JP3141007B2 - Hydraulic servo actuator system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic servoactuator system in which the outputs of a plurality of hydraulic actuators are coupled to restrain each other, and in particular, compensation for eliminating force fight caused by differences in output displacement between the actuators. The present invention relates to a hydraulic servo actuator system of a servo valve flow control type provided with an algorithm.

[0002]

2. Description of the Related Art Conventionally, a servo actuator system in which a plurality of hydraulic servo actuators are connected to each other so as to operate with their output portions restricted is used for flight control of an aircraft, for example. In this type of servo actuator system, a plurality of control surface control actuators connected in parallel or in series are each controlled by an electro-hydraulic servo valve (hereinafter, electro-hydraulic servo valve), and the displacement or the output of the actuator is controlled. Feedback control is performed by electrically extracting the displacement of the valve element of the electric / hydraulic servo valve using a position detector.

Further, if there is a difference in output displacement (position) between the control surface control actuators, an excessive force acts between the actuators even if the command input is zero, that is, a so-called force fight occurs, and performance such as resolution is reduced. . Further, not only the hydraulic servo actuator system but also the load-side fatigue resistance is significantly reduced. For this reason, measures have been taken to eliminate these problems.

For example, by detecting the differential pressure between the hydraulic chambers on both sides in the operation direction of each actuator and feeding back the differential pressure signal to the servo amplifier, the rigidity of the actuator can be reduced when unnecessary differential pressure is generated. Suppress Force Fight. Specifically, a pressure sensor detects a differential pressure (ΔP) between a pair of hydraulic chambers in a hydraulic cylinder due to a load change, and feeds back a differential pressure signal from the pressure sensor (differential pressure sensor) to the servo amplifier. Suppress Force Fight.

[0005] The main causes of the force fight are position feedback error, deviation of the neutral position of the servo valve (so-called NULL deviation), adjustment error at the time of mounting on the actual machine, temperature change and aging change of these errors. The temperature change of the entire electronic circuit and the change over time of the characteristic can be cited. Here, the position feedback error means, when the position detector is a differential transformer (LVDT), its gain error, linearity of output characteristics, excitation voltage error, demodulator gain error, summing amplifier gain error, etc. It is.

[0006]

However, in the above-mentioned conventional hydraulic servo actuator system for taking measures against force fight, in the case of the differential pressure feedback system, if the differential pressure feedback gain is increased, the resolution of the actuator output (output Minimum input that can change
Therefore, a sufficient force fight suppression (compensation) effect could not be expected.

SUMMARY OF THE INVENTION The present invention provides a highly reliable hydraulic servo actuator system that can expect a sufficient force fight compensation effect without lowering the output resolution.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a hydraulic actuator controlled by an electrohydraulic servo valve, wherein output rods of the hydraulic actuators are restrained from each other and a pair of hydraulic actuators is provided. In the hydraulic servo actuator system, which is operated by the differential pressure of the hydraulic chambers and each hydraulic actuator is feedback-controlled in accordance with the position of the restrained output rod and the command signal input, a pair of hydraulic actuators A differential pressure detecting means for detecting a differential pressure between the hydraulic pressure chambers, and a difference between the differential pressures of the one hydraulic actuator with respect to another hydraulic actuator, the one hydraulic pressure being determined via an integral element or a first-order lag element. By feeding back to the command signal input side of the electro-hydraulic servo valve that controls the actuator, the And Force Fight compensation means to reduce Osufaito, by interposing a non-linear elements in the path for feeding back the difference of the differential pressure, and suppression means for suppressing limit cycles generated by the non-linear resistance and the like of the servo loop, at least 2 Hydraulic actuators
Calculating the average value of the differential pressure between the hydraulic chambers for the
Compares differential pressure between hydraulic chambers of all hydraulic actuators
Which is the difference between maximum and minimum pressure
The differential pressure between the hydraulic chambers of the actuator is set to the average value of the differential pressure.
And a differential pressure calculating means for obtaining a substitute intermediate value.
The force fight compensating means is provided for each hydraulic actuator.
And the differential pressure calculated by the differential pressure calculating means.
The difference between the average value or the intermediate value of the differential pressure is defined as the differential pressure difference.
It is like that .

Here, the one hydraulic actuator is any one or a plurality of actuators among a plurality of actuators, and the other actuator is one or more hydraulic actuators different from the one hydraulic actuator. Actuator. Further, the differential pressure difference is defined as a difference between the differential pressure between the hydraulic chambers of the one actuator and another specific one actuator, the differential pressure between the hydraulic chambers of the one actuator and another specific one. Not only the difference between the average value and the intermediate value (differential pressure value between the maximum and the minimum when compared) of the pressure difference between the hydraulic pressure chambers for the two or more actuators, but also the hydraulic pressure chambers for all the actuators The difference between the average value of the differential pressure between the hydraulic pressure chambers and the differential pressure between the hydraulic pressure chambers for the one actuator may be used. That is, as long as the difference information changes according to the difference between the differential pressures of one actuator and another actuator, the method of calculating the average value or the intermediate value is arbitrary.

According to the present invention, in the control system of one or each of the plurality of hydraulic actuators, the difference between the differential pressures of the actuators and other hydraulic actuators is the difference between the hydraulic chambers of at least two hydraulic actuators. As the average of the differential pressure of all or all hydraulic actuators
Pressure difference between the maximum and the minimum when compared with the differential pressure between the hydraulic chamber
The difference between the hydraulic chambers of any of the hydraulic actuators
Each of the hydraulic pressures is determined by the differential pressure calculating means as a pressure intermediate value.
The differential pressure of the actuator and the differential pressure calculating means;
The difference between the average value or the intermediate value of the differential pressure calculated from
The force fight compensating means operates as the difference. Soshi
The difference between the differential pressures is fed back to the command signal input side via an integral element or a first-order lag element, and the respective input command signals are corrected so as to cancel the force fight between the hydraulic actuators. The difference in actuator output is reduced, and force fight is effectively reduced and compensated without lowering the resolution of the actuator. In addition, since the limit cycle generated due to the non-linearity of the servo loop is suppressed by the suppressing means, that is, by the non-linear element interposed in the feedback path including the integral element or the first-order lag element, the non-linearity is suppressed in the servo loop. The above-mentioned reduction and compensation of force fight can be performed without providing a complicated compensation element for compensation.

Furthermore, at least two hydraulic actuators
Or the average of the differential pressure between the hydraulic chambers
Either hydraulic actuator with a pressure difference between large and small
The differential pressure (intermediate value) between the hydraulic chambers of the
The differential pressure and the average differential pressure calculating means of the actuator
Since the difference from the calculated value is the difference between the differential pressures,
Even if a failure occurs in the actuator of
Signal processing becomes possible.

In addition, when a non-linear element such that the normal error range causing the force fight is set as an operation gap is interposed, a limit cycle can be easily prevented. Further, the stability of the force fight compensation loop can be enhanced by the primary delay element. Therefore, it is preferable to improve the stability and increase the loop gain by inputting the output from the non-linear element for inputting the differential pressure difference to the integrator or the first-order lag element. The non-linear element has, for example, a hysteresis characteristic.

Preferably, the nonlinear element and the first-order lag element include a first subtractor for inputting a difference between the average value of the differential pressure and the differential pressure of each hydraulic actuator, and an output of the first subtractor. A second subtractor for calculating a difference between the outputs of the integrators, a dead band circuit having a dead band near a zero point of a signal input from the second subtractor, and an output proportional to a time integration value of an output of the dead band circuit. An integrator that feeds back to the first subtractor and a command signal input side of an electrohydraulic servo valve that controls each of the hydraulic actuators. In this case, the non-linear characteristic of the closed loop including the dead band circuit and the integrator viewed from the second subtractor becomes hysteresis, and the limit cycle caused by the non-linearity of the servo loop can be compensated. Furthermore, by constructing a closed loop of the integrator and the subtractor, a function of first-order lag of low frequency is provided, and sufficient force fight compensation effect is obtained by increasing the loop gain despite the presence of the integrator. Can be.

[0014]

In addition, in the present invention, three or more hydraulic actuators are provided, and each hydraulic actuator is
Pressure difference between the hydraulic chambers and other
Average differential pressure for two or more hydraulic actuators
Or between the hydraulic chambers of each hydraulic actuator.
And the differential pressure between the hydraulic chambers of all hydraulic actuators
Which is the differential pressure value between the maximum and minimum when comparing
The difference between the pressure difference between the hydraulic pressure chambers of the hydraulic actuators is fed back to the command signal input side of the electro-hydraulic servo valve that controls each hydraulic actuator, thereby simplifying the calculation of the average differential pressure value. However, the same effects as above can be obtained.

[0016]

Preferred embodiments of the present invention will be described below with reference to the drawings. (1st Embodiment)

FIG. 1 is a diagram showing a hydraulic servo actuator system according to the first embodiment.

In FIG. 1, reference numeral 11 denotes a signal processing computer. The signal processing computer 11 breaks a loop at every predetermined sampling period and outputs an external command signal (command signal) Vc and two control systems A, B
And outputs a command signal based on the feedback signals Vpa and Vpb. Two control systems A and B (in the figure,
Ach and Bch) include a pair of hydraulic cylinders (a plurality of hydraulic actuators) connected in parallel, each manufactured with the same specifications.

First, one control system A will be described. A command signal output from the signal processing computer 11 is converted into an analog signal by a D / A converter (not shown), and then subtracted from the analog signal processing system. Table 12
A, known electro-hydraulic servo valve 15A (electro-hydraulic servo valve) via pre-amplifier 13A and current amplifier 14A
Is input to Although not shown in detail, the electro-hydraulic servo valve 15A has a spool (valve element) having a predetermined shape, a pair of cylinder ports communicating with a pair of oil chambers (working fluid pressure chambers) of the hydraulic cylinder 16A, and a hydraulic source. It has a supply pressure port that communicates and a return port that communicates with the tank,
The hydraulic oil is supplied to and discharged from the hydraulic cylinder 16A by the electrohydraulic servo valve 15A, and the operation thereof is controlled.
Output rod (not shown) of A (output part, piston rod)
Is controlled, for example, a control surface of an aircraft.

The displacement of the output rod of the hydraulic cylinder 16A is detected by a position detector 18A such as a differential transformer, and the detection signal is filtered to remove an AC component through a demodulator 19A and a filter 20A. Will be fed back. The subtracter 12A outputs a deviation signal obtained by subtracting the position feedback signal from the command signal input from the signal processing computer 11 to the preamplifier 13A.
Input to A.

In FIG. 1, q is a flow rate representing the supply of hydraulic oil from the electrohydraulic servo valve 14A to the hydraulic cylinder 16A, and Xp is an output of a position detector 18A for detecting displacement of the output rod of the hydraulic cylinder 16A. Signal.

The other control system B is provided between the signal processing computer 11 and the control target 17 in parallel with the control system A. And the signal processing computer 11
Is converted into an analog signal by a D / A converter (not shown), and is input to the electrohydraulic servo valve 15B via a subtractor 12B, a preamplifier 13B, and a current amplifier 14B. This electro-hydraulic servo valve 15
B controls the operation by supplying and discharging hydraulic oil to and from the hydraulic cylinder 16B, and controls the controlled object 17 connected to the output rod of the hydraulic cylinder 16B together with the hydraulic cylinder 16. Also, the hydraulic cylinder 16B
The displacement of the output rod is a position detector 18B such as a differential transformer.
The AC signal is removed from the detection signal through a demodulator 19B and a filter 20B.
Feedback to 2B.

On the other hand, 21A, 21B is a differential pressure between a pair of hydraulic chambers (not shown, but separated by a piston connected to an output rod) of the corresponding hydraulic actuators 16A, 16B. Is a differential pressure sensor (differential pressure detecting means). These differential pressure sensors 21A,
The 1B detection signal is fed back to the signal processing computer 11 via the demodulators 22A and 22B and the filters 23A and 23B.

The signal processing computer 11 has a control system A
The hydraulic cylinder 1 is output from the filter 23A and converted into a digital signal by an A / D converter (not shown).
A subtractor 24A that receives the differential pressure feedback signal Vpb from the hydraulic cylinder 16B that also receives the differential pressure feedback signal Vpa from the hydraulic cylinder 16B and also outputs a digital signal from the filter 23B. Integrator 25A that outputs a time integration value of a signal
(Integral element) and a subtracter 26A for subtracting the output of the integrator 25A from the external command signal Vc. The signal processing computer 11 also performs the same operation on the control system B for the subtractors 24B and 25B and the subtractor 2B.
6B, and the subtractor 24B has the hydraulic cylinder 16
The differential pressure feedback signal Vpb from the hydraulic cylinder 16A and the differential pressure feedback signal Vpa from the hydraulic cylinder 16A are subtracted and input.

The subtractor 24A, the integrator 25A, and the subtractor 26A determine the difference between the hydraulic chamber differential pressure (hereinafter, also referred to as cylinder differential pressure) of one hydraulic cylinder 16A and the other hydraulic cylinder 16B. The subtractor 24B, the integrator 25B, and the subtractor 26B are fed back to the command signal input side via 25A and subtracted from the command signal input Vc to the hydraulic cylinder 16A.
The difference of the differential pressure between the hydraulic pressure chambers with respect to the hydraulic cylinder 16A is fed back to the command signal input side via the integrator 25B, and is subtracted from the command signal input Vc to the hydraulic cylinder 16B. Thereby, the respective input command signals Vc are adjusted so as to reduce the differential pressure of the cylinder 16A or 16B having a large differential pressure among the hydraulic cylinders 16A and 16B and increase the differential pressure of the cylinder 16B or 16A having a small differential pressure. Therefore, the correction is performed so that the outputs between the pair of hydraulic actuators coincide with each other, and the force fight is reduced. That is, the signal processing computer 11 has a function as means for compensating for force fight between the pair of hydraulic cylinders 16A and 16B.

In the hydraulic servo actuator system of the present embodiment configured as described above, in the control systems A and B of the respective hydraulic actuators of the pair, the other hydraulic actuators 16B or 16B of the actuator 16A or 16B are used. Since the differential pressure difference with respect to 16A is negatively fed back through the integration elements 25A and 25B, and the respective input command signals are corrected so as to cancel the force fight between the hydraulic actuators 16A and 16B, the force fight is reduced. It is reduced and guaranteed.

That is, a pair of hydraulic cylinders 16A, 1
When a force fight occurs during 6B, statically,
An equal and opposite pressure difference (a state in which the magnitude relation of the internal pressures is reversed) is generated between the hydraulic chambers on both sides in the respective operating directions between the two hydraulic cylinders 16A and 16B. Therefore, integrating the difference between the two differential pressures and performing negative feedback means performing control to integrate the difference between the two cylinder differential pressures and perform negative feedback.
In addition, the steady-state deviation can be suppressed by feeding back via the integrators 25A and 25B. Therefore, it is possible to reliably perform force fight compensation with a simple configuration, improve stability, and increase a loop gain.

As described above, in the present embodiment, the feedback control that substantially takes the difference between the cylinder pressure differences when a pair of hydraulic cylinders is used can be realized with a simple configuration. It is not necessary to calculate the average value of the control signal, and the signal processing can be easily and quickly performed. Therefore, a highly reliable control surface control system or the like with a resistance strike can be provided.

In this embodiment, the subsequent servo loop is an analog processing system, but it is needless to say that this can be a digital processing system. (2nd Embodiment)

FIG. 2 is a block diagram showing a main configuration of a hydraulic servo actuator system according to a second embodiment.

In this embodiment, three hydraulic cylinders (hereinafter referred to as hydraulic cylinders 16A and 16B) similar to the hydraulic cylinders 16A and 16B are used to drive the control target 17 in the above-described embodiment.
A, 16B, 16C) are connected in parallel or in series such that their output rods are constrained to each other, and the control system of each actuator adopts a force fight compensation method different from that of the signal processing computer 11 in the above-described embodiment. The configuration and operation of each control system other than the signal processing computer are the same as those described above, provided with a force fight compensating means. Therefore, only the differences from the above example will be described in detail.

In FIG. 2, the signal processing computer 31
Are three first subtractions for inputting the differential pressure feedback signals Vpa, Vpb, Vpc from the hydraulic cylinders 16A to 16C converted into digital signals for each of the control systems of the three hydraulic cylinders 16A, 16B, 16C. The other two hydraulic cylinders ((16B, 16C), (16B) except for the units 32A, 32B, 32C and the three hydraulic cylinders 16A, 16B, 16C, respectively.
A, 16C), (16A, 16B)), the average value of the differential pressures, that is, (Vpb + Vpc) / 2, (Vpa
+ Vpc) / 2 and (Vpa + Vpb) / 2 for calculating the average differential pressure calculation means 33A, 33B, 33C (differential pressure calculation
Output means) and three second subtractors 34A, 34B, which input signals from the three subtracters 32A, 32B, 32C.
34C, the average value of the differential pressure and each hydraulic actuator 1
6A, 16B, or 16C, the difference between the pressure difference and the dead band circuits 35A, 35B, and 35C whose outputs are constant with no linearity with respect to the input near the zero point of the difference;
The signals from 4B and 34C are supplied to dead zone circuits 35A and 35B,
It has integrators 36A, 36B, and 36C that input through 35C and feed back an output proportional to the time integration value to the subtractors 34A, 34B, and 34C.

The second subtractors 34A, 34B and 34C function as first-order lag elements of low frequency by negatively feeding back the outputs of the integrators 36A, 36B and 36C.
Signals from 4A, 34B, 34C are converted to dead zone circuits 35A,
Integrators 36A, 36B, 36C through 35B, 35C
The dead zone circuits 35A, 35A
A hysteresis characteristic having an operation gap corresponding to B and 35C is provided. The operating gap is set to a normal error range that causes a force fight, and the second subtractors 34A, 34B, 34C, the dead band circuits 35A, 35B, 35C, and the integrators 36A, 36B,
The signal processing computer 31 equipped with the C.36C calculates the difference between the differential pressure of each of the hydraulic cylinders 16A, 16B, 16C and the average value of the differential pressures obtained for the other two hydraulic cylinders excluding the cylinders by using the nonlinear element and The signal is fed back to the command signal input side of each of the hydraulic cylinders 16A, 16B, 16C via the primary delay element, and is fed back to the subtracters 26A,
A force fight compensating means for reducing the force fight between the three hydraulic cylinders 16A, 16B, 16C by reducing the command signal input Vc at 6B, 26C. It should be noted that the differential pressure calculation means 33A, 33
B and 33C are adders 3 for adding and inputting two differential pressure signals.
7 and a circuit 38 for multiplying the addition result by 0.5 times
It is composed of Differential pressure calculating means 33A, 33B, 33
Instead of calculating the average value of the differential pressure by C, the differential pressure feedback signals Vpa, Vpb, and Vpc are compared and an appropriate value between the maximum and the minimum is set as an intermediate differential pressure signal. May be taken.

As described above, also in this embodiment, each of the hydraulic cylinders 16A and 16A is controlled by the differential pressure sensors 21A and 21B.
The differential pressure between the pair of hydraulic chambers 16B and 16C is detected, and the average value of the differential pressure between at least two hydraulic cylinders is calculated by the average differential pressure calculating means 33A, 33B and 33C, and the average value is calculated. And each hydraulic cylinder 16
A difference between the differential pressure of A, 16B or 16C and a command of an electrohydraulic servo valve for controlling each of the hydraulic cylinders 16A, 16B or 16C through a non-linear element and a first-order lag element having an operating gap near the zero point of the difference. It is fed back to the signal input side. And a first subtractor 34A-34C for inputting a difference between the average value of the differential pressure and the differential pressure of each of the hydraulic cylinders 16A, 16B or 16C,
Dead band circuits 35A to 35C for inputting signals from these.
And the integrators 36A-36C that feed back outputs proportional to the time integrals of the outputs of the dead zone circuits 35A-35C to the subtractors 34A-34C. Dead zone circuit 3
The limit cycle caused by the non-linearity of the servo loop can be compensated by using the non-linear characteristic of the closed loop including 5A to 35C and the integrators 36A to 36C as hysteresis. That is, the signal processing computer 31 also functions as suppression means for suppressing the limit cycle.

Further, the integrators 36A to 36C and the second
The low frequency first-order lag function is provided by forming a closed loop of the subtractors 34A to 34C of the integrators 36A to 36C.
, The loop gain can be increased and a sufficient force fight compensation effect can be obtained. Also, since the average differential pressure value to be compared with the differential pressure of each of the hydraulic cylinders 16A to 16C is the average differential pressure value between the other two hydraulic cylinders except for the respective cylinders, the average differential pressure calculating means 33A to 33C Can be easily and quickly performed.

The non-linear element constituting a part of the force fight compensating means is not limited to one using a dead zone. For example, as shown in FIG. 3 or FIG.
Average value of the differential pressure ((Vpb + Vpc) / 2, (Vpa +
Vpc) / 2, (Vpa + Vpb) / 2) and the hysteresis circuit 45 or 55 for inputting the difference between the differential pressures Vpa, Vpb, Vpc of the respective hydraulic cylinders 16A to 16C. Instead of the primary delay of a closed loop including an integrator and a subtractor as elements, a primary delay circuit 46 and an integrator 56 may be provided.

Further, when the suppression means 60, which is composed of some nonlinear element for suppressing the limit cycle generated by the nonlinearity of the servo loop, is provided outside the force fight compensating means, the average value of the differential pressure ((Vpb + V
pc) / 2, (Vpa + Vpc) / 2, (Vpa + Vpb)
/ 2) and the differential pressure Vpa between the hydraulic cylinders 16A to 16C,
The difference between Vpb and Vpc is fed back to each command signal input side via a primary delay element 66 or an integrator 76 as shown in FIG. 5 or FIG.
It is also conceivable that the integrator 6 or the integrator 76 cooperates with the suppression means 60 to reduce the force fight of the hydraulic cylinders 16A to 16C. Also in this case, a force fight compensation effect equivalent to that of each of the above embodiments can be expected without providing an element for compensating the non-linearity in the servo loop.

[0038]

According to the present invention, the difference in the pressure difference between one hydraulic actuator and another hydraulic actuator between the hydraulic chambers is fed back to the command signal input side via an integral element or a first-order lag element. As a result, since the force fight between the hydraulic actuators is offset, the force fight can be effectively reduced and compensated without lowering the resolution of the actuator. And sir
Limit cycle generated by voloop nonlinearity etc.
With the non-linear element in cooperation with the force fight compensator.
Can be effectively suppressed by means of
Complex to compensate for the non-linearity in the servo loop
Force fight as described above without any compensating element
And a compensation effect can be obtained.

Further, the difference between the differential pressure of each hydraulic actuator and the average value of the differential pressure calculated by the average differential pressure calculating means is defined as the differential pressure difference. Even if it occurs, stable signal processing can be performed.

Further, the nonlinear element in the feedback path
Operate the normal error bars that cause the element to forcefight
By setting the gap, the limit cycle can be easily prevented, and if the stability of the force fight compensation loop is enhanced by the first-order lag element, the stability and loop
The gain can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a hydraulic servo actuator system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a main part of a hydraulic servo actuator system according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a modified example in which a nonlinear element in a stability compensator in the second embodiment is set to hysteresis.

FIG. 4 is a block diagram showing another modification in which a non-linear element in the stability compensator according to the second embodiment has hysteresis.

FIG. 5 is a block diagram showing a modified embodiment in which only a first-order delay circuit is provided without providing a nonlinear element in the stability compensator in the second embodiment, and the effect of nonlinearity of the servo loop is externally removed. is there.

FIG. 6 is a block diagram showing another modified embodiment in which only an integrator is provided without providing a nonlinear element in the stability compensator in the second embodiment, and the effect of the nonlinearity of the servo loop is externally removed. is there.

[Explanation of symbols]

11 Signal processing computer (force fight compensation means) 12A, 12B, 12C Subtractor 13A, 13A Preamplifier 14A, 14B Current amplifier 15A, 15B Electro-hydraulic servo valve (electro-hydraulic servo valve) 16A, 16B Hydraulic cylinder (hydraulic actuator) 17 Control target 18A, 18B Position detector 19A, 19B Demodulator 20A, 20B Filter 21A, 21B Differential pressure sensor (differential pressure detecting means) 22A, 22B Demodulator 23A, 23B Filter 24A, 24B Subtractor 25A, 24B Integrator ( Integral element) 26A, 26B Subtractor 31 Signal processing computer (force fight compensating means, suppressing means) 33A, 33B, 33C Average differential pressure calculating means 34A, 34B, 34C Subtractor (primary delay element) 35A, 35B, 35C Dead zone circuit (Non Form elements) 36A, 36B, 36C integrator (first order lag element) 45, 55 hysteresis circuit (nonlinear element) 46 and 66 primary delay circuit 56, 76 integrator 60 suppressing means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-4601 (JP, A) JP-A-3-186601 (JP, A) JP-A-2-26301 (JP, A) JP-A 55- 30533 (JP, A) JP-A-8-314502 (JP, A) JP-A-63-310001 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F15B 9/09 G05B 11 / 36 501 B64C 13/40

Claims (5)

(57) [Claims] The output rods of a plurality of hydraulic actuators controlled by an electro-hydraulic servo valve are restrained from each other and actuated by a differential pressure between a pair of hydraulic chambers in each of the hydraulic actuators. A differential pressure detecting means for detecting a differential pressure between a pair of hydraulic chambers of each hydraulic actuator in a hydraulic servo actuator system in which each hydraulic actuator is feedback-controlled according to a position of an output rod and a command signal input. And feedback the difference of the differential pressure of one hydraulic actuator with respect to another hydraulic actuator to a command signal input side of an electro-hydraulic servo valve that controls the one hydraulic actuator via an integral element or a first-order lag element. To reduce the force fight between the plurality of hydraulic actuators. When, by interposing a non-linear elements in the path for feeding back the difference of the differential pressure, and suppression means for suppressing limit cycles generated by the non-linear resistance and the like of the servo loop, the liquid for at least two hydraulic actuators
Calculate the average value of the differential pressure between the pressure chambers, or
Maximum and minimum when comparing the differential pressure between the hydraulic chambers of the tutor
Of any of the hydraulic actuators with a pressure difference between
The differential pressure between the pressure chambers as an intermediate value instead of the average value of the differential pressure
Differential pressure calculating means , wherein the force fight compensating means comprises a hydraulic actuator.
And the differential pressure calculated by the differential pressure calculating means.
A hydraulic servo actuator system , wherein a difference between an average value and an intermediate value of the differential pressures is set as the differential pressure difference . 2. The hydraulic servo actuator system according to claim 1, wherein said nonlinear element has a hysteresis characteristic. 3. The output rods of a plurality of hydraulic actuators controlled by an electro-hydraulic servo valve are restrained from each other and actuated by a differential pressure between a pair of hydraulic chambers in each hydraulic actuator, and the restraint is performed. A differential pressure detecting means for detecting a differential pressure between a pair of hydraulic chambers of each hydraulic actuator in a hydraulic servo actuator system in which each hydraulic actuator is feedback-controlled according to a position of an output rod and a command signal input. And calculating the average value of the differential pressures for at least two hydraulic actuators, or comparing the differential pressures between the hydraulic chambers of all the hydraulic actuators, the differential pressure value between the maximum and the minimum is obtained. A differential pressure calculating means for obtaining a differential pressure between the hydraulic pressure chambers of any of the hydraulic actuators as an intermediate value instead of an average value of the differential pressure, and an average value of the differential pressure Feeds back the difference between the intermediate value and the differential pressure of each hydraulic actuator to a command signal input side of an electro-hydraulic servo valve that controls each hydraulic actuator via a subtractor, a dead zone, and an integrator. With
A force fight compensating means for reducing the force fight between the plurality of hydraulic actuators by feeding back the output of the integrator to the subtractor before the dead zone, wherein a limit generated by non-linearity of the servo loop or the like is provided. A hydraulic servo actuator system characterized by reducing force fight between hydraulic actuators while suppressing cycles. 4. The method according to claim 1, wherein three or more hydraulic actuators are provided, and a differential pressure between hydraulic chambers of each one hydraulic actuator and a differential pressure of two or more hydraulic actuators other than the actuator. The hydraulic servo actuator system according to any one of claims 1 to 3 , wherein a difference from the average value is fed back to the command signal input side. 5. An apparatus according to claim 5, wherein three or more odd-numbered hydraulic actuators are connected in parallel, and a differential pressure between hydraulic chambers of each hydraulic actuator and a differential pressure between hydraulic chambers of all hydraulic actuators are controlled. The difference between the differential pressure between the hydraulic chambers of any of the hydraulic actuators, which becomes an intermediate differential pressure value when compared, is fed back to the command signal input side. 4. The hydraulic servo actuator system according to any one of items 3 .