JPH04111768A - Finish work control device of robot - Google Patents

Abstract

PURPOSE:To unify a work finish by providing a control means which indicates a new correction route, in which the original route is corrected, to a robot in a manner wherein a displacement amount, detected by a detecting means, obtains a press-in amount in accordance with preset work force. CONSTITUTION:A new correction route, in which the original route is corrected, is indicated to a robot 1 so that the actual displacement amount of a contact part of a work means(belt sander device)20, detected by a detecting means, obtains a press-in amount in accordance with preset work force. In this way, the actual press-in amount of a workpiece 4 relating to the work means 20 is controlled so as to obtain a value always in accordance with the preset work force.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a finishing control device for a robot that performs finishing processing such as grinding and polishing on a work gripped by the robot.

"Conventional technology" Conventionally, in a workpiece gripping robot that moves the gripped workpiece along a designated path, a method for arbitrarily controlling the processing load on the workpiece is to detect the load current of the motor that drives the processing device. However, there is a method of feeding back this detection signal to the control system of the robot, and a method of detecting the load pressure applied to the wrist joint of the robot and feeding back this detection signal to the control system of the robot.

However, when performing finishing processing on a workpiece using finishing processing equipment such as a belt sander or grinder, the processing load occurs and disappears instantaneously.
With the method of detecting the load current and load pressure described above, it is not possible to keep the machining load on the work constant, and it is not possible to make the machining finish uniform. Therefore, when performing such finishing machining, an escape mechanism is provided on the finishing equipment side to allow a certain amount of movement, while the robot always pushes the workpiece a certain amount into the processing equipment. A method of teaching the path of the workpiece (teaching), or a method of teaching the path without pushing the workpiece and applying a certain amount of offset so that the workpiece is pushed in a certain amount during playback (repeat) has been proposed.

``Problem to be Solved by the Invention'' By the way, in the method described above in which a workpiece gripped by a robot is processed by pushing it a certain amount into a finishing device, the pushing amount of the workpiece as seen from the robot side is always constant. However, in reality, the positional relationship between the gripped workpiece and the finishing device differs slightly, making it difficult to achieve uniform finishing. For example, if there are errors (variations) in the shape of individual workpieces, even if the workpiece is pushed in a certain amount as seen from the robot side, it may not actually come into contact with the workpiece or processing equipment. Even if there is an error in the gripping position of the workpiece, the workpiece may not come into contact with the processing equipment, and the machining accuracy may decrease due to errors in the workpiece shape or gripping position. There was a problem with it. Furthermore, when applying a certain amount of offset, it is necessary to teach the push-in amount to always be constant depending on the shape of the workpiece, which poses the problem of placing a heavy burden on the operator when teaching. Ta.

This invention was made in view of the above-mentioned circumstances, and when finishing a workpiece gripped by a robot, it absorbs errors in the workpiece shape, workpiece gripping position, as well as errors in the teaching path, and improves machining and finishing. The purpose is to provide a robot finishing control device that achieves uniformity.

``Means for Solving the Problems'' The present invention includes a robot that grips a workpiece and moves the workpiece along a designated path, and a processing means that abuts the workpiece to perform finishing processing. and supporting a contact portion of the processing means that contacts the workpiece so as to be movable in a direction pushed by the workpiece,
a biasing support means for biasing with a constant pressing force in a direction opposite to the pushing direction; a detecting means for detecting the amount of displacement of the contact portion caused by being pushed by the work; and the detecting means. The amount of displacement detected by
The present invention is characterized by comprising a control means for instructing the robot to take a new corrected path by correcting the original path so that the pushing amount corresponds to a preset processing force.

"Operation" According to the above configuration, the original path is corrected so that the actual displacement amount of the contact part of the processing means detected by the detection means becomes the pushing amount according to the preset processing force. Since the robot is instructed to take the new correction path, the actual pushing amount of the workpiece into the processing means is controlled so that it always corresponds to the set processing force.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, l is a workpiece gripping robot, and an arm 3 is provided on a base 2 so that it can rotate horizontally, extend and contract, and swing freely in the Z-axis direction (vertical direction).
The arm 3 includes a hand mechanism 5 provided at the tip thereof to grip the workpiece 4, and inside the base 2 is a Z oil motor 6 for driving the arm 3 in the Z-axis direction.
is provided. In addition to the Z oil motor 6, inside the base 2, there are also motors for horizontally rotating and extending the arm 3, and for gripping the hand mechanism 5, but these motors and A description of the control system will be omitted.

The operation of the Z oil motor 6 is controlled by a robot controller 8. This robot controller 8 includes a CPU (central processing unit) 10 that executes an arithmetic processing program to be described later and controls the operation of each part, and this CPU10.
RO'M (read only memory) which stores the programs used in the program, and RAM (which temporarily stores data)
Random access memory) +2 and an input/output unit 13 that exchanges various data are interconnected by a pass line, and further, the Z-axis motor 6 is driven based on the Z-axis command value output from the human output unit I3. The configuration includes a Z-axis servo driver 14, which will be described later, and an A/D converter 15, which converts an analog signal output from a potentiometer 31 (described later) into digital data and supplies the digital data to the input/output section 13. Various operation data such as teaching data and a specified push amount value are input from the operation unit 16 to the input/output ff113 of the robot controller 8.

On the other hand, in the figure, reference numeral 20 denotes a belt sander device disposed near the robot 1. The belt sander device 20 includes a drive roller 2 driven by a motor 21.
2, a rotatable processing roller 23 and an idle roller 24, and a polishing belt 25 supported by these rollers 22 to 24.
The workpiece 4 is ground and polished by moving the workpiece 5 at high speed. Here, the drive roller 22 is in a fixed position, and the idle roller 24 at the lower end is constantly urged downward by a spring (not shown) in order to give an appropriate tension to the polishing belt 25, and the idle roller 24 is the one closest to the robot l. The processing portion roller 23 is capable of swinging in six directions indicated by arrows. That is, as shown in FIG. 2, the processing roller 23 is rotatably attached to one end of an arm 26, and a shaft 27 is attached to the approximate center of the arm 26. This shaft 27 is rotatably supported by a fixedly provided bearing (not shown). Further, the other end of the arm 26 is constantly pulled downward by a spring 28.

As a result, the processing roller 23 moves around the shaft 27 as indicated by the arrow A.
It is supported so as to be able to swing freely in the direction, and when it is pushed downward, it is always urged upward by the action of the spring 28 with a pressing force corresponding to the amount of pushing. Further, a gear 29 is attached to the arm 26 with its axis aligned with the shaft 27, and this gear 29 meshes with a gear 30 attached to the rotating shaft of the potentiometer 31. As a result, when the processing section roller 23 swings in the direction of arrow A,
The rotation of the gear 29 accompanying this swing causes the gear 30 to rotate in the direction of arrow B, and as a result, the vertical swing angle of the processing section roller 23 in the direction of arrow A is detected by the potentiometer 31. There is. In this case, when the processing section roller 23 is pushed downward by the workpiece 4, the amount of displacement in the Z-axis direction (pushing amount) can be approximated by the vertical swing angle of the processing section roller 23 in the direction of arrow A. Therefore, the actual pushing amount of the workpiece 4 is detected by the potentiometer 31 that detects this swing angle.

Next, the operation of the above-mentioned embodiment will be explained.

When the work 4 gripped by the robot 1 is pressed against the belt sander 20 for finishing processing, the CPU 10 of the robot controller S repeatedly executes the pushing amount correction process shown in FIG. 4 at predetermined time intervals.

First, in step SPI shown in FIG. 4, digital data output from the potentiometer 31 and converted by the A/D converter 15 is taken in as a displacement C. This displacement C is a value corresponding to the amount of displacement of the processing section roller 23 in the Z-axis direction, that is, the amount of pushing of the processing section roller 23 by the workpiece 4 .

Next, in step SP2, the push amount specified value zp inputted in advance by the operation unit 16 and stored in a predetermined storage area of the RAM 12 is read out, and further, in the next step SP3, the push amount specified value zp and the displacement are read out. The deviation from C, that is, the Z-axis correction value ΔZ is calculated. Then, in step SP4, the operation section! The current Z-axis teaching data 21 input in advance in step 6 and stored in a predetermined storage area of RAMI2 is read out.In the next step SP5, the Z-axis correction value ΔZ is added to the Z-axis teaching data 21. , calculates the corrected Z-axis command value Z, and further, in the next step SP6, Z
The axis command value Z is output to the Z-axis servo driver 14, and the series of processing is completed.

A control system diagram of such a push amount correction process is as shown in FIG. That is, the Z-axis teaching data 21 is corrected so that it becomes the actual displacement C of the f-processing roller 23 detected by the potentiometer 31, or the preset f-pushing amount specified value Zp, and this corrected new Z-axis command value Z is Z-axis servo driver 1
4 is instructed. As a result, even when there is an error in the shape of the workpiece 4 or when there is an error in the gripping position of the workpiece 4 by the robot l, the processing part roller 2
Push amount of work 4 relative to 3 or always push amount specified value Zp
The position of the workpiece 4 in the Z-axis direction is corrected so that it matches.

Next, other embodiments will be described. First, in the above-described embodiment, the rotation of the arm 26 is transmitted to the potentiometer 31 via the gear 29, 30 in order to detect the displacement of the processing roller 23. As shown, if the configuration is such that the information is transmitted via the link rod 33, the occurrence of detection errors due to bank craning can be prevented. In addition, in the Z-axis correction value calculation in step SP3 described above, the previous deviation is calculated as Δz (t-1)-z p(t-D-
c (t-D, the current deviation is ΔZ (t)-Z p(t
)-C(t), it may be calculated based on the difference between these values, the pushing amount change rate ΔZ゛-ΔZ(t)Δ2(1-+). Furthermore, in the embodiments already described, the case of finishing processing using the belt sander device 20 was explained, but if the same structure is adopted for the mechanism of the processing section, it can also be applied to grinding and polishing tools such as grinders and puffs. It is possible. In particular, the tool of a grinder wears out as it is used, but when the above configuration is applied, the wear amount of the grinder is also corrected as an error in the pushing amount, which has the remarkable effect of making it possible to achieve accurate finishing machining. play.

"Effects of the Invention" As explained above, according to the present invention, the actual displacement amount of the abutting portion of the processing means detected by the detection means becomes the pushing amount according to the preset processing force. In addition, the robot is instructed to take a new corrected path by correcting the original path, so the actual pushing amount of the workpiece into the processing means is always a value that corresponds to the set processing force. Errors in the gripping position of the workpiece are absorbed, resulting in uniform machining and finishing, improving machining accuracy.Furthermore, errors in the teaching path are also absorbed, reducing the burden of teaching. or can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a front view showing the configuration of the detecting section of the same embodiment, FIG. 3 is a front view showing another configuration example of the same detecting section, and FIG. 4 is the pushing amount correction processing operation according to the embodiment of the present invention. FIG. 5 is a control system diagram showing the correction operation of the pusher. 23... Processing section roller, 26... Arm, 27... Axis, 2
8... Spring (biasing support means), 31...
...Potentiometer (detection means).

Claims (1)

[Scope of Claims] A robot that grips a workpiece and moves the workpiece along a designated path; a processing means that abuts the workpiece and performs finishing processing; a biasing support means for movably supporting a contact portion that contacts the work in a direction in which the work is pushed in, and biasing the contact portion in a direction opposite to the pushing direction with a constant pressing force; a detection means for detecting the amount of displacement of the abutting portion caused by the contact portion, and correcting the original path so that the amount of displacement detected by the detection means corresponds to a pushing amount corresponding to a preset processing force. A finishing processing control device for a robot, comprising: control means for instructing the robot to take a new corrected path.