SU1246373A1 - Shaft turn angle-to-digital converter - Google Patents

Abstract

The invention relates to the field of automation and computer technology and is intended to measure the angular displacements in software systems for controlling machine tools and in control systems for optical and radio telescopes. The aim of the invention is to improve the accuracy and reduce the size of the converter. To this end, CO Exit

Description

the centers of the outer and inner circumferences of the measuring disk track are located on one straight line relative to the center of rotation of the disk, the eccentricity of the outer circumference being greater than the inner track eccentricity, and the length of the gap in front of the first sensitive element of each pair is smaller than the smallest width of the track; the second sensitive element of each pair, is greater than the maximum width of the track. By rotating the shaft

The invention relates to automation and computing and can be used in software systems for controlling machine tools, in control systems for optical and radio telescopes.

The purpose of the invention is to increase the accuracy and reduce the size of the manufacturer.

The drawing shows the transducer, the angle of rotation of the shaft in the code.

The converter contains a measuring disk I with track 2, an indicator disk (not shown) with slots 3-6, an excitation source (not shown), sensitive elements 7-10, differential amplifiers 11 and 12, and an amplitude modulated conversion unit 13. signals in the code.

The converter works in the following way.

When the measuring disk 1 rotates, the excitation source radiation modulated by track 2 and slits 3 and 5 of the indicator disk hits the sensitive elements 7 and 9. The outer bounding circle has an eccentricity L, ОА relative to the axis of rotation of the shaft, and the inner bounding circle is eccentricity b „ABOUT, with L ,, L.

The radiation reaching the sensing element 7 is determined by the function of the transmission of the coupling of the slit 3 and the track 2.

The skip P is determined by the expression

6373

the converter modulates the light fluxes of the indicator and tracks of the measuring disk to the sensitive elements. At their outputs, signals are generated that are proportional to the angle of rotation of the disk and do not contain the errors with which the track is applied. Transformation of the output film with sensitive elements. in the code is carried out. in the block. 1 il.

P-E (X - X) d,

(one)

where E is the conjugated illuminance

floor; the distance between the outer

the bounding circle and axis O of rotation of disk i; X., - the distance between the inner bounding circle and the axis O of rotation

disk 1;

d is the width of the slots 3. But since the tracks 2 surrounding the active portion of the circumference 2 have eccentricities OB and OA with respect to the rotation axis O and the directions of eccentricities are opposite,

1 s.in20 + Vos (ete.); (2)

 .

| h1y2v +, so5 (e1e „), (d)

2R,

 one

the magnitude of the eccentricity of the outer limiting circle;

o, are the eccentricity values due to the beating of the measuring disk 1;

9 - the angle of rotation of the converter shaft}

Oj, is the eccentricity value of the inner bounding circle;

 , R - radii of the outer and inner circles, respectively;

QO initial phase shift.

3

Substituting expressions (2) and (3) into (1), we obtain

P

 E, (S + S} cosQ- +

Si

+ -sin0-KS, COS (at t {

2R - (5x cos (0te) d.

As can be seen from expression (4) for full compensation

 / by, j

errors

it is necessary that S / 2R 6 / 2R, for this purpose be selected

Substituting expression (5) into (4), we obtain 20

P + (i + 5 ;,) cosej. (6)

As can be seen from expression (6), the function of transmission mate varies 25 according to a harmonic law and does not depend on the beat. Measure disk 1.

The radiation modulated by the track 2 and the slot 3 is incident on the sensitive element 7, at the output of which Q the signal U is formed:

1 - about

+ and .., cose,

35

where Uo is a constant component,

dependent on (R-R) d; and „- amplitude, depending on

(S, + &,) d.

Since the slit 5 is shifted relative to the slit 3 by 90, the output of the sensing element 9 of the signal 9 forms a signal and:

0 and „+.

Due to the fact that the length of the slots

4 and 6 are smaller than the minimum width of track 2, then constant light fluxes fall on the sensitive elements 8 and 10. By changing the steepness of the characteristics of the sensing elements 8 and 10, the voltage at their outputs becomes equal to U.

The signals from the outputs of the sensitive elements 7-10 are fed to the corresponding inputs of differential amplifiers 11 and 12, the outputs of which

VNIIPI

Order 4022/56 Edition 816

 +

12463734

the signals Uj and U are symmetric about zero:

Uj U cosS; U Ursine,

ten

f5

20

25

Q

35

45

50

55

rage 816

Amplitude modulated signals into a code 13, which is a transducer of sine-cosine signals into a code and can be constructed according to any known principle (tracking balancing, bitwise weighting, an interpolator on the basis of a potentiometric phase shifter and .d.)

Claims (1)

Invention Formula The converter of the shaft rotation angle into the code containing the excitation source optically connected through the first and second slots of the indicator disk and the track of the measuring disk with the first and second pairs of sensing elements installed with a 90 ° offset from each other, the outputs of the first and second pairs sensitive elements are connected to the inputs of the same differential amplifiers, the outputs of which are connected to the inputs of the amplitude-modulated signal-to-code conversion unit, while the active section of the tracker and The measuring disk is limited by the outer and inner circles, the center of the inner circle is offset from the center of the measuring disk by an eccentricity value L, characterized in that, in order to increase the accuracy and size of the dimensions, the indicator disk is made with third and fourth the center of the outer circumference is located on the straight line passing through the center of the inner circumference and the center of the measuring disk, the disk is on the other side of it and is offset from the center of the measuring disk by an eccentric value theta L, with L i Ц, the length of the first and second slots of the indicator disk in front of one sensitive element of each pair is less than the minimum width of the measuring track, and the length of the third and fourth slots of the indicator disk in front of the other sensitive element of each pair is greater than the maximum width track measuring disc. Subscription Random polygons pr-tie, Uzhgorod, st. Project, 4