JPS5838802B2 - Kogiyouyourobobotsutonadono Ichiseigiyosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position control device that corrects backlash and speed deviation of a position control device in a numerical control device, an NC machine tool, an industrial robot, or the like.

As is well known, in position control devices for NC machine tools, industrial robots, etc., closed-loop feedback type position control devices are generally used.

However, since this method is equipped with a means to detect the actual amount of movement using a position detector, it is difficult to prevent backlash due to backlash or friction in the mechanical system or dead zones of the detector, actuator, servo motor, hydraulic servo valve, etc. Because of these primary factors and secondary factors based on response delays in the control loop system, there is a drawback that positioning accuracy deteriorates due to errors (speed deviations) caused by differences in the positions of the command value and servo value.

In particular, there are relatively few problems with control devices that only deal with initial and final values, but with control devices that deal with intermediate processes such as NC machine tools and industrial robots, the second
Deviations as shown in the figure become a problem.

That is, the servo value always follows the command value from the initial value P1 toward P2 with a delay, and when the command value moves in the opposite direction from P2 to Pl, it appears as an error of the opposite component.

This error increases as the command speed increases.

When operating with a servo system of two or more axes, such as in profiling control, the error also differs in that the command speed differs depending on the profiling shape, resulting in a servo value that is quite different from the profiling shape.

In order to compensate for such drawbacks, a backlash correction device has conventionally been used in numerical control devices.

This device measures the total butteriness and speed deviation of the control system in advance, and when the actuator moves, the command value or A method is adopted in which the signal is added to the system as an electrical signal.

However, this bounce rate and speed deviation do not necessarily exist in steps by a predetermined unit amount; in control that is continuous and includes a speed variable, such as profile following control, the bounce rate and speed deviation also change in a complicated manner. Since the error component differs depending on the direction of movement of the actuator, it has been difficult to completely correct it using conventional methods.

Figure 3 is a block diagram of a general numerical control system.
In a system with no bumpiness and small speed deviation,
It is sufficient that the command value and the amount of feedback from the detector correspond to the error e at the addition point always be zero.

However, since the servo mechanism is a follow-up control system in which the controlled variable is a position or an angle, it cannot be expected that its response will be extremely fast.

The present invention aims to solve these conventional problems, and relates to a position control device that captures deviation signals of a robot's actuating device and automatically stores a correction program in a storage device. In FIG. 1, the feedback signal from the summing amplifier 5 is taken out, the deviation signal amplifier 10 performs impedance matching, the V-F converter 11 converts the analog quantity into a pulse,
The B register 12 is connected to the addition register 13, and the pulse fingers '>(direct) of the A register 3 and B register 12 are added and stored from the buffer register 14 to the storage register 15.

When reproducing from the storage device, the deviation of the actuator 8 is corrected and operated.

In that case, the switch 16 causes the deviation signal circuit 10. l
This is characterized by blocking L12 and eliminating malfunctions of the actuator 8.

Next, an embodiment of the present invention will be described with reference to FIG.

According to the analog signal set by the profiling device or the position command signal generator 1, the absolute amount is converted into the number of pulses, and the V-F converter 2, which outputs a direction signal, generates pulses proportional to the command signal. and sends it to the first register, ie, A register 3.

Then, after converting it into an analog quantity again with the D/A converter 4,
It is added to the summing amplifier 5 as a command value for a general analog feedback control system, and is added to the feedback signal from the position detector 9.

At this time, in order to improve the speed response, a factor of 1/8 is added to the integration circuit 6, and the voltage is amplified by the servo amplifier 7.
) Operate the tuator 8.

Therefore, a position signal is fed back to the summing amplifier 5 by a position detector 9 mechanically connected to the actuator 8, and the actuator 8 moves toward the command value while comparing it with the command value.

Here, a signal proportional to the backlash and speed deviation can be taken out as an output signal of the summing amplifier 5.

The deviation signal is captured by the deviation signal amplifier 10, amplified appropriately, and impedance matching is performed, then the V-F converter 1
1 to convert to the number of pulses.

Needless to say, this number of pulses is a value proportional to the deviation.

This is led to the second register, that is, the B register 12, added to the command value pulse from the A register 3 in the addition register 13, and stored in the storage device 15 via the buffer register 14.

The signal stored in the storage device 15 is a command value from the profiling device 1 that has been corrected for backlash and speed deviation components, and during reproduction, this signal becomes the command value to drive the controlled object. become.

This command signal opens the switch 5116 during playback and is applied from the storage device 15 to the D/A converter.
Correction feedback system deviation signal circuit 10. IL12 is blocked.

In this way, the present invention configures a correction feedback system with a deviation signal circuit consisting of a deviation signal amplifier 10, a V-F converter 11, and a B register 12 in addition to the normal feedback system.
By adding the deviation signal fed back to the summing amplifier 5 to the summing register 13 and adding it to the command value pulse from the A register 3, a signal corrected for errors due to backlash etc. is automatically stored in the storage device, and the signal is automatically stored in the storage device. Since it is regenerated by a signal, there are no extra loops and the actuator's operation is error-free.

Moreover, the deviation signal circuit is cut off by the switch 16.

Therefore, not only during playback but also during recording, the correction feedback system is configured completely separate from the entire servo mechanism system, so it is difficult to handle the instability of the system in conventional general correction measures and the response due to transient response. Unlike compensation circuits that tend to be delayed, optimal correction operations can be carried out sufficiently, giving complete reliability to robots and the like.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a position control device according to the present invention, FIG. 2 is an explanatory diagram of an error occurring between an initial value and a final value, and FIG. 3 is a block diagram of a conventional numerical control system. 1... Tracing device, 2... V-F converter, 3...
First register, 4...D/A converter, 5...Summing amplifier, 6...Integrator circuit, 7...Servo amplifier,
8... Actuator, 9... Position detector, 10.
... Deviation signal amplifier, 11... V-F converter, 12.
...Second register, 13...Addition register, 14.
...Buffer register, 15...Storage device.

Claims (1)

[Claims] 1 A V-F converter that converts an analog signal from a profiling device or a position command signal generator into a pulse number, a first register that stores the converted pulse signal, and an analog signal that converts a digital signal from the first register into an analog signal. a D/A converter that converts the command value from the summing amplifier to the summing amplifier; an integrating circuit and servo amplifier that transmits the command value from the summing amplifier to the actuator to operate the actuator; and a position detector that detects the position of the actuator and feeds it back to the summing amplifier. A position control device equipped with a deviation signal amplifier that extracts the deviation signal fed back to the summing amplifier and performs impedance matching, and a V-F converter that converts the amplified deviation signal into a pulse number. A deviation signal circuit consisting of a second register for storing a pulse signal is provided, and a second register is provided.
is connected to the first and second resistors via a switch.
It is equipped with an addition register that adds the command value pulses from the register, and a storage device that stores the addition result through a buffer register.During playback, the switch is opened to cut off the deviation signal circuit, and the command signal from the storage device is A position control device for an industrial robot, etc., characterized in that the signal is applied to a summing amplifier via a /A converter.