SU840798A1 - Follow-up system - Google Patents

Description

(54) FOLLOWING SYSTEM

The invention relates to following systems and can be used in various technological installations in which high dynamic performance is required over a wide range of amplitudes and rates of change of control actions. The following tracking systems are known, which contain a master device, an adder, a control signal driver, a correction circuit, an amplifier-conversion device, an executive motor, a gearbox, adjustable coordinate sensors, a tachogenerator: a torus, a coefficient switching unit and an ij and 2 character analysis block. The proposed system is a tracking system comprising successively connected a driver, an adder, a signal generator, an amplifier-converter device, and an actuator The motor, the input of which is connected to the second input of the amplifier-converting device through series-connected tachogenerator and variable coefficient unit, and through the series-connected gearbox and adjustable-coordinate sensor to the second input of adder, the output of which through the filter is connected to the first input of the comparison unit, the second input of which is connected to the second output of the control signal generator. The known system has a high dynamic accuracy when developing a sawtooth or sinusoidal control action changing at high speed by disconnecting a signal proportional to the speed of the output shaft of the executive motor generated by the tachogenerator from the input of the amplifying device when there is a special signal carrying information system operation mode A disadvantage of the known system is its low accuracy and speed in a wide range of amplitudes and rates of change of control actions in the absence of a priori known information about the mode of operation of the system. The purpose of the invention is to improve the accuracy and speed of the system. . The goal is achieved by the fact that in the tracking system, the output of the character comparison block is connected to the control input of the variable coefficient block. , FIG. Figure 1 shows block diagrams of a tracking system; in fig. 2 - signal curves explaining the operation of the proposed system. The following system contains a driver 1, an adder 2, a control signal generator 3, a code-voltage converter 4, an amplifier-converter device 5, an actuating motor .6, a gearbox 7, an adjustable coordinate sensor 8, a tachogenerator op 9, a block of variable coefficients , filter 11 is a block 12 of character comparison, output signal 13 of adder 2, output signal 14 of filter 11, output signal 15 of the amplifier and converter device 5, time t — first switching, time tj — second switching, time t –j is appropriate maximum value of the overshoot in the system. The proposed system can be implemented both in analog (continuous) form and in digital (discrete) form. In the latter case, when blocks 1, 2, 3, 4 and 8 are implemented in digital form, the system does not need to enter the voltage code 4 converter, which will serve to coordinate the digital part of the system with the analog one. The proposed system in the digital version works in the following way. The master device 1 generates a driver action in the form of a double code, which, depending on the mode of operation, can be changed according to a step, sawtooth or sinusoidal law. In the digital adder 2, the adjustable coordinate coming from the digital sensor 8 is also subtracted from the driving signal of the digital sensor, also in the form of a binary code. The difference signal calculated in digital adder 2 enters the control signal generator 3 (control register), the output of which forms the absolute values of the difference code as n binary digits (usually n 3-6) and the sign of the difference. Next, the difference signal code is converted by converter 4 to voltage into direct current voltage and fed to the input of amplifier converter device 5, d it is added to the signal from the output of the block of variable coefficients 10 by the formula and - slgnx-sign - KjXpbixnpH srgnx sign where X - t is the signal at the second output of the control signal generator 3, y is the signal 14 at the output of the digital filter 11 having a positive phase-frequency characteristic, X is the signal from the tachogenerator Bbfx torus 9 proportional to the speed of the output shaft of the executive motor Atel 6 with the coefficient K or Kz. and - the output signal of the transducer 4. The control signal m (15) in the amplifier-converter device 5 is converted into alternating current voltage, amplified and fed to the control windings of the actuating motor b, which is processing the existing error and through the gearbox 7 rotates code sensor 8 the angle at which the difference signal becomes zero. When the system is operating with a high-speed sawtooth output, the sign of the signal from the output of the digital filter 11 sign y in the linear part of the system’s motion is equal to the sign of the signal sign x from the second output of the control signal generator 3, and the sign comparison unit 12 generates a signal that switches a block of variable coefficients 10 by a factor K, the value of which is selected based on the requirements of the characteristics of the tracking system. When choosing the value of KO, the passage of the signal Xp from the output of the tachogenerator 9 through the block of 10 variable coefficients to the input of the amplifier-converter device 5 is prohibited. As a result, the system has a high quality factor, and a dynamic error in the input signal processing mode, which changes at high speed, significantly reduced. When a sinusoidally varying input signal is tested, variable variable block 10 connects the signal from the output of tachogenerator 9 to the input of the amplifying-converting device 5 with the coefficient K2 for a relatively short time during the half period, which also significantly increases the system accuracy in steady state mode. . The operation of the tracking system in the mode of testing step input signals / whose amplitude can vary over a wide range is as follows. Let the transfer function of the continuous part of the follow system be W, p, to such a form

lead, for example, the transfer function of the system, in which the asynchronous two-phase motor with a hollow rotor is used as the executive motor 6 under the condition of neglecting the time constant of the amplifier-converter device.

 / k

where K is the quality factor of an open signal

Topics,

T is the time constant of the executive engine with loading.

Up to the moment t (Fig. 2) the speed feedback from the output of the tachogenerator 9 through the variable coefficient unit 10 is connected to the input of the amplifying device 5, with the factor KO, the signal 13 from the output of the control register 3, changes according to x coswot a the rate of change of this signal is defined as x -w ,,. which provides a high value of processing speed. The condition of the first switching is a change in the sign of the signal 14 from the output of the digital filter 11. At the time t, the coefficient switching unit 10 connects the speed feedback signal from the output of the tacho generator 9 to the input of the amplifier-converter device K2 O, which causes a transient to slow down system due to a sharp decrease in its quality factor.

From the point of view of sensitivity of transient indicators to changing system parameters (for example, K - transfer coefficient, T - constant time), the most optimal choice is the coefficient K

of condition K2 - Moment t, in which

about

The second variable coefficient block 10 switches the signal transfer ratio from the output of the tachogenerator 9 from K. to K (K 0), corresponds to the moment of change of the sign of the signal 13 from the output of control register 3 and from condition x (t2) O is defined as

and 1 Wj, (tg wpt U

The maximum overshoot in the system corresponds to the point in time (Fig. 2) when the rate of change of the error x (t3) is O. In this case, the overshoot is equal to the error value x (1h) O taken with the opposite sign, and is defined as

6 (sin w, t - cos w;, t)

where the value of wgt is determined by the parameters of the digital filter 11. Thus

Thus, the appropriate choice of K and K2 coefficients and their switching in block 10 of variable coefficients as a function of the signal from the output of character comparison unit 12 allows obtaining a transient process in the proposed tracking system with a predetermined overshoot value and high speed in a wide range of amplitudes of the input step signals.

The use of new connections between known functional blocks favorably distinguishes the proposed follow system from the known one, since it allows to significantly reduce the value of dynamic error in the system when developing a sawtooth or sinusoidal input signal changing with high speed, in the absence of a priori information about the operating mode approximately 4–5 times, and increases the system’s performance by a factor of two, as with an amplitude of the input stepped signal, slightly different from zone of the system, as well as at large amplitudes.

Claims (3)

1. USSR author's certificate on application 2353243 / 18-24, cl. G 05 B 11/01, 1976. 2. Authors certificate of the USSR 438984, cl. .G 05 B 15/02, 1972. 3. Khlypalo E.I. Nonlinear correction devices in automatic systems. L., Energie, 1973, p. 6589 (prototype). 15 Fie.2