JPS6211113A - Position detector - Google Patents

Abstract

PURPOSE:To enable high-accuracy position detection with simple construction, by reading out a corrected value corresponding to a phase difference connected value between magnetic excitement signal phase difference of resolver and output signal phase difference from a storing apparatus which stored electric error correction values. CONSTITUTION:One of the phases of a magnetic excitation signal among a resolver ones is supplied to an LPF 10 for smoothening and smoothening of wave shape if conducted by supplying on output signal of the resolver to a LPF 16. Outputs is LPFs 10, 16 are converted to square-wave signals by zero- cross comparators 12, 18 respectively and clock signals during the period where they follow the phase difference after they wave supplied to a counting action controlling circuit 14 are counted. On the other hand, correction data of a position decting error due to electric error relative to the counted value of a circuit 20 are stored in a corrected table staring circuit 22 and the detected value corrected on the basis of the output of th circuit 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position detection device, and more particularly to a position detection device configured to correct errors inherent in each resolver to obtain an accurate position detection signal.

In a position detection device using a resolver, the position, that is, the rotation angle of the rotor of the resolver is detected by detecting the phase difference between the excitation signal of the resolver and the output signal from the resolver. However, with a position detection device using this type of resolver, it is difficult to imagine that the detected position is always accurate. That is, it generally includes a position detection error, and this detection error is caused by variations in resolver manufacturing, variations in excitation signals, and the like. Note that detection errors due to variations in resolver manufacturing, variations in excitation signals, etc. are called electrical i differences.

Therefore, in a position detection device using a resolver that includes an electrical error, the position detection error takes a unique value depending on the combination of the detection means for detecting a phase difference and each component when the resolver is configured. In fact, the position detection error has a period of one revolution of the resolver rotor shaft, and the error appears every time the resolver rotor shaft makes one revolution. Normally, the position detection error using a resolver is ±5' in terms of the resolver rotor axis.
~10', and this poses the problem of not being able to accurately detect the position.

The present invention has been made in order to overcome the above-mentioned disadvantages, and provides a position detection device using a resolver that has an hour wheel configuration and is capable of detecting a position with the same accuracy as a position detection accuracy measuring device. With the goal.

According to the invention, this purpose is to count the phase difference between the excitation signal phase and the output signal phase of the resolver using a counter. On the other hand, by providing a storage device storing data related to the corrected detection value, reading out the memory contents of the memory address corresponding to the count value of the counter, and obtaining the corrected detection value from the read memory contents. achieved.

That is, the present invention provides a position detection device that detects the rotation angle of the resolver rotor shaft by counting the phase difference between the phase of one of the excitation signals of the resolver and the phase of the output signal of the resolver, and the position detection device detects the rotation angle of the resolver rotor shaft. a storage device that stores data related to position detection values for correcting the phase difference, reads out storage contents corresponding to the counted value of the phase difference from the storage device, and calculates the position corrected from the read storage contents. It is characterized by obtaining a detected value.

Next, preferred embodiments of the position detection device according to the present invention will be described in detail with reference to the accompanying drawings.

First, in FIG. 1, reference numeral 10 indicates a low-pass filter for excitation signals of a resolver, and the output side of this low-pass filter 10 is connected to a first zero-cross comparator 12. The output side of the zero cross comparator 12 is connected to the counting operation control circuit 14. On the other hand, the output side of the output signal low-pass filter 16 is connected to a second zero-cross comparator 18, and the output side of the second zero-cross comparator 18 is connected to the counting operation control circuit 14. Next, the output side of the counting operation control circuit 14 is connected to a phase difference counting counter circuit 20, and this phase difference counting counter circuit 20 is connected to a correction table storage circuit 22.

In the above configuration, one of the excitation signals of the resolver
The phase excitation signal is supplied to a low-pass filter 10 for smoothing, and the output signal of the resolver is supplied to a low-pass filter 16 for smoothing its waveform. The output from low pass filter 10 is provided to zero cross comparator 12 for conversion to a square wave signal, and the output from low pass filter 16 is provided to zero cross comparator 18 for conversion to a square wave signal. The output signals from the zero cross comparators 12 and 18 are supplied to the counting operation control circuit 14, which outputs a signal with a period according to the phase difference between the re-inputs, and the output of the counting operation control circuit 14 and the clock signal are sent to the phase difference counting counter. The clock signal is supplied to the circuit 20 to count the period of the signal of the counting operation control circuit 14.

On the other hand, the correction table storage circuit 22 stores, for example, corrected position data obtained by correcting position detection errors due to electrical errors with respect to the count value of the counter circuit 20. Therefore,
The corrected detection value for the count value by the counter circuit 20 is
For example, if it is as shown in FIG. 2, the correction table storage circuit 22 stores correction position data for the count values shown in Table 1.

Table 1 Therefore, the counter circuit 20 is connected to the correction table storage circuit 22.
The data stored in the correction table storage circuit 22 is read out using the count value of the counter circuit 20, and is output as a corrected detection value.

In one embodiment of the present invention configured as described above, the waveform of one phase in the excitation signal of the resolver is, for example, as shown in FIG.
As shown in a), it is a waveform in which a minute vibration is superimposed on Es1nωt, and the output signal waveform of the resolver is a waveform in which a minute signal is superimposed on Es1n (ω is 10θ) as shown in Figure 3 (b). be. This re-input signal is passed through the low-pass filter 10.
and 16, the low-pass filter 10
The outputs of and 16 are Es1rllt and Es1n(ωt+θ), respectively, as shown in FIG. 3 (C1 and (d+). Here, θ obviously corresponds to the rotation angle of the resolver rotor .

The output signals of the low-pass filters 10 and 16 are shaped into square waveforms by zero-cross comparators 12 and 18 as shown in FIGS. 3(e) and 3(f).

On the other hand, the clock pulse signal is output as shown in FIG. 3 (gl), and the counting operation control circuit 14 receiving the square waves shown in FIGS. 3(e) and 3(f) compares the phases of both waveforms. , and outputs a signal of a period according to the phase difference as shown in FIG. 3 (g3) corresponding to the phase difference.

Furthermore, in the counter circuit 20 which receives the signal from the counting operation control circuit 14 and the clock pulse signal, the clock pulse signal during the signal generation period from the counting operation control circuit 14 shown in FIG. 3 (hl) is counted. (See Figure 3(i)).

Next, the correction table storage circuit 22 is addressed by the count value counted by the counter circuit 20, and the correction position data corresponding to the count value of the counter circuit 20 is read out. Position data without errors will be obtained.

Next, generation of data stored in the correction table storage circuit 22,
Explain memory.

The one-phase symbol and output signal in the excitation signal of the resolver A for position detection are supplied to the low-pass filter 10.16 in the present invention (7)-actual example shown in FIG. is supplied to the correction table storage circuit 22 as address data.

Reference number B in this case indicates a low-pass filter 10.16, a zero-cross comparator 1 in an embodiment of the invention.
2.18, Counting operation control circuit 14 and counter circuit 2
It shows a part consisting of 0. On the other hand, reference symbol C indicates a precision angle indexing table directly connected to the rotor shaft of the resolver A, and the rotation angle signal of the angle indexing table C is supplied to an indexing table position detection device and converted into digital data. , and is configured to be supplied to the correction table storage circuit 22 and written therein.

Therefore, the angle indexing table C is rotated at a very low speed, and the output from the indexing table position detection device is sent to the counter circuit 20.
is stored at the address of the correction data table storage circuit 22 indicated by the count value.

As described above, the correction position data is stored in the correction table storage circuit 22 as shown in Table 2.

Table 2 Next, another embodiment of the present invention is shown in FIG.

In the other embodiment of the present invention shown in FIG. 5, the same components as in the embodiment of the present invention shown in FIG. Further explanation will be omitted.

Therefore, in this embodiment of the invention, the output of the counter circuit 20 is supplied to the microcomputer 30. The microcomputer 30 includes at least a CPU 30a.
and a storage device 30b, and a part of the storage device 30b stores the same data as the storage contents of the correction table storage circuit 22.

Therefore, the microcomputer 30 uses the counter circuit 20
The corrected position data stored in the address corresponding to the counted value is read out and output. With such a configuration, the same effects as in the embodiment described above can be obtained.

Further, for example, error data can be stored for errors between the measured values and corrected detected values shown in Table 2, that is, for the counted values shown in Table 2. By storing the error in the storage device 30b in this way, the microcomputer 30 reads out the error data corresponding to the count read from the storage device 30b,
By adding the read error data and the read count value and outputting the result, corrected position data is output from the microcomputer 30. Here the first
As is clear from a comparison between the table and Table 2, this case has the advantage that the storage capacity corresponding to the correction table storage circuit 22 in the case of the first embodiment can be extremely small.

Furthermore, instead of the correction table storage circuit 22, the sections and the line approximation formula may be stored in a part of the storage device 30b. For example, if the relationship between the counted value and the corrected detected value is as shown in FIG. , sections A to 81B to c, c to D, D to E, and E to F are approximated by broken lines, and the approximate formulas for these broken lines, that is, the broken line approximation formulas are stored corresponding to the sections as shown in Table 3. You can leave it.

Table 3 When the broken line approximation formula is stored in the storage device 30b as described above, it is determined which category the read count value falls into,
Corrected position data is calculated using a broken line approximation formula corresponding to the determined classification, and the calculated corrected position data is output from the microcomputer 30. In this case, as the number of sections increases, corrected position data with smaller Sakai differences can be obtained.

Furthermore, as shown in Table 2 in the storage device 30b, there are cases where the error is constant for each section, and in such a case, the correction table shown in Table 4 can be used.

Table 4 In this case as well, the effect of reducing the storage capacity for the correction table can be obtained, as in the case of Table 2.

As explained above, according to the present invention, corrected position data can be obtained based on the counted value of the counter, so in position detection using a resolver, the accuracy is equivalent to that of the position detection measuring device used to obtain the corrected position data. can be obtained.

Further, the configuration for this purpose is also simple. Therefore, in order to make it possible to reduce position detection errors caused by electrical errors, it is necessary to improve the manufacturing accuracy of resolvers or to select and ship finished products with small electrical errors, which are problems that have existed in the past. is eliminated, resolvers can be manufactured with normal precision, and the effect of improving the maximum detection resolution is obtained.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and changes in design can be made without departing from the gist of the present invention. Of course.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIGS. 2 and 3 are relationship diagrams and waveform diagrams between count values and corrected detected values to explain the operation of the embodiment of the present invention. , 4th
The figure is an explanatory diagram for generating data stored in a correction table storage device, FIG. 5 is a block diagram showing the configuration of another embodiment of the present invention, and FIG. 6 is used to explain the operation of another embodiment of the present invention. FIG. 3 is a diagram showing the relationship between count values and corrected detected values. 10...Low pass filter 12...Zero cross comparator 14...Counting operation control circuit 16...Low pass filter

Claims (1)

[Claims] (1) Correcting electrical errors in a position detection device that detects the rotation angle of the resolver rotor shaft by counting the phase difference between the phase of one of the excitation signals of the resolver and the phase of the output signal of the resolver. a storage device that stores data related to position detection values for calculating the phase difference, reads storage contents corresponding to the counted value of the phase difference from the storage device, and corrects the position detection values from the read storage contents. A position detection device characterized by obtaining the following.