JPS5851303A - Numerical controller - Google Patents

Abstract

PURPOSE:To obtain position deviation in the form of a digital value by finding variation in position deviation from a phase difference signal and then converting the variation into the number of pulses in accordance with its value and direction. CONSTITUTION:A counter 22 counts reference clock pulses CLK through an AND gate 20, and a flip-flop 21 is set at a rise of its signal; and the reference clock pulses CLK are supplied to a reversible counter 24 through an AND gate 23 to decrease the contents of the reversible counter 24. In this case, the counted value of the counter 22 for the last phase difference signal is present in the reversible counter 24, and thus the counted values of the counter 22 and reversible counter 24 vary stepwise.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase servo type numerical control device using a resolver, and particularly relates to a phase servo type numerical control device that uses a resolver, and in particular obtains a large (2ri) position deviation change as a number of pulses according to the magnitude and deviation direction, and uses kneading and interpolation pulses. This invention relates to a single numerical control device which converts the digital position deviation amount obtained from the output into analog and provides it to a servo drive circuit as a single-stroke speed command signal.

In a constant phase servo type numerical control device using a resolver, a phase difference signal is generally obtained between a digital phase modulation signal and a feedback signal from the resolver, and this is rectified and DC amplified to drive a servo motor. It takes control. However, in such a numerical control device according to the prior art, since the positional deviation is an analog quantity, there is a drawback that it is easily influenced by drift and the like.

FIG. 1 shows an example of a phase servo type numerical control device according to the prior art. According to this, a position command output from a position command circuit 1 including an arithmetic circuit such as a microcomputer is converted into an interpolation pulse (position increase/decrease pulse) by an interpolation control circuit 2, and then given to a resolver control circuit 3. There is. The details of the resolver control circuit 3 will be described later, but the stator winding 8 of the resolver 7,
9, while outputting a phase difference signal as an error signal by comparing the phase modulation signal obtained from the Resol 370 rotor winding 10 and the phase modulation signal digitally created from the interpolation pulse. (The pulse width of the phase difference signal corresponds to the position 07M difference, but by giving this as a speed command to the servo motor 6 via the filter 4- and servo drive circuit 5, the phase difference signal The servo motor 6 is rotationally driven so that
The rotation of the servo motor 60 is stopped at this point when the phase difference becomes a waste.

Figure 2 shows the details of the resolver control circuit 3? show. The operation of this will be explained with reference to FIG. 12, a rectangular wave signal as a reference phase signal can be obtained as shown in FIG. The stator winding 8.9 is excited by a sinusoidal current having a phase difference of 90°.

FIG. 3 (el shows the sinusoidal current waveform with the leading phase. On the other hand, the reference clock pulse CLK is also provided to the reversible counter 14 as a digital phase modulator (DPM). Reversible The counter 14 receives an interpolation pulse +ΔX (increased pulse) from the interpolation control circuit 2.
3, the fT interpolation pulse -ΔX (reduced Hals) is directly input, and as a result, a digital phase modulation signal is obtained from the reversible counter 14 as shown in FIG. 12. In this case, the amount of phase shift is proportional to the number of input pulses, and the speed of phase shift is proportional to the density of input pulses.

The digital phase modulation signal obtained in this way is phase-compared with the signal from the rotor winding 10, but prior to the comparison, the signal from the rotor winding 10 is converted into a square wave. ing. The signal obtained from the rotor winding 10j is as shown in FIG. 3(e), and is converted into a rectangular wave as shown in FIG. After converting into
On the other hand, if the flip-flop 16 is reset by the rise of the rectangular wave obtained from the rectangular wave conversion circuit 17, a third pulse signal with a pulse width proportional to the positional deviation will be output from the output terminal of the flip-flop 160. This is obtained as shown in FIG. 1g+.

Therefore, if it passes through this pulse signal sound filter 4, the filter 4
From this, a DC signal is obtained at 5 in FIG.

The conventional numerical control device is as described above, but as can be seen from the above, since the position deviation is obtained in an analog manner, it is not only susceptible to drift etc., but also the position deviation is detected in the position command circuit. page

6 Difficult to grasp and manage current location 0
In addition, filters are difficult to configure because the pulse width of the input pulse signal changes greatly, and furthermore, the phase of the signal obtained from the resolver returns to its original phase after one rotation of the resolver. For some reason, there is a drawback in that it is not possible to determine from the phase difference whether the positional deviation is over one rotation or more. These drawbacks may be solved by obtaining the positional deviation as a digital quantity.The reality is that such a numerical control device has not yet been realized.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a numerical control device in which position deviations can be obtained as digital data.

For this purpose, the present invention obtains a phase difference signal by comparing the phases of the reference phase signal and the signal from the resolver rotor winding, and calculates the position deviation from the phase difference signal obtained in the same way immediately before. After determining the amount of change, this amount of change is converted into the number of pulses according to its magnitude and direction of deviation, and from this conversion, the digitized position deviation amount is obtained from the Jq pulse and the interpolation pulse. It is something.

The present invention will be explained below with reference to FIGS. 4 to 9.

First, FIG. 4 shows a schematic configuration of a numerical control device according to the present invention. As shown, the difference from the one shown in FIG. 1 is that the resolver control circuit 30 is replaced by a position error register and a
By exciting the position control circuit 18 consisting of an A converter and the stator windings 8 and 9 of the resolver 7, and processing the signal from the rotor winding 10 of the resolver 7, the change in position deviation is determined by its magnitude. A resolver signal conversion circuit 19 that outputs the number of pulses according to the direction of deviation is provided, and since the position control circuit 18 is provided, a filter is not required.

FIG. 5 shows details of the resolver signal conversion circuit 19. Of these, the counter 2, the sine wave conversion circuit 15, and the rectangular wave conversion circuit 17 operate in the same manner as in the case of FIG. 2, so no special explanation is required. The difference is that processing is also performed on the output of the flip-flop 16, which is set by the reference phase signal and reset by the rectangular wave pulse. The 190-times stepping operation of this resolver signal conversion circuit in the case of a decrease in deviation will be described below with reference to FIG.

That is, FIGS. 6(a), 6(b), and 6(e) respectively show the reference clock pulse CLK, the reference phase signal, and the rectangular wave pulse. When the reference phase signal and the rectangular wave pulse are as shown in the figure, the flip-flop It is clear that a phase difference signal can be obtained from the filter 16 as shown in FIG. 6(d). While this signal is being obtained, the reference clock pulse CLK is inputted by the counter n via the AND gate, and the rise of the signal sets the lip-flop 2 in FIG. By supplying the reference clock pulse CLK tt to the reversible counter through the gate, the contents of the reversible counter U are counted down. It is preset in advance,
Therefore, the counter n, the car in the reversible counter 9
~. The page runt value changes in a stepwise manner as shown in FIG. Later, the count state of the reversible counter 24 becomes zero, but at this point the reversible counter outputs a pulse indicating that the count state is zero, as shown in FIG. 6 (gl).

As a result, the flip-flop 21 is reset, and the AND gate which had been outputting the reference clock pulse CLK to the reversible counter n is closed, so that the clock output from the AND gate n becomes as shown in FIG. 6(r). Since the counting operation is stopped, the reversible counter operation stops the counting operation when the count state is zero.

It should be noted here that the output of flip-flop 2 indicates the immediately previous phase difference signal. Therefore, if the current phase difference signal obtained from the flip-flop 16 and the previous one are ORed by the exclusive OR gate 6, the phase difference change is calculated by the gate 5 as shown in FIG. 6 (ml). Furthermore, if this 10-page phase difference change is ANDed with the output of the flip-flop 2 and the reference clock pulse CLK using the AND gate I, a number proportional to the phase difference change is obtained from the AND gate (9). The reference clock pulse is obtained as shown in FIG. 6(n).

By the way, once the amount of change in the phase difference has been determined, it is necessary to transfer the count state of the counter n to the reversible counter U in order to deal with the next phase difference signal obtained from the flip-flop 16, and then reset the counter n. The output of the flip-flops 16 and 21 and the OR gate to which the pulse indicating that the count state is zero are input to the sixth output.
As shown in Figure (0), the one-shot circuits 27 to 29 connected in cascade are sequentially triggered by the fall of the output. One-shot circuit 27-
29, trigger outputs can be obtained sequentially as shown in Figure 6 (h3, (tl, (j)), but each trigger output can be used for resetting, data loading, and resetting. be.

The above is the case when the deviation decreases, but when the deviation increases, the AND gate 31 provides a number of reference clock pulses that are proportional to the partial voltage change in the position deviation. FIG. 7 shows the input/output waveforms of the main parts in that case. However, Fig. 7 (gl and (o) are respectively for anime)
20 and 31, and FIG. 7(at~(fl) is shown in FIG.
n) are shown in Figure 6 (h) to (nl), and furthermore,
Figure (p) corresponds to Figure 6 (01).

As mentioned above, pulses 10FB and -FB are obtained from 30 and 31 according to the magnitude of the change in position deviation and the direction of the deviation, but these pulses +FB
, -FB and the interpolation pulses +ΔX and -ΔX, the positional deviation amount can be detected. That is, the position error register 32, which constitutes a part of the position control circuit 18, is configured as a reversible counter, and inputs 10ΔX and -FB as up-count pulses, and inputs -ΔX and 10FB as down-count pulses. In this way, the count value becomes the positional deviation amount, and this digitalized positional deviation amount is D/A converted and then given to the servo drive circuit 5 as a speed command. The digitized position change amount is input into the position command circuit 1 as necessary, but by kneading, the position command circuit 1 knows how many revolutions the position deviation spans.

Although not directly related to the present invention, FIG. 8 shows an example of digitally detecting the number of rotations over which the positional deviation occurs and then controlling the reference value of the speed command voltage given to the servo drive circuit based on the detected value. It is.

The resolver control circuit in the figure functions in the same way as the one shown in Figure 2, and also generates a phase difference signal between the reference phase signal and the signal from the resolver rotor winding via the rectangular wave shaping circuit. It is designed to output the occurrence. The phase difference signal is processed by the resolver signal converter circuit A, which has some of the functions of the resolver signal converter circuit 19 shown in FIG. 5, to obtain a ±FB pulse. By inputting ±ΔX from the control circuit 2 to a rotation detection register key as a reversible counter, it is possible to know how many rotations the positional deviation is. For example, if one revolution of the resolver 3 corresponds to 2000 pulses, the count output will be 11N at 2000 pulses, and 12N at 4000 pulses.

Therefore, it is possible to know from the count output how many rotations of positional deviation exists. By the way, the speed command circuit has the function of receiving a pulse from the resolver control circuit and converting it into an analog quantity as in the conventional case. Therefore, it operates in the same way as a filter, but in the conversion to an analog quantity, there are no steps. An analog quantity generated by a pulse from the resolver control circuit is superimposed on the reference voltage which is made variable in the form of a reference voltage. What reference voltage is superimposed on depends on the count output of the rotation detection register.

When the speed command circuit controls the bias based on the count output, analog violet pulses are superimposed on the controlled reference voltage, and this is provided to the servo drive circuit 5 as a speed command.

FIGS. 9(a) to 9(6) show the input/output waveforms of each main part when the positional deviation ranges from one rotation to two rotations.

Of these, FIG. 9(at) and (b> are the outputs of the resolver control circuit, which are obtained from the flip-flop 16 in FIG. 2 and FIG. 5, respectively.

Moreover, FIG. 9 +el and (d) respectively show the outputs between the resolver signal conversion circuit and the rotation detection register.

If a rotation detection register is not provided, the analog quantity output from the speed command circuit at the start of the second rotation will be a sawtooth waveform as shown by the dotted line in Figure 9 (sl), but the rotation detection If a register is not provided, the output is shown as dl in Figure 9, but the analog quantity is
It changes as shown by the solid line in Figure fe).

As explained above, in the present invention, the positional deviation amount is obtained as a digital amount, and the stiffness is provided to the servo drive circuit via the D/A converter.

Therefore, the present invention has the effect of eliminating the conventional drawbacks.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a general configuration of a phase servo type numerical control device according to the prior art, Fig. 8g2 is a diagram showing a detailed example of a resolver control circuit in the configuration of Jikk on page 15, and Fig. 3 Figures (a) to (hl) are T
4 is a diagram showing the general configuration of the numerical control device according to the present invention, and FIG. 5 is a diagram showing details of the resolver signal conversion circuit and part of the position control circuit in the configuration. Figures 6 and 7 are input/output waveform diagrams of the main parts to explain the operation of the resolver signal conversion circuit.
The figure shows a schematic configuration of a numerical control device according to a combination of the prior art and a part of the present invention.
FIG. 4 is an input/output waveform diagram of main parts for explaining the operation. ,. 1...Position command circuit, 2...Interpolation control circuit, 5...
- Servo drive circuit, 6... Servo motor, 7... Resolver, 12... Reference phase signal generation color/reference, 16
... Phase difference detection, output free lag flop, 17 ... Rectangular wave conversion circuit, 318 ... Position control circuit, 19 ...
Resolver signal conversion circuit, 21... Free lag flop for detecting immediately preceding phase difference signal, 5... Exclusive OR gate for detecting position deviation change, 31゜ρ... AND gate for position deviation change pulse conversion . JP-A-58-51303 (5) Fig. 1 #12 Fig. 3 (h) Fig. 4 Fig. 316 (0)'" Fig. 7 (p) Fig. 398 Fig. 3g9 (C)" - [1-L1

Claims (1)

[Claims] In a phase servo type numerical control device that drives a servo motor via a servo drive circuit using a position command (Demosuku interpolation pulse and a signal from a resolver), the position of the reference phase signal and the signal from the resolver rotor winding is The phase difference change between the output of the flip-flop 70 that detects the phase difference and the phase difference signal outputted immediately before from the flip-flop is detected by a comparing means, and the phase difference change related to this detection is used as the position deviation change. The amount of positional deviation is detected by converting the pulses into a number of pulses according to the magnitude of the change and the direction of the deviation, and then manually applying a predetermined amount of force to a reversible counter using these pulses together with interpolation pulses as count pulses.
A numerical control device characterized by a configuration in which it is provided to a servo drive circuit via an A converter.