ROBOT CONTROL SYSTEM

Abstract

Robot control system (1), comprising: a robot (4) that performs a process for a process goal (2); a control unit which controls the drive of the robot (4), a first area setting unit that sets a first area (R1) where the process for the process goal (2) is carried out, and a second area setting unit that sets a second area (R2) outside the first area (R1) such that the robot (4) performs a retraction movement when a work device (5) provided on the robot moves out of the first area (R1) and into the second area (R2) while the robot (4) follows the moving process target (2).

Description

[0001] The present invention relates to a robot control system.

[0002] Typically, in a case where an industrial robot performs a process for a process target such as an article being fed on a production line, it is important to control the drive and stop (a stop position) of the robot for the fed process target with high accuracy.

[0003] For example, Patent Document 1 discloses a "robot device that grips a relative motion target object, the robot device including a gripping section having a gripping mechanism that grips the target object and is configured so that the gripping mechanism is movable, an imaging section that is movably fixed together with the gripping mechanism of the gripping section to pick up the target object, a feature amount extraction unit that extracts the coordinates of one or more feature amounts from an image of the target object captured by the imaging section, a storage section that stores the position of the gripping mechanism when the gripping mechanism grips the target object as a first hand tip position, the position of the gripping mechanism when the gripping mechanism moves within a range where the target object can be opened,and is captured by the imaging section as a second handtip position, and stores the coordinates of each feature amount of the target object extracted by the feature amount extraction section after imaging by the imaging section at the second handtip position, a calculation section that calculates a motion matrix for the movement from the second handtip position to the first handtip position, a tracking control section that moves the gripping section so that the coordinates of each feature amount of the moving target object extracted by the feature amount extraction section coincide with the coordinates of each feature amount stored in the storage section to perform control to cause the gripping mechanism to follow the moving target object, and a gripping control section that, when the gripping mechanism follows the moving target object, controls the gripping section sothat the gripping mechanism approaches the moving target object based on the motion matrix calculated by the computing section to grasp the target object.

[0004] Patent Document 2 discloses a "robot control method for performing predetermined operations for a moving object delivered by a feeder while tracking the moving object, wherein the moving object is detected, the position of the moving object in a coordinate system of the feeder is detected based on a detection result, the position of the moving object is sequentially updated in the coordinate system of the feeder based on the position of the moving object and the amount of operation of the feeder, and the track of a robot for tracking the moving object is generated by converting the position of the moving object from the coordinate system of the feeder to a coordinate system of the robot."

[0005] Furthermore, the inventor of the present application has devised a robot control system comprising one or more visual sensors provided on an arm of a robot, a storage unit that stores, as target data for causing the visual sensor to track a tracking target, a first feature amount regarding at least a position and posture of the tracking target, a feature amount detection section that uses images acquired by the visual sensors to detect a second feature amount regarding at least the position and posture of the tracking target, a movement amount calculation section that calculates an arm movement command based on a difference between the second feature amount and the first feature amount, and a movement command section that moves the arm based on the movement command and that controls the robot with high accuracy and causes the robot toTo follow an article exactly, for example. The applicant of the present application has already filed a patent application (Japanese Patent Application No. JP 2020 - 116687) relating to this technique.

[0006] See also patent documents 3-8. Patent document 1: JP 2002 - 018 754 A Patent document 2: JP 2002 - 192 486 A Patent document 3: DE 10 2018 003 762 A1 Patent document 4: DE 10 2012 007 242 A1 Patent document 5: DE 10 2005 063 217 B4 Patent document 6: EP 3 189 947 A1 Patent document 7: EP 3 142 088 A1 Patent document 8: US 2015 / 0 217 455 A1

[0007] It is conceivable that in a case where a robot performs a process while tracking an article being moved by a feeder, the robot may fail to complete the process in a timely manner.

[0008] For example, in a case where a robot is assembling a door on an automobile body moving along a production line, it is necessary to insert a pin to position the door so that it can be opened. At this point, there is a likelihood of equipment damage before the robot completes the process due to fit failure or pin biting.

[0009] For this reason, it is an object of the present invention to provide a method and a technique in which, even in a case where a robot process cannot be properly performed in a robot control system that performs the process by a robot for a continuously moving process target or a repeatedly moving / stopped process target, disadvantages such as occurrence of equipment damage can be avoided by detecting such a failure in the robot process.

[0010] This object is achieved by a robot control system including a robot that performs a process for a process target, a control unit that controls the drive of the robot, a first area setting unit that sets a first area where the process for the process target is performed, and a second area setting unit that sets a second area outside the first area so that the robot performs a retraction movement when a work device provided on the robot moves out of the first area and enters the second area while the robot follows the moving process target.

[0011] According to one aspect of the robot control system of the present disclosure, the control unit controls the drive of the robot to perform the retraction movement when the robot's work mechanism moves out of the first area where the process is safely performed for the process target and enters the second area. With this configuration, even in a case where the process cannot be performed properly due to an unforeseen situation, the robot control system, which continuously moves the robot or repeatedly moves / stops the robot to perform the process for the process target, can detect such a situation and can prevent, for example, the occurrence of equipment damage. Fig. 1 is a perspective view showing a robot control system of one aspect; Fig. 2 is a view showing an example of a first area, a second area, and a movable area set by the robot control system of an aspect; Fig. 3 is a view showing an example of the first area, the second area, and the third area set by the robot control system of one aspect; and Fig. 4 is a view showing an example of the first area and the second area set by the robot control system of one aspect.

[0012] Hereinafter, a robot control system according to an embodiment will be described with reference to Fig. 1 to 4. The robot control system of the present embodiment refers, for example, to a system provided on a production line to control a robot (an industrial robot) that performs a process for a supplied process target such as an article.

[0013] Specifically, the robot control system 1 of the present embodiment includes, as shown in Fig. 1, a robot 4 which performs, for example, the process of assembling a door 3 with the process target 2, such as an automobile body (not shown), and a control unit which controls the drive of the robot 4.

[0014] The robot 4 is formed, for example, in an articulated shape, and includes one or more visual sensors provided on a movable arm and a tool (work device) 5 attached to the arm to perform a predetermined process for the process target 2.

[0015] The control unit controls the drive of the robot 4 to perform the process for the process target 2, and based on detection results of the visual sensors, it operates and controls the robot 4 so that, for example, the tool 5 or an article gripped by the tool 5 follows the process target 2.

[0016] In addition to the robot 4 and the control unit, the robot control system 1 of the present embodiment includes, as shown in Fig. 2, an arm position checking unit which sequentially checks the position of the arm, a first area setting unit which sets a first area R1 as a work area where the process for the process target 2 is performed, and a second area setting unit which sets a second area R2 outside the first area R1 as an avoidance area where the arm is surely operable so that the robot 4 performs a retreat movement when the tool 5 provided on the robot 4 moves out of the first area R1 as the work area and enters the second area R2 as the avoidance area while the robot 4 follows the process target 2 which is moved by, for example, a feeder.

[0017] According to the process contents, the movement direction of the process target 2, the configuration of the robot 4, etc., the position and size of the first area R1 as the work area and the second area R2 as the avoidance area are set. The second area R2 as the avoidance area is a sufficient area to cause the robot 4 to perform the retraction movement, and the tool 5 of the robot 4 performs the retraction movement in the second area R2.

[0018] In a Fig. 2, a movable range R4 where the tool 5 of the robot 4 is operable is set as a large range, the small first range (work area) R1 where the robot 4 can actually perform the process is set within the movable range R4, and the intermediate second range (avoidance area) R2 is set to include the first range R1 as the work area.

[0019] In a Fig. 3, a portion remaining after the rectangular quadrangular first area R1 as the work area is removed from the rectangular quadrangular area surrounded by the outer periphery of the second area R2 as the avoidance area is the second area R2 as the avoidance area.

[0020] In a Fig. In the example shown in Fig. 4, the second area R2 as the avoidance area, taking into account the movement direction of the process target 2, is provided downstream of the rectangular, quadrangular first area R1 as the work area in the movement direction.

[0021] The arm position checking unit uses a technology such as a sensor or image capture as needed.

[0022] The robot control system 1 of the present embodiment includes an abnormality processing unit that determines as an abnormality a situation where the tool 5 of the robot 4 moves out of the first area R1 as the work area to perform abnormality processing.

[0023] In the present embodiment, as one type of abnormality processing, the abnormality processing unit outputs a notification when the tool 5 of the robot 4 moves out of the first area R1 as the work area, thereby causing an operator to recognize the occurrence of the abnormality and causing the control unit to perform drive control in the abnormality processing.

[0024] For example, when the tool 5 of the robot 4 moves out of the first area R1 as the work area and enters the second area R2 as the avoidance area, the abnormality processing unit stops the movement of the process target 2 or decreases a movement speed of the process target 2 to a predetermined speed, or causes the robot 4 to perform a retreat movement while the robot 4 continuously follows the continuously moving process target 2.

[0025] Furthermore, the robot control system 1 of the present embodiment preferably includes a third area setting unit that sets a third area R3 as a process restart area within the first area R1 as the work area, and the abnormality processing unit is preferably configured to continuously determine such a situation as an abnormality in a case where the tool 5 moves out of the first area R1 as the work area and enters the second area R2 as the avoidance area until the tool 5 enters the third area R3 as the process restart area.

[0026] For example, in a case where the tool 5 moves out of the first area R1 as the work area before completion of the process by the robot 4 due to fitting error or seizure of a pin in the process of assembling the door 3 to the automobile body as the process target 2, which is sequentially moved by the feeder by means of the robot 4, the robot control system 1 of the present embodiment as described above controls the robot 4 to perform the retreat movement when the tool 5 enters the second area R2 as the avoidance area.

[0027] In this case, the abnormality processing unit causes the robot 4 to perform the retreat movement while the robot 4 continuously follows the continuously moving process target 2, or stops movement of the process target 2, or decreases the movement speed of the process target 2 to a predetermined speed, so that the retreat movement of the robot 4 is properly performed.

[0028] That is, the second area R2 is set as the avoidance area mainly for 1) stopping the feeder by some kind of signal output when the tool 5 moves out of the first area R1 as the work area to continue the process, or 2) performing the retraction movement without stopping the feeder while the feeder is being fed forward. Furthermore, for the second area R2 as the avoidance area, the time required to perform the retraction movement with a certain time margin is obtained from, for example, the moving speed of the process target 2, and the size of the area is determined based on such time.

[0029] Thus, in the robot control system 1 of the present embodiment, the control unit controls the drive of the robot 4 to perform the retreat movement when the tool (work device) 5 of the robot 4 moves out of the first area R1 as the work area where the process is safely performed for the process target 2 and enters the second area R2 as the avoidance area.

[0030] Thus, according to the robot control system 1 of the present embodiment, even in a case where the process cannot be properly performed due to an unforeseen situation in the robot control system that continuously moves the robot 4 or repeatedly moves / stops the robot 4 to perform the process for the process target 2, such a situation can be detected and, for example, the occurrence of equipment damage can be avoided.

[0031] In a case where the process target 2 moves freely or a case where the retraction movement of the robot 4 is complicated, the tool that moves from the first area R1 as the work area to the second area R2 as the avoidance area once may move back and forth between the second work area R2 and the first area R1. If the operation is switched between the process in a normal state and the process in an abnormal state every time the tool 5 moves in and out of the areas R1 and R2 as described above, the control becomes complicated and the efficiency decreases significantly.

[0032] On the other hand, in the robot control system 1 of the present embodiment, the third area R3 is set as the process restart area within the first area R1 as the work area. With this configuration, in a case where the tool 5 moves out of the first area R1 as the work area and enters the second area R2 as the avoidance area, the abnormality processing unit continuously determines such a situation as the abnormality until the tool 5 enters the third area R3 as the process restart area. Thus, it is not necessary to switch the operation between the process in the normal state and the process in the abnormal state every time the tool 5 moves into and out of the second area R2 and the first area R1, and disadvantages such as complicated control and significant efficiency reduction can be solved. EXPLANATION OF REFERENCE SYMBOLS 1 robot control system 2 Process goal 4 robots 5 Tool (work equipment) R1 work area (first area) R2 Avoidance area (second area) R3 Process restart area (third area) R4 movable area

Claims

[1] Robot control system (1), comprising: a robot (4) that performs a process for a process goal (2); a control unit which controls the drive of the robot (4), a first area setting unit that sets a first area (R1) where the process for the process target (2) is performed, and a second area setting unit that sets a second area (R2) outside the first area (R1) so that the robot (4) performs a retraction movement when a work device (5) provided on the robot moves out of the first area (R1) and enters the second area (R2) while the robot (4) follows the moving process target (2). [2] Robot control system (1) according to claim 1, further comprising: an abnormality processing unit that determines a situation where the tool (5) of the robot (4) moves out of the first area (R1) as an abnormality to perform abnormality processing. [3] The robot control system (1) according to claim 2, wherein the abnormality processing unit issues a notification when the tool (5) of the robot (4) moves out of the first area (R1). [4] The robot control system (1) according to claim 2 or 3, wherein when the tool (5) of the robot (4) moves out of the first area (R1) and enters the second area (R2), the abnormality processing unit stops the movement of the process target (2) or decreases a movement speed of the process target (2) to a predetermined speed. [5] The robot control system (1) according to claim 2 or 3, wherein, when the tool (5) of the robot (4) moves out of the first area (R1) and enters the second area (R2), the abnormality processing unit causes the robot (4) to perform the retreat movement while the robot (4) continuously follows the continuously moving process target (2). [6] Robot control system (1) according to one of claims 2 to 5, further comprising: a third range setting unit that sets a third range (R3) within the first range (R1), wherein the abnormality processing unit continuously determines as the abnormality the situation where the tool (5) moves out of the first area (R1) and enters the second area (R2) until the tool (5) enters the third area (R3).

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