JPS6197523A - Position detecting circuit for reflection type magnetostrictive potentiometer - Google Patents

Abstract

PURPOSE:To measure the arrival time of the direct wave and the reflected wave accurately, by providing first and second comparators having positive and negative thresholds, a means of obtaining a signal for time range and the like. CONSTITUTION:First and second comparators 11 and 12, FFs 13-16, a pulse generator 17 and the like are provided. When a pulse is generated from the generator 17, a driving coil is electrically energized while the FFs 13 and 16 are set. As the Q output of the FF13 moves to a high level, the FFs 14 and 15 are reset and respective Q outputs go to High. Then, signals from a detection coil are applied to the comparators 11 and 12 to output pulse signals separately. Then, the arrival timing of the true direct wave and reflection wave corresponds to the rising time of the pulses. A pulse width signal coinciding with the arrival time t1 is obtained from the FF13. On the other hand, the pulse width signal signal corresponding to the arrival time t2 is obtained from the FF16. An arithmetic circuit 18 makes signals corresponding to the times t1 and t2 and holds a signal from a monomultistable vibrator 19 to compute.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a position detection circuit for a magnetostrictive potentiometer using reflected waves.

(Prior Art) FIG. 3 shows the principle groove diagram of a conventional magnetostrictive potentiometer. In the figure, 1 is a magnetostrictive wire, and detection coils 2+ and 22 for detecting magnetostrictive waves are attached to both ends of the wire, and a slidable drive coil 23 for generating magnetostrictive waves is arranged in the middle. It is established.

In such a configuration, the position X of the drive coil can be determined by driving the drive coil 23 to generate a distorted wave and measuring the time it takes for the wave to reach the detection coils at both ends.

However, in such a configuration, since the detection coils are arranged at both ends of the magnetostrictive wire, the variable range of the drive coil is narrow relative to the length of the magnetostrictive wire, and three coils are required. was there. As a method for dealing with this problem, a reflected wave type magnetostrictive potentiometer as shown in FIG. 4 has appeared. In this case, the drive coil 23
is fixed to one end of the magnetostrictive wire 1, the blind side of the detection coil 2 is made slidable, and the arrival time of the direct wave and the reflected wave of the distorted wave is measured. The position X of can be found.

(Problem to be solved by the invention) However, in such a reflected wave type magnetostrictive potentiometer, the phases of the direct wave and the reflected wave are reversed, and the threshold when detecting the direct wave and the reflected wave by level is The levels (+VTH and -VTR shown in Figure 5) cannot be increased too much because linearity deteriorates if they are increased, and this causes the problem that the direct wave gets caught in the threshold level for catching the reflected wave, causing an error in arrival time measurement. was there.

In view of these points, it is an object of the present invention to provide a position detection circuit that can accurately measure the arrival time of direct waves and reflected waves in a reflective magnetostrictive potentiometer.

(Means for Solving the Problems) In order to achieve such an object, the present invention provides a reflection type magnetostrictive potentiometer having a positive threshold level to which a distorted wave signal from a slidable detection coil is applied. 1 comparator and a second comparator having a negative threshold level; receiving the output pulse of the first comparator to obtain a signal with a time width corresponding to the arrival time of the direct wave; means for receiving an output pulse to obtain a signal with a time width corresponding to the arrival time of the reflected wave; means for generating a peak hold signal when the reflected wave arrives; and means having a time width corresponding to the arrival time of the direct wave. It is equipped with an arithmetic circuit that holds a signal with a time width corresponding to the arrival time of the signal and the reflected wave when a peak hold signal is given, performs a predetermined arithmetic operation, and obtains an analog signal corresponding to the position of the detection coil. It is characterized by

(Example) The present invention will be described in detail below using the drawings. FIG. 1 is a block diagram of essential parts showing an embodiment of a position detection circuit according to the present invention. In the same figure, 11.12 are +Vv and u, respectively.
The output signal of the detection coil 21 (
voltage waveform) is given in common. 13 to 16 are flip-flops (hereinafter abbreviated as FF), especially FF14.1
5 is an edge trigger type FF. A pulse generator 17 provides an excitation pulse to the drive coil 23 and sends the pulse generation timing to the FFs 13 and 16.

FF13 receives the output of comparator 11, and FFI4 receives the output of comparator 12. FF14 and 15 are FF13
It is designed to be reset by the Q output of . FF15
is given the mutual output of FF14, and FF16 is given the Q output of FF15. 18 is the position H (displacement) of the detection coil
A sieve circuit that calculates
Upon receiving one output, a value (t+t2)/(t++i2) corresponding to the position jlx of the coil 2I is calculated and output. The MM 19 receives the Q output of the FF 16, outputs a pulse with a certain time width, and supplies this to the arithmetic circuit 18 as a peak hold signal.

The operation in such a configuration will be explained next with reference to the time chart shown in FIG. When the pulse generator 17 generates the pulse shown in FIG. 2(A), the two drive coils are energized and the FFs 13 and 16 are set. FF13
When the Q output becomes HIGH level as shown in FIG. 2 (E), the FFs 14 and 15 are reset and each σ output becomes HIGH.

A signal from the detection coil 21 as shown in FIG. 2(B) is applied to the comparator 1"112. The comparator 11 is as shown in FIG. 2(C), and the comparator 12 is as shown in FIG. 2(D). outputs respective pulse signals.

The arrival timing of the true direct wave and the reflected wave is at the rising edge of pulses α and β in (c) and (d) of the same figure. Since the pulse α is the first pulse of the comparator 11, it is accurately captured by the FFI 3, and a pulse width signal matching the arrival time t1 is obtained from the FF 13 as shown in FIG. 2(E).

On the other hand, a pulse width signal corresponding to the arrival time t2 of the pulse β is obtained from the FF 16. Its operation is as follows.

In the FF 14, the Q output falls at the second output pulse of the comparator 12 as shown in FIG. 2(D), as shown in FIG. The FF 15 uses this Q output as a clock input, so that the Q output rises when a pulse β arrives and falls when the next pulse β arrives, as shown in FIG. Since the FF 16 is reset by this Q output, the Q output becomes a signal with a pulse width corresponding to time t2 as shown in FIG.

The MM19 is triggered by the fall of the Q output of the FF16, and generates a pulse with a constant time width as shown in FIG.

The arithmetic circuit 18 calculates the time t1 while the Q output of the FF 13 is HIG'H and the Q output of the FFI 6 is HIG'H.
Create a signal (data) corresponding to the period t2 in which it is H, hold the signal at that time when the peak hold signal from MM19 is given, and based on this, create a value (data) corresponding to the position of the detection coil 21. i+jz )/(j
+ +i2) and outputs it as an analog signal.

(Effects of the Invention) As described above, according to the present invention, it is possible to realize a position detection circuit that can accurately catch direct waves and reflected waves in a magnetostrictive potentiometer that uses reflected waves. By using such a position detection circuit, it is possible to realize a reflective potentiometer with a wide movable range and at low cost, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a position detection circuit of a magnetostrictive potentiometer according to the present invention, FIG. 2 is a time chart for explaining the present invention in detail, and FIG. 3 is a principle diagram of a conventional magnetostrictive potentiometer. , FIG. 4 is a principle diagram of a reflection type magnetostrictive potentiometer, and FIG. 5 is an operation waveform diagram of the potentiometer shown in FIG. 4. 1... Magnetostrictive wire, 2. ...Detection coil, 23...Drive coil, 11...First comparator, 12...Second comparator, 13-16...Flip 70 knob, 17...
・Pulse generator, 1st... Arithmetic circuit, 19... Mono multi-by-break.

Claims (1)

[Claims] a first comparator having a positive threshold level and a second comparator having a negative threshold level to which a distorted wave signal from a slidable detection coil in a reflective magnetostrictive potentiometer is applied, and said first comparator; means for receiving the output pulse of the second comparator to obtain a signal with a time width corresponding to the arrival time of the direct wave, and receiving the output pulse of the second comparator to obtain a signal with a time width corresponding to the arrival time of the reflected wave; Means for generating a peak hold signal when the reflected wave arrives, and a peak hold signal that is provided with a signal having a time width corresponding to the arrival time of the direct wave and a signal having a time width corresponding to the arrival time of the reflected wave. 1. A position detection circuit for a reflective magnetostrictive potentiometer, comprising an arithmetic circuit that holds the position of the magnetostrictive potentiometer and performs a predetermined calculation to obtain an analog signal corresponding to the position of the detection coil.