How to control a robot

Abstract

To avoid interference between an object, such a human or an article, in a robot movable range and an end effector provided at a tip of an arm.SOLUTION: The invention includes: an approach sensor (9) for detecting an end effect (4) and an object (7) approaching each other; and a motion sensor (11) for detecting motion of the end effector (4). A travel direction of the end effector (4) is obtained from a detection value of the motion sensor (11). Approach between the end effector (4) and the object (7) is detected by the approach sensor (9) with a sensing direction of the approach sensor (9) oriented in the travel direction of the end effector (4), and the motion of the end effector (4) is controlled based on a detection value of the approach sensor (9).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for controlling a robot to avoid interference between an object, such as a person or an object, within the movable range of the robot and an end effector provided at the tip of the robot's arm. [Background technology]

[0002] Robots have been widely used as industrial robots in the manufacturing industry, etc. In particular, in recent years, collaborative robots that work in cooperation with workers in factories have been attracting attention in order to compensate for the decline in the labor force.

[0003] In this robot, if it collides with a person, object, or other object within the robot's range of motion, there is a risk that the person may be injured or the object or robot may be damaged, so control is required to avoid such collisions (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-1217 A Summary of the Invention [Problem to be solved by the invention]

[0005] Some robots are equipped with an end effector at the end of an arm, and are controlled to perform various tasks using the end effector. In such robots, the end effector at the end of the arm may move quickly over a wide range, and the shape of the end effector is not necessarily smooth.

[0006] On the other hand, people and objects moving with them within the robot's range of motion can move quickly, and a collision with the robot's end effector could cause severe damage to the person's eyes, mouth, or other parts of the body, or could damage the object to the point where it loses its commercial value.

[0007] Therefore, in a robot having an end effector attached to the end of an arm, a challenge is how to avoid interference between the end effector and objects such as people or things. [Means for solving the problem]

[0008] Therefore, in the present invention according to claim 1, a method for controlling a robot that avoids interference between an end effector provided at the tip of the robot's arm and an object such as a person or an object within the robot's movable range, the method includes a proximity sensor for detecting the approach of the end effector to the object, a movement mechanism for moving the sensing direction of the proximity sensor, and a motion sensor for detecting the motion of the end effector (the moving direction and moving speed of the end effector), the moving direction and moving speed of the end effector are determined from the detection value of the motion sensor, the proximity sensor is moved by the movement mechanism faster than the moving speed of the end effector so that the sensing direction of the proximity sensor is directed to the moving direction of the end effector, the proximity sensor detects the approach of the end effector to the object, and the motion of the end effector is controlled based on the detection value of the proximity sensor. When it is recognized that an object has entered the movable area of ​​the robot based on the detection value of a recognition sensor that recognizes the position of the object, the movement mechanism controls the sensing direction of the approach sensor to face the moving direction of the end effector. I decided to do so.

[0009] In the present invention according to claim 2, in the present invention according to claim 1, a distance between the end effector and the object is determined based on a detection value of the proximity sensor. The relative distance is calculated, and when the relative distance is less than a first predetermined distance, the operation of the end effector is slowed down, and when the relative distance is less than a second predetermined distance (a distance closer than the first predetermined distance), the end effector is stopped. I decided to do so. Effect of the Invention

[0011] The present invention provides the following advantages.

[0012] That is, in the present invention, in a robot control method that avoids interference between an end effector attached to the tip of the robot's arm and objects such as a person or an object within the robot's moving range, the operation of the end effector is controlled based on the detection value of a proximity sensor that detects the approach of the end effector to an object, thereby making it possible to avoid interference between the end effector and objects such as a person or an object.

[0013] In particular, the direction of travel of the end effector is determined from the detection value of a motion sensor for detecting the movement of the end effector, the sensing direction of the proximity sensor is directed in the direction of travel of the end effector to detect the approach of the end effector to an object by the proximity sensor, and the movement of the end effector is controlled based on the detection value of the proximity sensor, thereby making it possible to accurately avoid interference between the end effector and objects such as people or things.

[0014] Furthermore, if the relative acceleration between the end effector and an object is calculated from the detection value of the approach sensor and the operation of the end effector is controlled in accordance with the relative acceleration, interference between a fast-acting end effector and an agilely moving object (person) can be avoided with even greater precision.

[0015] Furthermore, if the sensing direction of the approach sensor is controlled to face the direction of travel of the end effector based on the detection value of the recognition sensor that recognizes the position of the object, it is possible to detect the approach of an object such as a person or object to the end effector at an early stage, and interference between the object and the end effector can be effectively avoided. [Brief description of the drawings]

[0016] [Figure 1] FIG. [Diagram 2] The same configuration diagram. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A specific configuration of the robot control method according to the present invention will be described below with reference to the drawings.

[0018] As shown in Fig. 1, the robot 1 is installed in a work space 2 such as a factory, and an end effector 4 is attached to the tip of a movable arm 3. Generally, the arm 3 is made up of multiple axes and is designed to move freely within a predetermined range, but this is not limited thereto and the arm may be designed to move in a certain direction within a certain range. The end effector 4 includes various types of end effectors that perform one or more types of operations depending on the work content of the robot 1.

[0019] A recognition sensor 8 for recognizing the robot 1 and an object 7 such as a worker 5 or an object 6 is provided on the ceiling of the work space 2. Note that the recognition sensor 8 may be an imaging means such as a camera as long as it can recognize the robot 1 and the object 7, or may be a sensor using a laser or sound waves or a detection means using electromagnetic waves. In addition, the recognition sensor 8 is not limited to being a single device capable of simultaneously recognizing the robot 1 and the object 7, and may be a multiple device capable of simultaneously or separately recognizing the robot 1 and the object 7.

[0020] Furthermore, the end effector 4 of the robot 1 is provided with a proximity sensor 9 via a moving mechanism 10 for detecting the approach between the end effector 4 and the object 7. The approach sensor 9 may be any sensor capable of detecting the approach between the end effector 4 and the object 7, and is preferably a distance sensor capable of measuring the relative distance between the end effector 4 and the object 7. The approach sensor 9 has a predetermined detection range and directivity that allows detection in a specific direction. The moving mechanism 10 may be any sensor capable of moving the sensing direction (direction) of the approach sensor 9 relative to the end effector 4, and although there are no limitations on its structure, it is preferable that the moving mechanism 10 be configured to operate faster than the operating speed of the end effector 4.

[0021] Furthermore, the end effector 4 of the robot 1 is provided with a motion sensor 11 for detecting the motion (movement direction, movement speed, etc.) of the end effector 4. Note that the motion sensor 11 may be capable of detecting the motion of the end effector 4, such as the movement direction and movement speed, directly or indirectly by calculation, and for example, a combination of an acceleration sensor and a gyro sensor is preferable.

[0022] 2, the robot 1 (arm 3, end effector 4), recognition sensor 8, approach sensor 9, moving mechanism 10, and motion sensor 11 are connected to a controller 12. The controller 12 controls the robot 1 and the moving mechanism 10 according to a program for controlling the drive of the robot 1 and the moving mechanism 10 based on detection values ​​from the recognition sensor 8, approach sensor 9, and motion sensor 11. The controller 12 is not limited to being configured as a single device, and may be configured as a distributed system in which multiple devices perform individual control.

[0023] The controller 12 recognizes the robot 1 and the object 7 with the recognition sensor 8, and issues an alarm sound, a warning light, etc. as necessary. For example, the controller 12 divides the area recognized by the recognition sensor 8 into a working area, which is the entire area of ​​the working space 2, a movable area in which the robot 1 can move, and a danger area within a predetermined distance from the end effector 4 of the robot 1, and issues a different alarm for each area.

[0024] Furthermore, the controller 12 detects the approach between the end effector 4 and the object 7 by the approach sensor 9, and controls the operation of the robot 1 (end effector 4) based on the detection value of the approach sensor 9. For example, the controller 12 obtains the relative distance between the end effector 4 and the object 7 from the detection value of the approach sensor 9, and issues an alert and slows down the operation of the end effector 4 when the relative distance becomes less than a first predetermined distance, and stops the operation of the end effector 4 when the relative distance becomes less than a second predetermined distance (a distance closer than the first predetermined distance).

[0025] In this control based on the approach between the end effector 4 and the object 7, the operation of the end effector 4 is not limited to being controlled according to the relative distance between the end effector 4 and the object 7, but can also be controlled according to the relative speed, relative acceleration, relative jerk, etc. calculated from the change over time of the relative distance between the end effector 4 and the object 7. In this way, the relative speed and relative acceleration that take into account the change over time can more accurately detect interference between the end effector 4 and the object 7 that move together, and in particular, in the case of high-order acceleration such as relative acceleration, it is possible to flexibly respond to a person (worker 5) who is agile and whose actions are difficult to predict.

[0026] Furthermore, in control based on the approach between the end effector 4 and the object 7, the controller 12 determines the moving direction of the end effector 4 from the detection value of the motion sensor 11, and drives and controls the moving mechanism 10 so that the moving direction of the end effector 4 coincides with the sensing direction of the approach sensor 9. Then, the controller 12 detects the approach between the end effector 4 and the object 7 with the approach sensor 9 while facing the sensing direction of the approach sensor 9 to the moving direction of the end effector 4, and controls the operation of the end effector 4 based on the detection value of the approach sensor 9.

[0027] In this case, the controller 12 may always match the moving direction of the end effector 4 with the sensing direction of the approach sensor 9, or may recognize the positions and distances of the robot 1 and the object 7 with the recognition sensor 8 and match the moving direction of the end effector 4 with the sensing direction of the approach sensor 9 as necessary. For example, the moving mechanism 10 may be controlled so that the moving direction of the end effector 4 matches the sensing direction of the approach sensor 9 only when the recognition sensor 8 recognizes that the object 7 has entered the movable area. Also, the recognition sensor 8 may track the movement of the object 7 in chronological order, and when it recognizes that the object 7 is approaching the end effector 4, the moving mechanism 10 may be controlled so that the moving direction of the end effector 4 matches the sensing direction of the approach sensor 9.

[0028] As described above, the robot 1 is controlled to avoid interference between an object 7, such as a person (worker 5) or an object 6, within the moving range of the robot 1 and the end effector 4 provided at the tip of the arm 3 of the robot 1, and is configured to control the operation of the end effector 4 based on the detection value of a proximity sensor 9 for detecting the approach of the end effector 4 and the object 7.

[0029] Therefore, in the robot 1 configured as described above, interference between the end effector 4 and an object 7 such as a person (worker 5) or an object 6 can be avoided, and injury to the person (worker 5) and damage to the object 6 or robot 1 due to a collision with the robot 1 can be prevented.

[0030] In addition, the robot 1 is configured to determine the traveling direction of the end effector 4 from the detection value of a motion sensor 11 for detecting the movement of the end effector 4, to orient the sensing direction of an approach sensor 9 in the traveling direction of the end effector 4, to detect the approach between the end effector 4 and the object 7 by the approach sensor 9, and to control the movement of the end effector 4 based on the detection value of the approach sensor 9.

[0031] Therefore, in the robot 1 configured as described above, interference between the end effector 4 and an object 7 such as a person (worker 5) or an object 6 can be avoided with high precision, and injury to the person (worker 5) and damage to the object 6 or robot 1 due to a collision with the robot 1 can be more reliably prevented.

[0032] Moreover, the robot 1 is configured to obtain the relative acceleration between the end effector 4 and the object 7 from the detection value of the approach sensor 9, and to control the operation of the end effector 4 in accordance with the relative acceleration.

[0033] Therefore, the robot 1 having the above configuration can more accurately avoid interference between the end effector 4, which operates quickly, and the object 7 (particularly the person (worker 5)), which moves quickly and unpredictably.

[0034] Moreover, the robot 1 is configured to control the sensing direction of the approach sensor 9 so as to face the traveling direction of the end effector 4 based on the detection value of the recognition sensor 8 that recognizes the position of the object 7 .

[0035] Therefore, in the robot 1 configured as described above, approach of the object 7, such as a person or an object, and the end effector 4 can be detected at an early stage, and interference between the object 7 and the end effector 4 can be effectively avoided. [Explanation of symbols]

[0036] 1 Robot 2 Workspace 3 Arm 4 End effector 5 Worker 6 Object 7 Object 8 Recognition Sensor 9 Proximity sensor 10 Moving mechanism 11 Motion Sensor 12 Controller

Claims

1. A method for controlling a robot that avoids interference between an object, such as a person or an object, within a movable range of the robot and an end effector provided at the tip of the robot's arm, comprising: The robot has a proximity sensor for detecting the approach of an end effector to an object, a movement mechanism for moving a sensing direction of the proximity sensor, and a motion sensor for detecting a motion of the end effector (a moving direction and a moving speed of the end effector), determining a moving direction and a moving speed of the end effector from the detection value of the motion sensor, moving the proximity sensor by the moving mechanism faster than the moving speed of the end effector so that the sensing direction of the proximity sensor is oriented in the moving direction of the end effector, detecting the approach of the end effector to the object by the proximity sensor, and controlling the operation of the end effector based on the detection value of the proximity sensor; Furthermore, the robot control method is characterized in that when it is recognized that an object has entered the robot's movable area based on the detection value of a recognition sensor that recognizes the position of the object, the method controls the movement mechanism to orient the sensing direction of the approach sensor in the direction of travel of the end effector.

2. 2. The robot control method according to claim 1, further comprising the steps of: determining a relative distance between the end effector and the object from a detection value of the proximity sensor; and, if the relative distance is less than a first predetermined distance, slowing down the operation of the end effector; and, if the relative distance is less than a second predetermined distance (a distance closer than the first predetermined distance), stopping the end effector.

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