KR920010575B1 - Position correction system for fine positioning of robot - Google Patents

Abstract

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Description

Position correction system for fine positioning of robot

1 is a block diagram of a robot hand to which a sensing system is attached.

2 is a general configuration of an optical non-contact probe (Probe) using a laser.

3a and 3b are layout views of sensors for contactless sensing according to the present invention.

4a and 4b are explanatory diagrams showing the basic principle of sensing according to the present invention.

5 is a block diagram of a stud welding robot system according to the present invention.

6 is a structural diagram of a multi-tasking system.

* Explanation of symbols for the main parts of the drawings

1: laser (or optical) displacement sensor 2, 12: sensor attachment device

3: stud 4: welding gun

5: robot hand 7: light source

8: collimating lens 9: condenser lens

10: CCD-image sensor 11: power supply and signal processor

13: Work Object 14: Robot Controller

15: RS 232 C interface port 16: cable

17 multi-tasking system 18 personal computer

19: data collection system

According to the present invention, a laser (or optical) displacement sensor is attached to a general robot system to realize a non-contact distance sensing of a relative distance between an object and a robot when the robot motion is precisely performed. A position correction system.

In general, the use of robots in mass production lines has to bear a very large relative repetition error at points taught in advance due to the manufacturing accuracy, assembly error, and accuracy of the robot itself.

As the degree of work for improving productivity increases, a processor is required to add intelligence to the robot through the introduction of a position correction system using a sensor system in order to use the robot by avoiding the conventional simple work. In practice, the most important aspects of the use of sensing systems in mass production lines are the simplicity, speed, accuracy and robustness of sensor operation.

Unlike the conventional expensive sensing system, the main object of the present invention is to provide a non-contact sensing system that meets these characteristics and is inexpensive, and in particular, shortens the sensing time by using a laser displacement sensor.

Another object of the present invention is to mount the sensing mechanism configured using the laser displacement sensor to the robot by sensing the robot's workpieces in a non-contact manner, and then processed by the industrial computer to transmit the correction amount of the robot while the position correction function in the robot system To give.

These and other features of the present invention are described in detail below with reference to the accompanying drawings.

1 schematically shows an embodiment in which the sensing system according to the present invention is applied to a stud welding robot hand, in which a welding gun 4 is installed at the tip of the robot hand 5 and the welding is performed. One side of the gun 4 shows an example in which the laser (optical) displacement sensor 1 is attached by a separate sensor attachment device 2 in a form suitable for later use. In the drawings, reference numeral 6 denotes a workpiece, and 3 denotes a stud.

2 shows a general configuration of an optical non-contact ranging probe using a laser. When the light projected from the laser light source 7 through the collimation lens 8 onto the object under test is reflected from the surface of the object under test, part of it forms an image on the CCD-image sensor 10 by the condenser lens 9. The relative position of the surface under measurement can be calculated from the position on the image. By using the laser as a light source, the measurement accuracy can be increased and the range of the measurement distance can be set relatively wide.

3a and 3b show an arrangement in which the sensors for contactless sensing according to the invention may take different forms depending on the purpose of use or the accuracy of the workpiece.

FIG. 3A shows a case in which the workpiece 13 applied to the present invention is bent at an angle of 100-105 ° so that measurement is required as the entry direction of the welding gun 4. In this case, sensing in the angular direction is required, and the sensors 1 and 1 'should also be disposed perpendicular to the two surfaces of the workpiece 13, respectively. Accordingly, the sensor 1 is attached to one side of the sensor attachment device 2 so as to be disposed perpendicularly to the inclined surface 13a of the workpiece 13, and the sensor 1 ′ is the horizontal plane 13b of the workpiece 13. It is attached to the other side of the sensor attachment device (2) so as to be perpendicular to the. Therefore, as shown in the basic principle of sensing in FIG. 4A, the sensing values represented by S1 and S2 are calculated as the correction amounts Xtc and Ytc for the coordinate system of the robot through the following calculation and then sent to the robot. The vector value indicated by e is the final required correction amount, that is, the sum of S1 and S2.

However, when the angle of the workpiece 13 is close to the right angle or the positional accuracy of the robot on the vertical surface of the workpiece 13 perpendicular to the robot welding gun 4 is high (within about ± 1 mm), FIG. As shown in FIG. 2, sensing in the S2 direction may be omitted. Therefore, the entry direction of the welding gun 4 is not attached to the sensor (1) (1 '), and two sensors (1) (1') are installed on only one side of the sensor attachment device (2) so that the redundant sensing in only one direction is achieved. Can be done. This is because when the inclined surface 13a and the horizontal surface 13b of the workpiece 13 are perpendicular to each other, the tanθ value converges to zero. Because it decreases. In Fig. 4b, the values indicated by S1 and S2 are the respective measurands for each sensor. However, due to various reasons, the measured quantities of the two sensors are different, and in some cases, measurement failure occurs. For this case, two sensors were attached and a good measure was chosen and used. In the normal case, the sensing values S1 and S2 are processed as follows and calculated as the correction amounts Xtc and Ytc for the robot coordinate system.

The invention consists of a multi-tasking system 17 connected to an industrial robot and data collection system 19 and an RS232C interface port 15 as shown in FIG. The data collection system 19 converts the sensor signal into a digital signal and is connected to the personal computer 18, and the multi-tasking system 17 is installed to reduce time delay due to communication with each robot controller 14.

6 is a structural diagram of a multi-tasking system 17. The RIC card, which consists of an Intel 80186 microprocessor and a Z 8030 serial communication control device, was used to process and calculate and send and receive sensing signals to and from the robot in real time. As shown, several robot controllers are connected to the ARTIC interface and there is a separate executable program for each robot.

The position correction system for fine positioning of the robot according to the present invention configured as described above realizes quick and accurate sensing by using a non-contact laser displacement sensor, and by combining the two sensors, the bending of the workpiece, etc. Minimize the error, and easy to operate the software for teaching (Trach-in) and correction is possible to operate online, it is possible to control multiple robots at the same time using a multi-tasking system.

Claims (5)

Hardware consisting of a sensor (1 '), robot controller (14), RS232C interface port (15), cable (16), multi-tasking system (17), personal computer (18), and data acquisition system (19). It is composed of a control software package for processing the system and the signals obtained from it to realize communication with the robot.The robot detects the relative position with the workpiece during operation by a non-contact sensor attached to the sensor attachment device. Position correction system for fine positioning of the robot, characterized in that after the processing in the computer and the robot and communication in real time to correct. The system according to claim 1, characterized in that communication with the robot controller (14) is processed by a multi-tasking technique in order to minimize the time delay. The sensor attachment device (2) according to claim 1, wherein said sensor (1) (1 ') is a non-contact ranging sensor, wherein one of the two sensors (1) faces perpendicular to the inclined surface of the workpiece (13). It is attached to one side of the other sensor (1 ') is attached to the other side of the sensor attachment device (2) so as to face perpendicular to the horizontal plane of the workpiece 13, the sensing is made in two directions, or two sensors ( 1) The system, characterized in that (1 ') is installed on both sides of the sensor attachment device (2), the sensing is performed in only one direction. The system software of claim 1, wherein the system software converts a sensor signal from a non-contact sensor into a corresponding correction amount of a robot tool coordinate system in a personal computer and uses the multi-tasking technique in real time with two or more robots. A system characterized by a series of program packages for calibrating the position of the robot tool. 2. The system of claim 1, wherein the sensor is a combination of optical or laser displacement sensors in one or two dimensional form to measure an object surface.

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