JPH05322598A - Position detecting apparatus - Google Patents

Abstract

PURPOSE:To detect the position, which is synchronized with a position requesting signal by generating an AC exciting signal, which is synchronized with the position requesting signal at the period, which is 1/N of the measuring period measured with a period measuring means, with an exciting means. CONSTITUTION:Clocks f0, which are generated in an oscillator 10, are counted in a period measuring circuit 11. A period Tsq of a position requesting signal SQ is operated. The ratio (N:1) between a measuring period and an exciting period is operated in a frequency setting circuit 12. A frequency setting value M is operated and sent into a variable oscillator 13. Meanwhile, the clocks f0 are counted in the variable oscillator 13, and an exciting clock fx is generated and counted in a magnetic-voltage generating circuit 15. When a position requesting signal SQ from the outside is inputted, a phase setting value PHI, which is set with a phase setting circuit 7, is loaded. When the primary coil of a resolver 16 is excited by an AC exciting signal Vex, which has the period of Tsq/N and is synchronized with the position requesting signal SQ, detected AC signals Vs and Vc, which have undergone the amplitude modulation with the sine value and the cosine value of a deviated angle, are outputted from the secondary winding and amplified in amplifiers 17s and 17c. The results are sent out as sine signal Ds and the cosine signal Dc from A/D converter 19s and 19c. The rotary angle theta is computed in an interpolation circuit 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device used in a control device for synchronously controlling a plurality of axes of a machine tool or the like.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing an example of a conventional position detecting device, FIG. 7 is a block diagram showing a detailed example of an exciting voltage generating circuit 8 which is a main part thereof, and FIG. It is a chart. The clock f1 generated by the oscillator 6 is counted by the counter circuit 81 of the excitation voltage generation circuit 8, and the count value is stored in the ROM 82 and the decoding circuit 85.
Sent to. A sine table is stored in advance in the ROM 82, and the data of the address of the ROM 82 corresponding to the count value from the counter circuit 81 is converted into an analog value by the D / A converter 83, amplified by the amplifier 84, and amplified by the AC excitation signal Vex. Is transmitted to the resolver 16. Further, the phase setting value PHI set by the phase setting circuit 7 is sent to the decoding circuit 85 of the excitation voltage generating circuit 8, and when the phase setting value PHI and the count value from the counter circuit 81 match, the excitation synchronization signal. EXT is sent to the timing synchronization circuit 9. When the periodic position request signal SQ from the outside is input to the timing synchronization circuit 9, the hold signal SH immediately after that is synchronized with the excitation synchronization signal EXT to the S / H (sample and hold) circuits 18s and 18c. Sent out.

On the other hand, when the primary side coil of the resolver 16 is excited by the alternating current excitation signal Vex from the excitation voltage generating circuit 8, the alternating current amplitude-modulated into a sine value and a cosine value of the deviation angle θ from the reference position. The detection signals Vs and Vc are output from both ends of the two secondary windings, amplified by the amplifiers 17s and 17c, and sent to the S / H circuits 18s and 18c. The alternating-current detection signals Vs and Vc are held in the S / H circuits 18s and 18c at the timing of the hold signal SH, digitized by the A / D converters 19s and 19c, and output to the interpolation circuit 20 as sine signal Ds and cosine signal Dc. Sent out. Then, in the interpolation circuit 20, the rotation angle θ of the rotor is calculated and output by the calculation of Expressions 1 to 8 using the sine signal Ds and the cosine signal Dc.

[0004]

[Equation 1]

[Equation 2]

[Equation 3]

[Equation 4]

[Equation 5]

[Equation 6]

[Equation 7]

[Equation 8]

[0005]

A position detecting device used in a control device or the like for synchronously controlling a plurality of axes of a machine tool or the like has the same time for detecting the position of each axis, and detects the position. It is necessary that the intervals of time to do are constant. However, in the conventional position detecting device, the time when the position request signal is input and the time when the position is actually detected are t1 and t in FIG.
There is a problem that the control cannot be performed smoothly because the variation occurs as indicated by 2 and t3. The present invention has been made under the circumstances described above, and an object of the present invention is to provide a position detection device capable of detecting a position in synchronization with a position request signal.

[0006]

According to the present invention, by inputting an alternating current excitation signal, an alternating current detection signal amplitude-modulated according to a measurement position is output with respect to the alternating current excitation signal, and the alternating current detection signal is digitally output. The present invention relates to a position detection device that converts a value into a value and interpolates the digital value to calculate a measurement position, and the above object of the present invention is to measure a period of a periodic position request signal from the outside. Means and
This is achieved by including an excitation unit that generates the AC excitation signal in synchronization with the position request signal at a period of 1 / N (N is an integer) of the measurement period measured by the period measurement unit.

[0007]

In the present invention, the cycle of the position request signal is measured by the cycle measuring means, and the exciting means adjusts the cycle of the AC exciting signal to 1 / N of the measuring cycle. Since the synchronized AC excitation signal is generated, the position synchronized with the position request signal can be detected.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an example of the position detecting device of the present invention in correspondence with FIG. 6, and the same components are designated by the same reference numerals. 2 is a block diagram showing a detailed example of the period measuring circuit 11 which is the main part, FIG. 3 is a block diagram showing a detailed example of the variable oscillator 13, and FIG. 4 is a detailed example of the exciting voltage generating circuit 15. A block diagram and FIG. 5 are time charts of signals in the device of the present invention. The clock f0 generated by the oscillator 10 is counted by the counter circuit 111 of the cycle measuring circuit 11, and the count value is sent to the latch circuit 112. Here, the counter circuit 111 is a timer having a period longer than the input interval of the periodic position request signal SQ from the outside. When the periodic position request signal SQ from the outside is input to the latch circuit 112, the count value N2 at that moment is held. Further, when the periodic position request signal SQ from the outside is input to the latch circuit 113, the count value N1 held in the latch circuit 112 at that moment is held. Therefore, the count value N1 is equal to the count value N2.
Is the time when the position request signal SQ, which is one before the position request signal SQ at the time of holding, is input. Then, the count values N1 and N2 are sent to the subtraction circuit 114, the cycle Tsq of the position request signal SQ is calculated by the equation 9, and the frequency setting circuit 1 is calculated.
2 is sent. The number of bits of the counter circuit 111 is n.

[0009]

[Equation 9] Position request signal SQ sent to the frequency setting circuit 12
The ratio (N: 1) between the measurement period and the excitation period is calculated in accordance with the cycle Tsq of Eq. (10), and the frequency setting value M is then calculated in Eq. 11 and sent to the variable oscillator 13.

[Equation 10] However, Tex is a target excitation cycle with the cycle of the oscillator 10 as a basic unit. INT (X) is a function meaning that it takes an integer of X.

[Equation 11] However, k is the counter circuit 151 of the excitation voltage generation circuit 15.
Is the number of bits of the counter used for. m is the number of bits of the counter used in the counter circuit 131 of the variable oscillator 13.

On the other hand, the clock f0 generated by the oscillator 10
Is counted by the counter circuit 131 of the variable oscillator 13,
The carry fx is generated at the next clock f0 when the count value becomes 2 ^k −1. Then, the carry fx is used as the excitation generation clock and also as the load signal of the frequency setting value M. The loaded frequency set value M is used as an initial value for counting, and a desired excitation generation clock fx is generated by repeating the above-described operation and is sent to the excitation voltage generation circuit 15. The excitation generation clock fx is counted by the counter circuit 151 of the excitation voltage generation circuit 15,
When a periodic position request signal SQ from the outside is input to the excitation voltage generation circuit 15, the phase setting value PHI set by the phase setting circuit 7 is loaded. The loaded phase setting value PHI is used as the initial value of counting, and the above-described operation is repeated.

A sign table is stored in advance in the ROM 82, and the address data of the ROM 82 corresponding to the count value from the k-bit counter circuit 151 is converted into an analog value by the D / A converter 83 and amplified by the amplifier 84. Then, it is sent to the resolver 16 as an AC excitation signal Vex having a cycle of Tsq / N and synchronized with the position request signal SQ. When the primary side coil of the resolver 16 is excited by the AC excitation signal Vex, the sine value of the deviation angle θ from the reference position,
The AC detection signals Vs and Vc amplitude-modulated to the cosine value are output from both ends of the two secondary windings, and the amplifiers 17s and 17s are connected.
It is amplified by c and sent to the S / H circuits 18s and 18c. The AC detection signals Vs and Vc are held in the S / H circuits 18s and 18c at the timing of the position request signal SQ, and A
The sine signal Ds which is digitized by the / D converters 19s and 19c
And a cosine signal Dc are sent to the interpolation circuit 20. Then, in the interpolation circuit 20, the sine signal Ds and the cosine signal Dc
The rotation angle θ of the rotor is calculated and output by the calculation of Expressions 1 to 8 using

[0012]

As described above, according to the position detecting device of the present invention, the position can be detected from the detector such as the resolver in synchronization with the external periodic position request signal.
When used in a control device for controlling a plurality of axes in a machine tool or the like in synchronization with each other, smooth control can be performed. Also, while the cycle of the AC excitation signal is the cycle of the position request signal, the quotient obtained by dividing the cycle of the position request signal by the target excitation cycle is repeated as an integer, so that the AC of the detector such as the resolver is repeated. It can be synchronized with the position request signal without changing the frequency of the excitation signal so that there is no adverse effect due to the frequency characteristics of the detector or the circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a position detection device of the present invention.

FIG. 2 is a block diagram showing a detailed example of a cycle measuring circuit of the device of the present invention.

FIG. 3 is a block diagram showing a detailed example of a variable oscillator of the device of the present invention.

FIG. 4 is a block diagram showing a detailed example of an exciting voltage generating circuit of the device of the present invention.

FIG. 5 is a time chart of signals in the device of the present invention.

FIG. 6 is a block diagram showing an example of a conventional position detecting device.

FIG. 7 is a block diagram showing a detailed example of an excitation voltage generation circuit of a conventional device.

FIG. 8 is a time chart of signals in a conventional device.

[Explanation of symbols]

 10 Oscillator 11 Period Measurement Circuit 12 Frequency Setting Circuit 13 Variable Oscillator 15 Excitation Voltage Generation Circuit

Claims (2)

[Claims] 1. By inputting an AC excitation signal, an AC detection signal amplitude-modulated according to the measurement position is output with respect to the AC excitation signal, the AC detection signal is converted into a digital value, and the digital value is output. In a position detecting device for calculating a measurement position by interpolating with, a cycle measuring means for measuring the cycle of a periodic position request signal from the outside, and 1 / N of the measurement cycle measured by the cycle measuring means.
A position detecting device, comprising: an exciting unit that generates the AC exciting signal in synchronization with the position request signal at a cycle of (N is an integer). 2. The position detecting device according to claim 1, wherein the integer N is a number obtained by dividing a quotient obtained by dividing the measurement cycle by a preset target excitation cycle into an integer.