JP2022128609A - Hydraulic control system, and control method for hydraulic device - Google Patents

Abstract

To provide a highly reliable hydraulic control system that drives and controls a hydraulic device, and can stably control the hydraulic device even if the pulsation frequency of hydraulic pressure is changed.SOLUTION: A hydraulic control system comprises: a side branch connected to a high-pressure control oil pipe for supplying high-pressure control oil from a hydraulic source to a hydraulic device, and for damping the pulsation of the high-pressure control oil; a pressure intensifier arranged in a branch line branched from the high-pressure control oil pipe, and for intensifying the high-pressure control oil in the branch line; a servo valve for adjusting the pressure of the high-pressure control oil intensified by the pressure intensifier, and for supplying it to the side branch; a vibration sensor for measuring the vibration of the high-pressure control oil pipe; and a control device for controlling the servo valve on the basis of a measured value of the vibration sensor, adjusting the pressure of the high-pressure control oil to be supplied to the side branch, and thereby adjusting a branch length of the side branch.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to the configuration and control of a hydraulic control system that drives and controls hydraulic equipment, and more particularly to a technique effectively applied to a hydraulic system in which the pulsation frequency of hydraulic pressure changes.

Hydraulic control systems, which drive hydraulic actuators such as hydraulic cylinders and hydraulic motors with hydraulic fluid (hydraulic oil) pressurized by hydraulic pumps, can obtain a large amount of power even though they are small. It is widely used in various devices and machines such as agricultural machinery and machine tools.

In the field of electric power, for example, hydraulic control valves for steam turbines and fuel control valves for gas turbines are used, and hydraulic control systems with long life and high reliability are required.

By the way, positive displacement pumps, which are generally used as hydraulic pumps, perform a pumping action by moving solid walls such as pistons, vanes, and gears, and pressure pulsation occurs due to this mechanism. This pressure pulsation not only causes vibration or noise in the piping and hydraulic equipment connected to the hydraulic pump, but may also damage the piping and hydraulic equipment. Therefore, it is desired to reduce this pressure pulsation.

As a background art of this technical field, there is a technique such as Patent Document 1, for example. Patent Literature 1 discloses a "fluid pulsation damping device that detects pulsation and actively cancels it by a pulsation damping actuator".

In addition, Patent Document 2 discloses that "the length of the branched closed pipeline is controlled according to the pulsation frequency of the pressure pulsation in the hydraulic oil discharged from the hydraulic pump, and the Hydraulic pulsation suppressing device that causes the reflected pressure wave to act to cancel the pressure wave in the main pipeline.

In addition, Patent Document 3 states, "In a device using a gear pump or the like as a hydraulic oil discharge source, a throttle, a venturi, or the like is provided in the hydraulic pipeline, and the pressure difference between the upstream side and the downstream side (pressure difference as the flow rate increases A pulsation reducing device capable of reducing the frequency (rotational speed) of pulsation in a wide range by changing the length of the resonance pipe of the side branch type resonance pipe using the increase of the pulsation.

JP-A-9-126383 Japanese Utility Model Laid-Open No. 4-84890 Japanese Patent Application Laid-Open No. 2005-201323

As a means for reducing the above-mentioned pressure pulsation, a closed-ended pipeline branched to the main stream of the hydraulic system is provided, and the amplitude of the frequency component corresponding to the 1/4 wavelength of the branch pipeline and its odd multiple frequency component. Hydraulic silencers called "side branches" have been conventionally used to reduce the

However, since this side branch reduces the pressure pulsation due to the resonance phenomenon, it is not effective against the pressure pulsation at frequencies outside the resonance frequency, although it has a high damping effect in the vicinity of the resonance frequency.

Since the side branch is installed with a length that matches the pulsation analysis result, it can be used when there is an error in the analysis result or when the frequency of the pulsation source changes due to reasons such as using a mechanically driven or inverter driven pump. , the expected effect may not be obtained.

In Patent Document 1, a piezoelectric element is used for the actuator for damping pulsation. Even if the response speed of the piezoelectric element is extremely high, it takes a certain amount of time to move to a position where the pressure pulsation can be reduced. may not be sufficiently reduced. Further, even if the timing at which the piezoelectric element operates is corrected based on the measured pressure pulsation and the pulsation damping actuator is operated, if the pulsation frequency changes frequently, the characteristics of the piezoelectric element may may not be sufficiently effective in reducing pressure pulsation.

Further, in Patent Document 2, the hydraulic oil supplied to the drive cylinder 41 via the control valve (electromagnetic switching valve) 42 is located downstream of the branching position of the branch pipe 21 in the main pipeline ML (farther from the hydraulic pump P). ), and there is a possibility that the drive cylinder 41 cannot obtain the operating oil pressure that ensures the responsiveness that can sufficiently reduce the pressure pulsation.

Further, in Patent Document 3, the throttle 10a and the venturi 10b are provided in the middle of the main pipeline (discharge pipeline 24), and pressure loss occurs in the hydraulic pressure for driving the actuator 23.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly reliable hydraulic control system for driving and controlling hydraulic equipment, which is capable of stably controlling the hydraulic equipment even when the pulsation frequency of the hydraulic pressure changes. To provide a method for controlling hydraulic equipment using

In order to solve the above-mentioned problems, the present invention provides a side branch connected to a high-pressure control oil pipe that supplies high-pressure control oil from a hydraulic source to a hydraulic device and damping the pulsation of the high-pressure control oil, and the high-pressure control oil pipe. A pressure booster that is arranged in a branch line branched from and increases the pressure of the high-pressure control oil in the branch line, and a servo valve that adjusts the pressure of the high-pressure control oil pressure-increased by the pressure booster and supplies it to the side branch and a vibration sensor for measuring vibration of the high-pressure control oil pipe, and controlling the servo valve based on the measured value of the vibration sensor to adjust the pressure of the high-pressure control oil supplied to the side branch, thereby adjusting the side and a control device for adjusting the branch length of the branch.

In addition, the present invention includes: (a) a step of measuring vibration of a high-pressure control oil pipe that supplies high-pressure control oil from a hydraulic power source to a hydraulic device; (b) vibration of the high-pressure control oil pipe measured in step (a); (c) adjusting the pressure of the high-pressure control oil in the branch line branched from the high-pressure control oil pipe based on the branch length calculated in step (b); and adjusting the branch length of the side branch by supplying it to the side branch.

INDUSTRIAL APPLICABILITY According to the present invention, in a hydraulic control system for driving and controlling hydraulic equipment, a highly reliable hydraulic control system capable of stably controlling the hydraulic equipment even when the pulsation frequency of the hydraulic pressure changes, and the use thereof. It is possible to realize a control method for a hydraulic device that has been used.

As a result, it is possible to prevent damage to the hydraulic system and the hydraulic equipment due to pulsation of the hydraulic pressure while stably controlling the hydraulic equipment.

Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a figure showing a schematic structure of a hydraulic control system concerning one embodiment of the present invention. 2 is a block diagram showing a control system of the hydraulic control system of FIG. 1; FIG. 4 is a flow chart showing a control method for hydraulic equipment according to one embodiment of the present invention. FIG. 2 conceptually illustrates predictive properties and control of variable length side branches according to one embodiment of the present invention;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same configurations are denoted by the same reference numerals, and detailed descriptions of overlapping portions are omitted.

A hydraulic control system and its control method according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a diagram showing a schematic configuration of the hydraulic control system of this embodiment, and FIG. 2 is a block diagram showing a control system of the hydraulic control system of FIG. FIG. 3 is a flow chart showing the control method for the hydraulic equipment of this embodiment. FIG. 4 is a diagram conceptually showing expected characteristics and control of the variable-length side branch in the control method for the hydraulic equipment of this embodiment.

As shown in FIG. 1, the hydraulic control system 1 of this embodiment is installed in a high-pressure control oil pipe 4 that supplies high-pressure control oil from a high-pressure control oil pump 2, which is a hydraulic source, to a hydraulic device 3. Attenuates the pressure pulsation of the high-pressure control oil in the high-pressure control oil pipe 4 caused by the pumping action of the oil pump 2 .

The hydraulic control system 1 includes a variable length side branch 5, a servo valve 8, a pressure booster 9, a pipe vibration meter (vibration sensor) 11, and a control device 16 as main components.

The variable length side branch 5 is connected between a side branch pipe A12 (branch line) branched from the high pressure control oil pipe 4 and a side branch pipe B13 similarly branched from the high pressure control oil pipe 4. Further, the variable-length side branch 5 has a branch length adjusting mechanism, which will be described later, and by adjusting the branch length, the pulsation of the high-pressure control oil in the high-pressure control oil pipe 4 is attenuated.

The pressure intensifier 9 is arranged in a side branch pipe A12 (branch line) branched from the high pressure control oil pipe 4, and utilizes the pressure of the compressed air supplied from the air source 10 to increase the pressure in the side branch pipe A12. Increase control oil pressure.

The servo valve 8 adjusts the pressure of the high-pressure control oil increased by the pressure booster 9 and supplies it to the variable length side branch 5 . High-pressure control oil that is no longer needed due to the pressure adjustment of the high-pressure control oil by the servo valve 8 is discharged to an oil tank (drain) 15 via a drain pipe 14 .

A pipe vibration meter (vibration sensor) 11 is installed in the high-pressure control oil pipe 4, and measures the vibration of the high-pressure control oil pipe 4 generated due to the pulsation of the high-pressure control oil in the high-pressure control oil pipe 4, and detects the vibration of the control device. A vibration sensor output signal (vibration response signal) 20 is output to 16 .

The control device 16 outputs a servo valve command signal 18 to the servo valve 8 based on a vibration sensor output signal (vibration response signal) 20 output from the pipe vibration meter (vibration sensor) 11 to control the servo valve 8. Thus, the pressure of the high-pressure control oil supplied to the variable-length side branch 5 is adjusted, and the branch length of the variable-length side branch 5 is adjusted.

The variable-length side branch 5 has a piston 6 inside as a mechanism for adjusting the branch length described above. Adjust the branch length of 5.

The variable-length side branch 5 also includes an opening transmitter (opening sensor) 7 that detects the stroke position of the piston 6, and outputs a side branch stroke position signal (opening feedback signal) 19 to the control device 16. do.

The control device 16 calculates the stroke position of the piston 6 at which the vibration of the high-pressure control oil pipe 4 measured by the pipe vibration meter (vibration sensor) 11 is minimized, and the calculation result and the side branch stroke position signal (opening feedback signal ) 19 to adjust the stroke position of the piston 6 .

Next, the control system of the hydraulic control system 1 shown in FIG. 1 will be described in detail with reference to FIG. 2, in order to make the control system easier to understand, the configuration of FIG.

As shown in FIG. 2, the above-described side branch stroke position signal (opening feedback signal) 19 and vibration sensor output signal (vibration response signal) 20 are input to the control device 16 as input signals IN1 and IN2, respectively. Based on the side branch stroke position signal (opening feedback signal) 19 and the vibration sensor output signal (vibration response signal) 20, the control device 16 calculates the stroke position of the piston 6 at which the vibration of the high-pressure control oil pipe 4 is minimized. Then, the calculation result is output to the servo valve 8 as the output signal OUT1 (servo valve command signal 18), and the servo valve 8 is controlled.

A vibration sensor output signal (vibration response signal) 20 input to the control device 16 as the input signal IN2 is subjected to noise reduction processing by the LAG filter 21 .

A vibration sensor output signal (vibration response signal) 20 subjected to noise reduction processing by a LAG filter 21 is input to a change rate calculator 22, and the change rate calculator 22 calculates a change rate of the response level of the pipe vibration meter (vibration sensor) 11. is calculated.

The change rate of the response level of the pipe vibration meter (vibration sensor) 11 calculated by the change rate calculator 22 is input to the condition determination device 23, and the vibration detected by the pipe vibration meter (vibration sensor) 11 reaches a predetermined threshold value. to determine whether it is within the pipe vibration reduction range, that is, whether the vibration is at a level that should be reduced, or whether the vibration is at a level where there is no problem even if it is left as it is, and the determination result is sent to the switch 24 Output.

On the other hand, the side branch stroke position signal (opening degree feedback signal) 19 input to the control device 16 as the input signal IN1 is input to the condition determiner 25 to determine the stroke position of the piston 6 (that is, the branch of the variable length side branch 5). length) is compared with the longest position and the shortest position, and the judgment result is output to the switch 28 .

The switch 28 selects either the normal operation command 26 or the reverse operation command 27 based on the determination result of the condition determiner 25 and outputs it to the switch 24 .

The switch 24 selects one of the forward operation command 26, the reverse operation command 27, and the stop command 29 input from the switch 28 based on the determination result of the condition determiner 23, and outputs it to the side branch position command 30.

The control device 16 calculates (adds and subtracts) the side branch position command 30 and the side branch stroke position signal (opening degree feedback signal) 19, and then outputs it to the servo valve 8 as an output signal OUT1 (servo valve command signal 18). It controls the servo valve 8 .

Next, with reference to FIG. 3, a method of controlling hydraulic equipment by the hydraulic control system 1 described above will be described.

As shown in FIG. 3, first, in step S1, the vibration response signal 20 and the side branch position (opening degree feedback signal 19) are input to the control device 16 as data.

Next, in step S2, noise reduction processing is performed on the vibration response signal 20 by the LAG filter 21. FIG.

Subsequently, in step S3, the rate of change of the response level of the pipe vibration meter (vibration sensor) 11 is calculated by the rate of change calculator 22 based on the vibration response signal 20 subjected to noise reduction processing by the LAG filter 21. FIG.

Next, in step S4, the condition determiner 23 determines whether the change rate of the response level of the pipe vibration meter (vibration sensor) 11 tends to decrease.

If it is determined that the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 does not tend to decrease (N), the process proceeds to step S5, and the condition determiner 25 determines the stroke position of the piston 6 (that is, the variable length side branch 5 branch length) is compared to the longest position.

If it is determined that the stroke position of the piston 6 is equal to or less than the maximum position (N), the process proceeds to step S6, where the switch 28 selects a forward operation command (forward operation stroke command) 26, and the branch length of the variable length side branch 5 is changed. is adjusted to shorten the stroke position of the piston 6.

In step S4, if it is determined that the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 tends to decrease (Y), the process proceeds to step S9, where the change in the response level of the pipe vibration meter (vibration sensor) 11 Determine whether the rate is near 0 (zero).

If it is determined in step S9 that the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 is not near 0 (zero) (N), the process proceeds to step S5.

On the other hand, if it is determined in step S9 that the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 is near 0 (Y), the process proceeds to step S10, where the condition determiner 23 It is determined whether or not the rate of change of the response level of (vibration sensor) 11 is on an upward trend.

If it is determined in step S10 that the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 is on an upward trend (Y), the process proceeds to step S5. If it is determined that the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 does not tend to increase (N), the process proceeds to step S11, where the rate of change in the response level of the pipe vibration meter (vibration sensor) 11 changes from minus to zero. A point settled in the vicinity is determined as the minimum point of the vibration response, the stop command 29 is selected by the switch 24, and the stroke position of the piston 6 is fixed.

If it is determined in step S10 that the change rate of the response level of the pipe vibration meter (vibration sensor) 11 does not tend to increase (N), the process proceeds to step S9.

If it is determined in step S5 that the stroke position of the piston 6 is longer than the longest position (Y), the process proceeds to step S7, where the condition determiner 25 determines the stroke position of the piston 6 (that is, the variable length side branch 5 branch length) is compared with the shortest position.

When it is determined in step S7 that the stroke position of the piston 6 is shorter than the shortest position (Y), the process proceeds to step S6. On the other hand, if it is determined that the stroke position of the piston 6 is equal to or greater than the shortest position (N), the process proceeds to step S8, where the switch 28 selects a reverse operation command (reverse operation stroke command) 27, and the variable length side branch 5 is The stroke position of the piston 6 is adjusted in the direction of lengthening the branch length.

With reference to FIG. 4, the predicted characteristics and control concept of the variable length side branch 5 in the above-described hydraulic equipment control method will be described.

≪Expected characteristics≫
When a side branch with a variable length mechanism is attached to the hydraulic circuit, the side branch is aligned with the pulsation frequency (wavelength) of the system at a certain point length, and by being positioned there, pulsation (pipe vibration) can be reduced. However, other positions are considered to contribute nothing to pipe vibration.

FIG. 4(a) shows the relationship between the time (t) and the side branch length (l) when the side branch is moved from the shortest position to the longest position at a constant rate. At the same time, FIG. 4(b) shows the behavior in which the pulsation of the system is captured as a vibration response. Then, it is expected that the rate of change of the vibration response will be the curve shown in FIG. 4(c).

≪Control concept≫
The rate of change of the vibration response is captured and a command for increasing or decreasing the length of the side branch is calculated on the controller 16 . The rate of change is 0 (zero) at the minimum point of the vibration response, and the sign of the rate of change changes in steep change regions before and after that point.

For this reason, the point at which the rate of change stabilizes from minus to near 0 (zero) is considered to be the minimum point of the vibration response, and when this state is established, the operation of the side branch is fixed.

When the change rate of the vibration response increases due to external fluctuations, etc., the side branch position is considered to be out of the pulsation reduction region (minimum point of the vibration response), and the stroke operation is restarted. When the maximum position or the shortest position is reached, the operation command method is reversed and the operation is reversed. This behavior is shown by dashed lines in FIGS. 4(a)-(c).

By repeating this movement and following automatically, it can be expected to contribute to constant pulsation reduction.

As described above, according to the hydraulic control system and the control method thereof of the present invention, in the hydraulic control system that drives and controls the hydraulic equipment, stable control of the hydraulic equipment is possible even when the pulsation frequency of the hydraulic pressure changes. It is possible to realize a highly reliable hydraulic control system and a method of controlling hydraulic equipment using the same.

As a result, it is possible to prevent damage to the hydraulic system and the hydraulic equipment due to pulsation of the hydraulic pressure while stably controlling the hydraulic equipment.

For example, adopting the hydraulic control system of the present invention as a control system for hydraulically driven valves such as steam control valves for steam turbines and fuel control valves for gas turbines can contribute to improving the reliability of steam turbines and gas turbines. can.

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

1... Hydraulic control system 2... High-pressure control oil pump (hydraulic source)
3... Hydraulic equipment 4... High pressure control oil pipe 5... Variable length side branch 6... Piston 7... Opening transmitter (opening sensor)
8 Servo valve 9 Pressure booster 10 Air source 11 Pipe vibration meter (vibration sensor)
12... Side branch piping A
13... Side branch piping B
14... Drain pipe 15... Oil tank (drain)
16... Control device 17... High pressure control oil system 18... Servo valve command signal 19... Side branch stroke position signal (opening feedback signal)
20 Vibration sensor output signal (vibration response signal)
21...LAG filter 22...Change rate calculator 23, 25...Condition determiner 24, 28...Switch 26...Direct action command 27...Reverse action command 29...Stop command 30...Side branch position command 31...AND circuit A
32 AND circuit B

Claims (14)

a side branch that is connected to a high-pressure control oil pipe that supplies high-pressure control oil from a hydraulic source to a hydraulic device and that damps pulsation of the high-pressure control oil;
a pressure intensifier arranged in a branch line branched from the high pressure control oil pipe to increase the pressure of the high pressure control oil in the branch line;
a servo valve that adjusts the pressure of the high-pressure control oil intensified by the pressure intensifier and supplies it to the side branch;
a vibration sensor for measuring vibration of the high-pressure control oil pipe;
a control device for adjusting the branch length of the side branch by controlling the servo valve based on the measurement value of the vibration sensor and adjusting the pressure of high-pressure control oil supplied to the side branch;
A hydraulic control system comprising: The hydraulic control system of claim 1, wherein
the side branch has a piston;
A hydraulic control system, wherein the branch length of the side branch is adjusted by adjusting the stroke position of the piston with high-pressure control oil supplied from the servo valve. 3. The hydraulic control system of claim 2, wherein
The side branch has an opening sensor that detects the stroke position of the piston,
The control device determines a stroke position of the piston at which the vibration of the high-pressure control oil pipe is minimized based on the vibration of the high-pressure control oil pipe measured by the vibration sensor and the stroke position of the piston detected by the opening sensor. and
A hydraulic control system, wherein the stroke position of the piston is adjusted based on the calculation result. A hydraulic control system according to claim 3, wherein
The control device calculates a rate of change of the response level of the vibration sensor,
A hydraulic control system, wherein the servo valve is controlled based on the calculation result to adjust the stroke position of the piston. A hydraulic control system according to claim 4, wherein
The hydraulic control system according to claim 1, wherein the control device determines a point at which the rate of change of the response level of the vibration sensor stabilizes from minus to near 0 as the minimum point of the vibration response, and fixes the stroke position of the piston. A hydraulic control system according to claim 5, wherein
The hydraulic control system according to claim 1, wherein, when the rate of change of the response level of the vibration sensor increases, the control device determines that the vibration response has deviated from the minimum point, and restarts the stroke operation of the piston. A hydraulic control system according to any one of claims 1 to 6,
A hydraulic control system, wherein the hydraulic device is a steam control valve of a steam turbine or a fuel control valve of a gas turbine. A control method for hydraulic equipment comprising the steps of;
(a) measuring vibrations in a high pressure control oil line that supplies high pressure control oil from a hydraulic source to a hydraulic device;
(b) calculating the branch length of the side branch that minimizes the vibration of the high-pressure control oil pipe measured in step (a);
(c) adjusting the pressure of the high-pressure control oil in the branch line branched from the high-pressure control oil pipe based on the branch length calculated in step (b), and supplying the side branch to the side branch; Adjusting branch length. A control method for a hydraulic device according to claim 8,
In the above step (c), the branch length of the side branch is adjusted by adjusting the stroke position of the piston of the side branch with high-pressure control oil in the branch line. A control method for a hydraulic device according to claim 9,
In step (b), calculating the stroke position of the piston at which the vibration of the high-pressure control oil pipe is minimized;
A control method for hydraulic equipment, comprising: adjusting a stroke position of the piston based on the calculation result. A control method for a hydraulic device according to claim 10,
In step (b), calculating a rate of change in vibration of the high-pressure control oil pipe;
A control method for hydraulic equipment, comprising: adjusting a stroke position of the piston based on the calculation result. A control method for a hydraulic device according to claim 11,
A control method for hydraulic equipment, wherein a point at which a change rate of vibration of the high-pressure control oil pipe settles down from minus to near zero is determined as a minimum point of vibration response, and the stroke position of the piston is fixed. A control method for a hydraulic device according to claim 12,
A method of controlling a hydraulic device, wherein when a rate of change in vibration of the high-pressure control oil pipe increases, it is determined that the vibration response has deviated from a minimum point, and the stroke operation of the piston is restarted. A control method for a hydraulic device according to any one of claims 8 to 13,
A control method for hydraulic equipment, wherein the hydraulic equipment is a steam control valve of a steam turbine or a fuel control valve of a gas turbine.

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