JPH03170010A - Rotational position detector - Google Patents

Abstract

PURPOSE:To perform highly accurate rotational position detection by providing an eccentric error signal generating means which generates an eccentric error signal corresponding to an amplitude signal based on the relation between variation of the amplitude signal in one rotation of a rotary moving body and the eccentric error of the rotary moving body in its rotating direction. CONSTITUTION:An amplitude signal generating means 5 inputs a two-phase instantaneous value signal outputted by a two-phase instantaneous value signal generating means 13 and performs arithmetic based upon an equation I to generate a signal corresponding to the amplitude V. The eccentric error signal generating means 6 inputs the amplitude signal V from the amplitude signal generating means 5, and generates the signal corresponding to the eccentric error DELTAepsilonof the rotary moving body 1 in its rotating direction due to the influence of eccentricity at a position theta. A position signal generating means 7 adds the eccentric error signal DELTAepsilon found by the eccentric error generating means 6 to a position signal theta found from an equation II to find the actual position theta' of the rotary moving body 1 from an equation III. Then the wave number from a high-order digit signal generating means 14 is added to detect a position alpha' in one rotation of a gear 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotational position detection device, and more particularly to a rotational position detection device that corrects errors due to eccentricity.

(Prior Art) FIG. 5 is a configuration diagram of a conventional gear-type magnetic rotational position detection device. In the figure, gear 1. Permanent magnet 2
and a two-phase AC signal generating means 2 consisting of a magnetic sensor 3.4
Two-phase AC signal Vs having a phase difference of 90" from 0 to each other
inθ, Vcosθ are generated, sample and
A two-phase instantaneous value signal monitoring means l3 consisting of a hold (S/I1) circuit 11 and an analog/digital (8/I) conversion circuit 12 extracts and outputs a two-phase instantaneous value signal from a two-phase AC signal. . On the other hand, the comparison evening. The upper digit signal generating means 14, which consists of a pulse counter or the like, inputs the two-phase AC signal (I1. Based on the calculation θ・jan-' (Vsinθ/
Vcos θ), and then generate a high-order digit signal in 1,000 stages l4.
The position α within one revolution of the gear is detected by adding the wave number from .

(Problem to be Solved by the Invention) However, in the conventional rotational position detection device described above, it is difficult to accurately align the center of the gear with the center of the rotational axis, and in reality, the center of the gear and the rotational axis are difficult to match. There was a so-called eccentricity in which the center shifted, and this eccentricity caused a slight displacement error in the rotational direction of the gear depending on the rotation angle, so there was a problem that the accurate rotational position could not be detected using only the above-mentioned calculations. there were.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a rotational position detecting device 1d that can perform accurate value calculation.

(Means for Solving the Problems) The present invention relates to a rotational position detection device that corrects errors caused by eccentricity, and the above objects of the present invention are to
a two-phase AC signal generating means for generating a two-phase AC signal having a periodic waveform corresponding to the moving distance of the rotating moving body and having a predetermined phase difference therebetween; and counting the wave number of the two-phase AC signal. upper digit (a) No. 5 generating means which uses the obtained value as the upper digit of the position information of the rotary moving body; and a two-phase instantaneous value signal which detects the instantaneous value of the two-phase alternating current (g) and generates the signal thereof. a generating means; an amplitude signal generating means for generating an amplitude signal corresponding to the amplitude of the two-phase AC signal based on the instantaneous value signal;
An eccentricity error signal corresponding to the amplitude signal is generated based on the relationship between the fluctuation of the amplitude signal within one rotation of the rotary movable body and an eccentricity error that is a displacement error in the rotational direction of the rotary movable body due to eccentricity. Based on the mutual ratio of the two-phase instantaneous values output from the eccentricity error signal generation means and the two-phase instantaneous value signal generation means! Calculate the position within the period,
position signal generating means for generating a position fit{g within one rotation of the rotary moving body by adding the eccentricity error signal to the signal of the calculation result and further adding information of the upper digit; This is achieved by having Also,
The eccentricity error signal generation means includes a storage unit that stores data indicating a relationship between a difference and an amplitude, and generates the eccentricity error signal according to the value of the amplitude signal based on the data. It is achieved by admonishing.

(Function) In the present invention, the amplitude signal generation means generates the f3 signal corresponding to the amplitude of the two-phase AC signal, and the amplitude error fz signal generation means generates the eccentricity error signal corresponding to the amplitude based on the amplitude signal. The position signal generating means synthesizes the eccentricity error signals to generate a position signal, thereby making it possible to detect the rotational position while taking into account the error due to eccentricity.

(Example) Examples of the present invention will be described in detail below based on the drawings.
tt clear.

FIG. 1 is a block diagram of a gear-type magnetic rotational position detection device, which is an embodiment of the rotational position detection device of the Wood invention, in which two-phase AC signal generation means 20, two-phase instantaneous value signal generation means 13, and The upper digit number generation means 14 is the same as the conventional one, so the explanation will be omitted.

In FIG. 1, the amplitude signal generating means 5 inputs the two-phase instantaneous value signal outputted from the two-phase instantaneous value signal generating means 13, performs calculation based on the formula (!), and generates a signal corresponding to the amplitude V. to make use of.

v@s+n+V'cos
θ) 2 ...... (l) The eccentricity error signal generation means 6 manually inputs the amplitude {g V from the amplitude signal generation stage 5 and calculates the rotation due to the influence of eccentricity at the position θ of the rotary moving body based on it. A signal roughly corresponding to the eccentricity error 2ε in the direction is generated. The position signal generation stage 7 is as shown in equation (2), θ・jan-'(V'sinθ/V"cosθ)
Adding the eccentricity error {No. 3 2ε} obtained by the eccentricity difference generation 1,000 steps 6 to the position signal O obtained by the 7-ri-1 calculation, the actual position 11? Find θ゛.

θ = θ + Aε (2) Finally, the wave number from the upper digit signal generation stage 14 is added to detect the position α° of the gear within one rotation. In addition, amplitude signal generation means 5, (Q heart error signal generation 1,000 steps 6 position signal generation means 7)
The high-order digit signal generation stage 14 can be easily realized by using a microcomputer or the like.

Next, the eccentricity error signal generating means 6 will be explained in detail. FIG. 2 is a diagram illustrating a case in which the rotating eight-wheel body is assumed to be a simple disk and is attached to the rotating shaft in an eccentric state. By the way, since the magnetic sensor 3.4 is generally fixed at a predetermined distance from the center of rotation, if it is eccentric,
Distance from the outer peripheral edge of the rotating moving body to the magnetic sensor 3.4 (
(hereinafter referred to as gap length) varies depending on the rotational position. Therefore, Fi passing through the magnetic sensors 3 and 4
Since the flux density differs depending on the rotational position, if this rotating moving body is a gear, the amplitude of the sine wave output from the magnetic sensor 3.4 will change depending on the rotational position, as shown in Figure 3. It will change depending on the position. Here, as is clear from Fig. 2, the amplitude signal in Fig. 3 is maximum when the gap length is the shortest, and conversely, the amplitude signal is minimum when the gap length is the longest. It's time.

Therefore, by detecting the rotational position at the maximum value v2 and minimum value v1 of this amplitude signal, the eccentric direction of the gear can be known, and the difference between the maximum value v2 and the minimum value V of the amplitude signal V-V2- V. The maximum value AC1.8 of the eccentricity error (B) is given by the following equation (3), where k1 is a constant.

2εwax =k, - AV (3) Therefore, the eccentricity difference 10 is the center value of the fluctuation of the amplitude signal as shown in FIG. (-(Vl+V2)/2), and if k2 is a constant, it can be calculated by the approximate expression (4) according to the 1,κ11 hanging signal V that is +1 at a desired rotational position.

AεtaAε+aax−k2 l V0−V l
``'''' (4) Eccentricity error signal generation 1,000 stages 6 is
An eccentricity error signal Xte is generated based on the value of the eccentricity error calculated by this equation (4).

Incidentally, since the relationship between the actual absolute value IAε1 of the eccentricity error Ae and the amplitude is as shown in Fig. 4, the approximate equation (4) is not used, and the eccentricity error and amplitude as shown in Fig. 4 are calculated. Data corresponding to the relationship is stored in the fr:5 circuit in advance as a data table f(x), and the eccentricity error signal AC is generated by calculating the equation (5) according to the amplitude signal. You may.

Aε= J 6 max'f((Vo-V)/FV)...(5) Also, k3, k. ．． As a constant, (6) . (7)
The eccentricity error may be calculated based on the approximate expression.

A.E. mk+(V2-V)(V-V+)
"・"' (6) J6 phantom L (V2-V)' (
V-Vl)"-"" (7) Furthermore, in the above-mentioned embodiments, a gear-type magnetic rotational position detection device was explained, but the present invention is not limited to this, and other forms, such as a drum-type The present invention can be applied to any position detection device that generates a two-phase AC signal as a position detection signal, such as a magnetic rotational position detection device.

(Effects of the Invention) As described above, according to the rotational position detection device of the present invention, highly accurate rotational position detection can be performed in consideration of errors due to eccentricity.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a gear type magnetic rotational position detection device which is an embodiment of the rotational position detection device of the present invention, Fig. 2 is a diagram showing an eccentric rotary moving body, and Fig. 3 is a diagram showing the rotational position and A diagram showing the relationship between amplitude, Figure 4 is a diagram showing the relationship between amplitude and eccentricity error,
Figure 5 is a configuration diagram of a conventional gear-type magnetic rotational position detection device. DESCRIPTION OF SYMBOLS 1... Gear, 2... Permanent magnet, 3.4... Magnetic sensor, 5... Amplitude signal generation means, 6... Eccentricity error signal generation means, 7.17... Position signal generation Means, 1l.
・・S/11 circuit, l2...^/D conversion circuit, l3・
...Two-phase instantaneous value signal generation means, l4... Upper digit signal generation means, 20... Two-phase AC signal generation means. Figure 2

Claims (1)

[Claims] 1. Two-phase AC signal generating means for generating a two-phase AC signal having a periodic waveform corresponding to the moving distance of a rotating moving body and having a predetermined phase difference between them; Upper digit signal generation means for counting the wave number of the two-phase AC signal and using the resulting value as the upper digit of the position information of the rotary moving body; and 2 for detecting the instantaneous value of the two-phase AC signal and generating the signal. a phase instantaneous value signal generating means; an amplitude signal generating means for generating an amplitude signal corresponding to the amplitude of the two-phase alternating current signal based on the instantaneous value signal;
Generate an eccentricity error signal corresponding to the amplitude signal based on the relationship between fluctuations in the amplitude signal within one rotation of the rotary movable body and an eccentricity error that is a displacement error in the rotational direction of the rotary movable body due to eccentricity. calculating the position within one cycle based on the mutual ratio of the two-phase instantaneous values output from the eccentricity error signal generating means and the two-phase instantaneous value signal generating means;
A position signal generating means for generating a position signal within one rotation of the rotary moving body by adding the eccentricity error signal to the signal of the calculation result and further adding information of the upper digits. Rotational position detection device. 2. The eccentricity error signal generation means has a storage unit that stores data indicating a relationship between the eccentricity error and the amplitude, and generates the eccentricity error signal according to the value of the amplitude signal based on the data. The rotational position detection device according to claim 1, wherein the rotational position detection device is configured to: