JP2003148108A - Servo valve system and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a servo valve system preventing easy change of controlled variables of a control object even when one control system fails. SOLUTION: Failure detectors 8A, 8B and 8C are provided for detecting respective failures of a plurality of servo control systems 1A, 1B and 1C controlling a servo valve 2 on the basis of controlled variables of the control object 3. Each of the servo control systems 1A, 1B and 1C includes a controlled variable detector detecting the controlled variables YA, YB and YC of the control object 3, servo amplifiers 12A, 12B and 12C feeding power to the servo valve 2 in response to a deviation between the controlled variables YA, YB and YC and a predetermined target value U, and cutoff switches 7A, 7B and 7C interposed between the servo amplifiers 12A, 12B and 12C and the servo valve 2. When a failure of one servo control system of the plurality of servo control systems 1A, 1B and 1C is detected, one of the cutoff switches 7A, 7B and 7C included in the one servo control system cuts off power fed to the servo valve 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD This invention relates to servo valve systems. The present invention particularly relates to a servo valve system in which a control system for controlling a servo valve is multiplexed.

[0002]

Servo valves are widely used in steam turbine plants and other plants. By servo valve,
Actuators, valves, and other controlled objects are driven.

The control system for controlling the servo valve is often multiplexed. In the servo valve system in which the control system is multiplexed, in response to the sum of the coil currents supplied to the servo valve,
The servo valve is driven. By multiplexing the control systems, it is possible to prevent a situation in which the control target cannot be controlled when a failure of one control system occurs.

A servo valve system in which a control system for controlling a servo valve is multiplexed is disclosed in Japanese Patent No. 2682866.
Known to. The known servo valve system is a servo valve system in which the control system is tripled. The known servo valve system includes a controller that outputs a control command signal that controls a controlled variable of a controlled object, a servo amplifier that amplifies the control command signal so as to drive the servo valve, and a control command signal that is amplified. Three control systems each having a coil for driving the servo valve so that the valve opening degree is adjusted are provided. When an abnormality occurs in one or two of the three control systems, the remaining normal control system is used to drive the servo valve. In the known servo valve system, the servo valve is driven by the normal control system even when one or two of the three control systems are abnormal. This allows the plant to continue operating even if one or two of the three control systems are abnormal.

However, in the servo valve system in which the control systems are multiplexed, if one control system fails, the controllability of the controlled object deteriorates.

First, if one control system fails, the controlled variable of the controlled object may change although the target value is kept constant. If a failure occurs in one control system that continues to output the maximum current that acts in the direction of increasing the opening of the servo valve to the servo valve, another healthy control system cancels the output current. Operate. Therefore, if proportional control is adopted for the control system, an offset corresponding to the output of the failed control system may occur, and the control amount may fluctuate.

Secondly, if one control system fails, the output of the entire control system may decrease. The faulty control system
When a failure that continues to output the maximum current occurs, the current and the current output by another healthy control system may cancel each other. When the output current of the faulty control system and the current output from another healthy control system cancel each other out, the output of the entire control system decreases. This reduction in output slows the operating time of the servo valve.

Thirdly, if one control system fails, the responsiveness for controlling the controlled object deteriorates. When the number of control systems decreases by one, the gain of the entire control system decreases accordingly. As a result, the responsiveness for controlling the controlled object deteriorates.

It is desired to provide a servo valve system in which the controlled variable of the controlled object is unlikely to change even if one control system fails.

It is also desired to provide a servo valve system in which the output of the entire control system does not decrease even if one control system fails.

Further, it is desired to provide a servo valve system in which the responsiveness for controlling the controlled object does not deteriorate even if one control system fails.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a servo valve system in which the controlled variable of the controlled object is unlikely to change even if one control system fails.

Another object of the present invention is to provide a servo valve system in which the output of the entire control system does not decrease even if one control system fails.

Still another object of the present invention is to provide a servo valve system in which the responsiveness for controlling an object to be controlled does not deteriorate even if one control system fails.

[0015]

Means for solving the problem Means for solving the problem are expressed as follows. The technical matters appearing in the expression are accompanied by parentheses (), and numbers, symbols and the like are added. The numbers, symbols and the like are technical matters constituting at least one of the plurality of embodiments of the present invention, particularly technical matters expressed in the drawings corresponding to the embodiment. It corresponds to the reference number, reference symbol, etc. attached to. Reference numbers like this,
The reference symbol clarifies the correspondence / bridge between the technical matters described in the claims and the technical matters of the embodiments. Such correspondence / bridge does not mean that the technical matters described in the claims are interpreted as being limited to the technical matters of the embodiments.

The servo valve system according to the present invention comprises a servo valve (2) for driving a controlled object (3) and a controlled object (3).
A plurality of servo control systems (1A, 1B, 1C) for controlling the servo valve (2) based on the control amount of
A, 1B, 1C) and a failure detector (8A, 8B, 8C) for detecting each failure. Control of the servo control system (1A, 1B, 1C) each of the control target _{(3) (Y A, Y} B, Y C) control amount detector for detecting (5A, 5B, 5C, 9A , 9B, and 9C), the control amount _{(Y a, Y B, Y} C) and in response to the deviation between a predetermined target value (U), for supplying power to the servo valve (2) servo amplifier (12A, 12B, 12C) and servo amplifier (1
2A, 12B, 12C) and a cutoff switch (7A, 7B, 7C) interposed between the servo valve (2). When the failure detector (8A, 8B, 8C) detects a failure of one servo control system of the plurality of servo control systems (1A, 1B, 1C), a cutoff switch included in the one servo control system (One of 7A, 7B, and 7C) is a servo amplifier (12A, 12A) included in one servo control system.
The electric power supplied to the servo valve (2) from one of B and 12C is shut off.

At this time, the failure detector (8A, 8B, 8
When a failure of one servo control system is detected by C),
Servo amplifiers (12A, 12A, included in a healthy other servo control system among the plurality of servo control systems (1A, 1B, 1C)
12B, 12C) is preferably increased.

Further, failure detectors (8A, 8B, 8C)
Is the expected controlled variable (Y ^* ) expected to be taken by the controlled variable ^.
The expected control quantity calculator for calculating on the basis of the target value (U) and (31, 32), based on the expected control quantity and ^{(Y *)} and the control amount _{(Y A, Y B, Y} C) and, It is preferable to include a servo loop failure detector (24) for detecting a failure of the plurality of servo control systems (1A, 1B, 1C).

Further, the controlled variable detectors (5A, 5B, 5C)
Is the controlled variable (Y_A, Y_B, Y_C) Corresponding output voltage
(V_L1 ^A, V_L2 ^A, V_L1 ^B, V_L2 ^B,
V_L1 ^C, V_{L Two} ^C) Output linear variable differential transformer
(LVDT) (5A, 5B, 5C) and output voltage (V
_L1 ^A, V_L2 ^A, V_L1 ^B, V_L2 ^B, V_L1 ^C, V
_L2 ^CControl amount calculation circuit for calculating the control amount based on
(9A, 9B, 9C) may be included. At this time,
The failure detector (8A, 8B, 8C) outputs the output voltage (V_L1
^A, V _L2 ^A, V_L1 ^B, V_L2 ^B, V_L1 ^C, V_L2
^C), A plurality of servo control systems (1A, 1B, 1
Includes an LVDT fault detector (23) for detecting faults in C).
Preferably.

Further, a failure detector (8A, 8B, 8C)
By the servo amplifier (12A, 12B, 12C)
Expected voltage expected to be applied to the servo valve (2)
(V_A ^*) Is the controlled variable (Y_A, Y_B, Y_C) And the target value
(U) and the expected applied voltage value calculator (3
6, 37, 38) and expected voltage (V_A ^*) And the servo
Servo valve by pump (12A, 12B, 12C)
Servo valve applied voltage (V) applied to (2)_A, V_B, V
_C) And a plurality of servo control systems (1A, 1B,
1C) Servo amplifier failure detector (3
9, 40, 41).

Further, failure detectors (8A, 8B, 8C)
Is a pulse application circuit (27) for inputting a pulse to the servo amplifier (12A) and a plurality of servo control systems (V _A ) based on the servo amplifier output (V _A ) output by the servo amplifier (12A) in response to the pulse. It is preferable to include a second servo amplifier diagnostic circuit (26) for detecting a failure of 1A, 1B, 1C).

The operation method of the servo valve system according to the present invention is such that the servo valve (2) drives the controlled object (3) and the plurality of servo control systems (1A, 1B, 1C) allows the servo valve (2) to operate. Of the servo control system (1A, 1B, 1C) is detected. Controlling the servo valve (2), the controlled variable of the controlled object _{(Y A, Y B, Y} C) and detecting the control amount _{(Y A, Y B, Y} C) to a predetermined target value ( U)
In response to a deviation between the servo valve (2) and the failure of one of the plurality of servo control systems (1A, 1B, 1C) is detected, Shutting off the electric power supplied from one servo control system to the servo valve (2).

At this time, the control of the servo valve (2) is performed so that when a failure of one servo control system is detected,
It is preferable to include increasing the gain of another healthy servo control system of the plurality of servo control systems (1A, 1B, 1C).

[0024]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
An embodiment of a servo valve system according to the present invention will be described.

As shown in FIG. 1, the first embodiment of the servo valve system according to the present invention comprises an A system servo control system 1A, a B system servo control system 1B, and a C system servo control system 1C. ing. System A servo control system 1A, B
System servo control system 1B and C system servo control system 1C
It is connected to the servo valve 2 and drives the servo valve 2. The servo valve 2 supplies the hydraulic oil 4 to the valve 3 and adjusts the opening degree of the valve 3.

The servo valve 2 includes an A system servo control system 1A,
B system servo control system 1B and C system servo control system 1C
Are independently controlled by each of the. The A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C each independently detect the opening degree of the valve 3,
Further, the magnitude of the current supplied to the servo valve 2 is determined based on the detected opening degree. The servo valve 2 is a valve 3 according to the sum of the currents supplied by the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C.
The hydraulic oil 4 is supplied to and the opening degree of the valve 3 is adjusted. In the following description of the present specification, the opening degree of the valve 3 is 0% to 100%.
Expressed after being normalized to a value up to%. 0% indicates that the valve 3 is fully closed, and 100% indicates that the valve 3 is fully open.

The A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C respectively include an A system fault diagnostic device 8A, a B system fault diagnostic device 8B, and C.
The system fault diagnostic device 8C is connected. The A-system fault diagnostic device 8A, the B-system fault diagnostic device 8B, and the C-system fault diagnostic device 8C respectively have a fault in the A-system servo control system 1A, the B-system servo control system 1B, and the C-system servo control system 1C. To diagnose.

When the A-system servo control system 1A detects a failure in the A-system servo control system 1A, the A-system servo control system 1A is detected.
System failure occurrence signal ALM, which indicates that a failure has occurred
Output _A. When the B system fault diagnosis device 8B detects a failure in the B system servo control system 1B, the B system servo control system 1
B system fault occurrence signal AL indicating that a B fault has occurred
And outputs the M _B. When detecting a failure of the C system servo control system 1C, the C system failure diagnosis device 8C indicates a C system failure occurrence signal A indicating that a failure of the C system servo control system 1C has occurred.
And outputs the LM _C.

When a failure occurs in any of the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C, the failed servo control system is disconnected from the servo valve 2. As a result, it is possible to prevent the valve opening degree of the valve 3 from being offset by the current output to the servo valve 2 by the faulty servo control system, and to prevent the valve opening degree from varying. The disconnection of the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C from the servo valve 2 is performed by the A system failure occurrence signal ALM, respectively.
_This is performed in response to the _A , B system failure occurrence signal ALM _B and the C system failure occurrence signal ALM _C.

Further, when a failure occurs in any of the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C, the gain of other sound servo control systems is increased. As a result, it is possible to prevent the control response of the valve 3 from being lowered. The gain of another sound servo control system is increased in response to the A system failure occurrence signal ALM _A , the B system failure occurrence signal ALM _B , and the C system failure occurrence signal ALM _C.

Below, the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C will be described.
This will be described in more detail.

The system A servo control system 1A includes a linear variable differential transformer 5A (Linear Variable-Dif).
ference Transformer: Hereinafter, "L
VDT ”. ), Servo card 6A, switch 7A
including.

The LVDT 5A is attached to the valve 3. The LVDT 5A is connected to the servo card 6A. The servo card 6A is connected to the servo valve 2. The switch 7A is provided between the servo card 6A and the servo valve 2.

FIG. 2 shows the system A servo control system 1A in more detail. The LVDT 5A includes a movable iron core 15, a primary coil 16, secondary coils 17, and 18. The servo card 6A includes a system A valve opening detector 9A, a subtractor 10A,
The superimposing device 11A, the servo amplifier 12A, and the A system gain adjusting device 13A are included. The A system valve opening detector 9A includes a drive circuit 19, rectifying circuits 20 and 21, and a valve opening calculator 22.
including.

The movable iron core 15 of the LVDT 5A is attached to the valve 3. The position of the movable iron core 15 changes in one-to-one correspondence with the opening degree of the valve 3. A primary coil 16 and secondary coils 17 and 18 are provided so as to surround the movable iron core 15. The primary coil 16 is connected to the drive circuit 19 of the A system valve opening detector 9A. The drive circuit 19 inputs an AC voltage having a predetermined frequency into the primary coil 16. By applying the AC voltage to the primary coil 16, secondary output voltages V _L1 ^A and V _L2 ^A are induced in the secondary coils 17 and 18, respectively. The secondary side coils 17 and 18 have a secondary side output voltage V _L1.
^A and V _L2 ^A are output. Secondary output voltage V _L1 ^A , V
_L2 ^A is AC voltage. The effective values of the secondary side output voltages V _L1 ^A and V _L2 ^{A that} are output depend on the position of the movable iron core 15. That is, the secondary output voltage V _L1 ^A , V
_L2 ^A are both one-to-one correspondence to the opening degree of the valve 3.
The secondary side output voltages V _L1 ^A and V _L2 ^A are input to the rectifier circuits 20 and 21, respectively. The rectifier circuits 20 and 21 are
Each of the secondary output voltages V _L1 ^A and V _L2 ^A is rectified and output to the valve opening calculator 22.

The valve opening calculator 22 calculates the opening of the valve 3 based on the rectified secondary output voltages V _L1 ^A and V _L2 ^A. Opening the valve opening calculator 22 of system A valve opening detector 9A is calculated is described as A Keimiben opening Y _A. A Keimiben opening _{Y A} takes a value ranging from 0% to 100%. A
Line valve opening detector 9A is an A Keimiben opening _{Y A,} and outputs to the subtractor 10A. The valve opening target value U, which is the target value of the opening of the valve 3, is further input to the subtractor 10A. The valve opening target value U can take a value between -12.5% and 112.5%. The valve opening target value U can take a negative value or a value exceeding 100% when the valve 3 is instructed to be fully closed or fully opened, and the acting force acts on the valve in the fully closed direction or the fully open direction, respectively. To do so. Subtractor 10A outputs the deviation signal 71A indicating the deviation _{E A} and A Keimiben opening _{Y A} and valve opening degree target value U. The deviation signal 71A has a voltage proportional to the deviation E _A. The servo amplifier 12A outputs the deviation signal 7
The servo output voltage V _A proportional to the voltage of 1 _A is output.
At this time, the servo amplifier 12A supplies the drive current I _A to the servo valve 2. The gain of the servo amplifier 12A is K _A. The servo amplifier 12A is connected to the A system gain adjuster 13A.

The A-system gain adjuster 13A outputs the B-system fault occurrence signal ALM _B output from the B-system fault diagnostic device 8B.
If, in response to the C system fault occurrence signal ALM _C output from the C system fault diagnosis unit 8C, adjusts the gain _{K A} of the servo amplifier 12A. Gain K _{A of} servo amplifier 12A
Are B system servo control system 1B and C system servo control system 1
When none of C has failed, it is K ₁ . The A-system gain adjuster 13A has a failure in one of the B-system servo control system 1B and the C-system servo control system 1C due to the B-system failure occurrence signal ALM _B and the C-system failure occurrence signal ALM _C. Knowing this, the gain K _A is increased and the gain K _A is set to 1.5K ₁ . As a result, it is possible to prevent the control responsiveness of the valve 3 from being lowered when a failure occurs in either the B system servo control system 1B or the C system servo control system 1C and the system is disconnected from the servo valve 2. It is peeling.

Drive current I output from the servo amplifier 12A
_A is supplied to the servo valve 2 via the switch 7A.
The A system fault diagnostic signal ALM _A is supplied from the A system fault diagnostic unit 8A to the switch 7A. Switch 7A is A
When the system failure occurrence signal ALM _A informs that a failure has occurred in the A system servo system control system 1A, the system is turned off. When a failure occurs in the A system servo system control system 1A, the servo amplifier 12A and the servo valve 2 are disconnected,
The supply of the drive current I _A from the servo amplifier 12A to the servo valve 2 is cut off.

As shown in FIG. 1, the A system fault diagnostic device 8A outputs a test pulse signal 72A for diagnosing a fault in the A system servo system control system 1A. The test pulse signal 72A is supplied to the subtractor 10A and the servo amplifier 1
It is input to the superimposing device 11A interposed between the superimposing device 2A and 2A. The superimposing device 11A superimposes the test pulse signal 72A on the deviation signal 71A when the test pulse signal 72A is supplied. When the test pulse signal 72A is supplied to the superimposing device 11A, the servo amplifier 12A outputs a servo output voltage V _A proportional to the deviation signal 71A on which the test pulse signal 72A is superimposed.

A trigger clock generator 14 is connected to the A system fault diagnosing device 8A. The trigger clock generator 14 sends a trigger clock CLK to the A system fault diagnosis device 8A.
Supply _A. The A system fault diagnosing device 8A outputs the above-mentioned test pulse signal 72A in synchronization with the trigger clock CLK _A.

The B system servo control system 1B provided together with the A system servo control system 1A has the same configuration as that of the A system servo control system 1A described above, as shown in FIG. The B system servo control system 1B includes an LVDT 5B, a servo card 6B, and a switch 7B. Servo card 6
B is a B system valve opening detector 9B, a subtractor 10B, a superimposing device 11B, a servo amplifier 12B, and a B system gain adjuster 13.
Including B.

The LVDT 5B is attached to the valve 3. The LVDT 5B has the same configuration as the LVDT 5A described above. A voltage signal having a predetermined frequency is supplied from the B-system valve opening detector 9B to the primary side of the LVDT 5B. From the secondary side of LVDT5B, the secondary side output voltage V
_L1 ^B and V _L2 ^B are output. Secondary output voltage V _{L 1}
^{Both B 1} and V _L2 ^B have a one-to-one correspondence with the opening degree of the valve 3. The secondary output voltages V _L1 ^B and V _L2 ^B are input to the B system valve opening detector 9B of the servo card 6B.

The B-system valve opening detector 9B calculates the opening of the valve 3 based on the secondary side output voltages V _L1 ^B and V _L2 ^B, and opens the B-system actual valve indicating the calculated opening. Calculate the degree Y _B. The configuration of the B system valve opening detector 9B is the same as that of the A system valve opening detector 9A described above. B system valve opening detector 9B
It is a B Keimiben opening _{Y B,} and outputs to the subtractor 10B. The valve opening target value U of the opening of the valve 3 is further input to the subtractor 10B. The subtractor 10B outputs a deviation signal 71B indicating a deviation E _B between the B-system actual valve opening Y _B and the valve opening target value U. The deviation signal 71B has a voltage proportional to the deviation E _B. Servo amplifier 12B outputs a servo output voltage _{V B} which is proportional to the voltage deviation signal 71B. Servo amplifier 1
The 2B outputs the drive current I _B in response to the deviation signal 71B. The servo amplifier 12B is connected to the B system gain adjuster 13B.

The B system gain adjuster 13B fails in the C system.
C system failure occurrence signal ALM output from the diagnostic device 8C_C
And A system failure occurrence signal ALM_AIn response to the servo
12K gain K_BAdjust. Servo amplifier 12
B gain K_BIs C system servo control system 1C and A system support
When neither the servo control system 1A is out of order, K ₁
Is. The B system gain adjuster 13B causes the A system failure to occur.
Signal ALM_AAnd C system fault occurrence signal ALM_CAnd by
C system servo control system 1C and A system servo control system 1A
If you know that one of them has a failure, gain K
_BTo increase the gain K_B1.5K₁Set to. This
As a result, system A servo control system 1A and system C servo control
If a failure occurs in one of the system 1C and the servo valve 2
When separated, the control response of the valve 3 may deteriorate.
And are prevented.

Drive current I output from the servo amplifier 12B
_B is supplied to the servo valve 2 via the switch 7B.
The B-system fault occurrence signal ALM _B is supplied from the B-system fault diagnostic device 8B to the switch 7B. Switch 7B is B
When the system failure occurrence signal ALM _B is notified that a failure has occurred in the B system servo system control system 1B, the system is turned off. When a failure occurs in the B system servo system control system 1B, the servo amplifier 12B and the servo valve 2 are disconnected,
The supply of the drive current I _B from the servo amplifier 12B to the servo valve 2 is cut off.

The B system fault diagnostic device 8B outputs a test pulse signal 72B for diagnosing a fault in the B system servo system control system 1B. The test pulse signal 72B is input to the superimposing device 11B provided between the subtractor 10B and the servo amplifier 12B. The superimposing unit 11B superimposes the test pulse signal 72B on the deviation signal 71B when the test pulse signal 72B is supplied. Test pulse signal 72B
Is supplied to the superimposing device 11B, the servo amplifier 12B outputs the servo output voltage V _B in response to the deviation signal 71B on which the test pulse signal 72B is superimposed.

A trigger clock generator 14 is connected to the B system fault diagnosing device 8B. The trigger clock generator 14 sends the trigger clock CLK to the B system fault diagnosing device 8B.
Supply _B. The B system fault diagnosing device 8B outputs the above-mentioned test pulse signal 72B in synchronization with the trigger clock CLK _B.

The C system servo control system 1C also has the same configuration as the A system servo control system 1A described above. The C system servo control system 1C includes an LVDT 5C, a servo card 6C, and a switch 7C. The servo card 6C includes a C system valve opening detector 9C, a subtractor 10C, a superimposing device 11C, a servo amplifier 12C, and a C system gain adjuster 13C.

LVDT5C is attached to valve 3
It The primary side of the LVDT5C has a predetermined frequency
A voltage signal is provided. From the secondary side of LVDT5C,
Secondary output voltage V_L1 ^C, V_L2 ^CIs output. Secondary
Side output voltage V_L1 ^C, V_L2 ^CAre both open valve 3
There is a one-to-one correspondence each time. Secondary output voltage V_L1 ^C,
V_L2 ^CIs the C system valve opening detector 9 of the servo card 6C.
Input to C.

The C system valve opening detector 9C is a secondary side output power source.
Pressure V_L1 ^C, V_L2 ^CCalculate the opening of valve 3 based on
Then, the C-system actual valve opening Y indicating the calculated opening_CCalculate
It The configuration of the C system valve opening detector 9C is shown in FIG.
The configuration is similar to that of the A system valve opening detector 9A. C system valve
The opening detector 9C is, as shown in FIG.
Valve opening Y_CIs output to the subtractor 10C. Subtractor 10C
Further, the valve opening target value U of the opening of the valve 3 is further input to
It The subtractor 10C has a C system actual valve opening Y_CAnd valve opening target value
Deviation E from U_CThe deviation signal 71C is output. deviation
The signal 71C is the deviation E _CHas a voltage proportional to. Sir
The vo-amp 12C is a circuit proportional to the voltage of the deviation signal 71C.
Servo output voltage V_CIs output. The servo amplifier 12C is
The drive current I in response to the deviation signal 71C_CTo output
become. The servo amplifier 12C is a C system gain adjuster 1
It is connected to 3C.

The C-system gain adjuster 13C fails in the A-system.
A system failure occurrence signal ALM output from the diagnostic device 8A_A
And B system fault occurrence signal ALM_BIn response to the servo
12K gain K_CAdjust. Servo amplifier 12
C gain K_CIs system A servo control system 1A and system B servo
If neither the servo control system 1B is out of order, K ₁
Is. The C system gain controller 13C causes the A system failure to occur.
Signal ALM_AAnd B system fault occurrence signal ALM_BAnd by
A system servo control system 1A and B system servo control system 1B
If you know that one of them has a failure, gain K
_CTo increase the gain K_C1.5K₁Set to. This
As a result, system A servo control system 1A and system B servo control
The servo valve 2 is turned off due to a failure in either system 1B.
When separated, the control response of valve 3 decreases
Is prevented.

Drive current I output from the servo amplifier 12C
_CIs supplied to the servo valve 2 via the switch 7C.
The switch 7C is connected to the C system failure diagnostic device 8C
Fault signal ALM_CIs supplied. Switch 7C is C
System failure occurrence signal ALM_CC system Servo system Control system
When it is notified that a fault has occurred in 1C, it will be shut off.
Become. When a failure occurs in the C system servo system control system 1C,
Servo amplifier 12C and servo valve 2 are separated and
Drive current I from the amplifier 12C to the servo valve 2 _CSupply of
Is cut off.

The C system fault diagnosing device 8C outputs a test pulse signal 72C for diagnosing a fault of the C system servo system control system 1C. The test pulse signal 72C is input to the superposing device 11C provided between the subtractor 10C and the servo amplifier 12C. The superimposing device 11C superimposes the test pulse signal 72C on the deviation signal 71C when the test pulse signal 72C is supplied. Test pulse signal 72C
Is supplied to the superimposing device 11C, the servo amplifier 12C outputs the servo output voltage V _C in response to the deviation signal 71C on which the test pulse signal 72C is superimposed.

A trigger clock generator 14 is connected to the C system fault diagnosing device 8C. The trigger clock generator 14 sends the trigger clock CLK to the C system fault diagnosing device 8C.
Supply _C. The C system fault diagnosing device 8C outputs the above-mentioned test pulse signal 72C in synchronization with the trigger clock CLK _C.

Next, the A system fault diagnostic device 8A, the B system fault diagnostic device 8B, and the C system fault diagnostic device 8C will be described in detail. As shown in FIG. 2, the A-system fault diagnostic device 8 that supplies the A-system fault occurrence signal ALM _A to the switch 7A.
A is the LVDT failure detector 23, the servo loop monitor 2
4. Servo amplifier diagnostic circuit 25 for intermediate opening, servo amplifier diagnostic circuit 26 for fully open and fully closed, test pulse output circuit 2
7. A system deviation monitor circuit 28 and an OR circuit 29 are included.

The LVDT failure detector 23 is the LVDT 5A.
Determines whether or not the LVDT 5A has a failure, based on whether or not the effective values of the secondary side output voltages V _L1 ^A and V _L2 ^A output by the device are within a predetermined range. Figure 3 shows LVDT5A
Is normal, the secondary side output voltages V _L1 ^A and V _L2
^The range in which the effective value of ^A can be taken is shown. When the LVDT 5A is normal, the effective value of the secondary side output voltage V _L1 ^A is V
_It takes a value of _MIN1 or more and V _{MAX 1} or less. When the effective value of the secondary side output voltage V _L1 ^A is not V _MIN1 or more and V _{MAX 1} or less, the LVDT failure detector 23 determines that the LVDT 5A
It is determined that there is a failure in the. Similarly, the effective value of the secondary output voltage _{V L2} ^A _takes a _{V MIN2} or _{V MAX2} following values. The effective value of the secondary side output voltage V _L2 ^A is V
If _MIN2 above _{V MAX2} not less, LVDT fault detector 23 determines that failure LVDT5A has occurred. When it is judged that the LVDT5A is out of order,
The LVDT failure detector 23 sets the output ALM _A ¹ to the “H” level. As shown in FIG. 2, output AL
M _A ¹ is output to the OR circuit 29.

[0057] The servo loop monitor 24, based on the A Keimiben opening Y _A and valve opening degree target value U of the valve opening calculator 22 outputs, failure A system servo control system 1A occurs Judge whether or not. The servo loop monitor 24 sets the output ALM _A ² to the “H” level when it determines that the system A servo control system 1A has a failure. FIG. 4 shows the configuration of the servo loop monitor 24. Servo loop monitor 2
4 is a limiter 31, a change rate limiter 32, a subtractor 33,
A deviation monitor 34 and a timer 35 are included.

The limiter 31 and the rate-of-change limiter 32 calculate an expected opening Y ^* expected to be taken by the valve 3 based on the valve opening target value U. Expected opening Y ^* is
It is the same as the valve opening target value U. However, the valve opening target value U corrected by the limiter 31 and the change rate limiter 32 is output as the expected opening Y ^* .

[0059] limiter 31, A Keimiben opening _{Y A} is 0
The valve opening target value U input to the limiter 31 can take a value of -12.5% or more and 112.5% or less, while it is expressed by a value between 100% and 100%. Is provided. As described above, when the valve 3 is set to be fully open or fully closed, the valve opening target value U is set in order to allow the force to act on the valve 3 in the fully closing direction or the fully opening direction.
Can take a value of -12.5% or more and 112.5% or less. However, A Keimiben opening _{Y A} is only can assume only the values of 100% or less than 0%. Therefore, the limiter 31 is provided, and the output value that the limiter 31 outputs in response to the valve opening target value U is limited to 0% or more and 100%.

The rate-of-change limiter 32 is provided so that the speed at which the opening degree of the valve 3 actually changes is limited to a certain range. The change rate limiter 32 includes a limiter 31.
By this, the output value limited to a value of 0% or more and 100% or less is input. The expected opening Y ^* output by the change rate limiter 32 follows the output value of the limiter 31. However, the rate of change of the expected opening Y ^* is limited within a predetermined range. As a result, the actual movement of the opening of the valve 3 is reflected in the expected opening Y ^* .

[0061] The subtracter 33 calculates the difference [Delta] Y _A between the A Keimiben opening _{Y A} expected opening ^{Y *.} When the absolute value of the difference ΔY _A is larger than a predetermined reference value, the deviation monitor 34 sets its output to “H” level and outputs it. The output of the deviation monitor 34 is connected to the input of the timer 35. Timer 35
If the output of the deviation monitor 34 is continuously at “H” level for a certain period of time, the output ALM _A ^{2 is set} to “H”.
Output level. A Keimiben opening _{Y A} and the expected degree of opening Y
^When the difference from ^* is large for a certain period of time, output A
LM _A ² goes to “H” level. When the difference is large state between A Keimiben opening Y _A and the expected degree Y ^* has continued for a predetermined time, the servo loop monitor 24, A system servo control system 1
It is determined that A has a failure. This prevents erroneous detection of a failure. As shown in FIG. 2, the output ALM _A ² is output to the OR circuit 29.

The servo amplifier diagnostic circuit 25 at the intermediate opening is
A system actual valve opening Y_AAnd valve opening target value U and servo amplifier 12
Servo output voltage V output by A_AAnd based on the servo
It is determined whether the amplifier 12A is operating normally.
When it is determined that the servo amplifier 12A is out of order,
The servo amplifier diagnostic circuit 25 outputs the output ALM_A ^Three
To "H" level.

FIG. 5 shows the configuration of the servo amplifier diagnostic circuit 25 at the intermediate opening. Servo amplifier diagnostic circuit 2 at intermediate opening
5 includes a subtractor 36, a multiplier 37, a limiter 38, a subtractor 39, a deviation monitor 40, and a timer 41.

Subtractor 36, multiplier 37, and limiter 3
8, based on the valve opening target value U and A Keimiben opening Y _A, to simulate the operation of the servo amplifier 12A, the expected voltage V _A which is expected as the output of the servo amplifier 12A
Calculate ^* . Subtractor 36 calculates a deviation E _A ^* is the difference between the A Keimiben opening Y _A calculated by the valve opening target value U and the A-type valve opening detector 9A. The subtractor 36 outputs a voltage proportional to the deviation E _A ^* . The multiplier 37 outputs a voltage that is P times the voltage output by the subtractor 36. P is
It matches the gain K _A of the servo amplifier 12A. Multiplier 3
The voltage output by 7 is limited by the limiter 38 to a voltage range that can be output by the servo amplifier 12A. When the maximum voltage and the minimum voltage that the servo amplifier 12A can output are standardized as 100% and -100%, respectively,
The limiter 38 sets the voltage output from the multiplier 37 to −100.
The output voltage is limited to between 100% and 100% and output as the expected voltage V _A ^* .

The subtractor 39 detects the difference ΔV between the servo output voltage V _A output by the servo amplifier 12A and the expected voltage V _A ^*.
Output _A. The deviation monitor 40 outputs the output when the absolute value of the difference ΔV _A is larger than a predetermined reference value V _std.
The output of the deviation monitor 40 is H level.
It is connected to the input of the timer 41. If the output of the deviation monitor 40 is continuously at "H" level for a certain period of time, the timer 41 sets the output ALM _A ³ to "H" level and outputs it. When the state in which the difference between the servo output voltage V _A and the expected voltage V _A ^* is large continues for a certain time, the timer 4
1, the output ALM _A ³ becomes "H" level. At the intermediate opening, the servo amplifier diagnostic circuit 25 determines that the servo output voltage V _A
Then, when the state in which the difference from the expected voltage V _A ^* is large continues for a certain period of time, it is determined that a failure has occurred in the A system servo control system 1A. This prevents erroneous detection of a failure. As shown in FIG. 2, the output ALM
_A ³ is output to the OR circuit 29.

Servo amplifier diagnostic circuit 2 at the intermediate opening described above
No. 5 indicates that the valve opening target value U indicates full opening or full closing, and if the servo output voltage V _A output from the servo amplifier 12A is saturated for that reason, the failure of the servo amplifier 12A cannot be detected. . Therefore, in addition to the servo amplifier diagnostic circuit 25 at the intermediate opening, the servo amplifier diagnostic circuit 26 and the test pulse output circuit 27 at the fully open and fully closed state are provided in the servo amplifier 1
Used for 2A fault detection.

When the servo amplifier diagnostic circuit 26 is fully opened and fully closed,
The strobe output circuit 27 corresponds to the response of the servo amplifier 12A.
The servo amplifier 12A operates normally based on the response.
Judge whether or not. The test pulse output circuit 27 is
As shown in FIG. 2, the trigger clock CLK_ATo
Synchronously, output the test pulse signal 72A to the superimposing device 11A.
Force The superimposing device 11A polarizes the test pulse signal 72A.
The signal is superimposed on the difference signal 71A and output to the servo amplifier 12A.
It The test pulse signal 72A is shown in FIG.
As such, it is a bipolar rectangular pulse. Servo valve 2 is
To reduce the influence of the application of the pulse signal 72A
Therefore, the pulse width of the test pulse signal 72A is
It is set sufficiently small with respect to the time constant of the operation of valve 2.
It For example, the pulse width of the test pulse signal 72A is 1
Set the pulse width (0.5 ms) corresponding to the frequency of kHz.
Can be Servo output power output from the servo amplifier 12A
Pressure V _AIs the servo amplifier diagnostic circuit 26 when fully open and fully closed.
To be monitored. Rectangular pulse as test pulse signal 72A
Is output by the servo amplifier 12A when is input.
Servo output voltage V_AIf fluctuates, the servo amplifier 12A
It is judged that there is no failure that the output swings off. Te
A rectangular pulse is input as the strike pulse signal 72A
Also the servo output voltage V_AIf is not changed, when fully open and fully closed
The servo amplifier diagnostic circuit 26 is
It is judged that a trouble has occurred, and the output ALM_A ^Four"H"
Output as bells. Output ALM_A ^FourIs the OR circuit 29
Is output to.

The test pulse output circuit 27 outputs the test pulse signal 72A to the superimposing device 11A when it is determined that the servo amplifier diagnostic circuit 25 at the intermediate opening cannot determine the failure of the servo amplifier 12A. The test pulse output circuit 27 includes a servo output voltage V _A output by the servo amplifier 12A, a servo output voltage V _B output by the servo amplifier 12B, a servo output voltage V _C output by the servo amplifier 12C, and a valve opening target value U. Based on the above, it is determined whether or not the test pulse signal 72A should be output.

FIG. 7 shows the configuration of the test pulse output circuit 27. The test pulse output circuit 27 includes a fully-open side valve opening target value determiner 42, a fully-open side self-system servo voltage determiner 43,
Full open side other system servo voltage determiner 44, Full close side valve opening target value determiner 45, Full close side own system servo voltage determiner 46, Full close side other system servo voltage determiner 47, AND circuit 48, A
It includes an ND circuit 49, an OR circuit 50, an AND circuit 51 and a pulse output circuit 52.

The full-open side valve opening target value determiner 42, the full-open side own system servo voltage determiner 43, the full-open side other system servo voltage determiner 44, and the AND circuit 48 have the valve opening target value U
When the full open is instructed and the servo output voltage V _A output from the servo amplifier 12A is in a range in which the servo amplifier diagnostic circuit 25 cannot detect a failure at the intermediate opening,
Generating a full open instruction signal TRG _H taking H "level.

The valve opening target value U is input to the fully open side valve opening target value determiner 42. When the valve opening target value U is 100% or more, the output of the fully open side valve opening target value determiner 42 becomes the “H” level. When the valve opening target value U is less than 100%, the output of the fully open side valve opening target value determiner 42 becomes the “L” level.

The self-system servo voltage determiner 43 on the fully open side has
The servo output voltage V _A output from the servo amplifier 12A is input. Servo output voltage V _A is 100-V
When it is equal to or more than _std (%), the output of the fully open side self-system servo voltage determiner 43 becomes "H" level. Where V
As described above, _std is a reference value for the deviation monitor 40 of the servo amplifier diagnosis circuit 25 at the intermediate opening degree to determine the difference ΔV _A between the servo output voltage V _A and the expected voltage V _A ^* . However, the servo output voltage V _A and the reference value V _std
Is standardized and expressed as the maximum voltage and the minimum voltage that the servo amplifier 12A, the servo amplifier 12B, and the servo amplifier 12C can output are 100% and -100%, respectively. When the servo output voltage V _A output by the servo amplifier 12A is 100-V _std (%) or more,
The servo amplifier diagnostic circuit 25 at the intermediate opening cannot detect the abnormality of the servo amplifier 12A. In such a case, the output of the fully open side self-system servo voltage determiner 43 is set to the "H" level.

The fully open side other system servo voltage determiner 44 includes
The servo output voltage V _B output by the servo amplifier 12B,
The servo output voltage V _C output from the servo amplifier 12C is input. Servo output voltage V _B and servo output voltage V _C
Is 100% or more, the output of the fully-open side other system servo voltage determiner 44 becomes "H" level. When the sum of the servo output voltage V _B and the servo output voltage V _C is less than 100%, the output of the fully open side other system servo voltage determiner 44 becomes “L” level.

The outputs of the fully open side valve opening target value determiner 42, the fully open side own system servo voltage determiner 43, and the fully open side other system servo voltage determiner 44 are connected to the inputs of an AND circuit 48. The AND circuit 48 uses the fully open side valve opening target value determiner 4
2, and outputs a logical product of the outputs of the full-opening own line servo voltage determiner 43 and the fully open side other strains servo voltage determiner 44 as fully opened instruction signal TRG _H. Full open instruction signal TRG _H, the valve opening target value U is, has instructed the fully open, the servo amplifier 1
When the servo output voltage V _A output by 2 _A is in the range in which the servo amplifier diagnostic circuit 25 cannot detect the failure at the intermediate opening, the level becomes “H” level. At this time, only when the sum of the servo output voltage V _B and the servo output voltage V _C is 100% or more, the full open instruction signal TRG _H is, "H" level, and when the valve 3 is not actually fully open It is fully open instruction signal TRG _H can not be the "H" level.

On the other hand, the fully closed side valve opening target value determination device 45,
Closed side own system servo voltage determiner 46, fully closed side other system servo
The voltage determiner 47 and the AND circuit 49 have a valve opening target value.
U has instructed to fully close and the servo amplifier 12A
Output voltage V _AServo-un at intermediate opening
When the failure is not detected by the diagnostic circuit 25
In addition, the fully closed command signal TRG that takes "H" level_LGenerate
It

The valve opening target value U is input to the fully closed valve opening target value determiner 45. When the valve opening target value U is 0% or less, the output of the fully closed side valve opening target value determiner 45 is "
H level. When the valve opening target value U is larger than 100%, the output of the fully closed side valve opening target value determiner 45 is "
L level.

The self-system servo voltage determiner 46 on the fully closed side includes
The servo output voltage V _A output from the servo amplifier 12A is input. When the servo output voltage V _A is equal to or lower than V _std (%), the output of the fully closed side self-system servo voltage determiner 46 becomes “H” level. Here, as described above, V _std is determined by the deviation monitor 40 of the servo amplifier diagnosis circuit 25 at the intermediate opening degree from the servo output voltage V _A and the expected voltage V
It is a reference value for judging the difference ΔV _{A from A} ^* . The servo output voltage V _A output by the servo amplifier 12A is V
_{When s td} (%) or less, the servo amplifier diagnostic circuit 25 at the intermediate opening cannot detect the abnormality of the servo amplifier 12A. In such a case, the output of the fully closed self-system servo voltage determiner 46 is set to the "H" level.

In the fully closed side other system servo voltage determiner 47,
The servo output voltage V _B output by the servo amplifier 12B,
The servo output voltage V _C output from the servo amplifier 12C is input. Servo output voltage V _B and servo output voltage V _C
When the sum of and is 0% or less, the output of the fully-closed side other system servo voltage determiner 47 becomes "H" level. When the sum of the servo output voltage V _B and the servo output voltage V _C is greater than 0%, the output of the fully closed side other system servo voltage determiner 47 is “L”.
Become a level.

The outputs of the fully closed side valve opening target value determiner 45, the fully closed side own system servo voltage determiner 46, and the fully closed side other system servo voltage determiner 47 are connected to the inputs of an AND circuit 49. The AND circuit 49 uses the fully closed side valve opening target value determiner 4
5. The logical product of the outputs of the fully closed self-system servo voltage determiner 46 and the fully closed other system servo voltage determiner 47 is output as a fully closed instruction signal TRG _L. All closing command signal TRG _L, the valve opening target value U is, has instructed the fully closed, and the servo output voltage V _A of the servo amplifier 12A outputs the failure by the intermediate opening Servo amplifier diagnostic circuit 25 When it is in the undetectable range, it becomes "H" level. At this time, only when the sum of the servo output voltage V _B and the servo output voltage V _C is 0% or less, the fully closed instruction signal TRG _L becomes “H” level, and the valve 3 is not actually fully closed. In this case, the fully closed instruction signal TRG _L does not go to "H" level.

[0080] fully open instruction signal TRG _H and fully closed indication signal TR
The G _L is input to the OR circuit 50. OR circuit 50
Outputs a logical sum of the fully open instruction signal TRG _H and the fully closed instruction signal TRG _L. The output of the OR circuit 50 indicates that the valve opening target value U indicates full opening or full closing, and the servo output voltage V _A output by the servo amplifier 12A has failed due to the servo amplifier diagnostic circuit 25 at the intermediate opening. Goes to "H" level when is in the undetectable range. The output of the OR circuit 50 is connected to one input of the AND circuit 51.

The trigger clock CLK _A generated by the trigger clock generator 14 is input to the other input of the AND circuit 51. As shown in FIG. 8, the trigger clock CLK _A has a cycle 3T, and “H” is generated every cycle 3T.
It is a pulse signal that becomes a level. The AND circuit 51 calculates the logical product of the trigger clock CLK _A and the output of the OR circuit 50 and inputs the logical product to the pulse output circuit 52.

When detecting the rising edge of the output of the AND circuit 51, the pulse output circuit 52 outputs the test pulse signal 72A having the waveform shown in FIG. Figure 2
As shown in, the test pulse signal 72A is superimposed on the deviation signal 71A by the superimposing device 11A, and is input to the servo amplifier 12A. The servo amplifier diagnostic circuit 26 at full-open and fully-closed determines whether or not there is a failure in the servo amplifier 12A depending on whether or not the servo output voltage V _A output from the servo amplifier 12A changes in response to the test pulse signal 72A. When it is determined that the servo amplifier 12A has a failure, the servo amplifier diagnostic circuit 26 at the time of full opening and full closing detects the ALM.
And outputs to the OR circuit 29 in the the _A ⁴ "H".

On the other hand, the two-system deviation monitor circuit 28 is
A system actual valve opening Y calculated by the valve opening detector 9A_AAnd B system
B system actual valve opening Y calculated by the valve opening detector 9B_BDeviation from
ΔY _AB, And A system actual valve opening Y_AAnd C system valve opening detection
C system actual valve opening Y calculated by device 9C_CDeviation from_ACTo
Based on this, a failure has occurred in system A servo control system 1A.
Or not. Deviation ΔY_ABAnd deviation ΔY_ACWith
If both are large, the other B system servo control system 1B,
A situation that has not occurred in the C system servo control system 1C
It is presumed that it is occurring in the system servo control system 1A
It Deviation ΔY_ABAnd deviation ΔY_ACWhen both and
2 system deviation monitor circuit 28, A system servo control system 1
It is determined that A has a failure. 2 system deviation monitor times
Path 28 has a failure in system A servo control system 1A.
When it is determined that the output ALM of the two-system deviation monitor circuit 28
_A ⁵Goes to "H" level.

FIG. 9 shows the configuration of the two-system deviation monitor circuit 28. The two-system deviation monitor circuit 28 includes a subtractor 53, a deviation monitor 54, a subtractor 55, a deviation monitor 56, and an AND circuit 5.
7 and a timer 58. Subtractor 53 calculates the difference [Delta] Y _AB between A Keimiben opening _{Y A} and B Keimiben opening _{Y B,}
Output to the deviation monitor 54. When the absolute value of the difference ΔY _AB is larger than the predetermined reference value, the output of the deviation monitor 54 becomes “H” level.

[0085] The subtracter 55 calculates the difference [Delta] Y _CA with A Keimiben opening _{Y A} and C Keimiben opening _{Y C,} the deviation monitor 56
Output to. When the absolute value of the difference ΔY _CA is larger than the predetermined reference value, the output of the deviation monitor 56 becomes the “H” level.

One input of the AND circuit 57 is connected to the output of the deviation monitor 54, and the other input of the AND circuit 57 is
It is connected to the output of the deviation monitor 56. AND circuit 5
Reference numeral 7 outputs a logical product of the output of the deviation monitor 54 and the output of the deviation monitor 56. The timer 58 is an AND circuit 57.
When the output of A is continuously at the "H" level for a certain period of time, the output ALM _A ^{5 is set} to the "H" level and output. Output _ALM ^{A 5} is, A Keimiben opening _{Y A} and B Keimiben opening _{Y B}
If the absolute value of the difference [Delta] Y _AB of the absolute value of the difference [Delta] Y _CA with A Keimiben opening Y _A and C Keimiben opening Y _C are both greater than a predetermined reference value, It becomes "H" level.

Two-system deviation monitor circuit 2 having the above configuration
When the difference ΔY _AB and the difference ΔY _CA are both large, it determines that the system A servo control system 1A is out of order and outputs the output ALM _A ⁵ at "H" level. The output ALM _A ⁵ is, as shown in FIG.
It is output to the OR circuit 29.

The OR circuit 29 includes the LVDT failure detector 2
Output 3 of ALM_A ¹, Output A of the servo loop monitor 24
LM_A ^Two, Output of servo amplifier diagnostic circuit 25 at intermediate opening
ALM_A ^ThreeOutput of servo amplifier diagnostic circuit 26 when fully open and fully closed
Power ALM_A ^Four, And the output AL of the two-system deviation monitor circuit 28
M_A ⁵Is entered. The OR circuit 29 outputs the output ALM_A ¹
~ ALM_A ⁵When any of the above is at "H" level, A
System failure occurrence signal ALM_AIs output. LVDT failure inspection
Output device 23, servo loop monitor 24, servo at intermediate opening
Amplifier diagnostic circuit 25, servo amplifier diagnostic circuit when fully open and fully closed
26 or the dual system deviation monitor circuit 28
When it is determined that the servo control system 1A has a failure, the A system
Failure occurrence signal ALM_AIs output.

When the A system failure occurrence signal ALM _A is output, the switch 7A is turned off and the servo amplifier 1
The supply of the drive current I _A from 2 A to the servo valve 2 is cut off. At the same time, the servo amplifier 12B and the servo amplifier 1
The gains K _B and K _{C of} 2C are increased from K ₁ to 1.5K _1, and the reduction in the driving capability of the servo valve 2 due to the separation of the servo amplifier 12A is prevented.

The B-system fault diagnosing unit 8B and the C-system fault diagnosing unit 8C have the same configuration and are the same as the A-system fault diagnosing unit 8A, except that the signals input to them and the signals they output are different. The operation of. The B system fault diagnosing device 8B is
A Keimiben opening _{Y A} instead B Keimiben opening _{Y B} of, C Keimiben opening _{Y C} instead of B Keimiben opening _{Y B} is, C Keimiben opening _{Y C} instead of instead of a Keimiben opening Y _a is, servo output voltage V _B instead of the servo output voltage V _a is, servo output voltage V _C in place of the servo output voltage V _B is the servo output voltage V _C the servo output voltage _{V a} is the trigger clock CLK _B is input instead of the trigger clock CLK _a, except that instead of system a failure signal ALM _a is B lineage failure signal ALM _B is output, a system fault It has the same configuration as the diagnostic device 8A and performs the same operation. Similarly, C system fault diagnosis unit. 8C, C Keimiben opening _{Y C} instead of A Keimiben opening _{Y A} is, B Keimiben opening _Y instead A Keimiben opening Y of _{B A} is the B system actual valve opening Y _B instead of the C system actual valve opening Y _C , the servo output voltage V _C is the servo output voltage V _A , and the servo output voltage is the servo output voltage V _B. V _a is, servo output voltage _{V B} instead of the servo output voltage _{V C} is, trigger clock CLK trigger clock CLK _C instead of _a is inputted, a system fault occurrence signal ALM C system fault generation signal ALM instead of _a Except that _C is output, it has the same configuration as the A system fault diagnosis device 8A and performs the same operation. A detailed description of the B-system fault diagnostic device 8B and the C-system fault diagnostic device 8C will not be given.

However, as shown in FIG. 8, the time when the trigger clock CLK _A , the trigger clock CLK _B , and the trigger clock CLK _C are at “H” level is T
They are shifted one by one, and at the same time, they do not become "H" level. The test pulse signal 72A, the test pulse signal 72B, and the test pulse signal 72C that are output in synchronization with the trigger clock CLK _A , the trigger clock CLK _B , and the trigger clock CLK _C , respectively, are not output at the same time. As a result, the test pulse signal 72A, the servo amplifier 12B, the servo amplifier 12B, the servo amplifier 12C, the test pulse signal 72A,
It is avoided that the test pulse signal 72B and the test pulse signal 72C are input. Servo amplifier 12A,
If the test pulse signal 72A, the test pulse signal 72B, and the test pulse signal 72C are simultaneously input to the servo amplifier 12B and the servo amplifier 12C, the operation of the servo valve 2 may be affected. Therefore, the output times of the test pulse signal 72A, the test pulse signal 72B, and the test pulse signal 72C are shifted.

As described above, in this embodiment, when a failure occurs in any of the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C, the servo control in which the failure occurs is performed. The system is disconnected from the servo valve 2. As a result, the faulty servo control system causes the servo valve 2
The offset of the valve opening of the valve 3 is prevented from being shifted by the current output to the valve 3, and the fluctuation of the valve opening is prevented.

Furthermore, when a failure occurs in any of the A system servo control system 1A, the B system servo control system 1B, and the C system servo control system 1C, the gain of other sound servo control systems is increased. As a result, it is possible to prevent the control response of the valve 3 from being lowered.

Further, in this embodiment, the A system servo control system 1A, the B system servo control system 1B, and
Also, the failure of the C system servo control system 1C is detected, and the multifaceted failure detection is realized.

FIG. 10 shows a second embodiment of the servo valve system according to the present invention. In the second embodiment, the servo card 6A, the servo card 6B, and the servo card 6C are used.
A system gain controller 13A, B system gain controller 1
The 3B and C system gain adjuster 13C is not provided. Servo amplifier 12A, servo amplifier 12B, servo amplifier 1
The 2C gain is fixed at K. Instead, the A system valve opening for calculating the A system valve opening target value U _A , the B system valve opening target value U _B , and the C system valve opening target value U _{C based} on the valve opening target value U, respectively. Degree target value calculation unit 59A, B system valve opening target value calculation unit 59B, C system valve opening target value calculation unit 59C
Is provided. The A-system valve opening target value U _A , the B-system valve opening target value U _B , and the C-system valve opening target value U _C are input to the servo card 6A, the servo card 6B, and the servo card 6C, respectively. A system valve opening target values U _A , B
The servo amplifier 12A, the servo amplifier 12B, and the servo amplifier 12C determine their outputs based on the system valve opening target value U _B and the C system valve opening target value U _C , respectively.

The configuration and operation of the other parts of the servo valve system of the present embodiment are the same as those of the first embodiment, and the description thereof will not be given.

The A system valve opening target value U _A , the B system valve opening target value U _B , and the C system valve opening target value U _C are the A system servo control system 1A, the B system servo control system 1B, and C, respectively. When no failure has occurred in any of the system servo control systems 1C, the valve opening target value U matches. When a failure occurs in the A system servo control system 1A, the B system valve opening target value U _B , such that the gains of the B system servo control system 1B and the C system servo control system 1C are substantially 1.5 times, C strains valve opening target value _{U C}
And are input to the servo card 6B and the servo card 6C, respectively. Similarly, when a failure occurs in the B system servo control system 1B, the C system servo control system 1C and A
The C system valve opening target value U _C and the A system valve opening target value U _A are determined so that the gain of the system servo control system 1A becomes substantially 1.5 times, and the servo card 6C and It is input to the servo card 6A. Furthermore, if a failure occurs in the C system servo control system 1C, the A system servo control system 1A
And the A system valve opening target value U _A and the B system valve opening target value U _B are determined so that the gains of the B system servo control system 1B and the B system servo control system 1B are substantially 1.5 times, respectively. ,
And is input to the servo card 6B.

FIG. 11 shows an A system valve opening target value calculation unit 59A for calculating the A system valve opening target value U _A. The A-system valve opening target value calculation unit 59A includes a subtractor 60, a multiplier 61,
A switch 62 and an adder 63 are included. In the subtractor 60,
A valve opening target value U, and A Keimiben opening Y _A to A line valve opening detector 9A is calculated is input. Subtractor 60 subtracts the A Keimiben opening _{Y A} from the valve opening target value U, the deviation _{E A} '
To calculate. The multiplier 61 multiplies the deviation E _A 'by 0.5. The output of the multiplier 61 is 0.5E _A '.

The switch 62 uses the B system fault occurrence signal AL.
Depending on the M _B and C system fault occurrence signal ALM _C, connects the multiplier 61 and the adder 63, or disconnects the multiplier 61 and the adder 63. When it is recognized that a failure has occurred in either the B system servo control system 1B or the C system servo control system 1C by the B system failure occurrence signal ALM _B and the C system failure occurrence signal ALM _C , the switch 62 The multiplier 61 and the adder 63 are connected. When there is no failure in either the B system servo control system 1B or the C system servo control system 1C, the switch 62 disconnects the multiplier 61 from the adder 63.

When the multiplier 61 and the adder 63 are connected, the adder 63 adds the output of the multiplier 61 and the valve opening target value U to obtain the A system valve opening target value U. Output _A. When the multiplier 61 and the adder 63 are not connected, the adder 63 outputs the valve opening target value U as it is as the A system valve opening target value U _A.

When no failure has occurred in either the B system servo control system 1B or the C system servo control system 1C, A
The system valve opening target value U _A is equal to the valve opening target value U.

On the other hand, when a failure occurs in either the B system servo control system 1B or the C system servo control system 1C, the multiplier 61 and the adder 63 are connected, and the A system valve opening target value U _A is , U _A = 1.5U−0.5Y _A. At this time, the deviation E output from the subtractor 10A
_A becomes E _A = 1.5 (U−Y _A ). Therefore, the output of the servo amplifier 12A is 1.5
When K (U−Y _A ), and the multiplier 61 and the adder 63 are connected, the gain of the system A servo control system 1A is substantially in the state where the multiplier 61 and the adder 63 are not connected. It becomes 1.5 times. That is, in the second embodiment, the gain of the system A servo control system 1A is increased by 1.5 times in the same manner as in the first embodiment, while maintaining the gain K of the servo amplifier 12A as it is.

The B-system valve opening target value calculation unit 59B is
General fault occurrence signal ALM_BA system failure occurrence signal instead of
ALM_AOther than the point where is input, A system valve opening target value calculation
It has the same configuration as the unit 59A and performs the same operation. As well
C system valve opening target value calculation unit 59C
Raw signal ALM_CA system failure occurrence signal ALM instead of _A
Other than the point where is input, A system valve opening target value calculation unit 59A
It has the same configuration as and performs the same operation. B system valve opening
Target value calculation unit 59B and C system valve opening target value calculation unit 59C
Is omitted.

As in this embodiment, the servo card 6
A system gain controller 13A, B system gain controller 13B, C to A, servo card 6B, and servo card 6C
The system gain controller 13C is not provided, and instead, the A system valve opening target value calculation unit 59A, the B system valve opening target value calculation unit 59B, and the C system valve opening target value calculation unit 59C are provided. This is effective when it is difficult to add circuits to the servo card 6A, the servo card 6B, and the servo card 6C.

[0105]

As described above, the present invention provides a servo valve system in which the controlled variable of the controlled object is unlikely to change even if one control system fails.

The present invention also provides a servo valve system in which the output of the entire control system does not decrease even if one control system fails.

Further, according to the present invention, there is provided a servo valve system which does not deteriorate the responsiveness for controlling the controlled object even if one control system fails.

[Brief description of drawings]

FIG. 1 shows a first embodiment of a servo valve system according to the present invention.

FIG. 2 shows a configuration of an A system servo control system 1A and an A system failure diagnostic device 8A.

FIG. 3 shows a range in which a secondary output voltage V _L1 ^A and V _L2 ^A output by the LVDT 5A can be set.

FIG. 4 shows a configuration of a servo loop monitor 24.

FIG. 5 is a servo amplifier diagnostic circuit 25 at an intermediate opening.
Shows the configuration of.

FIG. 6 shows a waveform of a test pulse signal 72A.

FIG. 7 shows a configuration of a test pulse output circuit 27.

FIG. 8 shows waveforms of trigger clocks CLK _A , CLK _B , and CLK _C output by the trigger clock generator 14.

FIG. 9 shows a configuration of a two-system deviation monitor circuit 28.

FIG. 10 shows a second embodiment of the servo valve system according to the present invention.

FIG. 11 is a view showing a system A valve opening target value calculation unit 59A.
Shows the configuration of.

[Explanation of symbols]

1A: A system servo control system 1B: B system servo control system 1C: C system servo control system 2: Servo valve 3: valve 4: Hydraulic oil 5: Linear variable differential transformer (LVDT) 6A to 6C: Servo card 7A to 7C: switch 8A: A system fault diagnostic device 8B: B system fault diagnostic device 8C: C system fault diagnostic device 9A: A system valve opening detector 9B: B system valve opening detector 9C: C system valve opening detector 10A to 10C: Subtractor 11A to 11C: Superimposing device 12A to 12C: Servo amplifier 13A: A system gain controller 13B: B system gain controller 13C: C system gain controller 14: Trigger clock generator 15: Movable iron core 16: primary coil 17: Secondary coil 18: Secondary coil 19: Drive circuit 20: Rectifier circuit 21: Rectifier circuit 22: Valve opening calculator 23: LVDT failure detector 24: Servo loop monitor 25: Servo amplifier diagnostic circuit at intermediate opening 26: Servo amplifier diagnostic circuit when fully open and fully closed 27: Test pulse output circuit 28: Dual system deviation monitor circuit 29: OR circuit 31: Limiter 32: Change rate limiter 33: Subtractor 34: Deviation monitor 35: Timer 36: Subtractor 37: multiplier 38: Limiter 39: Subtractor 40: Deviation monitor 41: Timer 42: Full-open side valve opening target value determination device 43: Self-system servo voltage determiner on the fully open side 44: Full-open side other system servo voltage determiner 45: Full-closed side valve opening target value determiner 46: Self-system servo voltage determiner on the fully closed side 47: Servo voltage determiner for fully closed side other system 48, 49, 51, 57: AND circuit 50: OR circuit 52: Pulse output circuit 53: Subtractor 54: Deviation monitor 55: Subtractor 56: Deviation monitor 58: timer 59A to 59C: A system valve opening target value calculation unit 60: Subtractor 61: Multiplier 62: Switch 63: Adder

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3G071 BA22 BA25 BA31 CA09 DA01                       EA03 EA05 FA07 GA04 GA06                       HA00 JA02                 5H004 GA08 GA29 GB04 HA02 HA07                       HB02 HB07 JA03 KA66 LB08                       MA33                 5H303 AA18 BB01 BB06 BB11 CC03                       CC10 DD07 EE03 FF04 GG07                       HH05 LL01 MM05

Claims (8)

[Claims] 1. A servo valve for driving a controlled object, a plurality of servo control systems for controlling the servo valve based on a controlled variable of the controlled object, and a failure detector for detecting a failure of each of the servo control systems. Each of the servo control systems includes a control amount detector that detects the control amount, and a servo amplifier that supplies power to the servo valve in response to a deviation between the control amount and a predetermined target value. And a shutoff switch interposed between the servo amplifier and the servo valve, when a failure of one servo control system of the plurality of servo control systems is detected by the failure detector, The shutoff switch included in the one servo control system shuts off power supplied to the servo valve from the servo amplifier included in the one servo control system. 2. The servo valve system according to claim 1, wherein when a failure of the one servo control system is detected by the failure detector, the other servo control system of the plurality of servo control systems is activated. A servo valve system in which the gain of the included servo amplifier is increased. 3. The servo valve system according to claim 1, wherein the failure detector calculates an expected control amount expected to be taken by the control amount based on the target value. And a servo valve system including a servo loop failure detector that detects a failure of the plurality of servo control systems based on the expected control amount and the control amount. 4. The servo valve system according to claim 1, wherein the controlled variable detector is based on a linear variable differential transformer (LVDT) that outputs an output voltage corresponding to the controlled variable and the output voltage. And a control amount calculation circuit for calculating the control amount, wherein the failure detector includes an LVDT failure detector that detects a failure of the plurality of servo control systems based on the output voltage. 5. The servo valve system according to claim 1, wherein the failure detector sets an expected voltage expected to be applied to the servo valve by the servo amplifier to the control amount and the target value. An expected value of applied voltage calculated based on the expected voltage, and a servo that detects a failure of the plurality of servo control systems based on the expected voltage and the servo valve applied voltage applied to the servo valve by the servo amplifier. Servo valve system including amplifier failure detector. 6. The servo valve system according to claim 1, wherein the failure detector includes a pulse applying circuit that inputs a pulse to the servo amplifier, and a servo amplifier output that the servo amplifier outputs in response to the pulse. And a second servo amplifier diagnostic circuit for detecting a failure of the plurality of servo control systems based on the above. 7. A servo valve driving an object to be controlled, a plurality of servo control systems controlling the servo valve, and detecting a failure of each of the servo control systems. Controlling the valve includes detecting a controlled variable of the controlled object, supplying power to the servo valve in response to a deviation between the controlled variable and a predetermined target value, and controlling the plurality of servos. Shutting off the electric power supplied from the one servo control system to the servo valve when a failure of one servo control system of the control system is detected. 8. The method of operating a servo valve system according to claim 7, wherein controlling the servo valve further comprises: when a failure of the one servo control system is detected. A method of operating a servo valve system including increasing the gain of another servo control system.