JPH0254110A - Position detector by resolver phase shifter - Google Patents

Abstract

PURPOSE:To detect a position with high accuracy without receiving the effect of the temp. drift of a phase shifter by changing a resolver exciting signal on the basis of a nearly sine wave/nearly cosine wave signal. CONSTITUTION:The output pulse of a resolver phase shifter 6 having the same timing as the output (h) of a rising differentiation circuit 3 is held to a sampling hold circuit 7 and sampling hold voltage is subsequently converted to a pulse train of frequency proportional to said hold voltage by a V/F converter 8. Subsequently, the pulse train is counted by an incremental/decremental counter 9 to be outputted as phase difference data. This phase difference data is converted to an analogue almost sine wave/almost cosine wave signal by a converter means for an almost sine wave (SIN function converter 10, D/A converter 12a) and a converter means for an almost cosine wave (COS function converter 11, D/A converter 12b) and, by changing a resolver exciting signal by said nearly sine wave/nearly cosine wave signal, the phase shifter 6 is controlled so that the output thereof is brought to zero. By this method, a position can be detected with high accuracy without being affected by the temp. drift of the phase shifter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a position detection device using a resolver phase shifter used for position detection of high-precision machine tools and the like.

[Prior Art] FIG. 3 is an overall block diagram showing a position detection device using a conventional resolver phase shifter. Further, FIG. 4 is a time chart of a position detection device using a conventional resolver phase shifter. Note that a to f in FIG. 4 above are the same as a in FIG. 3.
- This is the signal waveform at point f.

In the figure, (1) is an oscillator that generates a reference signal; (2) is an oscillator that generates a reference signal;
) is a frequency divider to lower the frequency of the output of the oscillator (1), and (13) is a frequency divider that converts the rectangular wave of the output of the frequency divider (2) into an approximately sine wave (
(14) is an integrator for creating a substantially cosine wave (COS) from the substantially sine wave; (5a)
, (5b) is an excitation circuit for sending a signal to the resolver phase shifter (6) based on a substantially sine wave or a substantially cosine wave, and (15) is a filter for removing noise from the output of the resolver phase shifter (6). , (16) is a comparator that converts the approximately sine wave output from filter (15) into a rectangular wave, and (17) is oscillator (1).
The frequency divider (2) and comparator (16
) is a phase difference counter that counts the phase difference between the outputs.

Next, the operation of a position detection device using a conventional resolver phase shifter configured as described above will be explained.

Using the output of the oscillator (1) as a reference, the frequency divider (2) creates a rectangular wave that serves as the reference for excitation of the resolver phase shifter (6) and the reference for phase difference counting.The frequency division ratio at this time is determined by the resolver The value shall be the same as the resolution (position detection unit) of the phase shifter (6).

By removing the harmonic components of the rectangular wave as shown in Fig. 4 (a) created by the frequency divider (2) with the filter (13), it becomes approximately sine wave as shown in Fig. 4 (b). Convert to wave. In this case, the formula representing the square wave is Ve = 4Vp/3 x [sinωt + (sin(
3ωt))/3+(sin(5ωt))15 + --
-], and since the third and subsequent harmonic components are removed by the filter (13), the output signal VS becomes VS = 4VI)/3X5in ωt. Here, Vp is the maximum voltage of the rectangular wave.

Since the resolver phase shifter (6) has a two-phase input, it is necessary to create a signal with each phase of approximately sine and approximately cosine. Convert to cosine wave. As a result of passing the approximately sine wave through the integrator (14),
The output is VC-4VI)XCO3ωt, and a substantially cosine wave as shown in FIG. 4(C) is obtained.

The approximately sine wave and approximately cosine wave obtained in this way are transferred to the excitation circuit (5
Power is amplified by a) and (5b), and the resolver phase shifter (6)
Excite (excite). The resolver phase shifter (6) changes each phase to a level corresponding to the rotation angle θ, synthesizes it, and outputs it, so that the phase is shifted by θ at a constant voltage.

The output VO of the resolver phase shifter (6) is calculated using the formula: vo = 4Vp/3X(S+n(1)tXCO3θ
+cos ωt xsin θ) 4Vp/3 xsin (ω is 10).

The output signal of the resolver phase shifter (6) obtained as described above has noise removed by the filter (15), and becomes a substantially sinusoidal wave as shown in FIG. 4(d).

Next, a comparator (16) used as a waveform shape converts it into a rectangular wave synchronized with the approximately sine wave (d) as shown in (e) in Figure 4, and a phase difference counter (17) converts it into a rectangular wave synchronized with the sine wave (d). ) is counted in units of output pulses of the oscillator (1).

The phase difference count data created in this way has the same value as the rotation angle (θ) of the resolver phase shifter (6), so it can be used as position detection data (f).

[Problems to be Solved by the Invention] Since the conventional position detection device using a resolver phase shifter is configured as described above, in order to increase the resolution, it is necessary to increase the frequency of the oscillator (1) or to reduce the excitation frequency. In addition, there was a possibility that the position of the detected phase shift would shift due to temperature drift of the resolver phase shifter (6).

Therefore, it is an object of the present invention to provide a position detection device using a resolver phase shifter that can increase the resolution without changing the frequency of the oscillator and is not affected by the temperature drift of the resolver phase shifter.

[Means for Solving the Problems] A position detection device using a resolver phase shifter according to the present invention includes a rising differentiation circuit that differentiates the rising portion of a reference pulse, and a two-phase analog a switching circuit that switches voltage;
The output of this switching circuit is amplified by power 2.
a resolver excitation circuit, a resolver phase shifter excited by the outputs of the two resolver excitation circuits, and a sampling hold circuit that samples and holds the output pulse voltage of the resolver phase shifter by the output of the rise differentiation circuit. , a V/[converter that converts the sampler hold output horn voltage of this sampling hold circuit into a pulse train of a specific frequency according to the voltage value, and this V/F
comprising a phase difference detection circuit that detects a phase difference by counting output pulses of the converter, a means for converting phase difference data from the phase difference detection circuit into a substantially sine wave, and a means for converting into a substantially cosine wave, Two-phase analog voltages, which are the outputs of the means for converting into a substantially sine wave and the means for converting into a substantially cosine wave, are supplied to the switching circuit.

[Operation] The phase difference data in the present invention is converted into an analog substantially sine wave/substantially cosine wave signal by a means for converting into a substantially sine wave and a means for converting into a substantially cosine wave. By changing the resolver excitation signal with the signal, the output of the resolver phase shifter is made zero.

[Example] The present invention will be described in detail below.

FIG. 1 is an overall block diagram showing a position detection device using a resolver phase shifter according to an embodiment of the present invention. Also,
FIG. 2 is a time chart of the position detection device using the resolver phase shifter of the embodiment shown in FIG.

In Figure 1, (1) is an excavator, (2) is a frequency divider, (
3) is a rising differential circuit that generates a pulse at the rising edge of the output of the frequency divider (2), and (4a) and (4b) are switching devices that output an analog voltage with the width of the output pulse of the rising differential circuit (3). Circuit, (5a>, (5b)
is an excitation circuit, (6) is a resolver phase shifter, (7) is a sampling hold circuit for sampling the output of the resolver phase shifter (6) to remove the high frequency valve, and (8) is a sampling hold circuit (7). (9) is an up/down counter (phase difference detection circuit) for counting the output pulses of the V/F converter (8), (10) is an up/down counter that outputs pulses proportional to the output voltage of A SIN function converter that converts the phase difference data from the counter (9) into a substantially sine function, (11) a CO8 function converter that converts the same phase difference data into a substantially cosine function, (12a>) a SIN function converter A D/A converter (12b) converts the data from the CO8 function converter (11) into an analog voltage.
It is an A converter.

Next, the operation of the position detection device using the resolver phase shifter of this embodiment configured as described above will be explained.

Similar to the conventional example above, the output of the excavator (1) is divided into the frequency divider (2).
). The frequency division ratio at this time is, regardless of the resolution,
The value shall be set to the rated frequency of the resolver phase shifter (6). Note that in this embodiment, the output of the frequency divider (2) is defined as a reference pulse. Next, the output of the frequency divider (2) is converted into a pulse as shown in l) in FIG. 2 by a rising differentiation circuit (3). Using such a pulse as a reference, the analog voltage is switched in the switching circuit (4a>, (4b), and the output is used as an input to drive the resolver excitation circuit (5a), (
5b) amplifies the power and excites the resolver phase shifter (6). At this time, since both phases of the resolver excitation circuit (5a>, (5b)) are based on the same pulse, the output of the resolver phase shifter (6) is a rising differential, as shown by (+) in Figure 2. The pulse output has the same timing as the output (h) of the circuit (3), and its level is the same as that of the D/A converter (12a).
, (12b) approximately sine wave and approximately cosine wave excitation input 2
It becomes a synthesis of phases.

According to this embodiment, the output from the resolver phase shifter (6) is zero when it is stopped, and during rotation, a voltage is generated in the positive or negative direction depending on the rotational direction of the resolver phase shifter (6). (i> in FIG. 2) is when the resolver phase shifter (6) changes from positive rotation to negative rotation.
J) shows the waveform of one pulse of the pulse train shown in (i> in FIG. 2) with the time axis enlarged.

The output pulse of the resolver phase shifter (6) obtained in this way is sent to the sampling and hold circuit (7) based on the output pulse of the rising differentiation circuit (3), which is the same as the excitation reference.
The waveform is sampled and held to form a continuous waveform as shown in (k) in FIG. 2, and when the rotational speed is constant (for example, when the rotational speed is zero), it becomes a direct current. Next, this sampling hold voltage is converted by a V/F converter (8) into a pulse train with a frequency proportional to the holding voltage. As a result, for a sampling and hold voltage such as (k> in FIG. 2), there are different positive and negative pulse trains such as (m) and (n> in FIG. 2).

The pulse train obtained above is processed by an up/down counter (
9) and output as phase difference data. This output data is output as a digital signal, but if you convert the change into a waveform, it will look like (0) and (p) in Figure 2, where (0) has the rotation direction reversed halfway. When, (p
) is a constant rotation, and one cycle thereof corresponds to 360 degrees of the rotation angle (θ) of the resolver phase shifter (6).

Separately from the phase difference data, the same digital signal is input to the SIN function converter (10) and the CO8 function converter (11) to convert it into approximately sine wave and approximately cosine wave data, which is then input to the D/A converter (12a). >, (12b) into an analog signal (analog voltage) to produce approximately sine wave and approximately cosine wave signals as shown in (q) and (r) of FIG.

Here, the above-mentioned SIN function converter (10) and D/A converter (12a) are collectively defined as means for converting into a substantially sine wave, and the above-mentioned CO8 function converter (11) and D/A converter (1
2b) and is defined as means for converting the waveform into a substantially cosine wave.

Such substantially sine wave and substantially cosine wave signals (analog voltage) are sent to switching circuits (4a) and (4b). Then, the pulse train is changed by the switching circuit to a pulse train having a peak value proportional to the wave height of the substantially sine wave and the substantially cosine wave at the timing of the output of the rising differentiation circuit (3), and is used as the reference for excitation of the resolver phase shifter (6). Become.

With the configuration shown below, a pulse train with a peak value proportional to the wave height of a substantially sine wave and a substantially cosine wave is transmitted to the resolver phase shifter (6).
The phase difference data obtained based on the output of the resolver phase shifter (6) is used to control the excitation voltage so that the output of the resolver phase shifter (6) is always zero. It can be summarized as follows.

If the detection angle of the resolver phase shifter (6) is (θ) and its output is Vo, then vo = ys x cos θ + yc x sin θ,
When one cycle of phase difference data is 360 degrees, and α is the difference between the phase difference angle (angle conversion value of phase difference data) and the detection angle θ of the resolver phase shifter (6), The excitation voltage (pulse voltage) VS and VC are as follows: ys = yp xsin (θ + α) VC - - VD Xcos (θ + α). However, Vp is the maximum voltage value of excitation.

From the above formula, Vo = Vp xsin(θ −) − α )XCO
3θ−yp xsinθxcos(θ+α〉=yp x
sin α, and it can be seen that the output of the resolver phase shifter (6) changes depending on the angle difference α.

As described above, in this embodiment, while stopped, the angle conversion value of the phase difference data and the detected angle of the resolver phase shifter (6) are the same, and while rotating, the angle changes in proportion to the rotation speed. Since the difference becomes large and the excitation is controlled to reduce the difference to zero, the phase difference data obtained as a result can be used as position detection data.

In addition, in the above embodiment, a resolver phase shifter was used, but
A similar effect can be obtained even if the detector is an inductosyn.

[Effects of the Invention] As described above, according to the position detection device using the resolver phase shifter of the present invention, the means for converting the phase difference data of the resolver phase shifter into a substantially sine wave and the means for converting it into a substantially cosine wave are provided. , the output of the resolver phase shifter is controlled to zero by converting it into an analog approximately sine wave/approximately cosine wave signal, and changing the resolver excitation signal using this approximately sine wave/approximately cosine wave signal. Since it is configured to convert into a pulse with a wave height proportional to a substantially sine wave/substantially cosine wave signal using a means for converting into a substantially sine wave and a means for converting into a substantially cosine wave based on the phase difference data, the resolution is By simply changing the pulse repetition period and increasing the counter, there is no need to change the approximately sine wave and approximately cosine wave frequencies input and output to the resolver phase shifter, and there is no change in phase between input and output. This has the advantage of being able to perform highly accurate detection without being affected by temperature drift.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram showing a position detection device using a resolver phase shifter according to an embodiment of the present invention, and FIG. 2 is a time chart of the position detection device using a resolver phase shifter according to the embodiment of FIG. , FIG. 3 is a block diagram showing a conventional position detection device using a resolver phase shifter, and FIG. 4 is a time chart of the position detection device shown in FIG. 3. In the figure, 1: Oscillator, 2: Frequency divider, 3: Rising differential circuit, 4a, 4b Niswitching circuit, 5a, 5b: Excitation circuit, 6: Resolver phase shifter, 7: Sampling hold circuit, 8: V/F Converter, 9 near sub down counter, 10: SIN function converter, 11: CO3 function converter, 12a, 12b: D/A converter, In addition, in the figure, the same symbol and the same symbol indicate the same or equivalent part. It's something. Agent: Patent attorney, Daikan Masuo, and 2 others n --- Figure 4 Procedural amendment (voluntary)

Claims (1)

[Claims] a rising differentiation circuit that differentiates the rising portion of the reference pulse; a switching circuit that switches two-phase analog voltages using the output of the rising differentiation circuit; and two resolver excitation circuits that amplify the power of the outputs of the switching circuits. A resolver phase shifter excited by the outputs of these two resolver excitation circuits, a sampling hold circuit that samples and holds the output pulse voltage of this resolver phase shifter by the output of the rising differentiation circuit, and a sampling hold circuit of this sampling hold circuit. A V/F converter that converts the hold output voltage into a pulse train of a specific frequency according to the voltage value, a phase difference detection circuit that detects the phase difference by counting the output pulses of this V/F converter, and this phase difference. It is equipped with means for converting the phase difference data from the detection circuit into a substantially sine wave and a means for converting it into a substantially cosine wave, and the output of the means for converting into a substantially sine wave and the means for converting into a substantially cosine wave is two-phase. A position detection device using a resolver phase shifter, characterized in that an analog voltage of 1 is supplied to the switching circuit.