SU1383286A1 - Servo system - Google Patents

Abstract

The invention relates to automatic regulation and can be used in tracking systems, in particular, operating under conditions of significant distortion of the tracking error signal. The aim of the invention is to improve the accuracy and maintain the tracking error within the specified limits. The system contains a comparison element, an error isolation block, an adder, an amplifier, an executive element and n channels of the same type, each of which contains a correction amplifier, a threshold device, a pulse driver, a reversible counter and a digital-analog converter. The essence of the system operation is that when the tracking error signal increases to certain limits (different for each channel) in a stepwise manner, one or another constant signal is introduced into the error signal, which reduces the tracking error, as it decreases, 3 sludge. with "(L

Description

with

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The invention relates to the field of automatic control and can be used in tracking systems, in particular, operating under conditions of a significant distortion of the tracking error signal.

The purpose of the invention is to increase the accuracy and maintain the tracking error within the specified limits.

FIG. 1 shows a functional diagram of the device in FIG. 2 illustrates an example of a static tracking error conversion characteristic in an error highlighting unit; in fig. 3 is a static characteristic of a threshold device.

The following system (Fig. 1) contains a comparison element 1, an error isolation block 2, an adder 3, an amplifier 4, an executive element 5, a correction amplifier 6, a threshold device 7, a pulse shaper 8, a reversible counter 9, and a digital-to-analog converter ten.

The error highlighting block 2 is a block in the static characteristic: of which (Fig. 2) both physically determined and specially entered properties 1 of the devices for retrieving and converting information about the error signal are reflected. Examples of blocks are radio telescopes with a narrow radiation pattern, photoelectronic sensors with a limited field of view, etc. In such systems, even with a short-term error U, beyond the limits of allowable values ± idd, the disappearance of the signal and the failure of the follow-up signal can occur.

Consider the structure of one of the n correction channels. The output device of the correction channel is a correction amplifier 6. It is intended to amplify the error signal U over voltage and to smooth out the high-frequency component of the error caused by the control and disturbing effects. The filtering properties of the amplifier are determined by its bandwidth, which is chosen different for all n correction channels, the maximum at, the minimum at i i (i is the number of the correction channel). Gains of K amplifiers; all n channels are single.

The magnitude of the voltage threshold and triggered; for each of n channels

The corrections are chosen differently and increase with increasing channel number i. Threshold value

for channel n, it is selected based on the value of the maximum permissible system error.

When the signal at the input of the threshold device 7 (Fig. 3) reaches + U, or it is triggered and, depending on the sign of the system error, the output signal U - 1 changes (from logic level 1 to logic level

O), or the output signal U - 2 (from the logical O level to the logical 1 level).

The output signals of the threshold device 7U -, - 1 yi7 -2 come

to the corresponding inputs of the imaging unit 8 pulses.

Pulses are formed at the output of the driver of 8 pulses under different conditions: one of the outputs is from logical O to 1, the other output is from logical 1 to O. These signals are fed to the inputs of the forward and reverse counting of the reversible counter, 9, respectively which produces a summation of the number of pulses arriving at its inputs, with the total sum

K g - 1,

where g is the number of impulses arriving

at the input of the direct account 1 - the number of pulses that came

at the entrance of the countdown. In the bits of the reversible counter 9, the sum K is recorded as a binary code, which is converted into a correction signal at the output of the corresponding digital-analog converter 10, and a channel with a higher threshold value and a large voltage value corresponds to a channel with a large i at the output of the digital-to-analog converter 10, coming from the low-order unit of the reversible counter 9.

The system works as follows.

The signal U5 from the output of the error isolation unit 2, the passage through the cathode controller 3, goes to the input of the amplifier 4, where it is amplified to the values necessary for controlling the actuating element 5.

At the same time, the signal from the output of the error extracting unit 2 is fed to the input of the correction channel, consisting of n parallel analogue channels. The signals of all n channels are summed on a 3 "adder.

Suppose that during the tracking process, the system error reaches a certain magnitude and, |. At the same time, the voltage at the output of the correction amplifier 6 of the first correction channel, proportional to this error, reaches the value Uj, and at the output of the digital-threshold converter 10, a correction signal is formed corresponding to the number code recorded in the reversible counter 9. This signal, summing up adder 3 with an error signal causes the output coordinate of the system to change in the direction of decreasing the error.

one

If the system error, which tends to increase, again reaches the value and, the signal at the output of the digital-to-analog converter 10 doubles its value, since at this moment a new pulse is generated at the output of the pulse former 8 and another number is written in the reversible counter 9 etc.

A decrease in the voltage at the output of the digital-to-analog converter 10 occurs when the error of the tracking system changes sign, and the voltage at the output of the corrective amplifier b, proportional to this error, reaches the value -Up. In case of further increase of the error in the direction of negative values and repetition of voltage gain at the output of the amplifier 6 values -Ug, the described step-wise voltage rise process at the output of the digital-analog converter 10, but with a negative sign, takes place.

Thus, under certain control and disturbing effects, the system error is within certain limits, and this is ensured by generating additional correction signals at the output of the first correction channel.

However, at high rates of change of controlling and disturbing

action may be that the correction signal generated by the first correction channel is not enough to keep the error within the tolerance

J5 20 25

d /

45

50

five

 within the limits. In this case, when the system U reaches an error of a certain value U (U U,), the voltage at the output of the corrective amplifier of the second channel reaches the value UQ) in the reversible counter 9 is recorded a different number than the first channel. The magnitude of this voltage is greater than the voltage corresponding to the youngest bit of the digital-to-analog converter 10 of the first channel.

Thus, the joint operation of the first and second channels allows keeping the system error within large limits, which corresponds to a new range of rates of change of control and disturbing influences, etc.

To ensure stable tracking, it is necessary that the channel with a higher output voltage of the digital-to-analog converter 10 (or, equivalently, a larger channel number) corresponds to a lower bandwidth of the correction amplifier 6,

The parameters of the device as a whole — the revolution n of the correction channels, the threshold value Ug, the threshold device 7, the voltage at the output of the digital-to-analog converter 10, corresponding to the lower limit of the reversible counter 9 — are determined based on the requirements imposed on the system according to the maximum permissible error, from the maximum possible values of the control and disturbing influences and also the rates of their change from the dynamic properties of the uncorrected system.

The fact that the formation of a correction signal occurs due to the actual change in the error, regardless of what caused this change (control or disturbance) and without any time delay, indicates the effectiveness of the application of the proposed device in terms of slowly varying effects, and in the presence of factors that cause a discontinuous, pulsed change in error.

Claims (1)

The following system, comprising a comparison element, whose input is an input of the system, as well as a series-connected adder, an amplifier and an actuating element, the output of which is connected to the second input of the comparison element and is an output of the system, characterized in that In order to increase the accuracy and maintain the tracking error within the specified limits, an error highlighting block and C1 correction channels are additionally introduced, each of I which contains a series-connected correcting amplifier threshold device, a pulse shaper, a reversible counter, and a digital-to-analog converter, the output of which is connected to. the corresponding adder input, the output of the comparison element through the block, the error complement is connected to the inputs of the correction amplifiers and to the (n + 1) th input of the adder. Ft.2 Aogic g / L-hell fJH (6i) Pu, g.Z. Ufl, tlfZ fJrf / Logical o and, (i / e)