JP3151733B2 - Position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase shift type position detecting device for detecting a change in magnetic resistance caused by the movement of a moving body as a change in an electrical phase angle of an output AC signal.

[0002]

2. Description of the Related Art As a position detecting device utilizing a change in magnetoresistance, a rotary type differential transformer called a micro-sin has been well known. This has the disadvantage that, since it converts the rotational position into a voltage level, it is susceptible to disturbances and errors are likely to occur. For example, the resistance of the coil changes under the influence of the temperature change, which causes the detection signal level to fluctuate, or the level attenuation in the signal transmission path from the detector to the circuit using the detection signal. It varies depending on the transmission distance, and further has a drawback that level fluctuation due to noise appears as a detection error as it is.

Therefore, the applicant of the present invention has previously proposed a phase shift type rotational position detecting device capable of accurately detecting a rotational position without being affected by output level fluctuation due to disturbance or the like ( JP-A-57-60212, JP-A-57-88317, JP-B-62-58
445). The applicant of the present invention has also proposed a phase shift type linear position detecting device based on the same principle as the rotational position detecting device (Japanese Utility Model Application Laid-Open No. 57-13462).
No. 2, Japanese Utility Model Publication No. 57-151503, Japanese Utility Model Application Publication No.
No. 7-135917, Japanese Utility Model Application Laid-Open No. 58-136718 or Japanese Utility Model Application Laid-Open No. 59-175105).

FIG. 4 is a diagram showing a schematic configuration of a rotational position detecting device previously proposed by the applicant of the present invention. The rotating position detecting device shown in FIG. 4 has a stator in which a plurality of poles A to D protruding in a direction perpendicular to the rotating shaft (a normal direction about the rotating shaft) are provided at predetermined intervals (90 degrees) in a circumferential direction. 11a and a rotor 11b inserted into the space of the stator 11a surrounded by the poles A to D. That is, the stator 11a is provided to face the outer peripheral surface of the rotor 11b.

[0005] The rotor 11b has a pole A corresponding to the rotation angle.
To D, and is formed of a cylindrical body eccentric with respect to the rotation axis as an example. Each pole A to D of the stator 11a has 1
The secondary coils 1A to 1D and the secondary coils 2A to 2D are wound respectively. Then, a first pair of two poles A and C facing each other across the rotor 11b and poles B and D
Are wound so as to operate differentially and are configured to produce a differential reluctance change.

The primary coils 1A and 1C wound on a first pair of poles (poles A and C) are excited by a sinusoidal signal sinωt and wound on a second pair of poles (poles B and D). The primary coils 1B and 1C are excited by the cosine wave signal cosωt. As a result, the combined output signal Y is obtained from the secondary coils 2A to 2D. This composite output signal Y
As shown in FIG. 6, a signal Y = a signal Y = phase-shifted by an electrical phase angle corresponding to the rotation angle θ of the rotor 11b with respect to a primary AC signal (excitation signal of the primary coil) sinωt serving as a reference signal. sin (ωt−θ).

When the above-described inductive phase shift type position sensor is used, a reference signal generator for generating a primary AC signal sinωt or cosωt and an electrical phase shift θ of the combined output signal Y are measured. Then, a position sensor converting means including a phase difference detecting unit for calculating position data of the rotor 11b is required. FIG. 5 is a diagram showing a configuration example of the position sensor conversion means. In FIG. 5, the position sensor conversion means includes a reference signal generator for generating reference AC signals sinωt and cosωt, a mutual induction voltage Y = sin (ωt−θ) of the secondary coils 2A to 2D, and a reference AC signal sinωt.
And a phase difference detecting section for detecting a phase difference (phase shift amount) Dθ between the phase difference and the phase difference.

The reference signal generator comprises a clock oscillator 12, a synchronous counter 13, ROMs 14a and 14b, D / A converters 15a and 15b, and amplifiers 16a and 16b. The phase difference detector comprises an amplifier 17, a zero cross circuit 18 and a latch circuit. It consists of nineteen. The clock oscillator 12 generates a high-speed and accurate clock signal CLx, and other circuits operate based on this clock signal. The frequency fx of the clock signal CLx is 40.96 MHz.

The synchronous counter 13 is a cyclic counter for counting the clock signal CLx of the clock oscillator 12, and its count value Ny is used as an address signal in a ROM.
14a and 14b and output to the latch circuit 19 of the phase difference detection unit. The frequency of the reference AC signal sinωt, that is, the primary carrier frequency fc is determined by the cyclic count value (maximum count value) Nx of the synchronous counter 13. When the cyclic count value Nx is 4096, the primary carrier frequency fc
Is 10 kHz (= 40.96 MHz ÷ 4096), and when the cyclic count value Nx is 8192, the primary carrier frequency fc is 5 kHz (= 40.96 MHz ÷ 81).
92). That is, the primary carrier frequency fc is determined by the oscillation frequency fx of the clock oscillator 12 and the cyclic count value Nx of the synchronous counter 13. FIG. 6 shows a case where the cyclic count value Nx is 8192.

The ROMs 14a and 14b store the reference AC signal s
It stores amplitude data corresponding to inωt and cosωt, and generates amplitude data of a reference AC signal according to an address signal (count value Ny) from the synchronization counter 13. The ROM 14a stores the amplitude data of cosωt in the ROM
14b stores the amplitude data of sinωt. Accordingly, the ROMs 14a and 14b output two types of reference AC signals sinωt and cosωt by inputting the same address signal from the synchronous counter 13. In addition,
Even if the ROM having the same amplitude data is read out with the address signals having different phases, the two kinds of reference AC signals si
nωt and cosωt can be obtained.

The D / A converters 15a and 15b are connected to the ROM 1
The digital amplitude data from 4a and 4b are converted into analog signals and output to amplifiers 16a and 16b. Amplifiers 16a and 16b are D / A converters 15a and 15b
Amplify the analog signal from the reference AC signal si
The voltages are applied to the primary coils 1A, 1C and 1B, 1D as nωt and cosωt, respectively. When the cyclic count value of the synchronous counter 13 is Nx, the count value Nx corresponds to the maximum phase angle of 2π radians (360 degrees) of the reference AC signal. That is, one count value of the synchronous counter 13 corresponds to a phase angle of 2π / Nx radian.

The amplifier 17 amplifies the combined value of the secondary voltages induced in the secondary coils 2A to 2D, and amplifies the resultant value.
8 is output. The zero-crossing circuit 18 is provided with a mutual induction voltage (2
A zero cross point from a negative voltage to a positive voltage is detected based on the next voltage, and a latch pulse LP is output to the latch circuit 19.

The latch circuit 19 counts the count value of the synchronous counter started by the rising clock signal of the reference AC signal to a detection signal (latch pulse) L of the zero-cross circuit 18.
Latch at the output point of P (zero cross point). Therefore,
The value latched by the latch circuit 19 is exactly equal to the phase difference (phase shift amount) θ between the reference AC signal and the mutual induction voltage (synthetic secondary output).

That is, the combined output signal Y = sin (ωt−θ) of the secondary coils 2A to 2D is
Given to. The zero cross circuit 18 outputs a latch pulse LP to the latch circuit 19 in synchronization with the timing when the electric phase angle of the composite output signal Y is zero. Then, the latch circuit 19 latches the count value Ny of the synchronous counter 13 according to the rise of the latch pulse LP as shown in FIG.

At this time, the cycle of the synchronous counter 13 is set so as to coincide with one cycle Tc of the sine wave signal sinωt, so that the latch circuit 19 supplies the reference AC signal sinωt and the composite output signal Y = sin (Ωt-θ)
And the count value Ny corresponding to the phase difference θ is latched. Therefore, the latch circuit 19 outputs the latched count value Ny as digital position data. By multiplying the position data Ny by 2π / Nx, the position data in the rotation direction of the rotor 11b can be calculated. As described above, since the phase shift type position detecting device outputs the absolute position as a phase difference signal, it has an excellent feature that it is hardly affected by noise.

[0016]

The above-described phase shift type position detecting device outputs position data in synchronization with the latch pulse LP output from the zero cross circuit 18. That is, the position detection device of the phase shift system is configured as shown in FIG.
The oscillation frequency fx of the clock oscillator 12 is 40.96 M
Hz, the cyclic count value Nx of the synchronous counter 13 is 81
In the case of 92, the primary carrier frequency fc becomes 5 KHz, position data is output every 0.2 ms (200 μs), and the cyclic count value Nx of the synchronous counter 13 is 4 kHz.
096, the primary carrier frequency fc is 10 KH
z, and the position data is output every 0.1 ms (100 μs).

Therefore, when the rotational position detecting device of the phase shift type is mounted on the rotating shaft of the motor, the relationship between the reference AC signal sinωt of the rotational position detecting device and the combined output signal Y is as shown in FIG. Become. The position data DA4 to DA0 and DB4 to DB0 are
About 0.2 in synchronization with the latch pulse LP output from
Output every ms.

The reference AC signal sinωt and the combined output signal Y
, 2θ, 3 depending on the rotation of the motor.
θ gradually increases. The phase difference θ is a rotation angle of the rotating shaft sampled about every 0.2 ms in synchronization with the latch pulse LP, and is a value dependent on the rotation speed of the motor. Therefore, the motor (rotary shaft)
When the rotation speed is high, the phase difference θ increases, and when the rotation speed is low, the phase difference θ decreases.

In FIG. 7, position data DA4 to DA0
Indicates the lower 5 bits of the position data output from the latch circuit 19 when the primary carrier frequency fc is 5 KHz and the rotation speed of the motor is 30 rpm, and the position data DB4
ＤＢDB0 indicates the lower 5 bits of the position data output when the rotation speed of the motor is 40 rpm.

When the primary carrier frequency fc is 5 KHz and the rotational speed of the motor is 30 rpm, the value of the rotational position data that rotates and moves during 0.2 ms is 2π × 30 ÷ (60
× 5000) = π / 5000 radians, and the value of the rotational position data corresponding to one count value of the synchronous counter 13 is 2π / 8192 (= π / 4096) radians.
That is, the value of the rotational position data that rotates during 0.2 ms is smaller than the value of the rotational position data corresponding to one count value of the synchronous counter 13.

Therefore, when the position detecting device receives the latch pulse LP
Output position data about every 0.2ms in synchronization with
There is a portion that does not change as position data. For example,
In the 0th and 1st latch pulses LP, the position data D
A4 to DA0 are “00000”, and in the fifth and sixth latch pulses LP, the position data DA4 to DA0
Is "00100", and the position data DA4 to DA0 are "010" in the eleventh and twelfth latch pulses LP.
01 "and the 16th and 17th latch pulses L
In P, the position data DA4 to DA0 are “01101”, and the position data DA4 to DA0 are similar for the 21st and 22nd, 26th and 27th latch pulses LP.
DA0 has not changed.

When observing the position data output every about 0.2 ms, a portion where the position data changes and a portion where the position data does not change occur. This means that, although the motor is actually rotating at a constant speed (here, 30 rpm), the rotational speed of the motor fluctuates on the position data.

On the other hand, the primary carrier frequency fc is 5 kHz.
When the rotational speed of the motor is 40 rpm, the value of the rotational position data corresponding to one count value of the synchronous counter 13 is also π / 4096 radians. The value is 2π × 40 ÷ (6
0 × 5000) = π / 3750 radians, which is larger than the case of the rotation speed of 40 rpm. That is,
In the case of a rotation speed of 40 rpm, the value of the rotation position data that rotates during 0.2 ms is one of the values of the synchronization counter 13.
It is larger than the value of the rotational position data corresponding to the count value.

Accordingly, the position data changes and is output every time the latch pulse LP is output, contrary to the above-described case of the rotation speed of 30 rpm. At the time of the tenth latch pulse LP, “01010” is output as the position data DA4 to DA0, and at the time of the eleventh latch pulse LP, “0” is output as the position data DA4 to DA0.
1100 "is output. However, in practice the first
Between the time when the 0th position data is output and the time when the 11th position data is output, the position data DA4 to DA0
Must be output as "01011", but the position data "01101" is missing. This is because the value of the rotation position data that rotates and moves during 0.2 ms is larger than the value of the rotation position data corresponding to one count value of the synchronization counter 13.
It has occurred. Similarly, the position data “10111” is missing between the 21st and 22nd latch pulses LP.

The phenomenon that the position data drops off becomes noticeable as the rotational speed increases, and the number of position data that drops off also increases in proportion to the rotational speed. Note that the rotation speed Nr at which such a phenomenon that the position data drops out is determined by the fact that the oscillation frequency of the clock oscillator 12 is 40.96.
MHz and the primary carrier frequency 5 KHz,
Since the value of the rotational position data that rotates during 2 ms and the value of the rotational position data corresponding to one count value of the synchronous counter 13 are equal, 2π / 8192 = 2π × N
From r {(60 × 5000), Nr = 60 × 5000}
8192 ≒ 36.6 rpm.

Similarly, when the oscillation frequency of the clock oscillator 12 is 40.96 MHz and the primary carrier frequency is 10 KHz, it corresponds to the value of the rotational position data rotating and moving during 0.1 ms and one count value of the synchronous counter 13. 2π / 409 because the value of the rotational position data
From 6 = 2π × Nr ÷ (60 × 10000), Nr = 6
0 × 10000 ÷ 4096 ≒ 146.5 rpm.

Such a dropout of the position data is caused by
This is a problem peculiar to the phase shift type position detecting device, and is caused by the fact that the phase shift type position detecting device can output position data only in synchronization with the latch pulse LP output in synchronization with the primary carrier frequency. are doing. Therefore, even if the position data is output for each latch pulse LP as described above, if there occurs a portion where the position data does not change or the position data is dropped out, the rotational speed of the motor fluctuates on the position data. This is observed as if it were performed, which is a problem when controlling the rotation speed of a motor or the like or performing positioning control.

The present invention has been made in view of the above points, and it is an object of the present invention to reliably output position data without causing a dropout of position data when detecting a moving position of a moving body moving at high speed. It is an object of the present invention to provide a phase shift type position detecting device that can be used.

[0029]

A position detecting device according to the present invention uses a change in magnetoresistance caused by movement of a moving object as a change in an electrical phase angle of an output AC signal, and a sampling period according to a moving speed of the moving object. The position of the moving object is indicated by a digital value.
Absolute position detecting means of the phase shift that output as to the absolute position data, difference calculation for calculating a difference value between a previous value and a present value of the absolute position data output from the absolute position detecting means for each of the sampling periods Means and before said
A pulse generating means for subtracting a predetermined margin time from a sampling period corresponding to a sampling time difference between a round value and a current value, and generating a number of pulses corresponding to the difference value at equal intervals within the subtracted time. And interpolated position data between the previous value and the current value of the absolute position data in accordance with the input of the pulse from the pulse generation means, and sequentially outputs the interpolated position data from the previous value to the current value.
The absolute position data loss free up to that, the current value support
And position data generating means that is generated after a delay from the time of sampling .

[0030]

The phase shift type absolute position detecting means, as in the prior art, uses the rotational position data in the rotational direction in the case of the rotational position detecting means and the linear position in the linear direction in the case of the linear position detecting means. The position data is sampled as a change in the electrical phase angle of the output AC signal at each sampling cycle corresponding to the moving speed of the moving body (rotary moving body or linear moving body), and the sampling value is output as absolute position data. The difference calculation means calculates a difference value between the previous value and the current value of the absolute position data output from the absolute position detection means for each sampling cycle. When the moving speed of the moving object is low and the difference value is “1” or “0”, the position data does not drop out. However, if the difference value is “2” or more, it means that the position data is missing between the previous value and the current value of the absolute position data output every sampling cycle. Therefore, the pulse generation means subtracts a predetermined margin time from the sampling period, and uniformly generates a number of pulses corresponding to the difference value within the subtracted time. The allowance time is an allowance time provided when the moving speed of the moving body decreases or when the moving body rotates in the opposite direction, in consideration of the fact that the sampling cycle becomes smaller than the previous cycle. The position data generating means includes:
In accordance with the pulse input from the pulse generation means, the interpolation position data between the previous value and the current value of the absolute position data is sequentially output to generate absolute position data without omission. Thus, when detecting the moving position of the moving body moving at a high speed, the position data can be reliably output without causing a drop-out phenomenon of the position data.

[0031]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a position sensor conversion unit according to an embodiment of the present invention, and corresponds to FIG. In FIG. 1, components having the same configuration as in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. The point that the position sensor conversion means of this embodiment is different from the conventional position sensor conversion means is that the position data Nz without data omission is determined based on the phase difference θ (count value Ny) output from the latch circuit 19 in synchronization with the latch pulse LP. The point is that a position data generating means for generating is newly provided. The output cycle Tp of the latch pulse LP becomes the sampling cycle of the position sensor conversion means.

The position data generation means includes a current value data latch circuit 20, a previous value data latch circuit 21, a difference calculation circuit 22, a pulse interval conversion circuit 23, a pulse number storage circuit 24, a timing generation circuit 25, a pulse generation circuit 26, It comprises a position data generation circuit 27. For each timing generator circuit 25 for inputting the latch pulse LP from the zero cross circuit 18, and outputs to each circuit of the position data generating means a predetermined timing signal, also the previous latch time
Find the difference at the latch time this time, that is, the sampling time difference.
The sampling period Tp is calculated, and the sampling period Tp
Is output.

The current value data latch circuit 20 latches the count value Ny corresponding to the phase difference θ (i) of the latch circuit 19 in accordance with the latch pulse LPi output from the timing generation circuit 25, and changes it to the current value. The data value Nnew is output to the difference calculation circuit 22, and the count value Nold corresponding to the phase difference θ (i−1) latched before the input of the latch pulse LPi is output to the previous value data latch circuit 21. The count value Nold is the latch pulse L
This is the count value of the synchronous counter 13 latched by the latch circuit 19 one cycle before P. The previous value data latch circuit 21 counts the count value N corresponding to the phase difference θ (i−1) latched by the current value data latch circuit 20 according to the latch pulse LPi of the timing generation circuit 25.
Old is latched and output to the difference calculation circuit 22 and the position data generation circuit 27.

The difference calculation circuit 22 subtracts the count value Nold of the previous value data latch circuit 21 from the count value Nnew of the current value data latch circuit 20 according to the subtraction command pulse DP from the timing generation circuit 25, and calculates the difference value. The data DV is output to the pulse interval conversion circuit 23 and the pulse number storage circuit 24. The pulse interval conversion circuit 23
The difference value data DV from the difference calculation circuit 22 is input, the difference value data DV is converted into pulse interval data PW according to the conversion command signal CP from the timing generation circuit 25, and output to the pulse generation circuit 26. The pulse interval data PW specifies a pulse interval required to output a pulse train at equal intervals within the output cycle Tp of the latch pulse LP by the number indicated by the difference value data DV. Pulse interval
In the conversion circuit 23, the latch pulse LP
T obtained by subtracting a predetermined margin time Tm from the output cycle Tp of
Value obtained by dividing p-Tm by subtraction value data DV (Tp-Tm)
Output pulse interval data PW corresponding to / DV
It has become.

The pulse number storage circuit 24 includes the difference calculation circuit 2
2, and should be output within one cycle of the primary carrier frequency fc in accordance with the storage command pulse RP from the timing generation circuit 25 in accordance with the storage command pulse RP. (Number of pulse trains). The pulse generation circuit 26 is a cyclic counter that counts the clock signal CLK output from the timing generation circuit 25, and outputs a pulse train Pi to the position data generation circuit 27 every time the count value makes one round. The pulse generation circuit 26 can programmably change its cyclic count value by the pulse interval data PW from the pulse interval conversion circuit 23.

Therefore, when the pulse interval data PW from the pulse interval conversion circuit 23 is large, the count value of the pulse generation circuit 26 becomes large, so that the output interval of the pulse train Pi becomes large and within one cycle of the latch pulse LP. Is reduced. Conversely, when the pulse interval data PW from the pulse interval conversion circuit 23 is small, the count value of the pulse generation circuit 26 also becomes small, so that the output interval of the pulse train Pi also becomes small and is output within one cycle of the latch pulse LP. Also, the number of pulse trains Pi increases.

The position data generation circuit 27 is a cyclic counter for counting the pulse train Pi output from the pulse generation circuit 26, and its cyclic count value is set to be the same as that of the synchronous counter 13. The position data generation circuit 27 is set in advance as the initial count value to the count value Nold of the previous value data latch circuit 21, and in response to the output start pulse SP from the timing generation circuit 25, the pulse train from the pulse generation circuit 26. Pi is counted by the number corresponding to the difference value data DV of the pulse number storage circuit 24. That is, the position data generation circuit 27
The position data Nz falling off from the count value Nold to Nnew is sequentially output according to the input timing of the pulse train Pi.

Next, the operation of this embodiment will be described with reference to FIG. In FIG. 2, position data DC4 to DC0
Indicates the lower 5 bits of the position data Nz output from the position data generation circuit 27 when the primary carrier frequency fc is 5 KHz and the rotation speed of the motor is 100 rpm.

When the primary carrier frequency fc is 5 KHz and the rotational speed of the motor is 100 rpm, the value of the rotational position data that rotates during one cycle of the primary carrier frequency fc of 0.2 ms is 2π × 100 ÷ (60 × 5000) = π
/ 1500 radians, and the value of the rotation position data corresponding to one count value of the synchronous counter 13 is 2π / 8192
(= Π / 4096) radians.

Therefore, during one cycle of the primary carrier frequency fc of 0.2 ms, the synchronous counter 13 has its count value N
y is incremented by two or three. The count value Ny which was “0” at the time of the 0th latch pulse LP0
Also becomes "2" at the time of the first latch pulse LP1, and thereafter, the latch pulses LP2, LP3, LP4, LP5
.., "5", "8", "1"
0,13,16,19,21,24 ...
Are output one after another.

The latch pulse LP from the zero cross circuit 18
Is output to the latch circuit 19 and the timing generation circuit 25, the latch circuit 19 sets "2" as the count value Ny.
And the timing generation circuit 25 outputs the latch pulse L
Pi is output to the current value data latch circuit 20 and the previous value data latch circuit 21. As a result, the current value data latch circuit 20 latches “2” as the count value Ny, and the previous value data latch circuit 21 counts the count value Ny.
“0” is latched as y.

The timing generation circuit 25 outputs the latch pulse L
After outputting Pi to the current value data latch circuit 20 and the previous value data latch circuit 21, the subtraction command pulse DP is output to the difference calculation circuit 22. The difference calculation circuit 22 includes a current value data latch circuit 20 and a previous value data latch circuit 21.
The difference value “2” between the count value Nnew and the current value Nold latched is calculated and output to the pulse interval conversion circuit 23 and the pulse number storage circuit 24 as difference value data DV.

The pulse interval conversion circuit 23 to which the difference value data DV has been input converts the difference value data DV into pulse interval data PW and outputs the same to the pulse generation circuit 26. First,
Initially, for ease of understanding, the primary
A One cycle Tc (= 200 μ) of the frequency fc (= 5 KHz)
Number corresponding to difference value data DV within the same time width as in s)
Will be described. If so, now
In the example of the above, since the difference value is “2”, in order to output two pulse trains Pi during one cycle Tc (= 200 μs) of the primary carrier frequency fc (= 5 KHz), one cycle Tc
Is divided by DV (here, “2”), and the pulse train Pi may be output at an interval of about 100 μs, so that Tc / DV
Will be output.
You .

The pulse generating circuit 26 which has received the pulse interval data PW outputs a pulse train Pi at every time corresponding to the pulse interval data PW. Here, the pulse generation circuit 26 outputs pulse trains P1 and P2 approximately every 100 μs. Since the position data generation circuit 27 stores “0” as the position data Nold previously latched in the previous value data latch circuit 21, the position data generation circuit 27 stores the position data in response to the input of the pulse train Pi from the pulse generation circuit 26. Perform incremental processing. That is, at the time of the first latch pulse LP1, the position data generating circuit 27 sets the position data DA4 to DA0 to "00000" and "0000".
1 "," 00010 ".

In the period of the latch pulse LP1, the pulse generation circuit 26 only needs to output the two pulse trains P1 and P2. However, there is a case where the third incremental pulse is erroneously generated. In such a case, there is no problem since the position data generation circuit 27 processes even if a pulse train Pi of the difference value data DV or more from the pulse number storage circuit 24 is input, as if it was not input.

As described above, the position data can be appropriately output from the position detecting device of this embodiment without being limited to the primary carrier frequency fc. Further, one of the lower bits DC0 to DC3 of the position data output from the position detection device is set as an incremental pulse, and the difference value data DV output from the difference calculation circuit 22 is set as data indicating the rotation direction. By
An incremental encoder using the phase shift type position detecting device of the present embodiment can be realized.

In the above embodiment, when the rotation speed of the motor is 100 rpm, there is no problem because the output period Tp of the latch pulse LP and the period Tc of the primary carrier frequency fc are almost constant. As shown in FIG. 3, the output cycle Tp of the latch pulse LP depends on the rotation speed N of the motor and its rotation direction. In other words, as the rotation speed N of the motor increases, the output cycle Tp of the latch pulse LP becomes sufficiently larger than the cycle Tc of the primary carrier frequency fc, and when the motor rotates in the opposite direction, the motor rotates in the opposite direction. As the rotation speed N increases, the output cycle Tp of the latch pulse LP becomes sufficiently smaller than the cycle Tc of the primary carrier frequency fc.

Assuming that the rotation speed of the motor is Nrpm, the composite output signal Y = sin [2πfct−2π (N / 60)
t] = sin [(2π / Tp) t], the output cycle Tp of the latch pulse LP is Tp = 1 / (fc−N / 60), and the difference value data DV at this time is DV = (Nx × N /
60) / (fc−N / 60). Here, N is a negative value when the rotation direction of the motor is in the opposite direction. Therefore, when N is eliminated from the above equation, Tp = (Nx + DV) /
(Fc × Nx). Here, Nx is the synchronous counter 1
The cyclic count value of 3, that is, the number of divisions per rotation. For example, when the primary carrier frequency fc is 5 KHz and the rotation speed N of the motor is 30,000 rpm, the output cycle Tp of the latch pulse LP is about 222 μs, which is shorter than the cycle Tc (200 μs) of the primary carrier frequency fc.
(About 22 μs). Conversely, the rotation speed N of the motor
Is 30000 rpm in the opposite direction, the output cycle Tp of the latch pulse LP is about 182 μs, which is smaller than the cycle Tc (200 μs) of the primary carrier frequency fc by ta.
(About 18 μs).

Accordingly, the pulse interval conversion circuit 23 to which the difference value data DV has been inputted is converted into a value Tc obtained by dividing the period Tc by DV.
When the pulse interval data PW corresponding to / DV is output to the pulse generation circuit 26, the position data is output from the position data generation circuit 27 for the first 200 μs one after another.
This means that the position data does not change during a (about 22 μs). Conversely, when the rotation is in the opposite direction, the position data cannot be completely output during the output period Tp of the latch pulse LP.

Therefore, in order to output the position data evenly from the position data generation circuit 27 even in the case of such a high-speed rotation, the pulse interval conversion circuit 23 has a predetermined margin time from the output period Tp of the latch pulse LP. A value Tp−Tm obtained by subtracting Tm (time corresponding to about 1 to 3% of one cycle Tc of the primary carrier frequency, 5 μs when the primary carrier frequency is 5 KHz, and 2.5 μs when the primary carrier frequency is 10 KHz) The value divided by the subtraction value data DV (Tp−T
m) The pulse interval data PW corresponding to / DV is set to be output to the pulse generation circuit 26. Here, the allowance time Tm is provided in consideration of that the output cycle Tp of the latch pulse LP becomes smaller than the previous cycle when the rotation speed of the motor is reduced or when the motor is rotated in the opposite direction and accelerated. It is time to spare.

Therefore, the rotation speed N of the motor is 30,000.
In the case of rpm, the pulse interval conversion circuit 23 outputs the pulse interval data PW corresponding to the output period Tp of the latch pulse LP: a value obtained by subtracting 5 μs from approximately 222 μs: approximately 217 μs divided by the subtraction value data DV. Generation circuit 2
6 is output. When the rotation speed N in the opposite direction of the motor is 30,000 rpm, the pulse interval conversion circuit 23
Is a value obtained by subtracting 5 μs from the output cycle Tp of the latch pulse LP: approximately 182 μs: approximately 178 μs is subtracted from the value data D.
The pulse interval data PW corresponding to the value divided by V is output to the pulse generation circuit 26.

Although the above embodiment has been described with reference to the case of the phase shift type rotational position detecting device as an example, it is needless to say that the present invention can be similarly applied to a phase shift type linear position detecting device. Further, in the above-described embodiment, the pulse output from the pulse generation circuit 26 has been described as an incremental pulse. However, if the rotation direction is reversed, a decremental process is performed from the previous value based on the incremental pulse. Interpolation processing up to the value is performed.

[0053]

According to the present invention, when detecting the moving position of a moving body moving at a high speed, the position data can be reliably output without causing a drop-out phenomenon of the position data.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a position sensor conversion device that is a part of a position detection device according to the present invention.

FIG. 2 is a timing chart for explaining the operation of the position sensor conversion device of FIG.

FIG. 3 is a timing chart for explaining the operation of the position sensor converter of FIG. 1;

FIG. 4 is a diagram showing a schematic configuration of a rotational position detecting device previously proposed by the applicant of the present invention.

FIG. 5 is a diagram illustrating an example of a position sensor conversion device connected to the rotation position detection device of FIG. 4;

FIG. 6 is a diagram for explaining a basic principle of the rotational position detecting device of FIG. 4;

FIG. 7 is a timing chart for explaining the operation of the position sensor conversion device of FIG. 5;

[Explanation of symbols]

1A to 1F: primary coil, 11a: stator, 11b ...
Rotor, 12 clock oscillator, 13 synchronous counter,
14a, 14b: ROM, 15a, 15b: D / A converter, 16a, 16b, 17: amplifier, 18: zero cross circuit, 19: latch circuit, 20: current value data latch circuit, 21: previous value data latch circuit, 22: difference calculation circuit, 23: pulse interval conversion circuit, 24: pulse number storage circuit, 25: timing generation circuit, 26: pulse generation circuit, 27: position data generation circuit

Claims (4)

(57) [Claims] 1. A method according to claim 1, wherein a change in magnetic resistance caused by the movement of the moving body is sampled as a change in an electrical phase angle of an output AC signal at a sampling cycle corresponding to a moving speed of the moving body. Digitize the position
Calculating an absolute position detecting means of the phase shift method, a difference value between a previous value and a present value of the absolute position data output from the absolute position detecting means for each of the sampling period to output as an absolute position data indicating at Tal value Subtracting a predetermined margin time from a sampling cycle corresponding to a sampling time difference between the previous value and the current value, and arranging a number of pulses equivalent to the difference value within the subtracted time at equal intervals. in a pulse generating means for <br/> generating the interpolation position data between the previous value and the present value of the absolute position data sequentially output according to the pulse input from the pulse generating means, from the previous value
The absolute position data without loss of up to this value,
A position detecting device comprising: a position data generating means which is generated after a time point after the sampling of the current value . 2. The position detecting device according to claim 1, wherein said absolute position detecting means is a rotational position detecting means for detecting a rotational movement position of a moving body. 3. The position detecting device according to claim 1, wherein said absolute position detecting means is a linear position detecting means for detecting a linear moving position of the moving body. 4. The position detecting device according to claim 1, wherein an incremental pulse is formed from predetermined lower-order bits of the absolute position data output from said position data generating means and output.