JPS58121414A - Position detector - Google Patents

Abstract

PURPOSE:To obtain both an incremental position signal effective for digital processing and an absolute type position signal containing absolute stop position information by providing four terminals to a network where magnetoresistance effect elements are connected. CONSTITUTION:A magnetic recording medium 201 and the network 202 constitute a position signal detection part. One-side terminals of the magnetoresistance effect elements 301-304 are connected to a terminal 312 and one-side terminals of magnetoresistance effect elements 305-308 are connected to a terminal 313. The other-side terminals of the magnetoresistance effect elements 303-305 are grounded in common. The other-side terminals of the magnetoresistance effect elements 301 and 307 are connected to a terminal 310 and those of the magnetoresistance elements 302 and 308 are connected to a terminal 311. Then, a sine wave voltage of basic frequency is applied to the terminal 310 and a 90 deg. out-of- phase cosine wave voltage is applied to the terminal 311. Consequently, a signal V1 having phase and amplitude modulated corresponding to the rotational angle theta of a motor is outputted from between terminals 312 and 313.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position detection device used in a positioning control system.

Conventionally, conventional devices have been constructed as shown in Fig. 1 and controlled by positioning signals using an anosolute type position signal, and those that use phase modulation corresponding to the relative displacement of movable members as shown in Fig. 3. Some control positioning using signals.

In the conventional example shown in FIG. 1, a sine wave whose rear width changes according to the rotational angular displacement of the motor 10 is transmitted from a signal detector 2 connected to the rotating shaft of the motor 1, and the phase differs by 90 points from the above sine wave. Two amplitude modulated signals, each amplitude modulated by a cosine wave, are output. The demodulator 21 demodulates the above two amplitude modulated signals and outputs the output as shown in Figure @2.
0@ Obtain a sine wave signal M and a cosine wave signal N having different phases.

The above-mentioned sine wave signal M has one period for each fixed displacement of Tanabata 1, and the amount of displacement within the above-mentioned fixed displacement and 1
: Has a swing @ value corresponding to IK. That is, the amount of displacement within the above-mentioned fixed displacement can be detected by the amplitude value of the sine wave signal M(F). t, Differential circuit 22F! , a sine wave signal M, and a signal N having 90 different phases are differentiated, nine signals are synthesized, and a speed signal O is output. In addition, iikuro! Digital speed given by Rosetsusa! Analog speed with D/A converter Δ-23 that converts low-feel information from digital to analog! The field signal is converted into PK and inputted to the positioning control device 9.

The positioning control device 9 controls the motor to rotate at a predetermined speed and stop at a predetermined position using the analog speed tf flow signal P, the sine wave signal M, and the speed signal 0.

In the prior art 11 described above, an absolute type position signal is obtained by the sine wave output M, and accurate positioning of the positioning point barb is possible. However, as mentioned above, since position control is performed by analog signal processing, the disadvantages are that it is difficult to make the circuit small and unify it, and it is expensive.

Ninth bottle to solve the above drawbacks as shown in %$3UyJ,
A device is used that performs positioning control through digital processing using a phase modulated signal that is phase modulated in accordance with the displacement of a member. In this case, the position signal detector 2' connected to the motor IK phase-modulates the signal of the fundamental frequency f in accordance with the displacement of the motor and outputs a nine-phase modulated signal. The structure of the detector 2 will be described later. The phase modulated signal is amplified by a sense amplifier IK. Output signal A of amplifier 3
(See Figure 4(a))
A rectangular wave signal BK& as shown in FIG. 4(b) is converted.

The phase of the rectangular wave signal B corresponds to the displacement of the motor. The rectangular wave signal B is input to a direction/arm pulse generating circuit 5, and is compared with a clock signal F to determine the rotation direction, which is converted into a direction/arm pulse G or H and output. The clock signal F is a clock signal rotated at the fundamental frequency f when the phase modulation signal is not modulated), and has a frequency that is an integral multiple of the frequency fo. Therefore, the direction signals G and H are , ten phase amounts of the rectangular wave signal are digitally interpolated to form nine signals. That is, it is incremental digital position information. On the other hand, a 1 phase ratio # circuit 7 divides the four-wave signal F by a division period of 6 to generate a reference signal C synchronized with the fundamental frequency /. A phase difference signal compared to the phase difference is output. The phase difference of the phase difference signal is digitally measured by a phase difference measurement circuit 8, converted into r digital phase difference data E, and input to the positioning control circuit 9. The phase difference data E is a position signal that includes absolute stop position information corresponding to a displacement within a constant displacement.The 0 positioning control value f9 is determined by the direction Δrus G and H and the phase difference data EK. positioning control is possible.

The position signal detector 2Fi is constructed as shown in FIG. That is, a movable printed circuit board 101 that rotates in conjunction with the motor 1 is provided with an arm turn at a terminal 103, 104, in which folded electric paths/returns are connected in series at a constant pitch as shown in the figure. #Printed circuit board 10
1, the pinning cylinder board 102 has a
A circuit in which a folded turn of the same pitch as the above folded turn is connected in series to form a circuit between terminals 105 and 106, and a folded turn/naturn with a 1/4 pitch deviation from the folded turn of the above circuit are connected in series. A circuit is formed between the terminals 107゜1 (11) and a fundamental frequency IO sine wave V is formed between the terminals 105 and 106.
@-ωt is applied, and V@ is applied between the above terminals 107° and 1011.
When allωt is applied, the motor rotates to move/
The following (1
) A voltage Va is generated as shown by the equation.

Va=kV@cm(ωt + s e ) ------
・(1) In the beginning, k is the conductivity coefficient em#'i, the number of turns written on the movable lint board 101, and 0 is the motor rotation angle (2π radians for one rotation of the motor).

Equation (1) is a signal obtained by phase modulating the signal of the fundamental frequency f by the rotation angle of the motor.
There is a phase shift of 2g for each pitch of a turn, and this phase shift has the opposite sign if the direction of rotation of the motor is reversed. Therefore, as described above, by converting this signal into a rectangular wave signal n and comparing it with the four-wave signal r, it is possible to obtain a number of directional pulses corresponding to the rotation angle of the papermaking motor. This pulse is discrete incremental information and does not include ToI absolute stop information. Therefore, this pulse can be used to guide the motor to the vicinity of the target stop position.

However, absolute stop position information is required near the positioning stop point. Therefore, a circuit is required that compares the phase of the square wave polarization signal C and the reference signal C, measures the amount of displacement within the fixed pitch, and generates a position signal containing absolute stop position information. becomes. In the conventional example described above, by measuring the phase difference with the phase comparison circuit 7jiP and the phase difference adjustment circuit 8, phase difference data E corresponding to the amount of displacement is obtained and is used as absolute stop correct position information b. However, since the phase difference data E is a discrete value measured digitally, it has the drawbacks of poor positioning accuracy and complicated circuitry.

An object of the present invention is to provide a position detection device that can obtain both an incremental position signal, which is advantageous for digital processing, and an absolute position signal, which includes absolute stop position information, with a simple circuit. It's there.

The position detection device of the present invention is a position signal detection unit having a magnetic recording medium magnetized at a constant pitch on one side of a relatively moving member, and a magnetoresistive element on the other side, A circuit network in which a plurality of the magnetoresistive elements are connected is provided with four terminals, a sine wave alternating current signal of a fundamental frequency is input to the l terminal, and a cosine wave having the same frequency and amplitude as the above sine wave alternating signal is input to the other terminal. By inputting an alternating current signal, the phase modulation component corresponding to the relative displacement amount of the relatively moving member and the phase change of the phase modulation signal between the two terminals of the Zanmai are generated one period every integral multiple of 2. means for generating a modulated signal that is amplitude-modulated with a modulated sine wave signal and includes an amplitude-isolated modulated component; means for extracting the phase modulated component from the modulated signal; The method for extracting the amplitude modulated sine wave 1 is characterized by digitally detecting the relative displacement of the relatively moving member from the phase modulation component, and obtaining absolute stop position information from the amplitude modulated sine wave. shall be.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 6 is a block diagram showing an embodiment of the present invention)
FIG. 7 is a waveform diagram showing signals of each main part. In this embodiment, a motor P rotates in conjunction with a motor lK as shown in FIG.
The tumbling magnetic recording medium 2010 is magnetized alternately in the positive and negative directions in the circumferential direction to form a magnetization Δt of 9 constant pitches, and the above medium! A sine wave and a cosine wave of the fundamental frequency are input to a circuit network 202 consisting of eight magnetoresistive elements fixedly arranged at a position facing the four turns of magnetization of 01, and from the circuit network 202, a signal is generated according to the motor rotation angle. In this embodiment, a magnetic recording medium 201 and a circuit network 20 output a signal that is a phase-modulated wave and includes a component width-modulated with a sine wave having a period corresponding to the constant pitch of the rotation angle. , 2 constitute a position signal detection section. The above circuit network 202Fi,
As shown in FIG. 9, four magnetoresistive elements are installed per 1f of voice/data turn on the magnetic recording medium 201.
Eight elements are arranged in parallel at a pitch of /4, and the eight elements are connected as shown in FIG. That is, one ends of the magnetoresistive elements 301 to 304 are connected to the terminal 312, and one ends of the magnetoresistive elements 305 to 308 are connected to the terminal 31.
Connect to 3. The other ends of the magnetoresistive elements 303 to 305 are commonly connected and grounded. Magnetoresistive element 301
and 307 are connected to the terminal 310, and the other ends of the magnetoresistive elements 302 and 30g are connected to the terminal 311! i Ribbon. Then, a sine wave voltage V@^ωt with a fundamental frequency my is applied to the terminal 31G, and a cosine wave voltage V@cm#t with 90 different phases is applied to the terminal 311. Terminal 312.313
A modulated signal Yl that is phase-modulated and amplitude-modulated in accordance with the rotation angle θ of the motor is output from between.

Now, the basic resistance of the magnetoresistive elements 301 to 308 is Ro
, the maximum resistance change rate is j, and the error resistivity is q, then the resistance R, . . . ~R1- of each element is K as shown below.

Rs*z = (1+q) R@÷tR@sk+s#
--(2)8■嘗 = (1+f) Re +l
RI reserve---(3)R Hatake am-(1f)R・-1
・7s # --(4)"" = ("-Q)
Re-pRe et, s#-・-(5)Rsss=
(1+q) R, +p R, dall#”'-(6)
Rses = (1+l) RI + jl RI
eel 11'-"' (7) R1ma = (1f) Be
-PR*Internal attack-1・-<8) Rses = <1-Q
) Re -j) RI mll#-" (9) Therefore, the voltage Vt between the terminals 3t0.311 is -...-. This voltage is amplified by the amplifier 3, and the signal 1I
Ii, as shown in Figure 7 (1), the component phase modulated by the rotation angle - and the phase change of the cough phase modulated wave (i.e., the period in which 6 is an integer multiple of 2 is defined as one period) Contains amplitude modulated components with a modulated sine wave.

That is, in this embodiment, the position signal detecting section composed of the magnetic recording medium 21 and the circuit network 22 constitutes means for generating a modulated signal including a phase modulation component and an amplitude modulation component.

If the signal (2) is input to the detection and integration circuit 10 and detected, and high frequency components are removed, a position signal K as shown in FIG. 7(b) can be extracted. The position signal can be used as absolute stop position information because the rotation angle 0 corresponds to the displacement 1tK within the section in which 1 of the 4 turns of the magnetic field displaces the 4-turn of the magnetic field. A digital position signal obtained by converting the position signal K directly or into a digital signal by the M/D conversion circuit 11 is input to the positioning controller 9.

On the other hand, the phase modulation component of the signal I is extracted by the converter generator 4, and a rectangular wave signal J as shown in FIG.
K conversion. The rectangular wave signal J is the same as the rectangular wave signal B of the nine conventional examples explained in FIG.

That is, it is a digital phase signal, and as in the conventional example, the clock signal r
The positioning control fitting 9 compares the direction values G and H for each direction of rotation and gives them to the positioning controller 9. By counting the direction values G and H, the motor is moved close to the stop position. 1, and the absolute stop position can be controlled by a position signal K or a digital position signal M. That is, since both an absolute position signal including absolute stop position information and an incremental position signal can be generated with a simple configuration, it is possible to simplify the control circuit and improve positioning accuracy.

The number of magnetoresistive elements and the connection circuit of the circuit network of the position signal detection section are not limited to the above-mentioned embodiments, and other connection circuits may be used. So that waves are output! 19. Of course, the magnetic recording medium may be one that moves linearly in accordance with the rotation angle of the motor.

As described above, in the present invention, one of the relatively movable members has a magnetic recording medium, and the cough medium has a constant bit p.
A magnetic/mother turn is formed, a plurality of magnetoresistive elements are arranged on the other member facing the magnetic/mother turn to form a circuit network, and a sine wave and a cosine wave of a fundamental frequency are applied to the circuit network. A phase modulation component phase-modulated corresponding to the displacement of the moving member from the circuit network, and a phase transition 2π of the phase modulation.
Outputting a variable ii# signal containing an amplitude modulation component whose amplitude is changed by a modulated sine wave having a period corresponding to , extracting the phase modulation component and the amplitude modulation component from the signal,
Since it is constructed so that an absolute type position signal including an incremental position signal and absolute stop position information is generated from each, highly accurate positioning control is possible with a simple circuit.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional position detection device.
FIG. 2 is a waveform diagram showing the output signal of the conventional position signal detector, FIG. 3 is a block diagram showing another example of the conventional position detection device, and FIG. 4 is the conventional position signal detector described above. 5 is a side view and a plan view showing the conventional position signal detector shown in FIG. 3, and FIG. 6 is a block diagram showing an embodiment of the present invention. Figure, 7th
FIG. 8 is a waveform diagram showing signals of each main part of the above embodiment, and FIG. 8 is a circuit diagram showing a circuit network connecting side magnetoresistive elements showing the position signal detecting section of the above embodiment. In the figure, 1--motor, 2--position signal detector, 3--sense amplifier, 4--controller, 5--
One-way/+ pulse generation circuit, 6... Frequency divider circuit, 7...
Phase comparison circuit, 8--Phase difference measuring circuit, 9--Positioning control device, 10--Detection and integration circuit, 11-A/D conversion circuit, 21-Demodulator, 22--Differentiating circuit, 23-- D
/ Mumpata, 201-Magnetic recording medium, 202...
Circuit network, 301-308--magnetoresistive element. Daisanjin Bensanshi Resident 1) Toshi So Figure 1 Figure 2 Figure 3 ji4#lA Figure 5

Claims (1)

[Claims] A position signal detection unit having a magnetic recording medium that can be magnetized at a constant pitch on one side of a relatively moving member and a magnetoresistive element on the other side, the position signal detection unit having a plurality of the magnetoresistive elements connected to each other. By providing four terminals in the nine-circuit network, inputting a sine wave AC signal of the fundamental frequency to the l terminal and inputting a cosine wave AC signal having the same frequency and amplitude as the above sine wave AC signal to the other terminal. Between the remaining two terminals, the phase modulation component corresponding to the relative displacement amount of the relatively moving member and the phase change of the phase modulation signal are K1 every integer multiple of 21-.
means for generating a modulated signal including an amplitude modulated component that is amplitude modulated with a modulated sine wave signal having a period; and digitally detecting the relative displacement of the relatively moving member from the phase modulated component of the modulated signal. and the amplitude modulated sine wave ti
A position detection device characterized in that it obtains absolute stop position information.