Robot arm control device

Abstract

The invention provides a robot arm control device capable of suppressing erroneous detection in a non-contact sensor. This robot arm control device is a robot arm provided with a plurality of non-contact sensors (2e, 2b), and is provided with: a specifying unit that specifies the position of each of the non-contact sensors (2e, 2b) on the basis of the posture of the robot arm; and a determination unit that uses one of the plurality of non-contact sensors (2e, 2b) as a target sensor, and determines, on the basis of each of the determined positions, whether or not a non-contact sensor (2b) different from the target sensor interferes with a preset detection range (37e) of the target sensor.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a robot arm control device in a robot arm provided with a plurality of non-contact sensors. BACKGROUND

[0002] Sometimes, a person works on a workpiece in cooperation with a robot arm. A robot arm used in such a case is called a collaborative robot arm. In a collaborative robot arm, a non-contact sensor that detects an object such as a person in the vicinity is sometimes mounted.

[0003] For example, in Patent Literature 1, a technique is described in which a proximity sensor of an electrostatic capacitance type is provided on an arm of a robot arm to detect an object in the surroundings of the robot arm.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2021-20287 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, a robot arm can take various postures in order to perform a movement. Therefore, there is a possibility that non-contact sensors provided on the robot arm interfere with each other. In the case where interference occurs, it is possible that false detection occurs in the non-contact sensors.

[0009] In view of the above problem, an object of the present disclosure is to provide a robot arm control device capable of suppressing false detection in non-contact sensors.

[0010] METHOD FOR SOLVING THE PROBLEM

[0011] To solve the above problem, a robot arm control device according to the present disclosure is a robot arm control device in a robot arm provided with a plurality of non-contact sensors, and includes: a determination unit that determines a position of each of the non-contact sensors in correspondence with a posture of the robot arm; and a determination unit that takes one of the plurality of non-contact sensors as a target sensor and determines whether a non-contact sensor other than the target sensor interferes with a detection range of the target sensor that is set in advance, based on the determined position of each of the non-contact sensors.

[0012] Further, in the robot arm control device, the determination unit determines that the interference occurs in the case where the non-contact sensor other than the target sensor is located within the detection range of the target sensor.

[0013] Furthermore, in the robotic arm control device, the detection range of the object sensor is a range that is preset relative to the three-dimensional region of the object sensor.

[0014] Furthermore, in the robotic arm control device, the determination unit determines that the interference has occurred when the boundary surface of the detection range of the object sensor intersects with a non-contact sensor different from the object sensor, or when the entire non-contact sensor different from the object sensor is located inside the detection range of the object sensor.

[0015] Furthermore, the robotic arm control device also includes a sensor control unit, which, when the determination unit determines that the interference has occurred, controls the interfering non-contact sensors in a manner that avoids the interference.

[0016] Furthermore, in the robotic arm control device, the sensor control unit performs at least one of the following controls on the non-contact sensors that interfere with each other: control to invalidate object detection, control to change the detection range, and control to change the detection direction.

[0017] Invention Effects

[0018] According to the robotic arm control device disclosed herein, false detections in non-contact sensors can be suppressed. Attached Figure Description

[0019] Figure 1 A schematic diagram illustrating an example of the overall structure of a robotic arm system according to an embodiment of this disclosure.

[0020] Figure 2 To indicate Figure 1 A diagram illustrating an example of the various functions in a control device.

[0021] Figure 3 To indicate Figure 2 A diagram illustrating an example of position determination using a non-contact sensor in a position determination unit.

[0022] Figure 4 To indicate Figure 1 A diagram illustrating an example of the positional relationships among multiple non-contact sensors.

[0023] Figure 5 To indicate Figure 1 A diagram illustrating another example of the positional relationships among multiple non-contact sensors.

[0024] Figure 6 To indicate Figure 2 A diagram illustrating an example of avoidance control in the sensor control unit.

[0025] Figure 7 To indicate Figure 1 A flowchart illustrating an example of the interference determination process in a control device. Detailed Implementation

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, for ease of understanding, the same reference numerals will be used as much as possible to denote the same constituent elements in the drawings, and repetitive descriptions will be omitted where appropriate.

[0027] <Overall Structure>

[0028] Figure 1 This figure illustrates an example of the overall structure of a robotic arm system 10 having a control device 3, which is a robotic arm control device according to one embodiment of this disclosure, in a summary manner.

[0029] The robotic arm system 10 is an industrial robotic arm used for processing, such as machining and handling, workpieces. Furthermore, the robotic arm system 10 can be, for example, a collaborative robotic arm that shares the same space with a human to perform operations.

[0030] like Figure 1 As shown, the robotic arm system 10 mainly includes a robotic arm 1, a non-contact sensor 2, and a control device 3.

[0031] Robotic arm 1 is a multi-joint robotic arm, having multiple arms and multiple joints. Specifically, robotic arm 1 includes a base 7, a first arm A1, a second arm A2, a third arm A3, and a fourth arm A4. The number of arms is not limited. The base 7 is the base of robotic arm 1. The base 7 is fixed relative to, for example, the ground or a wall, thereby supporting the entire robotic arm 1. The first arm A1 is connected to the base 7 via a rotation axis. The first arm A1 rotates about this rotation axis relative to the base 7 via a motor (not shown). The second arm A2, third arm A3, and fourth arm A4 also rotate about their respective rotation axes via motors (not shown), just like the first arm A1. A tool or the like is provided at the top of the fourth arm A4. In this way, the arm is connected to other arms, etc., via rotation axes as joints, thereby enabling movement. By making each joint movable, robotic arm 1 performs predetermined actions.

[0032] The non-contact sensor 2 is a sensor that detects objects such as people in a non-contact manner. In this embodiment, "object" is a broad concept that includes people, workpieces, and other objects. For example, the non-contact sensor 2 detects the approach of an object. In addition, the non-contact sensor 2 can also detect the displacement of an object. In this embodiment, the case where the non-contact sensor 2 detects the approach of an object will be used as an example.

[0033] The non-contact sensor 2 is, for example, an electrostatic capacitance sensor. In addition, the non-contact sensor 2 is not limited to an electrostatic capacitance sensor as long as it is capable of detecting an object in a non-contact manner. For example, the non-contact sensor 2 can also apply a sensor of an infrared ray, an ultrasonic wave, a millimeter wave, a LiDAR, or the like. In the present embodiment, a case where the non-contact sensor 2 is an electrostatic capacitance sensor is described as one example.

[0034] The non-contact sensor 2 is provided to the robot arm 1 in a plurality of numbers. As shown in FIG. 1, the robot arm 1 is provided with, for example, a non-contact sensor 2a, a non-contact sensor 2b, a non-contact sensor 2c, a non-contact sensor 2d, a non-contact sensor 2e, and a non-contact sensor 2f as the non-contact sensor 2. In addition, the non-contact sensor 2 is not limited to the number of six as shown in FIG. 1. Figure 1 Figure 1 The non-contact sensor 2 is not limited to the arrangement position and the number as shown in the specific example shown in FIG. 1. Figure 1

[0035] The non-contact sensor 2 is configured using a detection electrode. The detection electrode is, for example, a flat plate shape. In addition, the detection electrode is, for example, a quadrangular shape. In addition, the shape of the detection electrode can also be designed to match the outer shape of the arm, and the shape is not limited. The non-contact sensor 2 generates an electric field in a prescribed direction from the detection electrode. Specifically, the non-contact sensor 2 generates an electric field on the side opposite to the main body side of the robot arm 1 on which it is mounted. That is, the non-contact sensor 2 generates an electric field around the robot arm 1. Furthermore, the detection electrode of the non-contact sensor 2 forms an electrostatic capacitance with a nearby object. In addition, the electrostatic capacitance changes depending on the distance between the detection electrode and the object. The non-contact sensor 2 outputs an output corresponding to the electrostatic capacitance formed between the detection electrode and the object as a sensor value. The non-contact sensor 2 amplifies a voltage corresponding to the electrostatic capacitance generated in the detection electrode by an amplifier or the like and outputs it as a sensor value. In addition, the specific circuit structure and the like in the non-contact sensor 2 are not limited. In addition, for the detection electrode, a known shield electrode, an active shield electrode, or the like can also be provided on the side opposite to the direction in which the electric field is generated (the main body side of the robot arm 1).

[0036] In this way, the non-contact sensor 2 outputs a sensor value corresponding to the electrostatic capacitance (that is, the distance) formed with the object.

[0037] The control device 3 is a robot arm control device. That is, the control device 3 is an information processing device that performs operation control of the robot arm 1. The control device 3 is, for example, configured to have a CPU, a memory, a communication device, a storage device, and perform various functions by executing a prescribed program. ​​

[0038] <Functional Configuration>

[0039] Figure 2 An example of indicating various functions in the control device 3 is shown. The control device 3 is provided with a control section 21, a determination section 22, a determination section 23, and a sensor control section 24.

[0040] The control section 21 performs motion control of the robot arm 1. Specifically, the control section 21 controls the motions of the arms of the robot arm 1 so that the robot arm 1 performs a prescribed motion. That is, the control section 21 controls the rotations of the respective rotation axes of the joints that constitute the robot arm 1.

[0041] Further, the control section 21 stops the motion of the robot arm 1 using the sensor value that is the output of the non-contact sensor 2. Specifically, the control section 21 compares the sensor value with a threshold value, thereby determining whether or not it is a state in which an object is approaching with respect to the robot arm 1. Also, the control section 21 stops the motion of the robot arm 1 in a case where it is determined that it is a state in which an object is approaching with respect to the robot arm 1. For example, in a case where the sensor value increases in correspondence with the approach of an object, the control section 21 determines that an object is approaching in a case where the sensor value becomes equal to or greater than the threshold value. For example, even if the robot arm 1 is in the middle of a prescribed motion, the control section 21 stops the motion. In addition, the control section 21 can decelerate the motion of the robot arm 1, not limited to stopping the motion of the robot arm 1.

[0042] The determination section 22 determines the positions (coordinates) of the respective non-contact sensors 2 in correspondence with the posture of the robot arm 1. Therefore, the determination section 22 is provided with a posture determination section 27 and a position determination section 28.

[0043] The posture determination section 27 determines the posture of the robot arm 1. Specifically, the posture determination section 27 acquires the angles of the rotation axes of the joints that constitute the robot arm 1. For example, the posture determination section 27 acquires the angles of the rotation axes (angles of the joints) from encoders provided with respect to the rotation axes. Also, the posture determination section 27 calculates the posture of the robot arm 1 from the angles of the respective rotation axes. The posture of the robot arm 1 is expressed by, for example, the positions and directions of the centers of rotation of the respective rotation axes that constitute the robot arm 1. The posture determination section 27 uses connection parameters and calculates the posture of the robot arm 1 from the angles of the respective rotation axes. The connection parameters are information that establishes a correspondence relationship between the angles of the respective rotation axes and the relative positions and directions of the respective rotation axes. Thus, the posture determination section 27 calculates the positions and directions of the centers of rotation of the respective rotation axes from the angles of the respective rotation axes, thereby determining the posture of the robot arm 1. The posture of the robot arm 1 is determined, for example, with the base 7 that is a fixed position as a reference.

[0044] The position determining section 28 determines the position (coordinates) of each non-contact sensor 2 provided on the robot arm 1 in accordance with the posture of the robot arm 1. Specifically, the position determining section 28 determines the position of each non-contact sensor 2 using the position and the direction of the center of rotation of each rotation axis determined by the posture determining section 27.

[0045] Figure 3 A diagram showing one example of the determination of the position of the non-contact sensor 2. The position determining section 28 determines the position of the sensor face 30 of each non-contact sensor 2. The sensor face 30 is the face of the detection electrode of the non-contact sensor 2. Figure 3 One example of the case where the position determining section 28 determines the position of the sensor face 30, i.e., the sensor face 30e, of the non-contact sensor 2e is shown. The non-contact sensor 2e is provided on the fourth arm A4. Therefore, the position of the non-contact sensor 2e is determined with reference to the rotation axis corresponding to the fourth arm A4. Figure 3 One example of the center of rotation of the rotation axis corresponding to the fourth arm A4 is shown as the center of rotation Cl, and one example of the direction of the center of rotation Cl is shown as the direction Dl. With respect to the posture of the robot arm 1, the relative positional relationship of the center of rotation Cl and the non-contact sensor 2e does not change. Therefore, the position determining section 28 determines the position of the non-contact sensor 2e using the sensor position parameter representing the relative positional relationship of the center of rotation Cl and the non-contact sensor 2e. Specifically, the position determining section 28 determines the position of the sensor face 30, i.e., the sensor face 30e, with reference to the center of rotation Cl. That is, the position determining section 28 determines the position of the non-contact sensor 2e as a three-dimensional offset position with respect to the center of rotation Cl and the size of the sensor face 30e. For example, the position determining section 28 determines the positions of the four corners (corners 31e, 32e, 33e, 34e) of the sensor face 30e of the non-contact sensor 2e with reference to the center of rotation Cl. Thus, even if the posture of the robot arm 1 changes, the position of the non-contact sensor 2e corresponding to the posture can be determined. Furthermore, by determining the position with reference to the center of rotation Cl, the direction (for example, the direction of the electric field) of the object detection performed by the sensor face 30e of the non-contact sensor 2e can be determined.

[0046] In this way, the position determining section 28 determines the position of the sensor face 30e of the non-contact sensor 2e in accordance with the posture of the robot arm 1. Also, the position determining section 28 determines the position of the sensor face 30 of the non-contact sensor 2 other than the non-contact sensor 2e in accordance with the posture of the robot arm 1 as well.

[0047] Back Figure 2The determination unit 23 determines the interference state between the non-contact sensors 2 provided in plurality based on the positions of the non-contact sensors 2 determined by the position determination unit 28. That is, the determination unit 23 determines the interference state in accordance with the position of the sensor face 30 of each non-contact sensor 2. The interference state refers to a state in which at least a part of another non-contact sensor 2 enters the detection range 37 of a certain non-contact sensor 2. The detection range 37 is a range in which an object can be detected by the non-contact sensor 2, and is set in advance corresponding to each non-contact sensor 2. Specifically, the detection range 37 is set in advance as a three-dimensional region with respect to the non-contact sensor 2. In the present embodiment, the detection range 37 is set as a cuboid region extending from the sensor face 30 of the non-contact sensor 2.

[0048] The determination unit 23 takes one of the plurality of non-contact sensors 2 as an "object sensor". Also, it determines whether or not the object sensor interferes with a non-contact sensor 2 different from the object sensor. That is, the determination unit 23 determines whether or not a non-contact sensor 2 different from the object sensor is located within the detection range 37 of the object sensor. That is, the determination unit 23 determines whether or not the sensor face 30 of a non-contact sensor 2 different from the object sensor is located within the detection range 37 of the cuboid extending from the sensor face 30 of the object sensor.

[0049] Figure 4 A diagram showing one example of the positional relationship of the object sensor and a non-contact sensor 2 different from the object sensor. Figure 4 The non-contact sensor 2e is shown as the object sensor. Also, Figure 4 The non-contact sensor 2b is shown as a non-contact sensor 2 different from the object sensor. That is, Figure 4 The positional relationship of the sensor face 30e of the non-contact sensor 2e whose position is determined by the position determination unit 28 and the sensor face 30b of the non-contact sensor 2b is shown. Also, the detection range 37e of the cuboid is set in a prescribed direction with respect to the sensor face 30e of the non-contact sensor 2e as the object sensor. That is, the detection range 37e becomes a cuboid with the four corners constituting the sensor face 30e, and the four corners of the boundary surface 41e departing from the sensor face 30e by a prescribed detection distance, the corner 42e, the corner 43e, the corner 44e, and the corner 45e as the apex. Also, the side surface between the sensor face 30e and the boundary surface 41e becomes the four surfaces of the boundary surface 46e, the boundary surface 47e, the boundary surface 48e, and the boundary surface 49e. Also, the sensor face 30b of the non-contact sensor 2b has the four edges of the edge 51b, the edge 52b, the edge 53b, and the edge 54b.

[0050] The determination section 23 determines whether or not interference has occurred between the object sensor and the non-contact sensor 2 different from the object sensor through first determination, second determination, and third determination.

[0051] The determination section 23 first performs the first determination. Specifically, the determination section 23 sets a plane obtained by extending the sensor face 30b of the non-contact sensor 2 different from the object sensor, i.e., the non-contact sensor 2b. The determination section 23 sets one direction orthogonal to the plane as a first direction, and sets the other direction orthogonal to the plane as a second direction. Also, the determination section 23 determines whether or not the entire region of the cuboid constituting the detection range 37e is located on the first direction side with respect to the plane. Specifically, the determination section 23 determines whether or not all of the eight corners (corners 31e to 34e, and corners 42e to 45e) constituting the detection range 37e are located on the first direction side with respect to the plane. Also, in the case where all of the eight corners constituting the detection range 37e are located on the first direction side with respect to the plane, the determination section 23 determines that no interference has occurred. Further, the determination section 23 determines whether or not all of the eight corners (corners 31e to 34e, and corners 42e to 45e) constituting the detection range 37e are located on the second direction side with respect to the plane. Also, in the case where all of the eight corners constituting the detection range 37e are located on the second direction side with respect to the plane, the determination section 23 determines that no interference has occurred. The determination section 23 performs the second determination in the case where not all of the eight corners constituting the detection range 37e are located on the first direction side or the second direction side with respect to the plane. For example, in the case of Fig. 10, not all of the eight corners constituting the detection range 37e are located on the first direction side or the second direction side with respect to the plane obtained by extending the sensor face 30b, so the second determination is performed. Figure 4

[0052] ​Then, the determination section 23 performs second determination. Specifically, the determination section 23 determines whether the boundary surface of the detection range 37e of the non-contact sensor 2e as the object sensor intersects with the non-contact sensor 2b as the non-contact sensor 2 different from the object sensor. The boundary surface corresponds to the detection range 37e, and is the six surfaces of the sensor surface 30e, the boundary surface 41e, the boundary surface 46e, the boundary surface 47e, the boundary surface 48e, and the boundary surface 49e. In addition, the boundary surface can be set to the five surfaces other than the sensor surface 30e. Also, the determination section 23 determines whether each boundary surface intersects with the sensor surface 30b of the non-contact sensor 2b. Specifically, the determination section 23 determines whether intersection occurs between each boundary surface and each edge (edge 51b, edge 52b, edge 53b, edge 54b) of the sensor surface 30b of the non-contact sensor 2b. Also, the determination section 23 determines that interference occurs if intersection occurs in even a part of the combination of each boundary surface and each edge of the sensor surface 30b of the non-contact sensor 2b. In this case, it means that a part (not the entirety) of the non-contact sensor 2b enters the range of the detection range 37e of the non-contact sensor 2e and interference occurs. Further, the determination section 23 performs third determination if intersection does not occur between each boundary surface and each edge of the sensor surface 30b of the non-contact sensor 2b. In addition, the determination section 23 can determine that no interference occurs if intersection does not occur between the boundary surface and the edge of the sensor surface 30b. For example, in the case of FIG. 19, the boundary surface of the detection range 37e of the non-contact sensor 2e intersects with the non-contact sensor 2b, and thus it is determined that interference occurs. Figure 4

[0053] Then, the determination section 23 performs third determination. Specifically, the determination section 23 determines whether the entirety of the non-contact sensor 2b as the non-contact sensor 2 different from the object sensor is positioned inside the detection range 37e of the non-contact sensor 2e as the object sensor. That is, the determination section 23 determines whether it is a state in which the entirety of the sensor surface 30b of the non-contact sensor 2b enters the region of the detection range 37e. Also, the determination section 23 determines that interference occurs if the entirety of the sensor surface 30b of the non-contact sensor 2b enters the region of the detection range 37e. Further, the determination section 23 determines that no interference occurs if the entirety of the sensor surface 30b of the non-contact sensor 2b does not enter the region of the detection range 37e. For example, as shown in FIG. 20, in the case where the entirety of the sensor surface 30b of the non-contact sensor 2b enters the inside of the detection range 37e of the non-contact sensor 2e, it is determined in the third determination that interference occurs. Figure 5

[0054] ​​By the first determination, the second determination, and the third determination, it is determined whether or not the object sensor and the non-contact sensor 2 different from the object sensor interfere. Also, the determination section 23 changes the object sensor to the other non-contact sensor 2 and performs the determination process of the interference state again. That is, the plurality of non-contact sensors 2 are respectively set as the object sensor, and the interference state with the other non-contact sensor 2 is determined.

[0055] The sensor control section 24, in a case where it is determined in the determination section 23 that the interference occurs, controls the non-contact sensors 2 that interfere with each other in such a way as to avoid the interference. Specifically, the sensor control section 24 performs control for making the plurality of non-contact sensors 2 that interfere with each other corresponding to the posture of the robot arm 1 to be in a state where they do not interfere in the state of the posture.

[0056] Figure 6 A diagram for a first example of avoidance control in the sensor control section 24 is shown. In Figure 6 In the figure, as one example, a case where the non-contact sensor 2e and the non-contact sensor 2b interfere with each other is shown. Specifically, the non-contact sensor 2b enters the range of the detection range 37e of the non-contact sensor 2e. Also, the non-contact sensor 2e enters the range of the detection range 37b of the non-contact sensor 2b. In such a case, the sensor control section 24 performs control to invalidate the detection of the object by the non-contact sensor 2e and the non-contact sensor 2b. That is, by the sensor control section 24, the detection of the object by the non-contact sensor 2e and the non-contact sensor 2b is invalidated. Invalidating means that each of the non-contact sensor 2e and the non-contact sensor 2b does not generate the detection range 37e and the detection range 37b. For example, the generation of the electric field is stopped in the non-contact sensor 2e and the non-contact sensor 2b. Also, it is possible to not perform control using the sensor value while each of the non-contact sensor 2e and the non-contact sensor 2b continues to generate the detection range 37e and the detection range 37b. In this way, by invalidating the detection of the object in the non-contact sensor 2e and the non-contact sensor 2b that interfere with each other, the interference state is eliminated, and further, it is possible to suppress the false detection caused by the interference state.

[0057] Here, Figure 6 A second example of avoidance control in the sensor control section 24 is also shown. The sensor control section 24 performs control to change the detection range 37 of the object. That is, by the sensor control section 24, the detection range 37e of the non-contact sensor 2e and the detection range 37b of the non-contact sensor 2b are changed. Specifically, the sensor control section 24 changes the detection range 37e and the detection range 37b respectively in the direction of shortening the detection distance (reducing the sensitivity). Figure 6An example of shortening the detection distance of detection range 37e is represented as detection range 50e, and an example of shortening the detection distance of detection range 37b is represented as detection range 50b. In this way, by shortening the detection distance, interference is eliminated. Specifically, non-contact sensor 2b will become so that it does not enter the detection range 50e of non-contact sensor 2e, and non-contact sensor 2e will become so that it does not enter the detection range 50b of non-contact sensor 2b. In this way, by changing the detection range 37 of the object in the interfering non-contact sensors 2e and 2b, false detections caused by interference can be suppressed.

[0058] also, Figure 6 A third example of avoidance control in the sensor control unit 24 is also shown. The sensor control unit 24 controls the change of the object detection direction. That is, the sensor control unit 24 changes the direction of the detection range 37e of the non-contact sensor 2e and the detection range 37b of the non-contact sensor 2b. Specifically, the sensor control unit 24 changes the direction in a way that prevents the non-contact sensor 2e or the non-contact sensor 2b, which interfere with the detection range 37e and the detection range 37b respectively, from entering the range. Figure 6 An example with the direction of the changed detection range 37e is denoted as detection range 55e, and an example with the direction of the changed detection range 37b is denoted as detection range 55b. In this way, by changing the detection direction, interference is eliminated. Specifically, the non-contact sensor 2b will not enter the detection range 55e of the non-contact sensor 2e, and the non-contact sensor 2e will not enter the detection range 55b of the non-contact sensor 2b. In this way, by changing the detection direction of the object in the interfering non-contact sensors 2e and 2b, false detections caused by interference can be suppressed.

[0059] <Processing flow>

[0060] Figure 7 This is a flowchart illustrating an example of the interference determination process involved in this embodiment. Each of the following steps is repeatedly executed during the movement of the robotic arm 1 at a predetermined control cycle. That is, the interference determination process is performed corresponding to the changing posture based on the movement of the robotic arm 1. Furthermore, the order and content of the following steps can be appropriately modified.

[0061] In addition, the plurality of non-contact sensors 2 provided with respect to the robot arm 1 are associated with the numbers from 1 to M. Furthermore, the number of the non-contact sensor 2 can be designated in the variable N and the variable V. Specifically, the variable N is a variable that designates the non-contact sensor 2 as the subject sensor. In addition, the variable V is a variable that designates the non-contact sensor 2 that determines whether or not interference has occurred with the subject sensor. In addition, the non-contact sensor 2 designated by the variable V is referred to as the "opponent side sensor". Furthermore, in the initial state, the variable N and the variable V are 1 (initial value). The variable N and the variable V are initialized when the following steps are started.

[0062] (Step SP10)

[0063] The posture determination section 27 acquires the angles of the respective axes of rotation of the robot arm 1 and determines the posture of the robot arm 1. Then, the processing is transferred to step SP11.

[0064] (Step SP11)

[0065] The position determination section 28 determines the positions of the respective non-contact sensors 2 provided on the robot arm 1 in correspondence with the posture of the robot arm 1. Then, the processing is transferred to step SP12.

[0066] (Step SP12)

[0067] The determination section 23 sets the non-contact sensor 2 corresponding to the variable N as the subject sensor. For example, the non-contact sensor 2 of variable N = 1 is set as the subject sensor. Then, the processing is transferred to step SP13.

[0068] (Step SP13)

[0069] The determination section 23 sets the non-contact sensor 2 corresponding to the variable V as the opponent side sensor. For example, the non-contact sensor 2 of variable V = 1 is set as the opponent side sensor. Then, the processing is transferred to step SP14.

[0070] (Step SP14)

[0071] The determination section 23 determines whether or not the variable N that designates the subject sensor and the variable V that designates the opponent side sensor are the same number. In the case where the variable N and the variable V are equal, the processing is transferred to step SP19. In the case where the variable N and the variable V are different, the processing is transferred to step SP15.

[0072] (Step SP15)

[0073] The determination section 23 performs the first determination with respect to the object sensor designated by the variable N and the counterpart sensor designated by the variable V. In the first determination, in a case where it is determined that interference does not occur, the process is transferred to step SP19. In the first determination, in a case where it is not determined that interference does not occur, the process is transferred to step SP16.

[0074] (Step SP16)

[0075] The determination section 23 performs the second determination with respect to the object sensor designated by the variable N and the counterpart sensor designated by the variable V. In the second determination, in a case where it is determined that interference occurs, the process is transferred to step SP18. In the second determination, in a case where it is not determined that interference occurs, the process is transferred to step SP17.

[0076] (Step SP17)

[0077] The determination section 23 performs the third determination with respect to the object sensor designated by the variable N and the counterpart sensor designated by the variable V. In the third determination, in a case where it is determined that interference does not occur, the process is transferred to step SP19. In the third determination, in a case where it is determined that interference occurs, the process is transferred to step SP18.

[0078] (Step SP18)

[0079] The sensor control section 24 performs interference avoidance control with respect to the non-contact sensors 2 (the object sensor of the variable N and the counterpart sensor of the variable V) that interfere with each other. Then, the process is transferred to step SP19.

[0080] (Step SP19)

[0081] The determination section 23 determines whether the variable V is M, which is the final number. In a case where the variable V is not M, the process is transferred to step SP20. In a case where the variable V is M, the process is transferred to step SP21.

[0082] (Step SP20)

[0083] The determination section 23 increments the variable V by 1. Then, the process returns to step SP13, and the process is performed again. That is, with respect to the object sensor of the variable N, the non-contact sensor 2 of a different number (the variable V after the increment) is set as the counterpart sensor, and the determination is performed.

[0084] (Step SP21)

[0085] The determination section 23 determines whether the variable N is M, which is the final number. In a case where the variable N is not M, the process is transferred to step SP22. In a case where the variable N is M, the process ends.

[0086] (Step SP22)

[0087] The determination section 23 adds 1 to the variable N. In addition, the determination section 23 returns the variable V to the initial value (i.e., 1). Then, the process returns to step SP12, and the process is executed again.

[0088] As described above, it is determined whether or not the non-contact sensors 2 interfere with each other in correspondence with the posture of the robot arm 1 in motion, and a countermeasure (avoidance control) can be executed in the case where interference occurs. In addition, it is preferable that, after the avoidance control of interference is executed on the non-contact sensors 2 that interfere with each other, the avoidance control of interference is released in the case where the posture of the robot arm 1 has changed to a state where interference does not occur.

[0089] <Effects>

[0090] In the present embodiment, it is possible to determine whether or not the non-contact sensors 2 are in an interference state in correspondence with the posture of the robot arm 1. Therefore, it is possible to distinguish whether the non-contact sensors 2 are in a state where the non-contact sensors 2 can detect an object that is intended to be detected, or in a state where the non-contact sensors 2 are detecting other non-contact sensors 2. That is, it is possible to suppress false detection of an object by the non-contact sensors 2. In addition, in the case where determination related to interference is not performed, the non-contact sensors 2 need to be disposed on the robot arm 1 in a manner that does not interfere with each other. However, since it is possible to perform interference determination to grasp an interference state, it is possible to mount more non-contact sensors 2 on the robot arm 1, or to increase the sensor faces 30 of the non-contact sensors 2. Therefore, it is possible to expand the detectable space of an object.

[0091] In addition, in the case where the other non-contact sensor 2 is located within the detection range 37 of the object sensor, it is possible to determine that interference occurs between the object sensor and the other non-contact sensor 2.

[0092] In addition, by setting the detection range 37 as a three-dimensional region, it is possible to three-dimensionally determine whether or not interference occurs, and thus the determination accuracy of interference is improved.

[0093] In addition, in the case where the boundary surface of the detection range 37 of the object sensor intersects the other non-contact sensor 2, or in the case where the entire other non-contact sensor 2 is contained inside the detection range 37 of the object sensor, it is possible to determine that interference occurs between the object sensor and the other non-contact sensor 2.

[0094] In addition, in the case where interference occurs, by controlling the non-contact sensors 2 that interfere with each other in a manner that avoids interference, it is possible to eliminate the interference state. That is, it is possible to suppress false detection of an object by the non-contact sensors 2.

[0095] Further, by performing the control to invalidate the detection of the object, the control to change the detection range 37, or the control to change the detection direction, it is possible to effectively eliminate the interference state. That is, it is possible to suppress the false detection of the object by the non-contact sensor 2.

[0096] Modified Example

[0097] In addition, the present disclosure is not limited to the above-described embodiments. That is, as long as the features of the present disclosure are possessed, structures obtained by appropriately applying design changes to the above-described specific examples by those skilled in the art are also included in the scope of the present disclosure. Further, the respective elements possessed by the above-described embodiments and the following modified examples can be combined in a range possible in the technical field, and structures obtained by combining them are also included in the scope of the present disclosure as long as the features of the present disclosure are included.

[0098] For example, although in the above-described embodiments, the case where the posture determination section 27 determines the posture of the robot arm 1 using the angles of the respective joints of the robot arm 1 is taken as one example, the method of determining the posture of the robot arm 1 is not limited. The posture determination section 27 can also determine the posture state of the robot arm 1 by capturing the robot arm 1 using a camera or the like and performing analysis. Further, the posture of the robot arm 1 can also be determined using the control signal of the control section 21 that performs motion control of the robot arm 1.

[0099] Further, although in the above-described embodiments, the case where the detection range 37 is set to a cuboid is exemplified, the detection range 37 can be appropriately set according to the sensor. That is, the shape, direction, size (distance), and the like of the detection range 37 are not limited to a cuboid, but can be appropriately set.

[0100] Further, although the above-described embodiments respectively show the first example, the second example, and the third example to which the avoidance control is applied, the respective controls can also be combined. Further, the avoidance control is not limited to the first example, the second example, and the third example. For example, it is also possible to physically change the angle of the sensor face 30.

[0101] Further, it is also possible to preliminarily limit the non-contact sensor 2 that has a possibility of interference in the motion of the robot arm 1 in the non-contact sensor 2 provided on the robot arm 1. That is, it is also possible to preliminarily limit the combination of the non-contact sensor 2 that is the object of interference determination. By preliminarily limiting the non-contact sensor 2, it is possible to suppress the pattern of the non-contact sensor 2 for which the interference determination is performed, so that the processing is efficiently performed. It is also possible to limit the non-contact sensor 2 that has a possibility of interference in correspondence with the pattern of the posture of the robot arm 1.

[0102] Further, in the above-described embodiment, a case where it is determined whether or not the non-contact sensor 2 has interfered with another non-contact sensor 2 is exemplified. It is also possible to determine which portion has interfered with another non-contact sensor 2 in the detection range 37 of the non-contact sensor 2, and to perform object detection in a region other than the portion of the detection range 37 where interference has occurred.

[0103] Symbol explanation

[0104] 1: robot arm

[0105] 2, 2a to 2f: non-contact sensor

[0106] 3: control device (robot arm control device)

[0107] 22: determination section

[0108] 23: determination section

[0109] 37, 37b, 37e: detection range

Claims

1. A robotic arm control device, which is a robotic arm control device for a robotic arm equipped with multiple non-contact sensors, characterized in that, have: The determining unit determines the position of each of the non-contact sensors based on the posture of the robotic arm; The determination unit takes one of the plurality of non-contact sensors as the target sensor and, based on the determined positions, determines whether the non-contact sensor, which is different from the target sensor, interferes with the detection range of the target sensor, which has been preset.

2. The robotic arm control device as described in claim 1, characterized in that, The determination unit determines that interference has occurred when a non-contact sensor, which is different from the object sensor, is located within the detection range of the object sensor.

3. The robotic arm control device as described in claim 1 or 2, characterized in that, The detection range of the object sensor is a range that is preset relative to the three-dimensional region of the object sensor.

4. The robotic arm control device as described in claim 1 or 2, characterized in that, The determination unit determines that interference has occurred when the boundary surface of the detection range of the object sensor intersects with a non-contact sensor different from the object sensor, or when the entire non-contact sensor different from the object sensor is located inside the detection range of the object sensor.

5. The robotic arm control device as described in claim 1 or 2, characterized in that, It also includes a sensor control unit, which, when the determination unit determines that the interference has occurred, controls the non-contact sensors that are interfering with each other in a manner that avoids the interference.

6. The robotic arm control device as described in claim 5, characterized in that, The sensor control unit performs at least one of the following controls on the non-contact sensors that interfere with each other: controlling to invalidate the detection of the object, controlling to change the detection range, and controlling to change the detection direction.

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