SU851722A1 - Follow-up electric drive - Google Patents

Description

The invention relates to electrical engineering, in particular, to the automation industry, and can be used in numerical control installations. In the following electric drives, either a direct current electric motor or a stepper electric motor are most often used as an actuator. The following electric drive is known, which contains two stepper electric motors connected by its inlet to the input shafts of the differential gearbox, the output shaft of which is connected to the working body. The closest to the technical essence is the following electric drive containing the direct current motor to the output. a power amplifier, a stepper motor with a control unit and a differential gearbox connected by one input shaft to the shaft of a DC motor, the second to a shaft stepper motor, and the output shaft - with a working body 2 |. A disadvantage of the known is the lack of speed and accuracy, as well as a limited range of speed control. The purpose of the invention is to increase speed and accuracy. The goal is achieved by introducing a pulse sensor, a code-frequency converter and a reversible counter, the input input of which is connected to the input of the power amplifier, subtraction input - with the output of a pulse sensor mounted on the output shaft of the differential gearbox, and the outputs of the reversible counter are connected to the inputs of the code-frequency converter connected by the outputs with the input of the control unit stepper motor. Such an embodiment of the drive leads to the fact that the speed of the dc motor controlled from the power amplifier is summed with the speed of the stepper motor differential gear. The speed deviation of the output shaft of the differential gearbox from the predetermined speed is fixed in the reversible counter.

the input of which receives the driving pulses, and the input of the subtraction receives the pulses from the feedback sensor mounted on the output shaft of the differential gearbox. The code-frequency converter converts the deviation recorded in the meter into pulse sequences at one of its two outputs, depending on the magnitude and sign of the deviation. A stepper motor, which has a higher speed than a DC motor, fulfills this deviation. As a result, the speed of the output shaft of the gearbox exactly follows the given speed and the resulting average errors in the angular position and velocity are zero.

The drawing shows a diagram of the following electric drive.

The mechanical summation of the motions of the direct current motor 1 and the stepper motor 2 is carried out by a differential gear 3. The driving force — in a series of pulses of a pulp, whose frequency determines the angular velocity of the output shaft of the gear unit 3, is fed to the input of a pulsed power amplifier 4. The outputs of the amplifier 4 are connected to a DC motor 1 DC. At the same time, the pulse sequence fphaE is supplied to the input of the addition of the reversible counter 5, to the subtraction input of which feedback pulses are fed to the feedback sensor mounted on the output shaft of the differential gear 3. The frequency of the feedback sensor pulses is proportional to the angular velocity of the output shaft . The outputs of the counter 5- are connected to the inputs of the code-frequency converter 7, which produces pulses either at the output + or at the output - depending on the state of the outputs of the counter 5. The outputs of the converter 7 of the code-frequency are connected to the inputs of the stepper motor control unit 8 switching the windings of the stepper motor 2 in the required sequence.

The device works as follows.

The speed of the output shaft of the gearbox 3, defined by the pulse frequency fjo at the input of the power amplifier -4, is determined by the algebraic sum of the speed of the direct current motor 1 (i) -)) and the stepper motor 2 (Wg.). In the steady-state mode, the pulse frequency f3ad of the addition input of counter 5 is equal to the pulse frequency fQ at the subtraction input, and the number that is written in it does not change. In this state of the counter 5, the code-frequency converter 7 produces pulses at its outputs and the stepping motor 2 is driven to rotate. When the frequency of the driving pulses at the input of the pulse amplifier 4 is changed by the speed CW;) / of the direct current motor 1, due to its inertia, it does not have time to quickly Change. As a result, the frequency of the pulses at the inputs of the addition and subtraction of the reversible counter 5 becomes different from each other and the deviation of the angular velocity of the output shaft of the gearbox 3 relative to a predetermined value is recorded. AT

5 depending on the magnitude and sign of the deviation recorded in the counter 5, the code-frequency converter 7 produces pulses at one of its outputs, the frequency of which is proportional to the deviation recorded in the counter 5. These pulses go to the control unit 8 and the stepper motor 2 begins to rotate this deviation, to those

5 P until the frequency of the pulses at the output of the 6 feedback sensor becomes equal to the frequency of the driving pulses.

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Claims (2)

1. Ismailov S. Yu. Automated systems and devices with stepper motors. M., Energie, 1968, p. 29.. 2. Patent of Germany No. 2103792, cl. H 02 R 7/00, 1975.