Automatic deflation system for hydraulic devices

Abstract

The subject matter of this specification can be implemented as a method that includes actuating a closure member between a first configuration and a second configuration at a predetermined first speed for a predetermined first number of cycles, actuating the closure member between the first configuration and the second configuration at a predetermined second speed for a predetermined second number of cycles, actuating the closure member at a predetermined third speed and the second configuration for a predetermined third number of cycles, actuating the closure member at a predetermined fourth speed and the second configuration for a predetermined fourth number of cycles, and actuating the closure member at a predetermined fifth speed to the second configuration for a predetermined flush period.

Description

[0001] Priority requirements This application claims priority to U.S. Patent Application No. 62 / 990,037, filed March 16, 2020, the contents of which are incorporated herein by reference. Technical Field

[0002] This manual relates to servo valve-based control of hydraulic actuators. Background Technology

[0003] Hydraulic actuators are used to actuate mechanical outputs such as valves and articulated motion control outputs. Various forms of redundancy are utilized to meet diverse safety, reliability, and performance requirements.

[0004] Some existing systems provide redundancy by including double the coil on a servo valve that controls the flow of fluid to the hydraulic actuator via a shared hydraulic path. Other existing systems provide redundant pressure control. Summary of the Invention

[0005] In summary, this document describes the systems and techniques for servo valve-based control of hydraulic actuators.

[0006] In a first aspect, a method of operating a hydraulic actuator system includes: actuating a closing member of a valve assembly at a predetermined first speed for a predetermined first number of cycles between a first configuration and a second configuration, wherein in the first configuration, fluid flow is discharged for a predetermined first discharge period, and in the second configuration, fluid flow path is flushed for a predetermined first flushing period; actuating the closing member at a predetermined second speed for a predetermined second number of cycles between a first configuration with a continuous predetermined second discharge period and a second configuration with a continuous predetermined second flushing period; actuating the closing member at a predetermined third speed for a predetermined third number of cycles between a first configuration with a continuous predetermined third discharge period and a second configuration with a continuous predetermined third flushing period; actuating the closing member at a predetermined fourth speed for a predetermined fourth number of cycles between a first configuration with a continuous predetermined fourth discharge period and a second configuration with a continuous predetermined fourth flushing period; and actuating the closing member at a predetermined fifth speed for a predetermined fifth number of cycles between a first configuration with a continuous predetermined fifth discharge period and a second configuration with a continuous predetermined fifth flushing period.

[0007] In the second aspect, according to the first aspect, the closing member is configured to flush out residual air trapped in the valve assembly using hydraulic fluid supplied to the valve assembly when in the second configuration.

[0008] In the third aspect, according to the first or second aspect, the second emission period is longer than the first and third emission periods, and the fourth emission period is longer than the second emission period.

[0009] In the fourth aspect, according to any one of the first to third aspects, the second flushing period is longer than the first flushing period and the third flushing period, the fourth flushing period is longer than the second flushing period, and the fifth flushing period is longer than the fourth flushing period.

[0010] In the fifth aspect, according to any one of the first to fourth aspects, the fifth speed is less than the first speed, the second speed, the third speed and the fourth speed.

[0011] In the sixth aspect, according to any one of the first to fifth aspects, one or more of the first cycle number, second cycle number, third cycle number, fourth cycle number, first discharge period, second discharge period, third discharge period, fourth discharge period, fifth discharge period, first flushing period, second flushing period, third flushing period, fourth flushing period, and fifth flushing period are based on the pressure of the hydraulic fluid supplied to the valve assembly.

[0012] In the seventh aspect, according to any one of the first to sixth aspects, the first emission period is less than 2 seconds, the second emission period is less than 5 seconds, the third emission period is less than 2 seconds, the fourth emission period is less than 30 seconds, the fifth emission period is less than 30 seconds, the first flushing period is less than 1 second, the second flushing period is less than 5 seconds, the third flushing period is less than 1 second, the fourth flushing period is less than 30 seconds, and the fifth flushing period is between 10 seconds and 360 seconds.

[0013] In the eighth aspect, according to any one of the first to seventh aspects, the method further includes providing hydraulic fluid at a pressure of less than or equal to 289 psig, wherein the first number of cycles is between 300 and 700, the second number of cycles is between 100 and 500, the third number of cycles is between 100 and 450, the fourth number of cycles is between 10 and 30, and the fifth number of cycles is between 1 and 10.

[0014] In the ninth aspect, according to any one of the first to eighth aspects, the method further includes providing hydraulic fluid at a pressure greater than 289 psig, wherein the first number of cycles is between 100 and 500, the second number of cycles is between 50 and 300, the third number of cycles is between 50 and 300, the fourth number of cycles is between 5 and 20, and the fifth number of cycles is between 1 and 10.

[0015] In the tenth aspect, according to any one of the first to ninth aspects, the first speed is between 500% / second and 1000% / second of the stroke of the closing member, the second speed is between 500% / second and 1000% / second of the stroke of the closing member, the third speed is between 500% / second and 1000% / second of the stroke of the closing member, the fourth speed is between 500% / second and 1000% / second of the stroke of the closing member, and the fifth speed is between 10% / second and 50% / second of the stroke of the closing member.

[0016] In an eleventh aspect, according to any one of the first to tenth aspects, the valve assembly includes a fluid supply port, a fluid discharge port, and a fluid control port, and the closing member is configurable to include a plurality of valve configurations including a first configuration, a second configuration, a third configuration, and a fourth configuration, wherein in the first configuration, the fluid control port is in fluid communication with the fluid discharge port and the fluid supply port is blocked; in the second configuration, the fluid control port is in fluid communication with the fluid supply port and is in fluid communication with the fluid discharge port via a fluid restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid restrictor; in the third configuration, the fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked; and in the fourth configuration, the fluid control port is in fluid communication with the fluid supply port and the fluid discharge port is blocked.

[0017] In a twelfth aspect, a hydraulic actuator system includes: a valve assembly having a fluid supply port in fluid communication with a main fluid supply line, a fluid discharge port, and a fluid control port in fluid communication with a main fluid control line; and a controller configured to control operation of the valve assembly, the operation including: actuating a closing member of the valve assembly at a predetermined first speed for a predetermined first number of cycles between a first configuration and a second configuration, wherein in the first configuration, fluid flow is discharged for a predetermined first discharge period, and in the second configuration, a fluid flow path is flushed for a predetermined first flushing period; and maintaining the closing member in the first configuration and the second configuration for a continuous predetermined second discharge period. Between the second configuration during the second flushing period, the closing member is actuated at a predetermined second speed for a predetermined number of cycles between the first configuration during a continuously predetermined third discharge period and the second configuration during a continuously predetermined third flushing period; between the first configuration during a continuously predetermined fourth discharge period and the second configuration during a continuously predetermined fourth flushing period, the closing member is actuated at a predetermined fourth speed for a predetermined number of cycles between the first configuration during a continuously predetermined fifth discharge period and the second configuration during a continuously predetermined fifth flushing period; and between the first configuration during a continuously predetermined fifth discharge period and the second configuration during a continuously predetermined fifth flushing period, the closing member is actuated at a predetermined fifth speed for a predetermined number of cycles.

[0018] In the thirteenth aspect, according to the twelfth aspect, the actuation of the closing member utilizes hydraulic fluid supplied to the valve assembly to flush away residual air trapped in the valve assembly.

[0019] In aspect fourteen, according to aspect twelf or thirteen, the second emission period is longer than the first and third emission periods, and the fourth emission period is longer than the second emission period.

[0020] In the fifteenth aspect, according to any one of aspects 12 to 14, the second flushing period is longer than the first flushing period and the third flushing period, the fourth flushing period is longer than the second flushing period, and the fifth flushing period is longer than the fourth flushing period.

[0021] In the sixteenth aspect, according to any one of aspects twelfth to fifteenth, the fifth speed is less than the first speed, the second speed, the third speed, and the fourth speed.

[0022] In the seventeenth aspect, according to any one of aspects twelfth to sixteenth, one or more of the first cycle number, second cycle number, third cycle number, fourth cycle number, first discharge period, second discharge period, third discharge period, fourth discharge period, fifth discharge period, first flushing period, second flushing period, third flushing period, fourth flushing period, and fifth flushing period are based on the pressure of the hydraulic fluid supplied to the valve assembly.

[0023] In the eighteenth aspect, according to any one of aspects twelfth to seventeenth, the first emission period is less than 2 seconds, the second emission period is less than 5 seconds, the third emission period is less than 2 seconds, the fourth emission period is less than 30 seconds, the fifth emission period is less than 30 seconds, the first flushing period is less than 1 second, the second flushing period is less than 5 seconds, the third flushing period is less than 1 second, the fourth flushing period is less than 30 seconds, and the fifth flushing period is between 10 seconds and 360 seconds.

[0024] In the nineteenth aspect, according to any one of aspects 12 to 18, the operation further includes providing hydraulic fluid at a pressure of less than or equal to 289 psig, wherein the first number of cycles is between 300 and 700, the second number of cycles is between 100 and 500, the third number of cycles is between 100 and 450, the fourth number of cycles is between 10 and 30, and the fifth number of cycles is between 1 and 10.

[0025] In the twentieth aspect, according to any one of the twelfth to nineteenth aspects, the operation further includes providing hydraulic fluid at a pressure greater than 289 psig, wherein the first number of cycles is between 100 and 500, the second number of cycles is between 50 and 300, the third number of cycles is between 50 and 300, the fourth number of cycles is between 5 and 20, and the fifth number of cycles is between 1 and 10.

[0026] In the twenty-first aspect, according to any one of aspects twelfth to twentieth, the first speed is between 500% / second and 1000% / second of the stroke of the closing member, the second speed is between 500% / second and 1000% / second of the stroke of the closing member, the third speed is between 500% / second and 1000% / second of the stroke of the closing member, the fourth speed is between 500% / second and 1000% / second of the stroke of the closing member, and the fifth speed is between 10% / second and 50% / second of the stroke of the closing member.

[0027] In the twenty-second aspect, according to any one of the twelfth to twenty-first aspects, the valve assembly includes a fluid supply port, a fluid discharge port, and a fluid control port; and the closing member is configurable to include a plurality of valve configurations including a first configuration, a second configuration, a third configuration, and a fourth configuration, wherein in the first configuration, the fluid control port is in fluid communication with the fluid discharge port and the fluid supply port is blocked; in the second configuration, the fluid control port is in fluid communication with the fluid supply port and is in fluid communication with the fluid discharge port via a fluid restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid restrictor; in the third configuration, the fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked; and in the fourth configuration, the fluid control port is in fluid communication with the fluid supply port and the fluid discharge port is blocked.

[0028] In one general aspect, a method of operating a hydraulic actuator system includes: actuating a closing member of a valve assembly at a predetermined first speed for a predetermined first number of cycles between a first configuration and a second configuration, wherein in the first configuration, a fluid flow path is flushed for a predetermined first discharge period, and in the second configuration, a fluid flow is flushed for a predetermined first flushing period; actuating the closing member at a predetermined second speed for a predetermined second number of cycles between a first configuration with a continuous predetermined second discharge period and a second configuration with a continuous predetermined second flushing period; actuating the closing member at a predetermined third speed for a predetermined third number of cycles between a first configuration with a continuous predetermined third discharge period and a second configuration with a continuous predetermined third flushing period; actuating the closing member at a predetermined fourth speed for a predetermined fourth number of cycles between a first configuration with a continuous predetermined fourth discharge period and a second configuration with a continuous predetermined fourth flushing period; and actuating the closing member at a predetermined fifth speed for a predetermined fifth number of cycles between a first configuration with a continuous predetermined fifth discharge period and a second configuration with a continuous predetermined fifth flushing period.

[0029] Various implementations may include some, all, or none of the following features. The closing member may be configured to flush residual air trapped in the valve assembly using hydraulic fluid supplied to the valve assembly when in the second configuration. The second discharge period may be longer than the first and third discharge periods, the fourth discharge period may be longer than the second discharge period, and the fifth flushing period may be longer than the fourth flushing period. The second flushing period may be longer than the first and third flushing periods, and the fourth flushing period may be longer than the second flushing period. The fifth speed may be less than the first, second, third, and fourth speeds. One or more of the first cycle number, second cycle number, third cycle number, fourth cycle number, first discharge period, second discharge period, third discharge period, fourth discharge period, fifth discharge period, first flushing period, second flushing period, third flushing period, fourth flushing period, and fifth flushing period may be based on the pressure of the hydraulic fluid supplied to the valve assembly. The first discharge period can be less than 2 seconds, the second discharge period can be less than 5 seconds, the third discharge period can be less than 2 seconds, the fourth discharge period can be less than 30 seconds, the fifth discharge period can be less than 30 seconds, the first flushing period can be less than 1 second, the second flushing period can be less than 5 seconds, the third flushing period can be less than 1 second, the fourth flushing period can be less than 30 seconds, and the fifth flushing period can be between 10 seconds and 360 seconds. The method may also include supplying hydraulic fluid at a pressure less than or equal to 289 psig, wherein the first number of cycles can be between 300 and 700, the second number of cycles can be between 100 and 500, the third number of cycles can be between 100 and 450, the fourth number of cycles can be between 10 and 30, and the fifth number of cycles can be between 1 and 10. The method may further include supplying hydraulic fluid at a pressure greater than 289 psig, wherein the first number of cycles is between 100 and 500, the second number of cycles is between 50 and 300, the third number of cycles is between 50 and 300, the fourth number of cycles is between 5 and 20, and the fifth number of cycles is between 1 and 10. The first speed is between 500% / second and 1000% / second of the stroke of the closing member, the second speed is between 500% / second and 1000% / second of the stroke of the closing member, the third speed is between 500% / second and 1000% / second of the stroke of the closing member, the fourth speed is between 500% / second and 1000% / second of the stroke of the closing member, and the fifth speed is between 10% / second and 50% / second of the stroke of the closing member.The valve assembly may include a fluid supply port, a fluid discharge port, and a fluid control port, and the closing member can be configured to include a plurality of valve configurations including a first configuration, a second configuration, a third configuration, and a fourth configuration. In the first configuration, the fluid control port is in fluid communication with the fluid discharge port, and the fluid supply port is blocked. In the second configuration, the fluid control port is in fluid communication with the fluid supply port and is also in fluid communication with the fluid discharge port via a fluid restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid restrictor. In the third configuration, the fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked. In the fourth configuration, the fluid control port is in fluid communication with the fluid supply port, and the fluid discharge port is blocked.

[0030] In another general aspect, a hydraulic actuator system includes: a valve assembly having a fluid supply port in fluid communication with a main fluid supply line, a fluid discharge port, and a fluid control port in fluid communication with a main fluid control line; and a controller configured to control operation of the valve assembly, said operation including: actuating a closing member of the valve assembly at a predetermined first speed for a predetermined first number of cycles between a first configuration and a second configuration, wherein in the first configuration, fluid flow is discharged for a predetermined first discharge period, and in the second configuration, the fluid flow path is flushed for a predetermined first flushing period; and maintaining the closing member in the first configuration and the second configuration for a continuous predetermined second discharge period. Between the second configuration during the second flushing period, the closing member is actuated at a predetermined second speed for a predetermined number of cycles between the first configuration during a continuously predetermined third discharge period and the second configuration during a continuously predetermined third flushing period; between the first configuration during a continuously predetermined fourth discharge period and the second configuration during a continuously predetermined fourth flushing period, the closing member is actuated at a predetermined fourth speed for a predetermined number of cycles between the first configuration during a continuously predetermined fifth discharge period and the second configuration during a continuously predetermined fifth flushing period; and between the first configuration during a continuously predetermined fifth discharge period and the second configuration during a continuously predetermined fifth flushing period, the closing member is actuated at a predetermined fifth speed for a predetermined number of cycles.

[0031] Various embodiments may include some, all, or none of the following features. Actuation of the closing member may mix residual air trapped in the valve assembly with the hydraulic fluid supplied to the valve assembly and flush it with the hydraulic fluid. The second discharge period may be longer than the first and third discharge periods, and the fourth discharge period may be longer than the second discharge period. The second flushing period may be longer than the first and third flushing periods, the fourth flushing period may be longer than the second flushing period, and the fifth flushing period may be longer than the fourth flushing period. The fifth speed may be less than the first, second, third, and fourth speeds. One or more of the first cycle number, second cycle number, third cycle number, fourth cycle number, first discharge period, second discharge period, third discharge period, fourth discharge period, fifth discharge period, first flushing period, second flushing period, third flushing period, fourth flushing period, and fifth flushing period may be based on the pressure of the hydraulic fluid supplied to the valve assembly. The first discharge period can be less than 2 seconds, the second discharge period can be less than 5 seconds, the third discharge period can be less than 2 seconds, the fourth discharge period can be less than 30 seconds, and the fifth discharge period can be less than 30 seconds. The first flushing period can be less than 1 second, the second flushing period can be less than 5 seconds, the third flushing period can be less than 1 second, the fourth flushing period can be less than 30 seconds, and the fifth flushing period can be between 10 seconds and 360 seconds. The operation may also include supplying hydraulic fluid at a pressure less than or equal to 289 psig, wherein the first number of cycles can be between 300 and 700, the second number of cycles can be between 100 and 500, the third number of cycles can be between 100 and 450, the fourth number of cycles can be between 10 and 30, and the fifth number of cycles can be between 1 and 10. The operation may further include supplying hydraulic fluid at a pressure greater than 289 psig, wherein the first number of cycles may be between 100 and 500, the second number of cycles may be between 50 and 300, the third number of cycles may be between 50 and 300, the fourth number of cycles may be between 5 and 20, and the fifth number of cycles may be between 1 and 10. The first speed may be between 500% / second and 1000% / second of the stroke of the closing member, the second speed may be between 500% / second and 1000% / second of the stroke of the closing member, the third speed may be between 500% / second and 1000% / second of the stroke of the closing member, the fourth speed may be between 500% / second and 1000% / second of the stroke of the closing member, and the fifth speed may be between 10% / second and 50% / second of the stroke of the closing member.The valve assembly may include a fluid supply port, a fluid discharge port, and a fluid control port, and the closing member can be configured to include a plurality of valve configurations including a first configuration, a second configuration, a third configuration, and a fourth configuration. In the first configuration, the fluid control port is in fluid communication with the fluid discharge port, and the fluid supply port is blocked. In the second configuration, the fluid control port is in fluid communication with the fluid supply port and is also in fluid communication with the fluid discharge port via a fluid restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid restrictor. In the third configuration, the fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked. In the fourth configuration, the fluid control port is in fluid communication with the fluid supply port, and the fluid discharge port is blocked.

[0032] In another general aspect, an electro-hydraulic positioning control system includes: a reciprocating valve configured to guide fluid flow between a fluid outlet and a selectable first fluid port and a second fluid port, the fluid outlet being configured to be fluidly connected to a fluid actuator; a first servo valve controllable to selectively allow flow between the first fluid port and a fluid source, allow flow between the first fluid port and a fluid discharge pipe, and block fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe; a second servo valve controllable to selectively allow flow between the second fluid port and the fluid source, allow flow between the second fluid port and the fluid discharge pipe, and block fluid flow between the second fluid port, the fluid source, and the fluid discharge pipe; a first servo controller configured to provide a first health signal and control the first servo valve based on a position demand signal, a position feedback signal, a first priority signal, and a second health signal; and a second servo controller configured to provide a second health signal and control the second servo valve based on the position demand signal, the position feedback signal, the second priority signal, and the first health signal.

[0033] Various embodiments may include some, all, or none of the following features. At least one of the first priority signal and the second priority signal may include a representation of one or more operating conditions, said operating conditions including: (a) a high priority command provided to a selected one of the first servo controller or the second servo controller to act as the master servo controller, and (b) a low priority command provided to the other one of the first servo controller or the second servo controller to act as the backup servo controller. The first servo controller may be configured to perform operations including: receiving a high priority command as the first priority signal by the first servo controller; controlling a first servo valve by the first servo controller to control the position of the fluid actuator by: (a) regulating the fluid connectivity from the fluid source to the first fluid port, (b) regulating the fluid connectivity from the first fluid port to the fluid discharge pipe, and (c) blocking the fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. At least one of the first health signal and the second health signal may be configured to include a representation of one or more operating conditions, said operating conditions including: (a) an operable condition indicating the absence of a failure, (b) a failure condition indicating a failure that can be resolved by closing the corresponding one of the first servo valve or the second servo valve, and (c) a failure indicating that a health signal cannot be sent for any of the above conditions. The first servo controller may be configured to perform operations including: receiving a low-priority command as a first-priority signal; detecting a failure condition in the second servo controller or the second servo valve; and controlling the first servo valve to control the position of the fluid actuator by: (a) adjusting the fluid connectivity from the fluid source to the first fluid port, (b) adjusting the fluid connectivity from the first fluid port to the fluid discharge pipe, and (c) blocking fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. The first servo controller can be configured to perform operations including: receiving a low-priority command as a first-priority signal; detecting operable conditions in the second servo controller and the second servo valve; and controlling the first servo valve to provide fluid connection from the first fluid port to the fluid discharge pipe and to block the fluid source.The first servo controller may be configured to perform operations including: receiving a low-priority command as a first priority signal; detecting a failure of a second health signal; determining a modified position requirement less than the position requirement represented by a position requirement signal based on the detection; and controlling a first servo valve to control the position of a fluid actuator based on the modified position requirement by: (a) adjusting the fluid connectivity from the fluid source to the first fluid port; (b) adjusting the fluid connectivity from the first fluid port to the fluid discharge pipe; and (c) blocking the fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. The first servo controller can be configured to perform operations including: receiving a low-priority command as a first priority signal; controlling the first servo valve to a standby position based on standby demand based on the received command; detecting operability conditions in the second servo controller and the second servo valve based on a second health signal; receiving a command signal indicating sediment reduction operation; controlling the first servo valve to a first modified position below the standby position based on standby demand based on the received first priority signal; and controlling the first servo valve to the standby position based on standby demand based on the received first priority signal.

[0034] In another general aspect, a method for controlling an electro-hydraulic positioning control system includes: controlling a first servo valve by a first servo controller configured to provide a first health signal to selectively allow flow between a first fluid port and a fluid source, allow flow between the first fluid port and a fluid discharge pipe, and block fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe, wherein the control is based on a position demand signal, a position feedback signal, a first priority signal, and a second health signal; the first health signal being provided by the first servo controller; controlling a second servo valve by a second servo controller to selectively allow flow between a second fluid port and a fluid source, allow flow between the second fluid port and a fluid discharge pipe, and block fluid flow between the second fluid port, the fluid source, and the fluid discharge pipe, wherein the control is based on a position demand signal, a position feedback signal, a second priority signal, and the first health signal; the second health signal being provided by the second servo controller; and guiding fluid flow between a fluid outlet and a selectable one of the first and second fluid ports, the fluid outlet being configured to be fluidly connected to a fluid actuator by a reciprocating valve.

[0035] Various implementations may include some, all, or none of the following features. At least one of the first priority signal and the second priority signal may include a representation of one or more operating conditions, said operating conditions including: (a) a high-priority command is provided to a selected one of the first servo controller or the second servo controller to act as the master servo controller, and (b) a low-priority command is provided to the other of the first servo controller or the second servo controller to act as the backup servo controller. The method may further include: receiving the high-priority command as the first priority signal by the first servo controller; and controlling a first servo valve by the first servo controller to control the position of the fluid actuator by: (a) adjusting the fluid connectivity from the fluid source to the first fluid port, (b) adjusting the fluid connectivity from the first fluid port to the fluid discharge pipe, and (c) blocking the fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. At least one of the first health signal and the second health signal may be configurable to include a representation of one or more operating conditions, said operating conditions including: (a) an operable condition indicating the absence of a failure, (b) a failure condition indicating a failure that can be resolved by closing a corresponding one of the first servo valve or the second servo valve, and (c) a failure indicating that a health signal cannot be sent for any of the above conditions. The method may include: receiving a low-priority command as a first priority signal by a first servo controller; detecting a failure condition in a second servo controller or a second servo valve by the first servo controller; controlling a first servo valve by the first servo controller to control the position of a fluid actuator by: (a) adjusting the fluid connectivity from a fluid source to a first fluid port, (b) adjusting the fluid connectivity from the first fluid port to a fluid discharge pipe, and (c) blocking fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. The method may also include: receiving a low-priority command as a first priority signal by the first servo controller; detecting operable conditions in the second servo controller and the second servo valve by the first servo controller; and controlling the first servo valve by the first servo controller to provide fluid connection from the first fluid port to the fluid discharge pipe and block the fluid source. The method may further include: receiving a low-priority command as a first priority signal by a first servo controller; detecting a failure of a second health signal by the first servo controller; determining a modified position requirement less than the position requirement represented by a position requirement signal by the first servo controller and based on the detection; controlling a first servo valve by the first servo controller to control the position of a fluid actuator based on the modified position requirement by: (a) adjusting the fluid connectivity from a fluid source to a first fluid port, (b) adjusting the fluid connectivity from the first fluid port to a fluid discharge pipe, and (c) blocking the fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe.The method may further include: receiving a low-priority command as a first priority signal by a first servo controller; controlling a first servo valve to a standby position based on standby demand by the first servo controller and based on the received command; detecting operability conditions in a second servo controller and a second servo valve by the first servo controller and based on a second health signal; receiving a command signal indicating sediment reduction operation by the first servo controller; controlling the first servo valve to a first modified position below the standby position by the first servo controller and in response to the received command signal; and controlling the first servo valve to the standby position by the first servo controller and in response to the received command signal.

[0036] The system and technology described herein offer one or more of the following advantages: First, the system provides redundant control of the controlled process. Second, the system improves system uptime. Third, the system can detect internal faults independently of the monitoring controller. Fourth, the system can utilize its redundancy features independently of the monitoring controller. Fifth, the system can release residual air without interrupting active control operations. Sixth, the system can automatically remove contaminant buildup without interrupting active control operations.

[0037] Details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the specification, drawings, and claims. Attached Figure Description

[0038] Figure 1 This is a perspective view of an example hydraulic control system.

[0039] Figure 2 This is a schematic diagram of an example hydraulic control system.

[0040] Figures 3A to 3D This is a schematic diagram of an example electro-hydraulic servo valve in various operating configurations.

[0041] Figure 4 An example schematic view of an example hydraulic control system is shown.

[0042] Figure 5 This is a cross-sectional view of an example hydraulic servo valve.

[0043] Figures 6A to 6D These are various views of the example closed component.

[0044] Figures 7A to 7E This is a coordinate graph showing the servo valve requirements during an example venting process.

[0045] Figure 8 This is a flowchart of an example venting process.

[0046] Figure 9 This is a flowchart of an example process for transmitting the health status of a servo valve.

[0047] Figure 10 This is a schematic diagram of an example of a general-purpose computer system. Detailed Implementation

[0048] This document describes systems and techniques for redundant hydraulic servo control. In general, system uptime and reliability are critical factors in some processes controlled by hydraulic servo control systems. For example, some operations require systems to operate for 8-10 years without downtime. To reduce operational risks to critical components, the hydraulic control systems described in this document include features that provide redundancy (e.g., main hydraulic servo valves and controllers, backup hydraulic servo valves and controllers kept online, and automatic failover procedures for transferring control between the main and backup units) and online serviceability (e.g., one servo valve can be replaced and cleaned while another servo valve maintains control), which reduce or eliminate operational downtime.

[0049] Figure 1 This is a perspective view of an example hydraulic control system 100. System 100 includes electro-hydraulic servo valve (EHSV) modules 120a and 120b connected to a single manifold 150. An electrical junction box 130 houses power and control components for system 100. Each of the EHSV modules 120a-120b includes a controller and electromechanical components that control the flow of hydraulic fluid to manifold 150. Manifold 150 includes an isolation valve, a needle valve, and a reciprocating valve subassembly. Pressure gauge 115a is configured to indicate the output pressure of EHSV module 120a, and pressure gauge 115b is configured to indicate the output pressure of EHSV module 120b. Isolation valve 140a provides the operator with the ability to fluidly isolate EHSV module 120a from the rest of system 100, and isolation valve 140b provides the operator with the ability to fluidly isolate EHSV module 120b from the rest of system 100 (e.g., to perform maintenance or replace one EHSV module while it remains operational).

[0050] In the illustrated example, system 100 provides two substantially identical redundant hydraulic position controllers (servo mechanisms), two substantially independent sensors, and substantially independent flow paths. In practice, the system typically uses EHSV module 120a as the main valve controller and reserves EHSV module 120b as a redundant backup (although in some implementations, the valve roles may be reversed).

[0051] Figure 2 This is a schematic diagram of an example hydraulic control system 200. In some embodiments, system 200 may be... Figure 1Example system 100. System 200 includes a fluid control system 210 configured to control the flow of fluid (e.g., hydraulic fluid) from a fluid reservoir 202 or other fluid pressure source to a fluid actuator 203 (e.g., a hydraulic cylinder, hydraulic actuator). The fluid reservoir 202 supplies fluid to a main fluid supply line 204. A main fluid control line 205 (e.g., a fluid outlet) is configured to provide fluid communication with the pressure chamber of the fluid actuator 203. A position sensor 207 is configured to provide a signal indicating the position or configuration of the fluid actuator 203.

[0052] The fluid control system 210 includes electro-hydraulic servo valves (EHSV) 220a and 220b. The configuration of EHSVs 220a and 220b will be... Figures 3A to 3D This will be discussed in more detail in the description.

[0053] EHSV 220a includes a fluid supply port 222a in fluid communication with the main fluid supply line 204, a fluid discharge port 224a in fluid communication with the discharge line 228a, and a fluid control port 226a in fluid communication with the main fluid control line 205. EHSV 220a is configured to actuate a closing member 229a to optionally provide several configurations that provide and / or block various fluid interconnections between the main fluid control line 205, the main fluid supply line 204, and the discharge line 228a.

[0054] EHSV 220a also includes valve controller 234a and valve position sensor 232a, which is configured to sense the configuration of closure member 229a. Valve controller 234a is configured to control the operation of EHSV 220a based on commands from controller 230 (e.g., priority signals identifying which EHSV will act as the primary controller and which will act as the secondary controller), position feedback from valve position sensor 232a, position feedback from position sensor 207, and a health signal from EHSV 220b. The health signal is transmitted via communication bus 238.

[0055] EHSV 220b includes a fluid supply port 222b in fluid communication with the main fluid supply line 204, a fluid discharge port 224b in fluid communication with the discharge line 228b, and a fluid control port 226b in fluid communication with the main fluid control line 205. EHSV 220b is configured to actuate a closing member 229b to optionally provide several configurations that provide and / or block various fluid interconnections between the main fluid control line 205, the main fluid supply line 204, and the discharge line 228b. In some embodiments, the discharge lines 228a and 228b may be fluidly interconnected (e.g., to provide fluid return to the fluid reservoir 202).

[0056] EHSV 220b also includes valve controller 234b and valve position sensor 232b. Valve controller 234b is configured to control the operation of EHSV 220b based on commands from controller 230 (e.g., priority signals identifying which EHSV will act as the primary controller and which will act as the secondary controller), position feedback from valve position sensor 232b, position feedback from position sensor 207, and a health signal from EHSV 220a. The health signal is transmitted via communication bus 238.

[0057] EHSVs 220a and 220b communicate with or are otherwise controlled by controller 230. Controller 230 is configured to provide control signals to EHSVs 220a and 220b to command the position requirements of fluid actuator 203 and to provide them with priority signals. Controller 230 is also configured to receive feedback signals from EHSVs 220a and 220b to determine the actual status of EHSVs 220a and 220b and the actual position of fluid actuator 203.

[0058] Fluid control ports 226a and 226b are in fluid communication with the main fluid control line 205 via a reciprocating valve 240. The reciprocating valve 240 is configured to selectively provide fluid communication between the main fluid control line 205 and one of the fluid control ports 226a and 226b, while blocking fluid communication to the other of the two fluid control ports. The reciprocating valve 240 is configured to select the interconnection based on which of the fluid control ports 226a and 226b is providing a relatively higher fluid pressure.

[0059] Under normal operation, EHSV 220a is controlled to actuate the fluid actuator 203, while EHSV 220b is kept in standby mode. Controller 230 is configured to detect the operating status of both EHSV 220a and EHSV 220b. In the event of failure of the primary EHSV or failure of communication with the primary EHSV, the auxiliary EHSV is used to provide substantially uninterrupted control of the fluid actuator 203.

[0060] In some embodiments, the auxiliary EHSV may be held in a sub-zero position so as not to interfere with the position of the reciprocating valve. For example, the fluid control port 226b may be disconnected from the fluid supply port 222b, but in cases where rapid action is required to allow EHSV 220b to take over control from EHSV 220a, the closing member 229b may be positioned close to the fluid communication position.

[0061] In some embodiments, system 210 can provide a demand offset when the condition of one of the EHSVs is unknown (e.g., a designated auxiliary EHSV is under control, but the health link is down). The offset demand for a designated auxiliary EHSV in operation (e.g., due to the unknown condition of another EHSV) can reduce or avoid hydraulic equalization at the input to reciprocating valve 240, and thus increase stable positioning and stable flow on the main fluid control line 205.

[0062] In some embodiments, system 210 may be configured to perform a bleed procedure (e.g., to facilitate online replacement of one of EHSVs 220a-220b). For example, one or both of EHSVs 220a-220b may be actuated in a manner that allows or facilitates the release of air from the enclosed cavity (e.g., air trapped within a newly installed, dry EHSV) without interfering with normal cylinder operation. Figures 6A to 8 An example of the venting procedure will be discussed in more detail in the description.

[0063] Figures 3A to 3D This is a schematic diagram of an example EHSV 300 in various operating configurations. In some embodiments, the EHSV 300 may be... Figure 1 Example EHSV module 120a, Example EHSV module 120b Figure 2 Examples of EHSV 220a and / or EHSV 220b. EHSV 300 includes a fluid supply port 322 configured to be in fluid communication with a supply line (e.g., main fluid supply line 204), a fluid discharge port 324 configured to be in fluid communication with a discharge line, and a fluid control port 326 configured to be in fluid communication with a main fluid control line (e.g., main fluid control line 205) via a reciprocating valve 240. EHSV 300 is configured to optionally provide several configurations that provide and / or block various fluid interconnections between the main fluid control line, the main fluid supply line, and the discharge line.

[0064] The EHSV 300 includes a housing 350 and a closing member 360. The closing member 360 is positioned relative to the housing 350 by an actuator 370. The actuator 370 is configured to be controlled by a controller, such as... Figure 2 Example valve controller 234a or example valve controller 234b. The EHSV 300 also includes a sensor 380 configured to provide a signal indicating the position of the closure member 360 relative to the housing 350 or the configuration of the EHSV 300. The sensor 380 is configured to provide a sensor signal as feedback to a controller, such as example valve controller 234a or example valve controller 234b.

[0065] The EHSV 300 is configured to provide four fluid interconnect configurations. Figure 3A In the configuration 390a shown, fluid control port 326 is fluidly connected to fluid discharge port 324, while fluid supply port 322 is fluidly blocked. Figure 3B In the configuration 390b shown, the fluid control port 326, fluid discharge port 324, and fluid supply port 322 are all fluid-blocked (e.g., at zero position). Figure 3C In the configuration 390c shown, the fluid control port 326 is fluidly connected to the fluid supply port 322, while the fluid discharge port 324 is fluidly blocked.

[0066] exist Figure 3D In the configuration 390d shown, the fluid control port 326 is fluidly connected to both the fluid discharge port 324 and the fluid supply port 322. In configuration 390d, the fluid connection 391 between the fluid control port 326 and the fluid discharge port 324 imposes a relatively (e.g., significantly) greater restriction on fluid flow than the fluid connection 392 between the fluid control port 326 and the fluid supply port 322.

[0067] Under various circumstances, air may become present in the fluid lines passing through the EHSV 300. For example, during maintenance or during rapid actuation of the example actuator 230, air may enter the fluid circuit (e.g., air may leak through the hydraulic seals defining the pressure chamber of the actuator). Such air is generally undesirable because it can degrade the performance of the controlled actuator (e.g., due to sponginess or elasticity resulting from the relative compressibility of the gaseous fluid compared to the liquid).

[0068] In use, EHSV 300 can be configured, as 390d, to purge (e.g., vent) air from the fluid passages within and / or downstream of EHSV 300. In previous designs, trapped air was manually purged from the fluid loop. This previous process typically required operational downtime and / or manual access to the fluid line (e.g., ground maintenance). In the illustrated example, air trapped in the fluid can be more easily discharged through fluid connection 391 to fluid discharge port 324 than the surrounding fluid, thus allowing air to be purged from the fluid loop as a mechanical or automatic function of EHSV 300 without requiring manual access to the fluid loop. In some implementations, the vented EHSV can be removed from process control, and such operation can be performed by its redundant paired EHSV, while the vented EHSV is purged of air.

[0069] EHSV 300 also includes a biasing member 362 configured to push the closing member 360 into a predetermined (e.g., fail-safe) configuration. In the illustrated example, the fail-safe configuration is configuration 390a, but in other embodiments, the fail-safe configuration may be any of configurations 390a-390d. In some embodiments, the biasing member 362 may be configured to push the closing member 360 away from a predetermined one of configurations 390a-390d (e.g., to prevent accidental use of configuration 390d).

[0070] Figure 4 An example schematic diagram of an example hydraulic control system 400 is shown. In some embodiments, system 400 may be... Figure 1 System 100 or Figure 2 It is part of System 200.

[0071] System 400 includes EHSV modules 401a and 401b. EHSV module 401a includes valve controller 434a and EHSV 420a, and EHSV module 401b includes valve controller 434b and EHSV 420b. In general, EHSV modules 401a and 401b are configured as redundant, substantially independent, and replaceable modules within system 400.

[0072] Valve controller 434a includes a control current output 410a actuating EHSV 420a and a position feedback input 412a configured to receive position feedback sensor signals from EHSV 420a (e.g., from a variable displacement transformer connected to a movable closing member of the valve). Valve controller 434a also includes position feedback inputs 413a and 414a, which are configured to receive position feedback sensor signals from fluid actuator 403 (e.g., from a variable displacement transformer or other suitable position sensor connected to the output of a movable member or actuator).

[0073] In some embodiments, the fluid actuator 403 may be configured with redundant position sensors, and position feedback inputs 413a and 414a may be configured to read redundant signals provided by the redundant sensors. The valve controller 434a also includes input / output modules 406a configured to receive commands and requests from the controller 430 and to send and / or receive feedback and / or status signals from the controller 430.

[0074] Valve controller 434b includes a control current output terminal 410b, a position feedback input terminal 412b, a position feedback input terminal 413b, a position feedback input terminal 414b, and an input / output module 406b, which perform functions substantially similar to their counterparts in valve controller 434a. In some embodiments, position feedback input terminals 413a and 413b may be configured to receive the same position feedback signal, and position feedback input terminals 414a and 414b may be configured to receive the same redundant position feedback signal.

[0075] Valve controller 434a includes a health status transmitter 416a and a health status receiver 418a, and valve controller 434b includes a health status transmitter 416b and a health status receiver 418b. The health status transmitter 416a is configured to transmit a health status signal 437a via a communication bus 438, and the health status receiver 418b is configured to receive the health status signal 437a. This configuration allows valve controllers 434a and 434b to monitor each other's status.

[0076] Valve controller 434a is configured to provide closed-loop control of EHSV 420a, and even closed-loop control of fluid actuator 403, by providing control current at control current output 410a based on demand signals (e.g., received from controller 430 at I / O module 406a), position feedback signals received at position feedback inputs 412a, 413a, and 414a, health status of EHSV module 401a, and health status signal 437a. Valve controller 434b is configured to provide closed-loop control of EHSV 420b, and even closed-loop control of fluid actuator 403, by providing control current at control current output 410b based on demand signals (e.g., received from controller 430 at I / O module 406a), position feedback signals received at position feedback inputs 412b, 413b, and 414b, and health status of EHSV module 401b, and health status signal 437a.

[0077] EHSV modules 401a and 401b are configured to receive commands (e.g., demand signals) from controller 430 to control fluid flow from fluid supply source 402 to fluid actuator 403 (e.g., hydraulic actuator or hydraulic cylinder) via reciprocating valve 440. Reciprocating valve 440 is configured to fluidly connect to either EHSV 420a or EHSV 420b that provides the highest output pressure. In use, one of EHSV 420a or 420b operates as a primary EHSV providing the operating flow rate and pressure, while the other EHSV operates as an auxiliary (e.g., backup) unit. In some implementations, the auxiliary EHSV may operate in parallel with the primary EHSV, but at a slightly lower position demand (e.g., sufficient to prevent the reciprocating valve from switching away from the primary EHSV). In the event of a sudden failure of the primary EHSV, the fluid pressure from the primary EHSV may drop abruptly. By keeping the auxiliary EHSV online but controlled slightly lower (e.g., based on modifications to the demand signal), the reciprocating valve 440 can switch based on the remaining auxiliary pressure with minimal interference to the operation of the actuator, allowing the auxiliary EHSV to immediately take over control and then recognize its new condition as that of the EHSV in control. Once the auxiliary EHSV recognizes its new condition (e.g., based on a response to a received health signal and / or a signal from the controller 430), it can remove modifications to its own demand, thereby controlling the cylinder position to follow the demand position without the slight reduction caused by the modification.

[0078] In some implementations, the "health" signal can be a signal sent when the transmitter recognizes itself as operating normally (e.g., no failed operating conditions, no identified faults). Since notifications provided by the valve controller (and subsequent detections by the paired valve controller) may have the highest priority in some implementations, changes in this condition need to be transmitted rapidly. The health signal can be sent at the relatively fastest frequency that can be correctly recognized by the receiver, and any further modifications detected on the receiver side can be detected as a failure of the transmitter.

[0079] In some implementations, the "slow failure" signal may be a signal sent when the transmitter identifies itself as experiencing or predicting a fault, failure, or other condition that can be resolved by a slow, controlled shutdown of the corresponding EHSV. In some implementations, the "fast failure" signal may be a signal sent when the transmitter identifies itself as experiencing or predicting a fault, failure, or other condition that can be resolved by a fast shutdown of the corresponding EHSV. In some implementations, the signal may be a health signal received by example EHSV modules 120a and 120b, example valve controllers 234a and 234b, or example valve controllers 434a and 434b from their respective redundant devices. Generally, the health signal can be received and interpreted by a receiver to determine several different health states of the transmitting device and / or the communication bus used to transmit the signal.

[0080] In some implementations, the operation of the example fluid control system 210 may be based at least in part on health signals. For example, system 210 may operate in a normal operating mode based on the identification of health signals. In an example of normal operation, a selected valve controller controls the position of fluid actuator 203 by adjusting the passage from the main fluid supply line 204 to fluid actuator 203 and from fluid actuator 203 to discharge ports 224a and 224b.

[0081] The unit, which is not performing control operations when in standby, provides a continuously open channel for discharging at a limited opening, thus allowing one side of its reciprocating valve 240 to have a low pressure equal to the discharge pressure. In cases requiring rapid action to take over control, servo positioning keeps the corresponding closing member 229a or 229b in a near-zero position (e.g., configuration 390b). When the required position of the fluid actuator 203 is near zero, the unit not performing control operations opens to full discharge. In some implementations, this is to allow full flow discharge from one side of its reciprocating valve 240 and to allow the EHSV, which is currently controlling, to position the fluid actuator 203 without interference (e.g., primarily during the closing of the rapid regulating valve).

[0082] Both valve controllers 234a and 234b receive position requests from controller 230, and both valve controllers 234a and 234b are configured to receive two (e.g., redundant) position feedback signals from fluid actuator 203 (e.g., both valve controllers always receive the same request and position feedback values). Valve controllers 234a and 234b send health signals to each other via separate lines to notify each other that they are healthy (e.g., operational, not in failure), experiencing a slow failure (e.g., a fault exists, but the failure is controlled, so the unit's shutdown is not severe), or experiencing a fast failure (e.g., a severe failure occurs, requiring the unit's shutdown to be performed at its maximum speed). Other signal states are considered line failures; however, it is the receiver that identifies the type of line failure—whether it is a short circuit, a disconnection, or noise.

[0083] In some implementations, system 210 may determine that the unit designated to control the process has failed. Due to the exchange of status information, in the event of a failure in valve controller 234a or 234b in control or in EHSV 220a or 220b in control, no action is required from an external system (e.g., controller 230). The failed valve controller in control may determine that it has failed and cannot continue to control the fluid actuator 203. The valve controller in control transmits this status to the standby valve controller by changing its transmitted health signal. The designated standby valve controller immediately takes control upon recognizing the changed health status. Since some positioning disturbance is expected, the standby unit adds boost pressure to its servo valve position upon gaining control to better achieve the required position of the fluid actuator 203. Once it has gained control, the designated standby valve controller communicates with controller 230 to inform controller 230 that it is now operating as the master controller for the operation of the controlled process. The failed valve controller communicates with controller 230 to inform controller 230 of the failure and that it is no longer in operation.

[0084] In some implementations, system 210 can determine that the unit currently in standby has failed. In some implementations, the failed auxiliary valve controller can notify another unit that it is faulty and therefore cannot take over control if needed. The failed standby unit also notifies controller 230 that it is faulty. The current main valve controller in control is informed that the other unit is inoperable and will maintain its own control over the position of fluid actuator 203, regardless of the mode requested by controller 230. For example, even if the valve controller in control is commanded to switch to standby operation, it will remain in control to maintain the continuity of controlled operation. Based on the internal exchange of health status information, no action is required from external systems (e.g., controller 230) in the event of a standby EHSV failure.

[0085] In some implementations, the valve controller can recognize and respond to communication link failures. For example, a backup unit can respond by outputting an alarm signal (e.g., to controller 230) to indicate a failure in communication bus 238. When the backup unit senses that the health signal is unrecognizable (e.g., short circuit, disconnection, noise signal), it then attempts to take over control and identifies itself as the master valve controller responsible for controlling fluid actuator 203. When the cause of the communication failure is unknown (e.g., it cannot be determined whether another valve controller has failed, or whether it is just a wiring problem and another unit is still functioning normally), the auxiliary valve controller can modify its demand by subtracting a small offset (e.g., about 2% of the fluid actuator's full stroke). In some implementations, this demand modification can create a slightly lower pressure on one side of its reciprocating valve 240 so as not to interfere with the operation of the master EHSV if both units attempt to control fluid actuator 203 simultaneously. The offset in the demand signal can reduce or avoid hydraulic equalization at the input of reciprocating valve 240 and can help maintain stable positioning and / or stable flow on the main fluid control line 205.

[0086] In another example, the main valve controller can determine a fault in health signal communication from the backup valve controller. In some implementations, the main valve controller may respond by outputting an alarm signal (e.g., to controller 230) to indicate a fault in communication bus 238. The main valve controller can maintain operational control of fluid actuator 203. Since the cause of the fault may not be fully known, the main unit can assume that the other unit may be inoperable and will maintain operation and control of fluid actuator 203 even if controller 230 commands it to switch to auxiliary or backup operation. Since the cause of the communication failure is unknown, the main valve controller can modify its requirements. For example, valve controllers 234a or 234b can modify their requirements by subtracting a small offset (e.g., about 2% of the fluid actuator's full stroke).

[0087] In some implementations, valve controllers 234a-234b can be commanded (e.g., by controller 230) to switch their operating roles. For example, an operator can access a control panel or other input of controller 230 to command the immediate switching of the primary / secondary designations of the two units. In some implementations, if any signal overlap is anticipated, both units can be initially designated as primary units before one is designated as secondary (e.g., designating both units as primary units for a short period may be preferred over designating both as secondary units). In such an example, both units are operable and healthy, and receive information that the other unit is also healthy. In such an example, both units can accurately execute the designations given by controller 230. The secondary unit will transition to primary operating mode based on commands from controller 230, and because of minimal disturbance to the expected position of fluid actuator 203 during control switching, the unit can apply additional boost pressure to the position control of its corresponding EHSV to compensate for process disturbances. In response to a control transfer signal from controller 230, the primary valve controller switches to auxiliary control mode, and it can control its corresponding EHSV to a configuration with slight emissions. In some implementations, both units can indicate their current primary / auxiliary status via discrete communication outputs (e.g., to controller 230).

[0088] In some implementations, valve controllers 234a-234b can perform operations to prevent or reduce deposits (e.g., dirt, sludge) that may have accumulated in EHSVs 220a-220b. Depending on site conditions and hydraulic oil quality, it may be desirable to perform a deposit reduction process. For example, periodically (e.g., daily, weekly, other cycles), valve controllers 234a-234b can cause their corresponding closing members 229a-229b to oscillate with a small amount (e.g., a single cycle) to allow the release of accumulated contaminants. In some implementations, this functionality may be useful when one or both of the EHSVs 220a-220b remain in a stable configuration for an extended period. When commanded to decontaminate, the main valve controller can respond by moving its corresponding closing member in short positional steps and then moving it above the desired servo valve position in similar increments (e.g., using the opposite semi-symmetrical movement reduces the impact on actuator position). Similar operations can also be achieved because auxiliary units are continuously in a venting state and typically remain in a stable position for extended periods. Because the auxiliary unit is configured not to interfere with the operation of the main unit, its output pressure needs to be maintained below the output pressure of the main unit at reciprocating valve 240. In some implementations, this can be considered by making the auxiliary valve controller respond to its own designation as an auxiliary unit, and by performing the buildup reduction process in only short steps, and in some examples also by maintaining that position for a longer period than the main unit, before returning to the normal position. Positive pulses are not executed to avoid disrupting system operation.

[0089] In some implementations, some or all of the EHSV modules (e.g., example EHSV modules 120a-120b, example EHSV 220a-220b, valve controllers 234a-234b) can be replaced online (e.g., a redundant part of the system can be replaced while another part maintains operational control). Reference Figure 1 Operators can use isolation valves 140a-140b, pressure gauges 115a-115b, and software tools to facilitate online replacement of redundant components. The mechanical design of system 100 reduces the volume of open cavities in the components and minimizes the space where air might become trapped during online replacement. The parameterization of this unit can be copied from a disassembled servo mechanism or from a previously stored configuration file. By loading the configuration file into the newly installed servo mechanism, the need for manual configuration of the configuration file is reduced, as is the need for cylinder calibration of the installed servo mechanism. In some embodiments, monitoring software (e.g., customer service tools) may be included to provide monitoring and verification of the correct operation of the newly installed EHSV before it is hydraulically connected to an operating (e.g., active, running, pressurized) system by opening the isolation valve.

[0090] Let's briefly return to... Figure 2 Valve controllers 234a-234b are configured to execute an automatic venting procedure that can be performed after an online replacement. This procedure is configured to release air from a closed cavity (e.g., air trapped in a newly installed dry EHSV) without substantially interfering with the normal operation of the fluid actuator 203.

[0091] Now for reference Figure 5 A cross-sectional view of an example hydraulic servo valve (EHSV) 500 is shown. In some embodiments, the EHSV 500 may be... Figure 1 Example EHSV module 120a or 120b Figure 2 Examples of EHSV 220a or 220b Figures 3A to 3D Example EHSV 300, or Figure 4 Examples include EHSV 420a or 420b. The venting procedure described above utilizes an additional hole 615 (in the closure member 510 of the EHSV 500, e.g., valve core) Figure 5 Not visible in the middle, see also Figures 6A to 6D Orifice 615 provides a small oil path for flushing out air that may be trapped or accumulate within the EHSV 500. Valve controllers 234a-234b are configured to move closing member 510 with dynamic movements of varying lengths to create a pressure differential and flow rate that releases trapped air. Figures 7A to 7E Examples of this motion are described in more detail in the description.

[0092] Figures 6A to 6D yes Figure 5 Various views of the example closure member 510. In some embodiments, the closure member 510 may be Figure 2 Example closed member 229a or 229b or Figures 3A to 3D Example of a closed component 360. Figure 6A A perspective view of one of the holes 615 and the closing member 510 is shown. Figure 6B The enlarged view shows part 601 of the closed member 510. Figure 6C A side view of the two holes in hole 615 and the closing member 510 is shown. Figure 6D The enlarged view shows a cross-sectional view of the closed member 510 taken through section 602.

[0093] A series of orifices 620 are configured to provide a primary fluid flow path that can be selectively controlled (e.g., by partially rotating the closure member 510 within the EHSV 500) via a closing member 510 (e.g., between various combinations of fluid sources, discharge lines, and / or control lines), while orifices 615 are configured to provide a restricted flow path (e.g., to allow purge air for discharge). In some embodiments, orifices 620 may provide Figures 3A to 3DExample fluid connection 392, while orifice 615 provides example fluid connection 391. Orifice 615 provides a limited passage that makes it possible to generate a controlled venting flow from the fluid supply source through a control line to the discharge port. This configuration allows residual air to be vented when rapid flow (e.g., high-volume flushing) processes are not permitted. The example design incorporates three such vents to allow the release of air trapped inside the closure.

[0094] Figures 7A to 7E This is a coordinate graph showing the servo valve requirements during an example venting process. In use, closing components, such as... Figure 2 Example closed members 229a or 229b Figures 3A to 3D Example of a closed component 360, or Figures 5 to 6D The example closure member 510 can be operated by one or more predetermined operation sequences configured to purge air trapped within the closure member 510. In some embodiments, the purging process may be predetermined for a particular application. In some embodiments, multiple purging processes may be determined for multiple particular applications.

[0095] In one example implementation where the controlled pressure is less than or equal to 289 psig, the closure member can operate in five stages.

[0096] Phase 1: The closing member can close (e.g., valve spool position = 0%, discharge position, configuration 390a) for 0.5 seconds, and then open (e.g., valve spool position = 100%, flush position, configuration 390d) for 0.0625 seconds. During this phase, the closing member can move at a rate of 750% / second (e.g., a complete transition from 0% to 100% can take approximately 133 ms, where 100% represents the travel between the minimum and maximum positions of the closing member). This movement can be repeated 500 times. In some implementations, this process can be visualized as... Figure 7A The coordinate diagram is 700a. In stage 1, dynamic pressure changes cause residual air to mix with oil, and oil-air foam can be generated depending on the supply pressure.

[0097] Phase 2: The closing member can close (e.g., configuration 390a) for 1 second, and then open (e.g., configuration 390d) for 1 second. During this phase, the closing member can move at a rate of 750% / second. This movement can be repeated 300 cycles. In some implementations, this process can be visualized as... Figure 7B The coordinate diagram is 700b. In stage 2, the air-oil mixture is stabilized, and more residual air is expelled as small bubbles in the oil or foam from the vent holes and internal unit leak points.

[0098] Phase 3: The closing member can close (e.g., configuration 390a) for 0.5 s, and then open (e.g., configuration 390d) for 0.0625 s. During this phase, the closing member can move at a rate of 750% / second. This movement can be repeated 250 times. In some implementations, this process can be visualized as... Figure 7C The coordinates of the graph are 700c.

[0099] Phase 4: The closing member can close (e.g., configuration 390a) for 10 seconds, and then open (e.g., configuration 390d) for 10 seconds. During this phase, the closing member can move at a rate of 750% / second. This movement can be repeated 20 times. In some implementations, this process can be visualized as... Figure 7D The coordinate graph is 700d.

[0100] Phase 5: The closing member can close (e.g., configuration 390d) for 10 seconds and then open (e.g., configuration 390d) for 120 seconds. During this phase, the closing member can move at a rate of 25% / second. This movement can be performed once or multiple times (e.g., three, five, ten, or other appropriate number of cycles). In some implementations, this process can be visualized as... Figure 7E The coordinates of the graph are 700e.

[0101] The five stages described above, when executed sequentially, provide an air purging process that can be completed in approximately 30 minutes.

[0102] In another example implementation where the control pressure is greater than 289 psig, the closure member can operate in five stages, as in another example: Phase 1: The closing member can close (e.g., valve spool position = 0%, configuration 390a) for 0.5 seconds, and then open (e.g., valve spool position = 100%, configuration 390d) for 0.0625 seconds. During this phase, the closing member can move at a rate of 750% / second. This movement can be repeated 300 times.

[0103] Phase 2: The closing member may close (e.g., configuration 390a) for 1 second, and then open (e.g., configuration 390d) for 1 second. During this phase, the closing member may move at a rate of 750% / second. This movement may be repeated 180 times.

[0104] Phase 3: The closing member can close (e.g., configuration 390a) for 0.5 s, and then open (e.g., configuration 390d) for 0.0625 s. During this phase, the closing member can move at a rate of 750% / second. This movement can be repeated 150 times.

[0105] Phase 4: The closing member may close (e.g., configuration 390a) for 10 seconds, and then open (e.g., configuration 390d) for 10 seconds. During this phase, the closing member may move at a rate of 750% / second. This movement may be repeated 12 times.

[0106] Phase 5: The closing member may close (e.g., configuration 390a) for 10 seconds and then open (e.g., configuration 390d) for 120 seconds. During this phase, the closing member may move at a rate of 25% / second. This movement may be performed once or multiple times (e.g., three, five, ten, or other appropriate number of cycles).

[0107] The five stages described above, when executed sequentially, provide an air purging process that can be completed in approximately 20 minutes.

[0108] As mentioned above, these are just two examples of a large number of possible combinations of having more or fewer stages, longer or shorter opening and closing (e.g., flushing and discharging) times, faster or slower actuation speeds, and / or more or fewer cycles per stage.

[0109] One of the benefits of performing online venting is that it makes it possible to release air from a closed cavity without using an opening such as a vent valve. For example, releasing pressurized oil supplied to an operating process with residual air could be dangerous.

[0110] In addition, a purge configuration can be selected, and a purge operation can be performed during normal operation if needed. For example, configuration 390c can be configured to provide pressurized fluid to actuate the actuator. If it is determined (e.g., manually or automatically) that purge is needed, valve 300 can be switched to configuration 390d. Configuration 390d still provides pressurized fluid to the actuator via fluid connection 392, but also provides fluid connection 391 for trapped air to escape.

[0111] Figure 8 This is a flowchart of an example venting process 800. In some implementations, process 800 may be... Figure 1 Example hydraulic control system 100 Figure 2 Example hydraulic control system 200 or Figure 4 The example hydraulic control system 400 is used to perform this.

[0112] In 810, the closing member of the valve assembly is actuated at a predetermined first speed and for a predetermined first number of cycles between a first configuration (e.g., configuration 390a) and a second configuration (e.g., configuration 390d). In the first configuration, fluid is allowed to flow from the control port to the discharge port for a predetermined first discharge period (e.g., maintained in configuration 390a). In the second configuration, fluid is allowed to flow from the supply source to the control port and from the control port to the discharge pipe for a predetermined first flushing period (e.g., maintained in configuration 390d). For example, the valve controller 234a may be such as Figure 7A The example pattern shown is used to control the closing member 229a of EHSV220a.

[0113] In some implementations, the closure member can be configured to mix residual air trapped in the valve assembly with hydraulic fluid supplied to the valve assembly when in a second configuration. For example, example closure member 360 includes a fluid connection 391 that provides a fluid passage for releasing air from fluid control port 326 to fluid discharge port 324.

[0114] In 820, the closing member is actuated at a predetermined second speed for a predetermined second number of cycles between a first configuration for a continuously predetermined second discharge period and a second configuration for a continuously predetermined second flushing period. For example, valve controller 234a may be such as Figure 7B The example pattern shown is used to control the closing member 229a of EHSV 220a.

[0115] In 830, the closing member is actuated at a predetermined third speed for a predetermined third number of cycles between a first configuration during a predetermined third discharge period and a second configuration during a predetermined third flushing period. For example, valve controller 234a may be such as Figure 7C The example pattern shown is used to control the closing member 229a of EHSV 220a.

[0116] In 840, the closing member is actuated at a predetermined fourth speed for a predetermined fourth number of cycles between a first configuration for a continuously predetermined fourth discharge period and a second configuration for a continuously predetermined fourth flushing period. For example, valve controller 234a may be such as Figure 7D The example pattern shown is used to control the closing member 229a of EHSV 220a.

[0117] At 850, the closing member is actuated at a predetermined fifth speed to a first configuration for a predetermined fifth discharge period, and actuated at a predetermined fifth speed to a second configuration for a predetermined fifth flushing period. For example, valve controller 234a may be such as Figure 7E The example pattern shown is used to control the closing member 229a of EHSV 220a.

[0118] In some implementations, the second emission period may be longer than the first and third emission periods, and the fourth emission period may be longer than the second emission period. For example, by Figure 7B The emission period of the example Phase 2 mode shown in the diagram is longer than that of the mode described above. Figure 7A and Figure 7C The diagram illustrates the emission periods for stages 1 and 3, and is composed of... Figure 7D The emission period of the example phase 4 mode shown in the diagram is longer than that of the mode described above. Figure 7B The diagram shows the emission period of Phase 2.

[0119] In some implementations, the second flushing period may be longer than the first and third flushing periods, and the fourth flushing period may be longer than the second flushing period. For example, by Figure 7B The illustrated example of phase 2 mode has a longer flushing period than that of the previous mode. Figure 7A and Figure 7C The diagram illustrates the rinsing periods of stages 1 and 3, and is composed of... Figure 7D The illustrated example shows that the flushing period in phase 4 mode is longer than that of the previous mode. Figure 7B The illustration shows the rinsing period of stage 2.

[0120] In some implementations, the fifth speed can be less than the first, second, third, and fourth speeds. For example, in a configuration where... Figure 7E The illustrated example shows that the closing speed of the member is slower during phase 5 than that used for phases 1-4.

[0121] In some implementations, one or more of the following: the first cycle number, the second cycle number, the third cycle number, the fourth cycle number, the first discharge period, the second discharge period, the third discharge period, the fourth discharge period, the first flushing period, the second flushing period, the third flushing period, the fourth flushing period, and the fifth flushing period can be based on the pressure of the hydraulic fluid supplied to the valve assembly. For example, in Figures 7A to 7E In its description, this document presents examples of two different configurations for five different venting stages across two different pressure ranges. Additional configurations may be used, as they can be adapted for use with different application-specific pressures, flow rates, actuator fluid viscosities, rated operating temperatures, and combinations of these and / or any other suitable factors that may affect the amount of air that can be trapped in the system and / or the system's ability to be purged.

[0122] In some implementations, the first emission period can be less than 2 seconds, the second emission period less than 5 seconds, the third emission period less than 2 seconds, the fourth emission period less than 30 seconds, the fifth emission period less than 30 seconds, the first flushing period less than 1 second, the second flushing period less than 5 seconds, the third flushing period less than 1 second, the fourth flushing period less than 30 seconds, and the fifth flushing period can be between 10 seconds and 360 seconds. For example, in the case of... Figure 7A During the example phase 1 illustrated, the closed member 360 can be in a discharge state for 0.5 seconds with each oscillation, as shown in the diagram. Figure 7B During the illustrated example phase 2, the closed member 360 can be in a discharge state for 1 second with each oscillation, in the case of... Figure 7C During the example phase 3 illustrated, the closed member 360 can be in a discharge state for 0.5 seconds with each oscillation, in the case of... Figure 7D During the illustrated example phase 4, the closed member 360 can be in a discharge state for 10 seconds with each oscillation, and... Figure 7E During the example phase 5 illustrated, the closing member 360 can be in the discharge state for 10 seconds.

[0123] In some implementations, the process may include supplying hydraulic fluid at a pressure less than or equal to 289 psig, wherein the first number of cycles is between 300 and 700, the second number of cycles is between 100 and 500, the third number of cycles is between 100 and 450, the fourth number of cycles is between 10 and 30, and the fifth number of cycles is between 1 and 5. For example, for pressures less than 289 psig, Figure 7A Example phase 1 is described as having 500 loops. Figure 7B Example phase 2 is described as having 300 loops. Figure 7C Example phase 3 is described as having 250 cycles. Figure 7D Example phase 4 is described as having 20 cycles, and Figure 7E Example phase 5 is described as having one cycle (e.g., between cycles 1 and 5).

[0124] In some implementations, process 800 may include supplying hydraulic fluid at a pressure greater than 289 psig, wherein the first number of cycles is between 100 and 500, the second number of cycles is between 50 and 300, the third number of cycles is between 50 and 300, the fourth number of cycles is between 5 and 20, and the fifth number of cycles may be between 1 and 5. For example, for a pressure greater than 289 psig, Figure 7A Example phase 1 is described as having 300 loops. Figure 7B Example phase 2 is described as having 180 loops. Figure 7C Example phase 3 is described as having 150 cycles. Figure 7D Example phase 4 is described as having 12 cycles, and Figure 7E Example phase 5 is described as having one cycle (e.g., between cycles 1 and 5).

[0125] In some implementations, the first speed can be between 500% and 1000% of the stroke per second of the closing member, the second speed can be between 500% and 1000% of the stroke per second of the closing member, the third speed can be between 500% and 1000% of the stroke per second of the closing member, the fourth speed can be between 500% and 1000% of the stroke per second of the closing member, and the fifth speed can be between 10% and 50% of the stroke per second of the closing member. For example, Figure 7A Example phase 1 is described as executing at a rate of 750% / second. Figure 7B Example phase 2 is described as executing at a rate of 750% / second. Figure 7C Example phase 3 is described as executing at a rate of 750% / second. Figure 7D Example phase 4 is described as executing at a rate of 750% / second, and Figure 7E Example phase 5 is described as executing at a rate of 25% / second.

[0126] In some implementations, the valve assembly may include a fluid supply port, a fluid discharge port, and a fluid control port, and the valve body can be configured to a series of valve configurations including a first configuration, a second configuration, a third configuration, and a fourth configuration. In the first configuration, the fluid control port is in fluid communication with the fluid discharge port, and the fluid supply port is blocked. In the second configuration, the fluid control port is in fluid communication with the fluid supply port and also in fluid communication with the fluid discharge port via a fluid restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid restrictor. In the third configuration, the fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked. In the fourth configuration, the fluid control port is in fluid communication with the fluid supply port, and the fluid discharge port is blocked. For example, process 800 may use... Figures 3A to 3D It is executed using EHSV 300.

[0127] Figure 9 This is a flowchart of an example process 900 for transmitting the health status of a servo valve. In some implementations, process 900 may be... Figure 1 Example hydraulic control system 100 Figure 2 Example hydraulic control system 200 or Figure 4 The example hydraulic control system 400 is used to perform this.

[0128] In 910, the first servo valve is controlled by a first servo controller configured to provide a first health signal to selectively allow flow between the first fluid port and the fluid source, allow flow between the first fluid port and the fluid discharge pipe, and block fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. The control is based on a position demand signal, a position feedback signal, a first priority signal, and a second health signal. For example, EHSV 220a may be controlled by valve controller 234a.

[0129] At 920, a first health signal is provided by a first servo controller. For example, valve controller 434a can send health status signal 437a via communication bus 438.

[0130] In 930, the second servo valve is controlled by a second servo controller to selectively allow flow between the second fluid port and the fluid source, allow flow between the second fluid port and the fluid discharge pipe, and block fluid flow between the second fluid port, the fluid source, and the fluid discharge pipe, wherein the control is based on a position demand signal, a position feedback signal, a second priority signal, and a first health signal. For example, EHSV 220b may be controlled by valve controller 234b.

[0131] In 940, the second servo controller provides a second health signal. For example, valve controller 434b can send health status signal 437b via communication bus 438.

[0132] At 950, the reciprocating valve directs fluid flow between a selectable first fluid port and a second fluid port and a fluid outlet configured to be fluidly connected to a fluid actuator. For example, the reciprocating valve 240 can switch between connecting the main fluid control line 205 to the fluid control port 226a and connecting the main fluid control line 205 to the fluid control port 226b.

[0133] In some implementations, at least one of the first priority signal and the second priority signal may include a representation of one or more operating conditions, said operating conditions including: (a) a high-priority command provided to a selected one of the first servo controller or the second servo controller to act as the master servo controller, and (b) a low-priority command provided to the other one of the first servo controller or the second servo controller to act as a backup servo controller. For example, controller 230 may send a command to valve controller 234a to operate as the master controller of fluid actuator 203, and controller 230 may send a command to valve controller 234b to operate as an auxiliary (e.g., backup or standby) controller of fluid actuator 203.

[0134] In some implementations, process 900 may further include: receiving a high-priority command as a first priority signal by a first servo controller; controlling a first servo valve by the first servo controller to control the position of the fluid actuator by: (a) adjusting the fluid connectivity from the fluid source to the first fluid port, (b) adjusting the fluid connectivity from the first fluid port to the fluid discharge pipe, and (c) blocking the fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. For example, when valve controller 234a is commanded to act as the master controller, valve controller 234a can take over control of the fluid actuator 203 by controlling EHSV 220a.

[0135] In some implementations, at least one of the first health signal and the second health signal includes an indication of one or more operating conditions, including an operable condition indicating the absence of a failure, a failure condition indicating a failure that can be resolved by closing the corresponding one of the first or second servo valves, and a failure indicating that a health signal cannot be sent for any of the above conditions. For example, a health status receiver 418b may receive a health status signal 437a and determine whether the valve controller 434a is in normal operating condition or whether it has detected a fault and needs to be closed.

[0136] In some implementations, process 900 may further include: controlling a first servo valve by a first servo controller to control the position of the fluid actuator by adjusting the fluid connectivity from the fluid source to the fluid actuator and from the fluid actuator to the fluid discharge pipe; and controlling a second servo valve by a second servo controller to provide a restricted fluid connection from the second fluid port to the fluid discharge pipe when the position demand signal indicates a non-zero demand position, and to provide an unrestricted fluid connection from the second fluid port to the fluid discharge pipe when the position demand signal indicates a near-zero demand position. For example, when EHSV 220b is acting as the master EHSV to control fluid actuator 203, EHSV 220a may bring 229b close to the zero position (e.g., configuration 390b) in cases where a rapid action is needed to take over control.

[0137] In some implementations, process 900 may further include: receiving a low-priority command as a first-priority signal by a first servo controller; detecting a failure condition in a second servo controller or a second servo valve by the first servo controller; and controlling the first servo valve by the first servo controller to control the position of the fluid actuator by: (a) adjusting the fluid connectivity from the fluid source to the first fluid port, (b) adjusting the fluid connectivity from the first fluid port to the fluid discharge pipe, and (c) blocking the fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. For example, when valve controller 234a is commanded to act as an auxiliary controller but a fault is detected in servo controller 234b, valve controller 234a may immediately take over control of the fluid actuator 203 under the full control of EHSV 220a.

[0138] In some implementations, process 900 may further include: controlling a first servo valve by a first servo controller to control the position of the fluid actuator by adjusting the fluid connectivity from the fluid source to the fluid actuator and from the fluid actuator to the fluid discharge pipe; detecting a fault condition in the first servo controller or the first servo valve by the first servo controller; sending a fault signal indicating the detected fault condition as a first health signal; and controlling a second servo valve by a second servo controller in response to the fault signal to selectively allow flow between the second fluid port and the fluid source, allow flow between the second fluid port and the fluid discharge pipe, and block fluid flow between the second fluid port, the fluid source, and the fluid discharge pipe. For example, valve controller 234a may identify a fault within itself while acting as the master controller of fluid actuator 203 and respond by modifying its health signal to indicate the fault (e.g., a slow failure signal or a fast failure signal). Valve controller 234b may receive and interpret the health signal and respond by taking over control of fluid actuator 203 from valve controller 234a.

[0139] In some implementations, process 900 may further include: receiving a low-priority command as a first priority signal by a first servo controller; detecting operability conditions in a second servo controller and a second servo valve by the first servo controller; and controlling the first servo valve by the first servo controller to provide fluid connection from a first fluid port to a fluid discharge pipe and to block the fluid source. For example, controller 230 may command valve controller 234a to operate as an auxiliary backup controller, and if it also detects that valve controller 234b is indicating that it is fully operable, valve controller 234a may switch to standby mode by controlling EHSV 220a to configuration 390a.

[0140] In some implementations, process 900 may further include: controlling a first servo valve by a first servo controller to control the position of the fluid actuator by adjusting the fluid connectivity from the fluid source to the fluid actuator and from the fluid actuator to the fluid discharge pipe; detecting a fault condition in the second servo controller or the second servo valve by a second servo controller; sending a fault signal indicating the detected fault condition as a second health signal; receiving a command signal configured to transfer control of the fluid actuator from the first servo controller and the first servo valve to the second servo controller and the second servo valve by the first servo controller; and ignoring the command signal by the first servo controller based on the fault signal. For example, when valve controller 234a is acting as the master controller of fluid actuator 203 and receives a fault signal from valve controller 234b, valve controller 234a may ignore the command from controller 230 to transfer control to valve controller 234b (e.g., to prevent switching to a faulty EHSV module).

[0141] In some implementations, process 900 may further include: receiving a low-priority command as a first priority signal by a first servo controller; detecting a failure of a second health signal by the first servo controller; determining a modified position requirement less than the position requirement represented by the position requirement signal by the first servo controller and based on the detection; and controlling a first servo valve by the first servo controller to control the position of a fluid actuator based on the modified position requirement by: (a) adjusting the fluid connectivity from the fluid source to a first fluid port, (b) adjusting the connectivity from the first fluid port to a fluid discharge pipe, and (c) blocking fluid flow between the first fluid port, the fluid source, and the fluid discharge pipe. For example, when valve controller 234b detects a failure of a health signal from valve controller 234a (e.g., contrary to a fault in valve controller 234a itself), the exact condition of valve controller 234a may be unknown (e.g., it cannot be distinguished between a fault in the valve controller or a fault in communication downstream of the valve controller). In situations like these, valve controller 234b can switch to a parallel master controller mode, where EHSV 220b is controlled based on modifications to the required position to place EHSV 220b in an operating state that closely follows the output that EHSV 220a may or may not still be providing. In some examples, this type of operation can create a safe backup position that does not cause reciprocating valve 240 to switch from EHSV 220a if EHSV 220a is still operating normally.

[0142] In some implementations, process 900 may further include: detecting a failure of the first health signal by a second servo controller; determining a modified position requirement less than the position requirement represented by the position requirement signal by the second servo controller and based on the detection; and controlling a second servo valve by the second servo controller and based on the modified position requirement. For example, valve controller 234b may detect a short circuit to ground, a short circuit to the battery, or an undefined (e.g., noise) state on the health signal from valve controller 234a. Those skilled in the art utilize many existing communication technologies that can be used to transmit operating status and / or control messages while also determining the operating status of the communication link itself. For example, a 4mA to 20mA current loop may be used, where information is communicated on a digital signal that uses 20mA as a high signal or "1" and 4mA as a low signal or "0", while a current close to zero may indicate a short-circuit or open-circuit communication circuit. In another example, digital communication may include checksums, where the communicated information (e.g., commands, status) is accompanied by mathematical hash information that can be compared with received communication to determine whether the information was received correctly or has been corrupted by noise. Since these statuses indicate communication rather than control failure (e.g., valve controller 234a and EHSV 220a may still be operating normally), valve controller 234b can respond by controlling EHSV 220b to provide a pressure slightly less than commanded by controller 230. Therefore, the provided pressure is nearly identical to the pressure that EHSV 220a may or may not provide (e.g., to act as a near backup to the commanded pressure level), but will not cause switching of reciprocating valve 240 if EHSV 220a is still operating normally.

[0143] In some implementations, process 900 may include: receiving, by a first servo controller, a command signal configured to transfer control of the fluid actuator from a first servo controller and a first servo valve to a second servo controller and a second servo valve; receiving, by a second servo controller, a command signal configured to transfer control of the fluid actuator from a first servo controller and a first servo valve to a second servo controller and a second servo valve; controlling, by the second servo controller and in response to the received command signal, the second servo valve to selectively allow flow between a second fluid port and a fluid source, allow flow between a second fluid port and a fluid discharge pipe, and block fluid flow between the second fluid port, the fluid source, and the fluid discharge pipe; and controlling, by the first servo controller and based on the received command signal, the first servo valve to at least allow fluid flow between the first fluid port and the discharge pipe, and block the fluid supply. For example, if valve controller 234a is in the control process and controller 230 requests a switch, valve controller 234b may respond by controlling EHSV 220b to control fluid actuator 203, and valve controller 234a may control EHSV 220a to provide an output pressure slightly below the command pressure.

[0144] In some implementations, process 900 may further include: receiving a low-priority command as a first priority signal by a first servo controller; controlling a first servo valve to a standby position based on standby demand by the first servo controller and based on the received command; detecting operability conditions in a second servo controller and a second servo valve by the first servo controller and based on a second health signal; receiving a command signal indicating sediment reduction operation by the first servo controller; controlling the first servo valve to a first modified position below the standby position by the first servo controller and in response to the received command signal; and controlling the first servo valve to the standby position by the first servo controller and in response to the received command signal. For example, controller 230 may request valve controller 234a to switch to standby (e.g., auxiliary, backup) mode, and valve controller 234a may switch to standby operation if valve controller 234a determines that doing so is safe (e.g., receiving a healthy operation signal from valve controller 234b). Controller 230 may request valve controller 234a to perform operations to prevent or reduce deposits (e.g., dirt, sediment) that may have accumulated in EHSV 220a. In response, valve controller 234a may cause closing member 229a to vibrate slightly in a manner that alters its position by a certain distance to release accumulated dirt from the closing member and valve surface (e.g., to agitate and loosen internal contaminant buildup). This movement is directed only in the discharge direction to avoid potential interference with the fluid actuator.

[0145] In some implementations, process 900 may further include: receiving a command signal indicating a sediment reduction operation by a first servo controller; receiving the command signal by a second servo controller, wherein the second servo controller operates under standby demand; controlling the first servo valve to a first modified position below the position demand indicated by a position demand signal by the first servo controller and in response to the received command signal; controlling the first servo valve to a second modified position above the position demand by the first servo controller and in response to the received command signal; controlling the first servo valve based on the position command by the first servo controller and in response to the received command signal; controlling the second servo valve to a third modified position below the standby demand by the second servo controller and in response to the received command signal; and controlling the second servo valve based on the standby demand by the second servo controller and in response to the received command signal. For example, controller 230 may request valve controller 234a to perform an operation to prevent or reduce deposits (e.g., dirt, sediment) that may have accumulated in EHSV 220a. In response, valve controller 234b can operate EHSV 220b at a pressure slightly below the required pressure (e.g., to act as a backup in case EHSV 220a fails during the cleaning process). Valve controller 234a maintains control of fluid actuator 203 and causes closing member 229a to oscillate slightly in a manner that causes the output pressure to repeatedly change slightly above and slightly below the required pressure (e.g., to agitate and loosen internal contaminant buildup).

[0146] In some implementations, process 900 may further include: moving a selected one of a first servo valve and a second servo valve between first positions to allow flow between a discharge pipe and a corresponding one of a first fluid port and a second fluid port; and moving an optional one of the selected servo valves to a second position configured to provide a venting fluid path between the fluid discharge pipe and a fluid source and a corresponding one of the first fluid port and the second fluid port. For example, one or both of EHSVs 220a and 220b may be controlled to have Figure 3D Example configuration 390d. In another example, one or both of EHSV 220a and 220b can be controlled to perform... Figures 7A to 8 The exemplary venting operation discussed in the description.

[0147] Figure 10 This is a schematic diagram of an example of a general-purpose computer system 1000. System 1000 can be used for operations described in association with any or all of the example controller 230, example EHSV module 120a, example EHSV module 120b, example controller 230, example valve controller 234a, example controller 324b, example valve controller 434a, or example controller 434b.

[0148] System 1000 includes a processor 1010, a memory 1020, a storage device 1030, and an input / output device 1040. Each of components 1010, 1020, 1030, and 1040 is interconnected via a system bus 1050. Processor 1010 is capable of processing instructions for execution within system 1000. In one implementation, processor 1010 is a single-threaded processor. In another implementation, processor 1010 is a multi-threaded processor. Processor 1010 is capable of processing instructions stored in memory 1020 or storage device 1030 to display graphical information of a user interface on input / output device 1040.

[0149] Memory 1020 stores information within system 1000. In one implementation, memory 1020 is a computer-readable medium. In another implementation, memory 1020 is a volatile memory cell. In yet another implementation, memory 1020 is a non-volatile memory cell.

[0150] Storage device 1030 provides large-capacity storage for system 1000. In one implementation, storage device 1030 is a computer-readable medium. In various other implementations, storage device 1030 may be a floppy disk device, hard disk device, optical disk device, or magnetic tape device.

[0151] Input / output device 1040 provides input / output operations for system 1000. In one implementation, input / output device 1040 includes a keyboard and / or a pointing device. In another implementation, input / output device 1040 includes a display unit for displaying a graphical user interface.

[0152] The described features can be implemented in digital electronic circuits, or in computer hardware, firmware, software, or a combination thereof. The apparatus can be implemented in a computer program product tangibly embodied in an information carrier (e.g., in a machine-readable storage device) for execution by a programmable processor; and the method steps can be executed by a programmable processor of a program executing instructions to perform the function of the implementation by manipulating input data and generating output. The described features can advantageously be implemented in one or more computer programs executable on a programmable system including at least one programmable processor configured to receive and send data and instructions from a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used directly or indirectly in a computer to perform an activity or produce a result. Computer programs can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0153] For example, suitable processors for executing instructions include both general-purpose and special-purpose microprocessors, as well as a single processor or one of several processors in any type of computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The fundamental elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data. Typically, a computer will also include one or more mass storage devices for storing data files or operatively coupled to communicate with said mass storage devices; such devices include: disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly representing computer program instructions and data include all forms of non-volatile memory, such as semiconductor storage devices, such as EPROM, EEPROM, and flash memory devices; disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM discs. The processor and memory may be supplemented or incorporated into ASICs (Application-Specific Integrated Circuits).

[0154] To provide interaction with the user, these features can be implemented on a computer having: a display device for displaying information to the user, such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor; and a keyboard and clicking device, such as a mouse or trackball, through which the user provides input to the computer.

[0155] These features can be implemented in computer systems that include back-end components such as data servers, or middleware components such as application servers or internet servers, or front-end components such as client computers with graphical user interfaces or internet browsers, or any combination thereof. The components of the system can be connected via digital data communication in any form or medium, such as a communication network. Examples of communication networks include, for example, LANs, WANs, and the computers and networks that form the internet.

[0156] Computer systems may include clients and servers. Clients and servers are typically geographically separated and interact via networks such as those described above. The client-server relationship is established by computer programs running on the respective computers and having a client-server relationship with each other.

[0157] While some implementations have been described in detail above, other modifications are possible. Furthermore, the logical flow depicted in the accompanying drawings does not require a specific order or sequence to achieve the desired result. Additionally, other steps may be provided, or steps may be eliminated from the described flow, and other components may be added to or removed from the described system. Therefore, other implementations are within the scope of the appended claims.

Claims

1. A method for operating a hydraulic actuator system, the method comprising: The closing member of the valve assembly is actuated at a predetermined first speed for a predetermined first number of cycles between a first configuration and a second configuration, wherein in the first configuration, fluid flow is discharged for a predetermined first discharge period, and in the second configuration, fluid flow path is flushed for a predetermined first flushing period. The closing member is actuated at a predetermined second speed for a predetermined number of cycles between the first configuration during a predetermined second discharge period and the second configuration during a predetermined second flushing period. The closing member is actuated at a predetermined third speed for a predetermined third number of cycles between the first configuration during a predetermined third discharge period and the second configuration during a predetermined third flushing period. The closing member is actuated at a predetermined fourth speed for a predetermined fourth number of cycles between the first configuration during a predetermined fourth discharge period and the second configuration during a predetermined fourth flushing period. and The closing member is actuated at a predetermined fifth speed for a predetermined fifth number of cycles between the first configuration during a predetermined fifth discharge period and the second configuration during a predetermined fifth flushing period.

2. The method according to claim 1, wherein, The closing member is configured to flush out residual air trapped in the valve assembly using hydraulic fluid supplied to the valve assembly when in the second configuration.

3. The method according to claim 1, wherein, The second emission period is longer than the first emission period and the third emission period, and the fourth emission period is longer than the second emission period.

4. The method according to claim 1, wherein, The second rinsing period is longer than the first rinsing period and the third rinsing period, the fourth rinsing period is longer than the second rinsing period, and the fifth rinsing period is longer than the fourth rinsing period.

5. The method according to any one of claims 1 to 4, wherein, The fifth speed is less than the first speed, the second speed, the third speed, and the fourth speed.

6. The method according to any one of claims 1 to 4, wherein, One or more of the first cycle count, the second cycle count, the third cycle count, the fourth cycle count, the first discharge period, the second discharge period, the third discharge period, the fourth discharge period, the fifth discharge period, the first flushing period, the second flushing period, the third flushing period, the fourth flushing period, and the fifth flushing period are based on the pressure of the hydraulic fluid supplied to the valve assembly.

7. The method according to any one of claims 1 to 4, wherein, The first emission period is less than 2 seconds, the second emission period is less than 5 seconds, the third emission period is less than 2 seconds, the fourth emission period is less than 30 seconds, the fifth emission period is less than 30 seconds, the first flushing period is less than 1 second, the second flushing period is less than 5 seconds, the third flushing period is less than 1 second, the fourth flushing period is less than 30 seconds, and the fifth flushing period is between 10 seconds and 360 seconds.

8. The method according to any one of claims 1 to 4, further comprising supplying hydraulic fluid at a pressure less than or equal to 289 psig, wherein, The first number of cycles is between 300 and 700, the second number of cycles is between 100 and 500, the third number of cycles is between 100 and 450, the fourth number of cycles is between 10 and 30, and the fifth number of cycles is between 1 and 10.

9. The method according to any one of claims 1 to 4, further comprising providing hydraulic fluid at a pressure greater than 289 psig, wherein, The first number of cycles is between 100 and 500, the second number of cycles is between 50 and 300, the third number of cycles is between 50 and 300, the fourth number of cycles is between 5 and 20, and the fifth number of cycles is between 1 and 10.

10. The method according to any one of claims 1 to 4, wherein, The first speed is between 500% / second and 1000% / second of the stroke of the closing member, the second speed is between 500% / second and 1000% / second of the stroke of the closing member, the third speed is between 500% / second and 1000% / second of the stroke of the closing member, the fourth speed is between 500% / second and 1000% / second of the stroke of the closing member, and the fifth speed is between 10% / second and 50% / second of the stroke of the closing member.

11. The method according to any one of claims 1 to 4, wherein, The valve assembly includes: Fluid supply port, fluid discharge port, and fluid control port; and The closing member can be configured as a plurality of valve configurations, the plurality of valve configurations including: In the first configuration, the fluid control port is in fluid communication with the fluid discharge port, and the fluid supply port is blocked; The second configuration, wherein the fluid control port is in fluid communication with the fluid supply port and in fluid communication with the fluid discharge port via a fluid flow restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid flow restrictor; A third configuration in which fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked; and The fourth configuration, wherein the fluid control port is in fluid communication with the fluid supply port, and the fluid discharge port is blocked.

12. The method according to claim 2, wherein, The second emission period is longer than the first emission period and the third emission period, and the fourth emission period is longer than the second emission period.

13. The method according to claim 2, wherein, The second rinsing period is longer than the first rinsing period and the third rinsing period, the fourth rinsing period is longer than the second rinsing period, and the fifth rinsing period is longer than the fourth rinsing period.

14. The method according to claim 3, wherein, The second rinsing period is longer than the first rinsing period and the third rinsing period, the fourth rinsing period is longer than the second rinsing period, and the fifth rinsing period is longer than the fourth rinsing period.

15. A hydraulic actuator system, comprising: A valve assembly having a fluid supply port in fluid communication with a main fluid supply pipeline, a fluid discharge port, and a fluid control port in fluid communication with a main fluid control pipeline; and A controller configured to control the operation of the valve assembly, the operation including: The closing member of the valve assembly is actuated at a predetermined first speed for a predetermined first number of cycles between a first configuration and a second configuration, wherein in the first configuration, fluid flow is discharged for a predetermined first discharge period, and in the second configuration, fluid flow path is flushed for a predetermined first flushing period. The closing member is actuated at a predetermined second speed for a predetermined number of cycles between the first configuration during a predetermined second discharge period and the second configuration during a predetermined second flushing period. The closing member is actuated at a predetermined third speed for a predetermined third number of cycles between the first configuration during a predetermined third discharge period and the second configuration during a predetermined third flushing period. The closing member is actuated at a predetermined fourth speed for a predetermined fourth number of cycles between the first configuration during a predetermined fourth discharge period and the second configuration during a predetermined fourth flushing period; and The closing member is actuated at a predetermined fifth speed for a predetermined fifth number of cycles between the first configuration during a predetermined fifth discharge period and the second configuration during a predetermined fifth flushing period.

16. The hydraulic actuator system according to claim 15, wherein, Actuation of the closing member utilizes hydraulic fluid supplied to the valve assembly to flush away residual air trapped in the valve assembly.

17. The hydraulic actuator system according to claim 15, wherein, The second emission period is longer than the first emission period and the third emission period, and the fourth emission period is longer than the second emission period.

18. The hydraulic actuator system according to claim 15, wherein, The second rinsing period is longer than the first rinsing period and the third rinsing period, the fourth rinsing period is longer than the second rinsing period, and the fifth rinsing period is longer than the fourth rinsing period.

19. The hydraulic actuator system according to any one of claims 15 to 18, wherein, The fifth speed is less than the first speed, the second speed, the third speed, and the fourth speed.

20. The hydraulic actuator system according to any one of claims 15 to 18, wherein, One or more of the first cycle count, the second cycle count, the third cycle count, the fourth cycle count, the first discharge period, the second discharge period, the third discharge period, the fourth discharge period, the fifth discharge period, the first flushing period, the second flushing period, the third flushing period, the fourth flushing period, and the fifth flushing period are based on the pressure of the hydraulic fluid supplied to the valve assembly.

21. The hydraulic actuator system according to any one of claims 15 to 18, wherein, The first emission period is less than 2 seconds, the second emission period is less than 5 seconds, the third emission period is less than 2 seconds, the fourth emission period is less than 30 seconds, the fifth emission period is less than 30 seconds, the first flushing period is less than 1 second, the second flushing period is less than 5 seconds, the third flushing period is less than 1 second, the fourth flushing period is less than 30 seconds, and the fifth flushing period is between 10 seconds and 360 seconds.

22. The hydraulic actuator system according to any one of claims 15 to 18, wherein the operation further comprises providing hydraulic fluid at a pressure less than or equal to 289 psig, wherein, The first number of cycles is between 300 and 700, the second number of cycles is between 100 and 500, the third number of cycles is between 100 and 450, the fourth number of cycles is between 10 and 30, and the fifth number of cycles is between 1 and 10.

23. The hydraulic actuator system according to any one of claims 15 to 18, wherein the operation further comprises providing hydraulic fluid at a pressure greater than 289 psig, wherein, The first number of cycles is between 100 and 500, the second number of cycles is between 50 and 300, the third number of cycles is between 50 and 300, the fourth number of cycles is between 5 and 20, and the fifth number of cycles is between 1 and 10.

24. The hydraulic actuator system according to any one of claims 15 to 18, wherein, The first speed is between 500% / second and 1000% / second of the stroke of the closing member, the second speed is between 500% / second and 1000% / second of the stroke of the closing member, the third speed is between 500% / second and 1000% / second of the stroke of the closing member, the fourth speed is between 500% / second and 1000% / second of the stroke of the closing member, and the fifth speed is between 10% / second and 50% / second of the stroke of the closing member.

25. The hydraulic actuator system according to any one of claims 15 to 18, wherein, The valve assembly includes: Fluid supply port, fluid discharge port, and fluid control port; and The closing member can be configured as a plurality of valve configurations, the plurality of valve configurations including: In the first configuration, the fluid control port is in fluid communication with the fluid discharge port, and the fluid supply port is blocked; The second configuration, wherein the fluid control port is in fluid communication with the fluid supply port and in fluid communication with the fluid discharge port via a fluid flow restrictor, and the fluid flow includes flow from the fluid control port to the fluid discharge port via the fluid flow restrictor; A third configuration in which fluid communication between the fluid control port, the fluid supply port, and the fluid discharge port is blocked; and The fourth configuration, wherein the fluid control port is in fluid communication with the fluid supply port, and the fluid discharge port is blocked.

26. The hydraulic actuator system according to claim 16, wherein, The second emission period is longer than the first emission period and the third emission period, and the fourth emission period is longer than the second emission period.

27. The hydraulic actuator system according to claim 16, wherein, The second rinsing period is longer than the first rinsing period and the third rinsing period, the fourth rinsing period is longer than the second rinsing period, and the fifth rinsing period is longer than the fourth rinsing period.

28. The hydraulic actuator system according to claim 17, wherein, The second rinsing period is longer than the first rinsing period and the third rinsing period, the fourth rinsing period is longer than the second rinsing period, and the fifth rinsing period is longer than the fourth rinsing period.

29. The hydraulic actuator system according to claim 19, wherein, The fifth speed is less than the first speed, the second speed, the third speed, and the fourth speed.

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