JPS62291515A - Inductosyn - Google Patents

Abstract

PURPOSE:To enable miniaturization of an exciting circuit without phase adjustment, by wave-form processing in a digital manner a phase difference of sine- and cosine-waves of an output wave form and making the excitation in a pulse form. CONSTITUTION:Rising and trailing of a reference rectangular wave generator 1 are converted into each pulse with rising pulse circuit 2 and trailing pulse circuit 3. And exciting amplifiers 4a, 4b convert them into triangle form pulses repectively for introducing them to a slider 5. Then an output which came out from a scale 6 by a change of its electroinductive voltage is subjected to sampling sample-holds 7a, 7b for sine- and cosine moves. Further, these are switched by switching circuits 8a, 8b for sine- and cosine waves of rectangular waves and analog calculations are made by an order 9 respectively. A signal from this adder is formed into the reference wave only by a filter 10 and converted into a rectangular wave by a comparator 11 and becomes a feedback output 12.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an inductosyn, which is frequently used as a detector for an NC servo mechanism of a machine tool.

[Conventional technology]

Figure 3 shows 7'1) using the conventional Inductosin. Is the explanatory diagram of the NC servo mechanism, Figure 4, the conventional position detection method using feedback? In the block diagram shown in the figure, 1 is a reference rectangular wave generator that serves as a reference for the position detection output (which serves as an excitation reference wave for the slider 5), and 21 is a reference rectangular wave generator 1.
22 is an integrator for creating a cosine wave (cos wave) from the sine wave (dlI wave), 4a+4b is an integrator that amplifies the sine wave and cosine wave and inputs the sine wave. Excitation circuit for exciting ductsin, 5
is an inductosin slider, 6 is a scale, 10 is a filter for converting the output of the scale 6 into only a sine wave, 1) is a comparator that converts the sine wave output from the filter 10 into a rectangular wave, A feedback system 12 feeds back the rectangular wave output of the comparator 1) as a position feedback signal to the amplification control section of the NC servo. (Here, we will briefly discuss the operating principle of Inductosin.

Structurally, the secondary winding (scale) corresponds to the primary winding (scale).
A slider) is provided, and the position is detected by extracting changes in the induced voltage of the slider.

That is, two conductor scales and a slider are placed in parallel opposition to each other with a small gap in between, and when alternating current is excited in one, a voltage is induced in the other due to electromagnetic induction. Since the magnitude of this induced voltage changes depending on the degree of electromagnetic coupling between the scale and the slider, that is, the relative movement position of the slider, it is used as a position detector that requires high accuracy. ) Next, the operation will be explained. First, the output waveform of the reference rectangular wave generator 1 shown in FIG. A current is passed through the pattern (Figure 5 (a)). Further, the output of the reference filter 21 is changed by the integrator 22 into a cosine wave whose phase is shifted by 90 degrees from the sine wave of the excitation circuit 4a, and the output is used as an input to apply the other pattern of the slider 5 to the excitation circuit 4b. 5. Apply the current shown in Figure 5. Therefore, the input signal waveforms input to the slider 5 are as shown in (A) and (T) in Fig. 5.
The waveform will be Then, as the slider 5 is excited, a voltage is output from the inductosin scale 6, which is converted into a sine wave as shown in Fig. 5 (3) through a filter 10, and then by a comparator 1). Shape the waveform into a square wave. The phase difference of the rectangular wave (FIG. 5 (4)) with respect to the reference rectangular wave generator 1 changes in proportion to the change in the position of the slider 5 with respect to the inductosyn scale 6. It can be output as a signal.

The phase difference between the output waveform of the feedback system 12 and the reference rectangular wave generator 1 with respect to the relative position of the slider 5 and scale 6 of the inductosin is determined by the input voltage of the slider 5 (
sine wave) maximum value eVs, maximum value of other cosine waves vc,
If the ratio of the input and output voltages of the inductosyn is G (input/output), the phase difference is θ, and the pitch of one pattern of the inductosyn is 2eπ (rad), then the machine position is ψ, then the scale 6 The output voltage VO of is expressed by the fi1 formula.

Vo=(vsφSTNωt−cosψ+Vc−cO8ω
t-8 engineering Nψ)×G... (1) Here, if Vc=Vs, Vo=VsxGXSIN(ωt+ψ) -...12
+(From Equation 21, the phase difference θ with the reference sine wave Vs-8Nωt is θ=ψ, which is the same position as the inductosin.

[Problem that the invention seeks to solve]

Since the conventional inductosin is constructed as described above, 1. For example, when generating and exciting a 5V sine wave signal from a ±12V (DC) power supply, the voltage is dropped in the excitation circuits 4a and 4b to generate a sine wave. Because of this, a large amount of heat is generated in the excitation circuit. At the same time, the output circuit also has a large capacity. Also, the phase difference is 90°
In order to make the sine wave and cosine wave of
There were problems such as having to adjust 0 at the same time.

This invention was made to solve the above-mentioned problems.In order to increase the output voltage of the inductosin, it is possible to completely suppress and adjust the input voltage and current. The purpose is to obtain inductosin by making it possible with only voltage.

[Means for solving problems]

The inductosin according to the present invention converts the waveform of the excitation wave into a triangular pulse and inputs it, while dividing the output of the inductosin into two phases, a sine wave and a cosine wave, and adding them in an adder. The output of the adder is used as a feedback signal.

[Effect]

In this invention, the inductosin output generated by triangular wave pulse excitation is divided into a sine phase rectangular wave and a cosine phase rectangular wave by a sample, and hold, and switching circuit, and added by an adder, and the added output is It is fed back to the feedback system via a filter.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In the figure, parts that are the same as those in Figure 4 are designated by the same symbols fc
In FIG. 1, 2 is a rising pulse circuit that converts the rising edge of the reference square wave generator 10 into a pulse, and 3 is a falling pulse circuit 7 that converts the falling edge of the reference square wave generator 1 into a pulse.
a+7b are (first and second) sample holds for sampling the output of the inductosin, γa is for a sine wave, and 7b is for a cosine wave. Above 8. a and sb are switching circuits that switch the outputs of sample holds 7a and 7b to convert them into rectangular waves; 8a is for sine waves;
8b is for cosine waves. Further, 9 is an adder for analog addition of the outputs of the switching circuits 8a and 8b, 13 is a rising divider for creating a sine wave phase from the reference rectangular wave, and 14 is a falling divider for creating a cosine wave phase. It is a peripheral organ.

Next, the operation will be explained. First, the output waveform of the reference square wave generator 1 shown in FIG. 2A is converted to the rising and falling pulse circuit 2.
3 into a pulse as shown in FIG. 2B. Next, the pulse waveform is input to the excitation amplifier 4a.
, 4b causes a current of +1) and +21 in FIG. 2 to flow to excite the inductosin slider 5. Since inductosin has only a resistance component and almost no reactance component,
Slider 5 has C□.

A current like C2 and a voltage with the same waveform are applied. Since there is a differential characteristic between the output of the inductor, the output waveform shown in the second diagram is generated at the output of the scale 6. In this output signal, every other pulse has a sine wave phase and a cosine wave phase, so the sine wave and cosine wave are sampled and held at 7.
Rising and falling pulse circuit 2.3 by a, 7b
Output pulse B1. When sampling at B2, when the inductosyn slider 5 moves at one foot speed, Fig. 2 +
1. A sine wave or cosine wave with a frequency proportional to the speed of the slider 5, such as E2, is obtained. However, as it is, it cannot be added by the blade calculator 9, so the switching circuits 8a, s
At b, switching is performed at half the frequency of the output waveform of the reference rectangular wave generator 1. The output of this poetry up frequency divider 13 is switched to a sine wave phase, and the down frequency divider 1
The one switched by the output of 4 is considered to be the cosine wave phase.

The signals switched by the switching circuits Qa and 8b are rectangular waves like F2 and F2 in FIG. 2, and the voltage of the waveform changes like a sine wave E and B2 in FIG. 2. (F1 in FIG. 2) In F2, the time axis is extended with respect to El and B2 in order to make the waveform easier to see. ) Thereafter, the outputs of the switching circuits 8a and sb are synthesized in an analog manner by an adder 9, and passed through the filter 10 to form a fundamental sine wave, which is the same signal as the inductosin output waveform of the conventional example. In other words, a rectangular wave has more than three times the harmonics added to the fundamental sine wave, and if it is filtered to only the fundamental wave, the output voltage of scale 6 is V.
O is expressed by the formula (3) +41.

Vo=VsX(SINLJJt・CO8ψ+cosωt
-S INψ)xG...13+ Vo=VsXGXSIN(ωt+9')
・−・・−・+41 again. The output signal sampled by the sample holds 7a and 7b of the inductosyn scale 6 is as follows.

Vos=VsXSIN95XG −
------(51Voc=VcXSIN91XG
・Old: +61. In addition, V
O8 is the output of sample hold 7aO, and VOc is the output of sample hold 7b. and.

When the switching circuits 8a and 8b switch,
The fundamental wave components are expressed by equations (7) and (8).

V o 5=VsXs lN9)XCO8ωtXG
・・=-(71V oc=VcXcO89)X
SINQItXG ---・-・f81 here.

If Vo=Vos+Voc Vc=Vs, the output voltage vO of school 6 is Vo=VsXS
lN9)XCO8GJtXG+VsXCO895XS
INωtXG=VsXGX(SIN9)XCO8ωt
+CO8ψX5INωt)=VsXGXSIN(Q'
t+? ) ==...(9+)

The signal added by the adder 9 is converted into only the fundamental wave by the filter 10, and converted into a rectangular wave by the comparator 1), which becomes the feedback 12.

Although adjustment of the voltage waveform is necessary here, the phase difference (90) between the sine wave and the cosine wave is obtained by digitally dividing the reference square wave generator 1.

It becomes unnecessary.

In the above embodiment, an inductor was used as a detector, but a resolver phase shifter may also be used, and the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the phase difference between the sine wave and the cosine wave, which are the output waveforms of the inductosin, is digitally processed using a sample hold, a switching circuit, an adder, etc., and error intervention is performed using analog signal processing. The circuit is constructed in such a way as to reduce the margin of error, eliminating the need for one-phase adjustment, and since the excitation is pulsed, the excitation power is reduced and the excitation circuit can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an inductosin circuit configuration according to an embodiment of the present invention, FIG. 2 is a time chart showing the main waveforms of FIG. 1, and FIG. 3 is a conventional inductosin N
An explanatory diagram of the C servo mechanism, Fig. 4 is a block diagram showing the conventional inductosyn feedback system, and Fig.
3 is a time chart showing main waveforms in the figure. In the figure, 1 is a reference square wave generator, 2 and 3 are rising edges,
Falling pulse circuit, 4a and 4b are excitation up, 5 is slider %, 6 is scale, 7a and 7b are sample hold, 13a and 8b are switching circuits, 9 is adder, 1
3.14 is a rising and falling frequency divider. Patent applicant Mitsubishi Electric Co., Ltd. agent Patent attorney 1) Hiroshi Sawa (other 2)
name)-' Fig. 2 81・82-bit]-1- C1・C2-1/'\-1

Claims (3)

[Claims] (1) In an inductosyn that extracts changes in the induced voltage of a slider corresponding to the scale and performs position detection based on the phase difference between their rectangular wave outputs, the input waveform to the slider of the inductosyn is converted into two sets of triangular wave pulses. an excitation amplifier for converting, a sample hold for extracting two sets of feedback output signals from the output signal of the scale and sampling the feedback outputs, a switching circuit for switching the output of the sample and hold, and each of the signals switched by the switching circuit. An induct sin, comprising: an adding circuit for adding output waveforms, and extracting a set of phase modulated output signals. (2) Set the sample hold to 2 for sine wave and cosine wave.
Claim 1, characterized in that the sampling time of the sample and hold is determined by the output signals of the rising and falling pulse circuits of the reference square wave generator output, which are the input signals of the excitation amplifier. Inductosin as described in section. (3) The switching circuit is divided into two types for sine waves and cosine waves.
The patent is characterized in that the switching time of the switching circuit is determined by the output signals of the rising and falling periods of the output of the reference square wave generator, which are the input signals of the rising and falling pulse circuits. Inductosin according to claim 1.