SU851335A1 - Electric hydraulic servo-drive - Google Patents

Description

The invention relates to electro-hydraulic follow-up drives and can be used in the construction of redundant drives for automatic and remote control systems.

Closest to the present invention is an electro-hydraulic follower drive I comprising a serially connected feedback sensor, a first adder, an amplifier, an actuator, a position sensor, a second adder, a comparator and a key, and a third adder connected in series, an integrator and an inverter whose output is connected with the second input of the second cyNMaTopa and the first input of the third adder, and the feedback sensor input is connected to the output of the actuator t l The disadvantage of this circuit is that uets extension threshold comparator relatively minims1lno possible magnitude in connection with the change of the maximum rate of movement of the working channel when changing the operating conditions and the external load and the insensitivity to changes in these conditions, the maximum output speed signssha

electronic control channel, which reduces the reliability of the drive.

The purpose of the invention is to increase the reliability of the drive.

This goal is achieved due to the fact that the drive contains a voltage limiter, the input of which is connected to the output of the second adder, and the output to the second input of the integrator.

FIG. drive diagram shown; in fig. 2 is a diagram of the testing of the drive with smoothly varying input signals in FIG. 3 and 4 - diagrams

5 test driven jump input signals under different initial conditions; in fig. 5 is an example of a failure of a working channel of a drive due to arrival at its input. false control signal.

The drive consists of operating 1 and electronic control 2 channels connected to independent input sources Ujx.p and Ug. The working channel consists of the first adder 3, the electrohydraulic amplifier 4, the key 5, the executive me-,. B, sensor 7 feedback and sensor 8 position of the output element of the working channel. In the electronic control channel 2 one of the two inputs of the third adder 9 is connected to the input source, the output of the third adder 9 is connected to the first input of the integrator 10, the output of the integrator 10 is connected to the input of the inverter 11, the output of the inverter 11 is connected to the second input of the third adder 9 and the second input of the second adder 12, the first input of the second adder 12 is connected to the output of the sensor 8 of the position of the output element of the working channel, the output of the second adder 12 is connected to the input of the comparator 13 and through the voltage limiter 14 vtopESM input of the integrator 10 and the output of comparator 13 is connected to the input key (electro valve) 5 working channel. The drive works. As follows. The working channel of the drive under the action of the input signal ensures proportional displacement of its output element (.). At the same time, at the output of the sensor 8 of the position of the output element of the working channel, an electric signal is formed that is proportional to the movement of the working channel and, consequently, to the input signal Ugyp. when no element is saturated, the rate of change for Si1: 1 at the output of sensor 8 of the position of the output element of the working channel is equal to the speed of the input signal, and the reproduction error of the input signal is determined by the static and dynamic accuracy of the working channel depending on the gain factors and tolerances elements of the working channel. With a step change in the input signal, the electrohydraulic amplifier 4 may be saturated with the flow rate of the working fluid, due to the restriction in the flow areas of the spool valve, which limits the rate of change of the signal at the output of the sensor 8 to the position of the output element of the working channel. The task of the electronic control channel is to imitate the main characteristics of the working channel: gain, quality factor and maximum rate of change of the output signal, as well as generating an output signal similar to the output signal of the position sensor 8 of the operational element of the working channel, and comparing these signals with each other and issuing a command to the operating channel key 5 to turn it off when the difference is exceeded compared to the set value of the required value of the gain factor and the quality factor of the control channel is provided by an appropriate choice of the coefficient-foB gain of the third adder 9 and the integrator 10. The output signal of the control channel is the output signal of the inverter 11. Comparison of the output signals of the control channel and position sensor 8 of the output element of the working channel and outputting a signal for disconnecting the working channel The second adder 12 to the comparator 13. Without. taking into account the newly introduced correction connection between the output of the second adder 12 and the second input of the integrator 10, the maximum speed of the output signal of the control channel is determined by the maximum voltage at the output of the third adder 9 and the transfer coefficient of the integrator 10. Using a special device to limit the output voltage of the third adder 9, or taking into account its natural restriction and, accordingly, choosing the integrator transfer coefficient 10, in the original (normal) exp uatatsionnyh conditions the maximum rate of change in the pilot channel output signal is set equal to (within tolerances), the nominal or actual maximum rate of change of the output signal of the working channel element 8 position sensor output. If there is corrective negative feedback between the output of the second adder 12 and the second input of the integrator 10, the maximum rate of change of the output signal of the control channel is automatically controlled as a function of the relative difference between the output signal of the control channel and the sensor signal 8 of the output element of the working channel in a limited range determined by the limiter 14 voltage and the corresponding range of variation of the maximum speed of the output signal of the sensor 8 position of the output voltage of the working channel under specified operating conditions. If, for example, it is known that the maximum output speed of the sensor 8 of the position of the output element of the working channel varies within i.50% of the nominal value, then the output voltage level of the limiter 14 is set so that the maximum integration speed of the correction signal is 50 % of the maximum integration rate of the output signal of the third adder 9. With the drive operating correctly in the linear zone and without taking into account the corrective connection between the output of the second

adder 12 and the second input of the integrator 10 is the mismatch between the output signals of the sensor 8 of the position of the upper element of the working channel and the electronic control channel (the conditional error U () is determined by the difference of the input signals Ujjy, p and Llgy, y, as well as technological and operational tolerances on the characteristics of the elements In the presence of corrective communication, this discrepancy decreases, since the control channel in a certain range of discrepancies tracks the movement of the working channel. tracking determined by the ratio correction coefficient and the basic feedback control channel bonds. Until the saturation voltage limiter 14 conditional mismatch between the outputs of the reference and the working channel is reduced by an amount defined by the expression

6ech .kor.

rf.

About c .-,

iwv.

()

where l is the conditional mismatch between the output signals of the control and working channels without taking into account corrective communication; K, is the gain factor of the first adder 9; Kj - the transfer coefficient of the integrator 10 in the output signal circuit of the first adder 9;

Kft is the transmission coefficient of the integrator 10 along the correction signal circuit, KI is the gain factor of the second adder 12. The magnitude of the conditional mismatch between the output signals of the control and working channels, at which the correction circuit is saturated, is determined from the equation

/....8es.top.V If If u

. nasmm-shzh 1 - .. l.

(K, -k, -44,) n ogp. H and /

The left side of this equation is an expression that determines the necessary and sufficient value of the maximum integration speed of the correction signal to equalize the speeds of the control and working channels in all operating conditions, and the right part is the nominal value of the maximum rate of change of the output control signal.

From this equation

oro.ilK.

l, .5g.k.orch V Lebiv,).

s h-sat. box

The maximum reduction in the misalignment between the output signals of the control and operating chords, corresponding to the saturation of the voltage limiting device 14, is equal to

0

l, ... p. Pur,. / bwY.motr k, where n is the ratio of the maximum integration rate of the correction signal to the maximum maximum integration rate of the output signal of the third adder 9; Upj-p - maximum signal on

the output of the third adder 9.

0

The actual value of the mismatch between the output signals of the control and working channels, controlled by the comparator 13, is equal to

6et,. «Op. 56 "OR

25 - at (. / 1

H01Se1sh, .kor.

..

, (6)

 t l ubw / lH, -.

li-k.

0

. k, 5ech,. «op.

.KOp. -prm uu,. ) .cor

lyh.

topSe.Kop n Iogrc „f

.,--(&four,,. ()

Let the control signals come to the input of the control and working channels, the rate of change of which does not exceed the minimum possible maximum rate of change of the output signal of the working channel, the input signals differ from each other by the maximum permissible value, and the characteristics of the channels are extremely nonidentical. Diagram fig.Z

shows the nature and magnitude of the change in the input signals (and U.p) i of the output signal of the working channel (), the output signal of the control channel in the absence and presence

corrective connection between the output of the second adder 12 and the second input of the integrator 10 (and, and; .. respectively, COiV - ",

factually), the marginal difference of the output signals of the working and control channels in the absence and presence of the specified correction circuit (UJJ; and °, respectively) and the required values for setting the thresholds of the comparators 13 in either case

(ffe ... ", 5 and t.JfP).

Claims (1)

It can be seen from the diagram that when introducing a correction, the actual mismatch between the control and working channels is somewhat reduced, therefore, for timely detection of a malfunction in the drive, the response horn 13 of the comparator 13 / / presence of corrective communication () should be slightly reduced compared to the required threshold calculated on the condition that there is no correction. And ..) cor. “Threshold ubiy. before, where is the calculated value of the limit of possible mismatch between the output signals of the intact control and work channels in the absence of a corrective connection between W: 1 input of the second adder 12 and the second input of the integrator 10. Let the input-like input enter the control and working channels signals under different initial conditions (see figs. 3 and 4). From the diagrams it can be seen that, in the absence of a correction, a significant increase in the mismatch is possible, and, which would require a corresponding expansion of the threshold the comparator is flushed down or a time delay element is inserted before it. With the introduction of the correction and under any initial conditions, the jump-like input signals do not cause an increase in the mismatch between the output signals with respect to the maximum possible static mismatch. In this connection, the expansion of the trigger threshold of the compiler 13 or the introduction of a time delay for its triggering is not required. The failure of the working or control channels leads to an increase in misalignment between their output signals, the operation of the comparator 13 and the removal of hydraulic supply from the working canap using a key - electrohydraulic valve 5. Consider the example of a working channel failure due to the input of a false input signal ( Due to the corrective signal, the control channel in a limited range follows the working channel, reducing the heme the most mismatch between its output signal and the output signal About the channel, which is taken into account when choosing the threshold for triggering the comparator 13 (in accordance with expression 6.) The amount of movement of the output element of the working channel into the result, failure (,) is proportional to the threshold of the comparator 13. Because there is a corrective link, there is no need for an additional increase comparator triggering threshold for eliminating false disconnection at discontinuous input signals; the drive with the entered fault correction has a smaller random movement of its output element one that enhances the fail-safe drive. Thus, the proposed electro-hydraulic servo drive for aircraft control systems increases the drive's fail-safe safety by reducing disturbance from the drive side to the aircraft in case of working channel failures by reducing the response threshold of the control system by introducing a correction for the change in the output signal of the electronic surflight channel. relative mismatch between the outputs of the control and working channels. Moreover, using the proposed device reduces the weight of a multichannel unit by replacing one module with an electronic control channel, there is no need to master new technological processes and purchase high-quality software to increase the accuracy of manufacturing working slits of spool pairs. Claims of the invention Electro-hydraulic servo drive containing a series-connected feedback sensor, a first adder, an amplifier, an actuator, a position sensor, a second adder, a comparator and a key, and a third cyNwaTOp connected in series, an integrator and an inverter whose output is connected to the second input of the second the adder and the first input of the third adder, and the feedback sensor input is connected to the output of the actuator, characterized in that, in order to increase the driveability of the actuator, it contains voltage limiter having an input coupled to an output of the second adder, and an output - to a second input of the integrator. Sources of information taken into account during the examination 1. Proceedings of the IV Scientific and Technical Conference, Moscow City Conservatory, 1976, p. 351 (prototype). «« Ft, Ufvx AKfgj MfM / Msiy Vf tffb / h / ttff x ; g  .i . ff, fifjt tnax yfcj kop x 411 K MX to Mr , ail -Ch - tec  kr K nopo / / r nopoi one ifcj Chh. , 6c f e3iic