SU583465A1 - Method of conversion of angular position to code - Google Patents

Description

1The invention relates to the field of automation and computer technology and can be used to connect analog sources of information with a digital printer.,

Methods for converting an angle into a code are known.

Some of the known methods are based on converting the angle to the phase shift of two sinusoidal signals, measuring the phase shift between the first and second signals, switching the signals and measuring the phase shift between the second and first signals, determining the correction and calculating the angle value by summing the measured angle with correction value i}

The disadvantage of this method is its precision, since the phase-error error is not smoothed.

There is also known a method for converting an angle based on double converting an angle into a phase and then into a code with opposite directions of rotation of the pop phase shifter and calculating the angle as half the difference of the measured results 2 j.

The disadvantage of this method is the low resolution capability.

The closest technical solution to the invention is a method of converting an angle into a code, based on transforming the angle into two phase voltages that are out of phase relative to the other, forming the reference frequency from two voltages and the heterodyne frequency, less than the reference frequency, two signals of difference frequency and measurement of the magnitude of the phase shift between the first harmonic components of difference frequency signals.

A disadvantage of the known device is low accuracy caused by phase instabilities of filters and null organs.

The aim of the invention is to improve the accuracy of angle measurement.

The goal is achieved by the fact that of the two voltages of the reference frequency and the voltage of the heterodyne frequency, larger than the foot of the difference frequency, form an additional two differential frequency signals, measure the magnitude of the phase shift. between the first harmonic components of the additional difference frequency signals and the determinant angle code based on the phase difference of the first harmonic components of the difference frequency signals. The drawing shows a functional diagram of the device that implements a method for converting an angle into a code. The device contains a reference frequency generator 1 connected to stator windings of phase shifter 2 and one input of mixer 3, local oscillator 4 with tunable frequency, connected to other inputs of mixer 3 and mixer 5, the first input of which is connected to rotor windings of phase shifter 2. Outputs of mixer 3 and 5 are connected through filters 6 and 7 to zero. Organs 8 and 9 whose outputs are connected to a phase shift transformer to a code. The control unit 11 synchronizes the operation of the device and switches its modes. The first value of the phase shift between the reference signal from the output of the generator 1 and the information signal of the phase shifter 2 is determined at its heterocine frequency, the lower frequency oJ of the file generator. In this case, the instantaneous value of the first harmonic compulsive voltage between the outputs of mixers 3 and 5 for the difference frequency can be written as Uj Ucos (CL) f (l) where OQ is u (X is the phase shift, proportional to the rotation angle of the rotor of the phase shifter relative to the stator. Pass the filters and the nulls of the organ, the direction and acquire additional phase shifts8 "., (Sjt Sd) (2) The instantaneous value of the first harmonic component of the voltages between the outputs of mixers 3 and 5 for the difference frequency at the heterodyne frequency dig, higher frequency Phase driver power UJo is written as UCOSflgt + t.), 5g 2t) e- When the ratio of Si is fulfilled. expression of voltage U, can be typed in the form, cos («, t -) (3) Pass the filters and null organs, the voltage Uj (h) also acquires additional phase shifts. i U UGOsfSI, t-oL4 d-ol) (4) Measuring phase shifts between 1 input signals of null organs 8 and 9 using the Yun converter, determine the half-difference of the measured values, get a code proportional to the angle of rotation. In this case, the error caused by the phase BbfK .H filter shifts and their instability is eliminated, which allows the use of elements in filters that are not subject to precision requirements for a long time. temporal and temperature stability. There are also no strict requirements on the stability of the threshold for triggering null-organs, which allows the use of the simplest comparators. High noise immunity. allows to fully realize the accuracy properties of the system. As a result, the predictability of the measurement of the shift decreases from 5 ... 1, O to a value of L 0.5 .., 0.1. The economic effect of using the method is determined by its technical advantages. Claims method of converting an angle into a code based on converting an angle to a phase shifted relative to each other two on the reference frequency voltage, forming two reference voltage voltages and a heterodyne frequency voltage less than the reference frequency, two difference frequency signals and measuring the magnitude phase shift between the first harmonic components of the difference frequency signals, which is due to the fact that, with an increase in accuracy, of the two voltages of the reference frequency and the voltage of the heterodyne frequency, With a reference frequency equal to the frequency, additional two differential frequency signals are generated, measuring the phase shift between the first harmonic components of the additional differential frequency signals, and determining the angle code based on the phase difference of the first harmonic components of the signals. difference frequencies. Sources of information taken into account in the examination: 1. USSR author's certificate number 455356, e-08 C 9 / OO, 11.O9L972. 2. USSR Author's Certificate No. 317090, G 08 C 9 / O4 2O.O3.1969. Part 3. USSR Author's Certificate No. 409258. G-O8 C 9 / OO, 08/30/1971.