SU809055A1 - Discrete electric drive - Google Patents

Description

(54) DISCRETE ELECTRIC DRIVE

The invention relates to automation, in particular to following drives. Discrete drives with a phasing system are known in which the angular position of the output shaft is set in accordance with the clock pulses (phasing pulses) and which are the first approximation of a tracking drive closed in angle 1. The disadvantage of these drives is their low stability and accuracy. The closest to the present invention is an electric drive comprising a phase discriminator connected in series, a power amplifier, a motor, a gearbox, a differential sensor and a stable speed drive, the output of which is connected to the second input of the differential sensor; the engine output is connected to the first input of the phase discriminator through the speed sensor; the input of which is connected to the output of frequency divider 2. The disadvantage of this drive lies in the narrow field of application and low accuracy. This goal is achieved by the fact that the drive contains two binary multipliers, an adder, a code-phase converter and a logic unit, the first and second inputs of which are connected respectively to two outputs of the differential sensor, the third input - to the output of the code-phase converter, one input of which is connected to the output of the logic block, and the second input with the first input of the first binary multiplier, the second input and output of which are connected respectively with the second output and the fourth input of the logic block, the fifth input of which with the output of the second binary multiplier, one input of which is connected to the second output of the first binary multiplier and the first input of the adder, and the other input to the third output of the logic unit and the second input of the adder, the third input of which is connected to the second output of the second binary multiplier, and outputs connected respectively to the input of the power amplifier and the input of the frequency divider. The drawing shows a block diagram of a discrete electric drive, where the code of the reference angle (dj) and the reference frequency are indicated, which determines the discreteness of the angle

(fa).

Discrete electric drive contains serially connected phase discriminator 1, power amplifier 2, motor 3, speed sensor 4, gearbox 5, stator 6 of differential sensor G, the rotor 8 of which is connected to a stable speed drive 9, the input of which is connected to the output of the fixed stator 10 of differential sensor 7 and the input of logic block II, the other input of which is connected to the output of the movable stator 6, and the third input - to the output of the Codphase 12 converter, one input of which is connected to the input of the electric drive 0., the other to od - to the output unit 11, and {tretr minutes schinoy input coupled to the reference frequency input and a first binary multiplier 13, a second binary multiplier 14, an adder 15 and a frequency divider 16.

Discrete drive works as follows.

Let the code for the drive angle L3 at the input of the code-phase converter 12 be zero and the output shaft of the stable speed drive 9 will not rotate. In this case, the movable stator 6 of the differential sensor 7 occupies a certain angular position and, if this position is such that the shift between the teeth of the movable 6 and the stationary

10stator sensor 7 is missing, the pulses from the outputs of the movable 6 and the stationary 10 stators of the sensor 7 in-phase. The logic unit 11 with the arrival of a pulse from a stationary stator 10 permits the passage of pulses of a reference frequency f, which is determined by the required angle resolution, to the code-phase converter 12. The latter is a counter if the driving angle is supplied in a digital binary code, and setting the code to zero a pulse from the output of the code-phase converter 12 is formed with the first frequency pulse {e. Logical block

11 when a pulse is received from the code-phase converter 12, it prohibits the passage of f impulses to the last. until the next pulse from the fixed stator 10.

Logic unit 11 analyzes the magnitude of the phase mismatch between the pulse from the code-phase converter 12 and the pulse from the movable stator 6. If the magnitude of this mismatch does not exceed the period of frequency f, then the frequency fa does not arrive at the binary multiplier 13 and its output frequency is zero.

If the code of the driving angle is not zero, the pulse from the output of the code-phase converter 12 is phase shifted relative to the pulse from the stationary stator 10 by a time proportional to the code of the driving angle d, i.e. a phase error occurs between the pulse from the converter code - Phase 12 and the pulse of the movable stator 6, which the discrete actuator 9 should work. Logic unit 11 for a time equal to the phase mismatch between the indicated pulses permits the passage of the frequency pulses -fj to the binary multiplier 13, where the error code between the specified angular position and the position of the moving stator 6 is generated. From the output of the binary multiplier 13, an adder 15 and a binary multiplier 14, which serves to increase the accuracy of the electric drive. The point of introducing the binary multiplier 14 into the electric drive is that

due to the correction signal produced by it, the necessary speed can be developed by the electric drive with a relatively small value of the error signal. Depending on the mismatch sign, the frequency from the binary multiplier 13

arrives at the positive or negative input of the reversible counter of the binary multiplier 14, and to facilitate the generation of the output signal of the binary multiplier 14 in the pulse-frequency form, the logic unit 11 calculates the correction signal only in the forward code. This is achieved by the logic unit 11 fixing each zero state of the reversible counter included in the binary multiplier Q. 14. If, after the zero state, the reversible counter of the binary multiplier 14 receives at the beginning pulses corresponding to a positive mismatch, i.e. When the pulse from the movable stator 6 lags behind the pulse from the code5 converter, phase 12, they arrive at the positive input of the reversible counter, and the pulses corresponding to the negative mismatch arrive and its negative input, and the sign of the result is positive. If, after the zero state of the reversible counter of the binary multiplier 14, the pulses corresponding to the negative mismatch arrive first, then they also arrive at its positive input, and the pulses

5 corresponding to a positive mismatch, they arrive already at the negative input of the reversible counter, and the sign of the result will be negative.

Logic unit 11 captures the zero 0 state of the reversible counter of the binary multiplier 14 and connects its positive input to the output of the binary multiplier 13, and sets the sign of the result to a similar mismatch sign at the first moment. When the mismatch sign changes from the binary multiplier 13, the logic unit 11 connects its output to the negative input of the reversible counter of the binary multiplier 14, but the sign

the result changes only when its zero state is fixed, and the input after that will be received the signal of a mismatch of another sign.

The frequency from the output of the binary multiplier 14, proportional to the correction signal, arrives at the second input of the adder 15, which produces an algebraic addition of frequencies from the outputs of the binary multipliers 13 and 14. Since the pulse sequences from these blocks are uneven, their sum and difference will also have uneven, and therefore the algebraic sum of the frequencies of the adder 15 is fed to the phase discriminator 1 through a frequency divider 16, which serves to smooth out the unevenness of the pulse sequence elnosti. Phase discriminator 1 detects the phase mismatch of frequencies from frequency divider 16 and frequency speed sensor 4 and, as a phase error function, controls motor 3 through power converter 2.

Thus, the introduction of the above-mentioned blocks into a known electric drive makes it possible to use it in the following mode and to significantly increase the tracking accuracy, i.e., to create a noise-resistant, thermostable, high-precision electric drive, which has much better mass-dimensional characteristics compared to, for example, digital electric drives.

Claims (2)

1. USSR Author's Certificate No. 2152282/24, cl. G 05 B 11/30, 1975. 2. USSR author's certificate No. 2310754/24, cl. G 05 B 11/30, 1977 (prototype).