JPH07107644B2 - Robot control method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling the operation of a support part of a robot using a visual sensor.

2. Description of the Related Art In a robot controller that detects the position of the workpiece in the X and Y directions with a visual sensor, and moves the robot in the X and Y directions based on the detected position to position the support portion of the robot at the workpiece position, The coordinate system of the visual sensor and the coordinate system of the robot do not match and the robot bearing cannot be accurately positioned at the work position.

In other words, the coordinate system of the visual sensor has distortion due to lens aberration and distortion of the image sensor, etc., and the actual position of the workpiece does not match the detected position, and the robot's coordinate system converts each joint angle to Cartesian coordinates. Therefore, if there is distortion due to rattling of each joint or drive error, and if the position of the bearing is input based on the robot coordinate system to control the operation, the position on the coordinate system and the actual position The position of does not match.

Problems to be Solved by the Invention For this reason, it is necessary to match the coordinate system of the robot with the coordinate system of the visual sensor in order to accurately control the operation of the work by the robot, but the work is very troublesome. And it is difficult and takes a lot of time and effort.

Means and Actions for Solving the Problems This is a method for controlling the operation of a robot in which the support portion 7 can be freely moved to an arbitrary position with respect to the base body 2, and a visual sensor 10 attached to the base body 2 is used to make a predetermined determination. A large number of marks arranged at a distance of 10 mm between them are detected, and the distortion of the coordinate system of the visual sensor is detected by the difference between the detected distance between the marks and the actual distance between the marks. The position is moved to a plurality of predetermined target positions, each position of the supporting portion 7 at this time is detected by the visual sensor 10, and the detected position is corrected by the distortion and the actual position of the supporting portion 7 is detected. Depending on the target position, the transformation parameter from the coordinate system of the visual sensor to the coordinate system of the robot and the distortion of the coordinate system of the robot are detected, and when the support portion 7 of the robot is moved to the target position based on the input data, The conversion parameters and A robot control method in which correction is performed based on the distortion of the robot coordinate system.

Thereby, by correcting the distortion of the coordinate system of the visual sensor 10 and the distortion of the coordinate system of the robot 1, both coordinate systems match,
The support part 7 correctly moves to the target position based on the input data.

The robot 1 of the embodiment has a main body 3 rotatably mounted on a base body 2,
The column 4 is swingably mounted on the column 4, the head 5 is swingably mounted on the column 4, the arm 6 is rotatably mounted on the head 5, and the support part 7 of the hand or the suction tool is rotated on the arm 6. And it is provided so that it can be swung freely.

Then, each actuator (not shown) is driven to move the support portion 7 in the horizontal X and Y directions and the vertical direction.

The visual sensor 10 is arranged above the robot 1 in a frame 11, and a pair of light sources 12 are arranged on both sides of the frame 11.

The visual sensor 10 is a combination of an ITV and a CCD sensor or a combination of an ITV and an image pickup tube, and a detection signal is input to the control unit 13 as a video signal, and each actuator is supplied from the controller 14. It is designed to be driven by the operation signal.

As shown in FIG. 1, a large number of marks, such as black dots 20, are marked with Xs.
・ The visual sensor 10 includes the plates 21 having an equal interval in the Y direction.
A large number of black dots 20 are detected by the visual sensor 10 and output from the control unit 13 to the calculation unit 22 as a video signal.

The calculation unit 22 calculates the position of each black dot 20 and obtains it as an X / Y location, and sends it to the comparison calculation unit 23, and inputs the preset position of each black dot 20 input from the setter 24 to the correctly set reference data. The distortion of the coordinate system of the visual sensor is detected by the difference in the distance between the adjacent black points, and the distortion is fed back to the control unit 13 to correct the detected video signal thereafter.

Next, as shown in FIG. 2, the support portion 7 of the robot 1 is moved to the i-th position.
~ Input the input data to the controller 14 to move to the rectangular vertices and the center points of the fifth positions I, II, III, IV, V, and the bearing 7
To the first to fifth positions I to V. That is, the controller 14 receives the input data for moving the support portion 7 to the first to fifth positions, whereby each part of the robot moves to move the support portion 7 to the first to fifth positions IV. . Then, a plate 26 having black dots 25 is arranged on the substrate 27 at a position facing each position of the support portion 7. At this time, the position based on the movement based on the input data, that is, the coordinate position and the actual position are different due to the distortion of the robot coordinate system described above.

After this, the support portion 7 of the robot 1 is set at a position apart from the visual sensor 10, and the visual sensor 10 detects the position of each black dot 25 as the XY location by the arithmetic unit 22 and the detected position is corrected by the correction circuit 28. It is corrected by the calculation result of the calculation circuit 23, that is, the distortion of the coordinate system of the visual sensor, and sent to the calculation circuit 29 as the actual position of the support unit 7, and the actual position of the support unit 7 and the support unit corresponding to the input data. The position of 7 is compared and calculated, and the conversion parameter from the coordinate system of the visual sensor to the robot coordinate system and the distortion of the robot coordinate system are calculated and stored in the storage unit 30.

When the operation of the robot 1 is controlled based on the input data, the operation is controlled by correcting the value based on the value stored in the storage unit 30.

It should be noted that the video signal is corrected by the distortion of the coordinate system of the visual sensor calculated in advance without providing the correction circuit 28, and the corrected video signal is sent to the arithmetic circuit 22 so that the actual operation of the support unit 7 is performed. The position may be detected.

Effect of the Invention The distortion of the coordinate system of the visual sensor 10 and the distortion of the coordinate system of the robot 1 are corrected so that both coordinate systems coincide with each other and the bearing can be correctly moved to the target position based on the input data.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIGS. 1 and 2 are perspective views for explaining the operation, and FIG. 3 is an overall perspective view. 1 is a robot, 7 is a bearing, and 10 is a visual sensor.

Claims (1)

[Claims] 1. A method of controlling a movement of a robot, wherein a support portion 7 is movable to an arbitrary position with respect to a base body 2, wherein a visual sensor 10 attached to the base body 2 sets a predetermined distance in advance. A large number of the arranged marks are detected, the distortion of the coordinate system of the visual sensor is detected by the difference between the detected distance between the detected marks and the actual distance between the marks, and the bearing 7 of the robot is predetermined. It is moved to a plurality of target positions, each position of the support portion 7 at this time is detected by the visual sensor 10, and the detected position is corrected by the distortion and the actual position and the target position of the support portion 7 are detected. When the transformation parameter from the coordinate system of the visual sensor to the coordinate system of the robot and the distortion of the coordinate system of the robot are detected, and when the support portion 7 of the robot is moved to the target position based on the input data, the transformation parameter and the robot are used. To the distortion of the coordinate system of Robot control method and correcting by Zui.