SU407367A1 - METHOD OF CONVERSION OF ANGLE OF TURNING SHAFT INTO CODE - Google Patents

Description

I

It is not necessary to adapt to technology, namely, to methods of converting the angle of rotation of the shaft into a code, which can be used to create automated information and control systems with digital computers.

The known method of converting the angle of rotation of the shaft into a code based on successive transformations of the angle of rotation of the shaft to the amplitudes of alternating voltages (currents) and using the sipus-cosipusnon of an electric machine, and then the amplitudes of the alternating voltages (currents) to a phase shift using phase-shift, RC-chain with subsequent measurement of the phase shift.

In converters constructed according to the well-known method, the conversion error depends on the electrical machine onshore voltage, the RC phase chain error, the PMnulse driver error, the optic signal caused by the RC circuit load and the phase shift between the supply and output voltages of the electric machine, and errors caused by delays in the communication lines between the elements of the transducer.

Some of these errors can be reduced by using the initial setup of the electrical system, as well as by using two phase-shifting RC circuits. However, since these errors are substantially

2

MSN5POTS, depending on the environment and on time, the accuracy of the transformation is not achieved under the conditions of tough mechanical and climatic influences for a long time. This primarily relates to the error introduced by the phase-shifting RC-chain due to a change in the capacitance values of the capacitor and the resistor as a result of their aging, which is a serious factor preventing the wide use of this method in converters of the angle of rotation of the shaft in the code .

The aim of the present invention is to improve the accuracy of converting the angle of rotation of the shaft into a code by eliminating RC errors, pulse shaper, errors caused by a phase shift between the supply and output voltages of the electric machine, the load on the phase shifting R (neH04Ky, line delays communication, as well as a significant reduction in the number of other open sides.

After measuring the phase shift in a known manner, the inputs of the RC chain are reversed, then the phase shift is measured again in a known manner, after which the conversion result in the code is found as half-difference of the two measurements.

According to the proposed method, the following sequence of operations is performed. 1. Convert the angle of rotation of the shaft a into electric signals of alternating current Ui and Ua, the amplitudes of which are proportional to the sine and cosine of the angle of rotation of the shaft a, respectively: U, and Uo sina sincot; U wo cosa sincot. 2. Convert the received AC signals L / i and Uc to the code of the angle of rotation of the shaft Na. For example, in accordance with one of the known methods, the voltage U is first shifted in phase by the angle +, and the voltage U2 is shifted by angle - and then the resulting 4. The voltages Ui and Uaa are added together and the resulting voltage phase Ua convert to code Nii: Uo sina-sin (w1 | - -); and.,;,: -:: bo cosa sin (); and,: and ,, -, and ,,,. and "sin" is the proportionality factor between the code and the angle of rotation. 3. After converting the code into a code in a known manner, the alternating current signals are reversed, and then the electrical signals of the alternating current are again converted into a code of the angle of rotation in a known manner. First, shift the voltage Ua in phase by angle + a, the incidence of U | - by angle -, and then the voltages obtained from this and, c, are added, and the phase of the resulting voltage Us is converted into the code Ns: .6 b ,, cosa-sin {m {j- - j; U | 5- .: Co sina.sin (u) t -);

U ,,, -, -U ,, -,: U ,, Sin (o) t-i

N ,. a

4. After this, the result of the converted angle of rotation of the shaft to the N code is found as the half-difference of the results of two transformations of the Nil, No and

Where; Na is the result of the conversion in case switch 3 is in position

K - scale factor; “Is the measured angle; Ala is the error of the phase-shifting NS-chain caused by changes in the values of resistor resistance and capacitor capacitance; (N, -N,) .-. K (..). Consequently, the value of the code N found in accordance with the actions indicated in the wording of the subject matter of the invention is proportional to the value of the angle of rotation of the shaft a. The drawing shows one of the possible options for the Converter circuit that implements the proposed method. The converter comprises an electric machine U having a stator 2 and a rotor 3, a switch of the inputs of the phase-shifting chain 4, a phase-shifting chain 5, pulse shapers 6 and 7, a high-frequency pulse generator 8, an enable-disable device 9 and a counter 10. The converter works as follows. The low-frequency sinusoidal supply voltage is applied to one of the stator windings 2 of the electric machine /, as well as to the shaper of the reference phase 6. Sine-wave voltages from the rotor windings 3, the amplitudes of which are proportional to the sine and cosine of the rotation angle of the rotor 3, respectively, are fed to the input switches phase-shifting chain 4, having two positions a and b. In the position "a", the voltage from the sine winding is applied to the resistor, and the voltage from the cosine winding is applied to the phase-shifting capacitor capacitor 5. In the position "b of the switch, the inputs of the phase-shifting chain 5 are swapped. The voltage from the RC-chain 5 is applied to the pulse shaper 7, which generates a pulse to the rapping-prohibiting device 9, the phase of which is proportional to the angle of rotation of the rotor 3 of the electric machine. The pulse from the imaging unit 6 is enabled, and the pulse from the imaging unit 7 prohibits the passage of signals from the high-frequency pulse generator 8 to the input of the counter 10. As a result, the counter 10 records the number of pulses proportional to the rotation angle of the rotor 3 of the electric machine 1. The code from the counter 10 is transmitted to the digital computing maplipu (digital computer). If switch 4 is in position “a, then the number transferred to the digital computer will be N. K (J + a-fAn, -fA.u-fA.a + Au. + Aa + -fAc -.- f ATH) ,