JP2767417B2 - Robot control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a robot control device that controls a robot using CAD / CAM. (Conventional technology) Conventionally, in a robot control device that controls a robot using CAD / CAM, after positioning, for example, an arm of the robot with respect to an object to be worked, and performing various teachings A predetermined operation is performed on an object. When performing work on an object, positioning of the robot or positioning of the object is virtually performed by an offline programming system using CAD / CAM, i.e., if the robot arm does not bend, etc. It is calculated and determined. (Problems to be Solved by the Invention) However, in such a conventional virtual off-line programming system, the positioning of the robot is rough, and for example, the robot is required to be spot-arc-welded which requires sufficient accuracy. Not suitable when applied to That is, for example, when a spot gun or the like is attached to the robot arm as an end effector, the robot arm bends due to the effect of the weight and moment of the end effector, but the virtual off-line programming system does not consider this warp at all. The arm cannot be accurately positioned with respect to the object. Furthermore, in a conventional off-line programming system, for example, when performing spot welding on a vehicle body, it is assumed that the position of the body carried on a transfer line that is a work target of the robot is predetermined, and the position of the robot arm with respect to the object is assumed. Although the relative position is determined, the position of the target object may actually shift due to the error of the transport line, and in this case also, it is not possible to accurately position the robot arm with respect to the target object. There was a problem. SUMMARY OF THE INVENTION It is an object of the present invention to provide a robot control device capable of correcting a position shift of a robot itself and a target object and accurately and accurately determining a position of the robot with respect to the target object. (Means for Solving the Problems) The present invention relates to a camera attached to a robot that recognizes a reference point of a work object, and an image of a reference point of the work object recognized by the camera. A robot system including a vision system for calculating data, and a robot control unit for correcting a virtual program position of the work object obtained by CAD / CAM using the calculation data calculated by the vision system. The robot controller performs the operation of the work object using three points provided at predetermined positions on the work object and image data obtained by capturing the three points at different positions using the cameras provided on the robot. Work object position determining means for obtaining position data of a three-dimensional relative positional relationship between each point on the object and the camera; The position data of the virtual undertaking object, and correcting means for correcting the position data obtained by the work object position determining means,
It is an object of the present invention to solve the above-described problems of the related art by providing a robot control device for controlling a robot including: (Function) In the present invention, the object to be worked by the robot is moved to a predetermined position virtually determined by a transport line, and three or more reference points of the object are recognized by the camera. To three-dimensionally recognize the object. Information on three or more points of the object three-dimensionally recognized by the camera is sent to the vision system, and the vision system determines the relative positional relationship between the camera and each point of the object recognized. The vision system sends this positional information to the robot controller, and the robot controller corrects the target program by correcting the virtual program position obtained by CAD / CAM based on the relative positional relationship determined by the vision system. And accurate positioning. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a robot control device of the present invention, FIG. 2 is a diagram showing a positional relationship between an object and a robot that three-dimensionally recognizes the object, and FIG. 3 is a point on the object. FIG. 6 is a diagram showing how this point is recognized from a plurality of postures in a camera coordinate system. In FIG. 1, a robot body 1 includes a table 2 and the table 2
Arm 3a rotatably and bendably mounted on the arm 3b, arm 3b rotatably and bendably mounted on the arm 3a, and a rotatable and bendable end of the arm 3b And an end effector 4 provided freely. The movements of the arms 3a, 3b and the end effector 4 of the robot body 1 are controlled by a robot controller 5. The robot controller 5 operates the robot body 1 under the control of a CAD / CAM offline programming system using a microprocessor (not shown) to position the arms 3a and 3b or the end effector 4. Has become. In the robot control device of the present invention, a camera 6 is further installed near the end effector 4, and the camera 6 is directed to the object 8 to be worked by the robot so that an image of the object 8 is captured and sent to the vision system 7. It has become. The vision system 7 analyzes the image captured by the camera 6 and recognizes the relative positional relationship between the end effector 4 of the robot body 1 and the object 8. If a positional shift or the like occurs, the recognition result is obtained. To the robot controller 5 and
The control by the offline programming system in the robot controller 5 is corrected. The operation of the robot control device having the above configuration will be described with reference to FIG. FIG. 4 is a flowchart showing a flow of processing of the robot control unit 5 and the vision system 7. In FIG. 4, first, in step ST1, an object 8 to be subjected to work, for example, a vehicle body to be subjected to spot / arc welding by a robot is moved on a transfer line (not shown) so as to be moved with respect to the robot main body 1. To a predetermined position virtually determined in advance. Next, the camera 6 recognizes a reference point of the object 8 (step ST2).
In order to three-dimensionally recognize an object, three or more points are required. In FIG. 2, for example, points P1, P2, and P3 correspond to these points. Further, in order to determine the three-dimensional positional relationship between the camera 6 and each of the points P1, P2, P3, one point, for example, the point P1 for a plurality of camera postures PS1, PS2 as shown in FIG.
Must recognize from. Therefore, in order to recognize the object 8 three-dimensionally and determine the positional relationship of each point of the object 8,
It is necessary to change the position, that is, the attitude of the camera 6 at least six times. Further, the image of each point of the object captured in each posture by the camera 6 is analyzed by the vision system 7 to determine the positional relationship. Thus, in step ST3 following step ST2, the vision system 7 determines a three-dimensional relative positional relationship between the camera 6 and each point P1, P2, P3 of the object. Next, in step ST4, by correcting the virtual program position obtained by CAD / CAM based on the positional relationship determined in this way, for example, by attaching a spot gun or the like as an end effector to the arm of the robot, It is possible to perform operations such as spot / arc welding on the object with sufficient accuracy under accurate positioning by correcting the bending of the arm and the displacement of the object carried on the transport line. The relationship between the robot control unit 5 and the vision system 7 is such that, for example, a processor that realizes a CAD / CAM offline programming system of the robot control unit 5 is a main processor, and a processor used in the vision system 7 is a processor dedicated to image processing. Then, the processor dedicated to image processing becomes a coprocessor of the main processor, and can independently execute image processing under the control of the main processor. (Effect of the Invention) As described in detail above, according to the present invention, the robot control unit obtains the virtual program position obtained by CAD / CAM based on the relative positional relationship between the object and the camera determined by the vision system. , The object to be worked can be accurately and accurately positioned, and can be applied to work requiring sufficient accuracy, for example, spot / arc welding work. The effect can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram of a robot control device according to the present invention;
FIG. 2 is a diagram showing a positional relationship between an object to be worked on and a robot which three-dimensionally recognizes the object, and FIG. 3 is a diagram showing a point of the object with camera coordinates. FIG. 4 is a flowchart showing a state of recognition from a plurality of postures in the system, and FIG. 4 is a flowchart showing a flow of a positioning process of the robot controller. 1 ... robot body, 2 ... table, 3a, 3b ... arm, 4
... End effector, 5 ... Robot control unit, 6 ...
Camera 7, Vision system 8, Object.

   ────────────────────────────────────────────────── ─── Continuation of front page       (56) References JP-A-60-258613 (JP, A)                 JP-A-61-103207 (JP, A)                 JP-A-61-173878 (JP, A)                 JP-A-60-229109 (JP, A)                 Japanese Utility Model Showa 58-169987 (JP, U)

Claims (1)

(57) [Claims] A camera attached to a robot that recognizes a reference point of the work object, a vision system that calculates image data of a reference point of the work object recognized by the camera, and a vision system that calculates the image data. A robot control unit that corrects a virtual program position of the work object obtained by CAD / CAM using the calculated data. And three-dimensional relative positions of each point on the work object and the camera using image data captured at a plurality of different positions by the camera provided on the robot for each of the three points. Work object position determination means for obtaining position data of a positional relationship, and position data of a virtual work object on a program created offline. And a correcting means for correcting the data by the position data obtained by the work object position determining means. 2. The work object position determination means performs three-dimensional relative positional relationship between the point and the camera by using image data obtained by capturing one point with a plurality of camera postures at each of the three points. A robot control device for controlling a robot according to claim (1).