JPS62239059A - Speed detecting device - Google Patents

Abstract

PURPOSE:To detect the angular speed of a rotating body accurately without contacting by performing numerical arithmetic operation based on two reference position signals of sine waves obtained from a position sensor. CONSTITUTION:The position sensor 1 generates four signals, i.e. mutual 90 deg. out-of-phase sine wave reference position signals e1 and e2. Those signals e1 and e2, and inverted position signals -e1 and -e2 obtained by applying said signal to sign inverting amplifiers 4 and 7, i.e. four signals are inputted to corresponding differentiators 1 and 6, and 6 and 8 respectively. The output signal of the differentiators 2 and 6, and 6 and 8 are all determined on the basis of the product of the term of an angular speed and the term of the signals e1 and e2, or -e1 and -e2. Those signals are rectified synchronously in every rectification section of its 1/4 period to obtain continuous pulsating flows and output signals after the synchronous rectification are divided through a divider 9 by part of the signals e1 and e2 and -e1 and -e2 corresponding to each rectification section to extract only the angular velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a speed detection device that detects the angular velocity of a rotating body without contact in order to control the speed of the rotating body.

(Prior Art) Conventionally, as this type of speed detection device, one shown in FIG. 4 is known. That is, in the same figure, 21 is a pulse encoder, and this pulse encoder 21 generates a number of pulses proportional to the angular velocity of the rotating body using optical means or the like from a rotating slit disk that is linked to a rotating body (not shown). is configured to detect. Here, the pulse encoder 21 uses two-phase pulses (A-phase pulse and B-phase pulse) whose phases are shifted by 90 degrees, as shown in FIG. pulse). Such output pulses are generated by the F/V circuit in FIG.
The signal is input to the converter 22, converted into a voltage value as an analog signal corresponding to the pulse frequency, and output. Therefore, by measuring this voltage value, the angular velocity of the rotating body can be detected.

(Problems to be Solved by the Invention) However, in such a speed detection device, due to the structure of the rotating slit disk etc. attached to the rotating body, the number of pulses output from the pulse encoder 21 may vary. Above, there are restrictions. For this reason, when the rotating body rotates at high speed as shown in Figure 5 (b), it is possible to detect the voltage value, that is, the angular velocity, even if the sampling time of the output pulse is shortened.
When the rotating body rotates at a low speed, as shown in FIG. 2(A), as the sampling time is shortened, the number of pulses included in the period decreases, and as a result, it becomes impossible to detect the angular velocity. In other words, in the past, when the rotation speed was low, the sampling period had to be long, which resulted in a significant detection delay, and the F/V
There were problems such as an increase in the ripple rate of the analog signal output from the converter 22.

These drawbacks have been a major hindrance to quick and accurate speed control of a rotating body.

The present invention has been proposed to solve the above problems, and its purpose is to reduce the detection delay and output signal by performing various calculations on a sinusoidal position signal corresponding to the angular velocity of a rotating body. An object of the present invention is to provide a speed detection device that accurately detects the angular velocity of a rotating body without contact by reducing the ripple rate.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a first waveform having a sine wave shape and a phase shift of, for example, 90 degrees with respect to the rotation angle of a rotating body.
a position sensor that outputs a second reference position signal; a second reference position signal and a first signal with the signs of these signals inverted;
．． A differentiator that differentiates the second inversion position signal with respect to time, a synchronous rectification controller and an analog switch that sequentially synchronously rectify the output signals of these differentiators over four rectification sections every 90 degrees according to the rotational direction of the rotating body. etc., and the output signal after synchronous rectification by these means is first . the second reference position signal and the first. It is characterized by comprising a divider that divides each by a part of the second inversion position signal.

(Function) In the present invention, by time-differentiating the sinusoidal reference position signal and the reversed position signal, each output signal has a term of the reference position signal or the reversed position signal and a term of the angular velocity. By focusing on the fact that this output signal is included, the output signal is synchronously rectified every 1/4 period of the rectification section to obtain a continuous pulsating flow, and the output signal after this synchronous rectification is set to a standard corresponding to each rectification section. By dividing by part of the position signal and the inverted position signal, only the angular velocity is extracted and detected.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 1 is a block diagram of a speed detection device according to the present invention. In the figure, numeral 1 detects the position of a rotating body (not shown) in a non-contact manner, and as shown in FIG. A position sensor is shown that generates sinusoidal reference position signals e, , e2 that are shifted by degrees. This position sensor 1 is
For example, it can be configured by a magnetic sensor using electromagnetic induction. The output side of the position sensor 1 includes a series circuit of a differentiator 2 and an analog switch 3a, and a sign-inverting amplifier 4 with a gain of 1. Differentiator 5 and analog = 4
- a series circuit of the switch 3b, a series circuit of the differentiator 6 and the analog switch 3c, and a sign-inverting amplifier 7 with a gain of 1.
A series circuit of an m divider 8 and an analog switch 3a are connected in parallel with each other, and a divider 9 is connected to the output side of these parallel circuits.

Furthermore, a synchronous rectification controller IO is connected to the output side of the position sensor 1, and its output signal is transmitted to each analog switch 3.
8 to 3d and the divider 9.

To explain the operation in such a configuration, first, if the maximum value of the reference position signal ex*e2 is 1, then the following (
It can be expressed by equations 1) and (2).

e1=sinθ・・・・・・・・・・・・・・・
・・・・・・・・・(1) e2:=cosθ...A・
(2) Here, θ (rad,) indicates the rotation angle of the rotating body.

These reference position signals e1. e2 and the inverted position signal -611- obtained by adding these to the sign inverting amplifiers 4 and 7.
The four signals 62 are input to corresponding differentiators 2 and 6 and differentiators 5 and 8, respectively. Now, et+ez and -e1. ．． Since both e2 are composite functions regarding θ and t, the output signals of the differentiators 2, 6, and 5.8 are as shown on the right sides of the following equations (3) to (6), respectively.

de1/dt=(dθ/dt)・cosO...
・・・・・・・・・・・・・・・(3) de2/dt=(
d O/dt) (-sin θ')---= ・・−・
・-・(4) d(-el)/dt=(d f)/dt
)・(-cosO)・・・・・・・・・(5) d(e
2)/dt=(dθ/dt)・sin 13---
- (6) Here, it is clear that (dθ/dt) represents the angular velocity of the rotating body, and the differentiators 2, 6, 5.
All the output signals of 8 are this angular velocity term (dθ/dt).

Reference position signal e□, e2 or inverted position signal -61t-
It is established by the product of the term 02.

On the other hand, if the rotational direction of the rotating body detected from the phase shift of the reference position signal e□182 is, for example, clockwise, the sign of the angular velocity (dθ/dt) in equations (3) to (6) above is positive. If it is determined that there is, the output signal of each analog switch 3a to 3d at this time appears every 1/4 period,
The control signal is outputted from the synchronous rectification controller 10 so as to form a pulsating continuous synchronous rectification waveform as shown by the solid line in FIG. 3 as a whole.

That is, in FIG. 3, in the rectification period I, the analog switch 3a outputs ONL and the divider 9 (dθ/dt)・cosO according to the control signal from the synchronous rectification controller 10.
Similarly, in the rectification section ■, the analog switch 3d turns ONL and sends the signal te(dθ/dt)・sinO, and in the rectification period ■, the analog switch 3b turns ON and (
The analog switch 3C turns ONL the signal of dθ/dt)・(-cosO) in the rectification section ■, and turns the signal of (dθ/dt)・
It is configured to send a signal of (-sinO).

Further, in this synchronous rectification control circuit 10, cosO and 5inO correspond to each of the above-mentioned rectification sections 1 to 2, respectively.

(-cosO) and (-sinO) signals are sent to the divider 9.

Note that the synchronous rectification control circuit 10 receives, for example, a reference position signal e.
11 e 2 each full-wave rectified waveform to 1/l of its maximum value
The reference level of T is input to a given comparator to obtain pulses corresponding to each rectification section I to ■, and these pulses are distributed and applied as control signals to the analog switches 3a to 3d in a predetermined order. , the full-wave rectified waveform may be input to the divider 9 in synchronization with these pulses.

With the above configuration, the output signal of the divider 9 corresponds to each rectification section I to ■ in FIG.
dt)・cosθ/cosθ=dO/dt Rectification section II
; (dθ/dt)・Sinθ/sir+0=dθ/
dt rectification section III; (dθ/dt)・(-cos
O)/(-cosO)=dθ/dt Rectification section IV; (dθ/dt) ・(-sinO
)/(-sinO)=dθ/dt, and d B /dt, that is, the angular velocity of the rotating body, is detected over the entire rectification section (■) to (■).

In addition, in the above division, the divisor Ce2O,sin
O, (-cosO) and (-sinO) are all 1/
, /T and 1, and since it does not become O, division is possible.

In addition, when the rotating body reverses, the rotation angle θ increases in the negative direction and the order of the rectification sections 1 to 2 is reversed.
Operationally, there is virtually no difference. Furthermore, in this embodiment, the phase shift (referred to as φ) of the reference position signal e/le2 is 90
Although we have explained the case where φ is set to an arbitrary angle other than 90 degrees, the divisor in the divider 9 is set to coS(O+φ) for each rectification section I to ■, respectively.
5in (O+φ).

-cos(θ+φL −5in((1+φ)), the angular velocity can be detected in the same way.

(Effects of the Invention) As detailed above, according to the present invention, the angular velocity of the rotating body is detected by numerical calculation based on two sinusoidal reference position signals obtained from the position sensor. Compared to conventional analog detection means, it is possible to always accurately detect angular velocity regardless of the speed of the rotating body.
A speed detection device without detection delay can be obtained. Therefore, by using the present invention, it is possible to control the speed of a rotating body with high responsiveness.

Further, the influence of ripples included in the waveform after synchronous rectification can also be removed by dividing this waveform to numerically obtain the angular velocity, and does not pose any problem in speed detection.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention,
Figure 1 is a block diagram, Figure 2 is a waveform diagram of the reference position signal,
Figure 3 is an output waveform diagram of the analog switch after synchronous rectification.
Figures 4 and 5 show conventional examples; Figure 4 is a block diagram; Figure 5 (a) is a diagram showing the output signal of the pulse encoder when the rotating body rotates at low speed; 2 is a diagram showing the output signal of the pulse encoder during high-speed rotation.

Claims (1)

[Claims] a position sensor that outputs first and second reference position signals that are sinusoidal and out of phase with each other with respect to the rotation angle of the rotating body; a differentiator for time-differentiating the first and second inversion position signals, a means for sequentially synchronously rectifying the output signals of these differentiators over a plurality of rectification sections corresponding to the rotational direction of the rotary body, and the synchronous rectification. A speed detection device comprising: a divider that divides the subsequent output signal by the first and second reference position signals and the first and second inverted position signals for each of the rectification sections.