JPS6346441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a robot or the like that moves and controls welding guns, tools, etc.

A conventional control device includes an actuator that moves a moving body, a transducer that generates an output signal corresponding to the position of the moving body, an output terminal connected to the actuator, and one input terminal connected to a DA converter. , a servo amplifier having another input terminal connected to the output terminal of the transducer and having a gain adjuster, and a servo amplifier which stores a target position value of the moving object and transmits the read position target value to the D- A
It consists of a storage device that supplies the converter.

The servo amplifier of this control device moves the actuator at a faster speed as the gain is increased.
Since the robot will suddenly stop at the next position target value, the shaft of the robot or other device will wear out quickly, and the mounting section of the device may become loose or loose, and the rigidity of the mounting frame must be increased. On the other hand, if the gain is made smaller, the working time becomes longer, so the gain is set at an appropriate value that can shorten the working time within a range where the adverse effects such as wear are not too great.

However, with the above-mentioned conventional control device, when the controlled object, such as a tool, moves in the direction of gravity or in the opposite direction, the moving speed becomes faster or slower than the appropriate value, resulting in wear of the shaft of the device and damage to the device. Disadvantages such as rattling or loosening of the mounting portion and prolonging the working time have not yet been fully resolved.

An object of the present invention is to obtain a control device free from such drawbacks, and in the conventional control device described above, the memory further stores the gain selection signal of the servo amplifier, and the control means includes:
Furthermore, the gain selection signal of the servo amplifier is read out, and the gain adjuster is characterized in that the gain of the servo amplifier is set in accordance with the gain selection signal read out from the memory.

Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a memory device which stores a plurality of position target values of a movable body such as a welding gun and a gain selection signal for a servo amplifier (described later) when moving to each position target value, and reads it out using the output signal of the controller 2. The controller 2 as a control means consists of, for example, a clock pulse generator, a counter, a decoder, etc.
In order to sequentially read out a plurality of target position values of the moving object from the storage device 1, output signals corresponding to the addresses where the target position values are stored are sequentially generated and output. 3 is D-A
The transducer 4 is a servo amplifier and has a gain adjuster 5, for example a potentiometer. 6
7 is an ammeter, 7 is an actuator connected to an actuating device such as a robot that supports a movable object such as the welding gun, such as a hydraulic servo motor driven by a hydraulic power source 8, and 9 is a mechanical device connected to the actuator 7. This is a potentiometer that is connected to the servo amplifier 7 and outputs a feedback signal to the input terminal of the servo amplifier 4 in accordance with the movement of the actuator 7.

Thus, when driving the moving body from a certain positional target value to the next positional target value in a state where no unbalanced load is currently applied to the moving body, the output signal from the controller 2 to read the next positional target value is sent to the memory 1. , the storage device 1 outputs the position target signal and gain selection signal of the next position target value.

This position target signal is converted into an analog quantity by the DA converter 3 and applied to the servo amplifier 4, where it is amplified and becomes a servo current, which operates the actuator 7. When this actuator 7 operates, a corresponding feedback signal from the potentiometer 9 is applied to the feedback input terminal of the servo amplifier 4 in the direction in which the servo current becomes zero, so the actuator 7 finally causes the servo current to become zero. Stop at a certain point. The gain selection signal of the servo amplifier 4 output from the memory 1 together with the position target signal has a constant value such that the servo amplifier 4 has an optimal gain while no unbalanced load is applied, and the gain is adjusted according to that value. The device 5 outputs a gain setting signal.

When a moving body is driven in the same direction as the gravity direction from a certain position target value to the next position target value, the actuator 7 is operated by the servo current of the servo amplifier 4 whose gain is set by the gain selection signal. , the moving body is driven by the actuator 7 at a faster speed and suddenly stops, so the gain selection signal output from the memory 1 at this time is such that the gain of the servo amplifier 4 adjusted by this signal is the same as before. Set it to a lower value.
Thus, even in such a case, the moving body will be driven at an appropriate speed as in the case where it is not affected by gravity.

When the moving body is driven in a direction opposite to the direction of gravity from a certain position target value to the next position target value, the actuator 7 is driven at a slow speed, contrary to the case in the same direction, so at this time, the memory The gain selection signal output from servo amplifier 1 is set so that the gain of servo amplifier 4, which is adjusted by this signal, is set to a higher value than before. Thus, even in such a case, the moving body will be driven at a suitably high speed as in the case where it is not affected by gravity.

FIG. 2 shows a gain adjuster for a servo amplifier that outputs a gain setting signal corresponding to a gain selection signal.

In the same figure, 10-1, 10-2, 10-
Reference numerals 3 and 10-4 are gain setters constituted by, for example, potentiometers, each of which is connected to the multiplexer 11. This multiplexer 11 selects and outputs a predetermined voltage which is a gain setting signal for one of the gain setters 10-1 to 10-4 from the digital value of the gain selection signal a from the memory 1, and outputs the selected voltage to the servo amplifier. Add to control terminal 4. The servo amplifier 4 is, for example, a differential amplifier,
It is comprised of a multiplier that multiplies the output signal by a predetermined voltage that is a gain setting signal, and is set to a predetermined gain according to a gain selection signal. When a tool, etc. is moved using an actuating device such as a robot, a control mechanism having a circuit as shown in the first diagram is installed in each of the multiple axes that determines the moving direction of the tool, etc. in the actuating device, such as a robot. However, when there is an obstacle in the direction of moving a tool or the like to the next position target value by one axis, the gain selection signal of the servo amplifier is determined by considering the following in addition to the above.

In other words, in order to move a moving object such as a tool in a curve to the next positional target while avoiding obstacles, the gain of the servo amplifier in the drive circuit of the actuator that drives one axis is adjusted to the gain of the servo amplifier in the drive circuit of the actuator that drives the other axis. The gain selection signal is determined so that it is smaller than the gain of the amplifier, and the gain of the servo amplifier in the drive circuit of the actuator that drives other axes is set to be smaller than the gain of the servo amplifier of one axis from the obstacle position to the next position target value. Determine the gain selection signal for the servo amplifier of the other axis.

By setting the gain of the two-axis servo amplifier as described above, there is no need to store the position where the obstacle was avoided as a dummy position target value in the memory, and the next position target can be reached while avoiding the obstacle. be able to. Therefore, the teaching time and working time for the memory device can be shortened.

As described above, according to the present invention, the gain selection signal of the servo amplifier when moving the moving body to the position target value is stored in the memory together with the position target value of the moving body, and the gain selection signal of the servo amplifier when moving the moving body to the position target value is stored in the memory, Since the read gain selection signal is used to obtain a gain setting signal corresponding to the gain selection signal from the gain adjuster of the servo amplifier, a moving object such as a tool can be driven at an appropriate speed under any circumstances. As a result, the shafts of actuating devices such as robots are less likely to wear out quickly, and their mounting parts are less prone to rattling or loosening.
Moreover, there is no need to increase the rigidity of the mounting frame excessively, and the working time is shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure shows a concrete block diagram of the gain adjuster. DESCRIPTION OF SYMBOLS 1... Memory device, 2... Controller, 3... D-A converter, 4... Servo amplifier, 5... Gain adjuster, 6... Ammeter, 7... Actuator, 9...
...Potentiometer, 8...Hydraulic power source, 10-1~
10-4...gain setting device, 11...multiplexer.

Claims (1)

[Claims] 1: an actuator that moves a moving body; a transducer that generates an output signal corresponding to the position of the moving body; a servo amplifier having a gain adjuster whose output terminal is connected to the actuator; a memory for storing a target value and a gain selection signal for the servo amplifier, a control means for reading out the target position value of the moving body and a gain selection signal for the servo amplifier stored in the memory; a D-A converter that converts a digital signal of a target position value of the moving object into an analog signal, one input terminal of the servo amplifier is connected to the D-A converter, and the other input terminal is connected to the transducer. A control device, wherein the gain adjuster is connected to an output terminal of a user, and the gain adjuster sets the gain of the servo amplifier according to a gain selection signal read out from a memory.