JPS6055415A - Speed offset adjusting device of positioning servo device - Google Patents

Abstract

PURPOSE:To make a zero adjustment of a speed offset automatically by detecting the speed offset value on the basis of a speed command in a positioning state, and comparing it with a permissible value and correcting the speed command. CONSTITUTION:A microcomputer 1 supplies a position command Xi to a position control unit 2 to control a servomotor 4 through a speed control unit 3. For the purpose, an offset abnormality detecting and correcting unit 7 is provided, and this unit 7 consists of the speed offset detecting circuit consisting of a positioning decision timer 8 and an offset storage device 9 and the compensating circuit consisting of a switch circuit 14 and an adder 2c. The timer 8 having received an offset detection command CM1 stores the speed command value va in the offset storage part 9, and a comparing circuit 11 compares it with the speed offset permissible value vr of a permissible value setter 10 to output the result to the microcomputer 1 and an AND circuit 13. Then, the switch circuit 14 is turned on to input the speed offset value vd of the storage device 9 to the adder 2c as a correcting amount.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to a speed offset adjustment device for a positioning servo device.

In general, a positioning servo device is constructed as shown in FIG. 1, for example.

In the figure, five position target values Xi are sequentially given to a position control unit 2 from a microcomputer 1 which constitutes a control system of a machine to which this positioning servo device is applied.

Next, in the position control unit 2, which includes an adder 2a and a preamplifier 2b having a gain characteristic as shown in FIG.
Position current value X from 6. In order to bring XO closer to the target position value Xi from the microcomputer 1, a speed command υa in the direction (polarity) that brings the difference, the positional deviation ξX=Xi XO, closer to zero is output to the speed control unit 3.

Then, in the speed control unit 3 consisting of an adder 3a, a servo amplifier 3b, etc., a speed offset value υ based on factors such as disturbance is applied to the speed command ua from the position control unit 2.
The rotational speed of the servo motor 4 is set to the speed target value υC while feeding back the current speed value υ0 from the speed detector (T/G) 5 attached to the servo motor 4, with the value added by b as the speed target value υC. control to follow.

Note that the speed offset value vb is naturally added to the speed command value υa, and the symbols indicating the adder in FIG. 1 are merely shown for convenience.

Therefore, the current 1-position value XO approaches the target position value Xi, and accordingly the position deviation εX and speed command υa become smaller, and eventually the target speed value υC and the current speed value υ0 become zero and the servo motor 4 stops. As a result, a positioning state is established near the positional target value Xi.

By the way, in such a positioning servo device, when the speed offset value υb as described above is superimposed on the speed command υa, constant speed movement is performed in which the speed command υa becomes the constant speed command value υwax as shown in FIG. Sometimes, the constant speed command value υwax varies ±υb depending on the direction of movement, as shown in Figure 3.
As a result, the moving speed does not match the commanded speed, making control difficult. In addition, in the positioning state, as shown in FIG. 3, the steady position deviation ε. (ε.

= υb/K (K minus gain)), resulting in poor positioning.

Therefore, conventionally, the speed offset was adjusted to zero in the following manner.

That is, in addition to cutting off the position feedback loop, when the speed command υa is forcibly set to zero, a visual inspection is performed to see if the servo motor 4 moves due to the speed control unit 3 that is powered on, and if it moves, it is stopped. The speed offset value υb was adjusted to zero by operating a zero adjustment volume (not shown) provided in the speed control unit B.

However, this conventional speed offset adjustment method relies on the operator's intuition, which tends to cause zero adjustment failures, and is susceptible to disturbances (temperature Each time a speed offset based on drift (drift) occurred, one person had to make adjustments one by one, making it extremely complicated.

This invention has been made in view of the above-mentioned background, and it is an object of the present invention to enable automatic zero adjustment of the speed offset as described above.

Therefore, the speed offset adjustment device for a positioning servo device according to the present invention takes advantage of the fact that the speed command in the positioning state matches the speed offset value, and adjusts the speed offset value based on the speed command in this state. The detected speed offset value is compared with a predetermined tolerance value, and if the speed offset value is within the tolerance range, a speed command is issued to make the steady position deviation zero based on the speed offset value. This is corrected, and only when the speed offset is outside the allowable range is a warning issued as a speed offset abnormality, prompting readjustment of the speed offset.

夾] L Salmon Hereinafter, embodiments of the present invention will be described with reference to FIG. 4 and subsequent drawings.

FIG. 4 is a block diagram showing an embodiment of the present invention.

In this figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and explanations of these parts will be omitted.

In the figure, 7 is an offset abnormality detection correction unit;
It is structured as follows.

That is, a positioning judgment timer 8 generates a storage timing pulse SL after a certain period of time after receiving an offset detection command CM from the microcomputer 1 when the device is powered on, and the storage timing pulse SL is output from the positioning judgment timer 8. an offset memory 9 that stores the value of the speed command υa in the positioning state as a speed offset value υd; By comparing the value 1) r, υrl<
The OK signal S1 as the first signal at the time of tir is υd
The comparator circuit 11 that outputs the NG signal S2 as the second signal when ≧υr and the offset detection command CM are set to N
The logical product of the signal inverted by the OT circuit 12 and the OK signal Sl is calculated, and only when the offset detection command CM is not output from the microcomputer 1 and the OK signal S1 is output from the comparison circuit 11. , an AND circuit 13 that outputs a switch-on signal So, and a switch-on signal S from this AND circuit 13. The switch circuit 14 is turned on only when .

When the microcomputer 1 receives the OK signal s1 from the offset abnormality detection and correction unit 7, it stops outputting the offset detection command CM, waits for an external activation command, and then sends the position target value X to the position control unit 2.
i and receives the NG signal S2, it issues a lighting command CM to the driver circuit 16 that drives the indicator lights 1 and 5 as alarm devices.
Give 2.

In the position control unit 2, when the switch circuit 14 is off, the speed command υa is set to υe, and when it is on, the speed command υa is set to υe.
+υd is output to the speed control unit 3 as υe.

Further, in the offset abnormality detection correction unit 7, a positioning judgment timer 8 and an offset memory 9 constitute a speed offset detection circuit, and the switch circuit 1
4 and the adder 2c in the position control unit 2 constitute a correction circuit.

Further, a one-shot multivibrator can be used as the positioning judgment timer 8, a latch circuit can be used as the offset memory 9 if this servo device is a digital DC servo system, and a CMOS transmission gate can be used as the switch circuit 14. .

Next, the action will be explained.

The microcomputer 1 gives a high level "H" offset detection command CM to the positioning judgment timer 8 in the offset abnormality detection and correction unit 7 at power-on time tx of the apparatus (see FIG. 5(A)).

The positioning judgment timer 8 that receives the offset detection command CM□ is set to a time τX (see Figure 5 (b)), which is sufficient for the servo device to enter the positioning state after power is turned on, and the set time has passed. and outputs a storage timing pulse SL (see FIG. 5(b)) to the offset storage device 9.

Offset storage device 9 receiving storage timing pulse SL
Now, the value of the speed command υa from the position control unit 2 is stored.

Note that at this time, the switch circuit 14 is off, so
The speed offset υd is not input to the adder 2c (υd
=o), and since the servo device is stopped in the positioning state, the speed target value υC is zero, so the value of the deceleration command υa stored in the offset memory 9 is equal to 1 υb.

The comparison circuit 11 compares the absolute value of the value υd stored in the offset storage circuit 9 with the speed offset tolerance value ur preset in the tolerance value setter 10, and determines whether vd is vd or not. If <υr is within the allowable range, OK signal S
1 is output to the AND circuit 13 and the microcomputer 1, and if vd is outside the allowable range with υd≧υr, an NG signal S2 is output to the microcomputer 1.

Note that the allowable value υr of the speed offset is determined by the value of the corrected speed command υe as shown in FIG.
and shall be set within a range that does not exceed the capacity limits of the speed control units 1 to 3.

When the OK signal S1 is output from the comparison circuit 11, the microcomputer 1 stops outputting the offset detection command CM, so the AND circuit 13 outputs the switch-on signal S.
o, thereby turning on the switch circuit 14 and setting the speed offset value υ stored in the offset memory S.
d (=-υb) is input to the adder 2C of the position control unit 2 as the speed command correction amount.

Therefore, the position control unit 2 adds the speed command correction amount υd (=-vb) to the speed command υa, and outputs the corrected speed command υ, (=υa - υb) to the speed control unit B. Therefore, the influence of the speed offset υb of the speed control unit 1-3 is canceled, and as a result, not only the steady position deviation ε0 becomes zero, but also the position target value Xi is output from the microcomputer 1 to the position control unit 2, and the speed Even when the command υa becomes the constant speed command value υ+max, the speed target value υC matches the constant speed command value υmax.

Further, when the comparison circuit 11 outputs the NG signal S2, the microcomputer 1 stops the servo device, outputs a lighting command CM2 to the driver circuit 16 to light the indicator lamp 15, and then the operator prompts you to readjust the speed offset.

As explained above, according to the present invention, if the speed offset value is within the allowable range, it is automatically corrected, and if it is outside the allowable range, an alarm is issued to prompt manual correction. , (1) Positioning accuracy increases (2) The movement speed during constant speed movement matches the command value, so
(3) It is possible to make the zero adjustment of the speed offset rough. (4) It is possible to simplify measures against temperature drift of the speed control unit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a positioning servo device used to explain the background of the present invention. 2 and 3 are diagrams for explaining problems based on conventional speed offset adjustment, respectively, FIG. 4 is a block diagram showing an embodiment of the present invention, and FIG. FIG. 6 is a timing diagram for explaining the operation of the positioning judgment timer in FIG. 4. FIG. 1... Microcomputer 2... Position control unit 2a, 2c... Adder 2
b...Preamplifier 3...Speed control unit 1-38
...Adder 3b...Servo amplifier 4...Servo motor 5...Speed detector 6...Position detector 7...Off Sera!・Abnormality detection correction unit 8...Positioning judgment timer

Claims (1)

[Claims] 1. In a positioning servo device, a speed offset detection circuit detects a speed offset value based on a speed command in a positioning state, and a speed offset value detected by this speed offset detection circuit is compared with a predetermined tolerance value, The first when the speed offset value is smaller than the allowable value.
and a comparison circuit that outputs a second signal when the speed offset value is greater than or equal to the allowable value; A speed offset for a positioning servo device, comprising: a correction circuit that corrects a speed command based on a speed offset value; and an alarm that issues an alarm only when a second signal is output from the comparison circuit. Adjustment device.