a divided space corresponding to the rotation region where the drive link member specified from the on / off signals of the plurality of detection units in the rotation region specifying process is located. Then, the actuator is driven in the driving direction set for each of the actuators, and the driving process is executed.
The parallel link robot according to claim 1. The control unit moves the output member from the divided space where the interferer exists to the divided space where the interferer does not exist when there is an interferer that interferes with the output member in the divided space where the output member is located. Executing the location mode after
The parallel link robot according to claim 2.   The said control part performs the origin return process which drives the said actuator and moves the said output member to the preset origin position after execution of the said position specific process. 4. The parallel link robot according to any one of 3 above. An output member having an output shaft;
A plurality of actuators supported by a fixed member to move the output member;
A drive link member provided between each of the output shaft and the plurality of actuators and driven in conjunction with the actuator; and a driven link member connected to the output shaft and driven by the drive link member; A link mechanism for positioning the output member according to the connection relationship of the driven link member when the drive link member is driven;
A rotating member having a detected portion and whose rotational position moves in conjunction with the drive link member;
A plurality of detection units in which the on and off signals are switched according to the rotational position of the detected unit;
In a control method for a parallel link robot comprising a control unit having a position specifying mode for specifying the position of the output member,
Rotation in which the control unit executes a rotation region specifying process for specifying in which rotation region the drive link member is located among a plurality of rotation regions having different on / off signals from the plurality of detection units. Region identification processing step;
Of the boundary positions of each rotation region where the on / off signal of any one of the plurality of detection units is switched, the control unit includes a rotation region where the drive link member is located and a rotation region adjacent to the rotation region. A drive processing step of performing a drive process of moving the detected portion by driving the actuator to a boundary position;
The control unit includes a position specifying process step of executing the position specifying process for specifying the position of the output member by executing the rotation area specifying process and the driving process for all of the plurality of actuators.
A control method for a parallel link robot. A plurality of actuators for moving the position of the output member;
A plurality of actuator position detection sensors which are provided in each of the plurality of actuators and detect which rotation region is used to drive the rotation region among the plurality of rotation regions;
In a control method for a robot, comprising: a control unit that divides a movable region of the output member into a plurality of divided spaces and controls the position of the output member by combining each rotation region of the plurality of actuators;
A rotation region specifying processing step for executing a rotation region specifying process in which the control unit detects a rotation region driven by each of the plurality of actuators with the actuator position detection sensor at the time of starting or after starting the robot; ,
A drive processing step in which the control unit determines a divided space including a position of the output member from a combination of the rotation regions, and executes a drive process for driving the plurality of actuators;
A position where the control unit specifies positions from the origin of the plurality of actuators and the output member when the actuator position detection sensor detects that each of the plurality of actuators has reached the boundary position of the rotation region. A position specifying process step for executing the specifying process,
A robot control method characterized by the above.

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