Control strategy for hydraulic system

A method of operating a hydraulic component, wherein the hydraulic component comprises a hydraulic supply side and a hydraulic return side, and a controlled leakage is provided between the hydraulic supply side and the hydraulic return side through a bleed restrictor connected between the hydraulic supply side and the hydraulic return side, the method comprising:

• providing a plurality of hydraulic supply systems, each configured to selectively supply pressurized hydraulic fluid to the component,
• and the steps of:
• (A) fluidly connecting one of the hydraulic supply systems with the component until (i) a predetermined pressure is reached on the hydraulic supply side and/or the hydraulic return side, and/or (ii) a predetermined amount of time has passed;
• and then
• (B) isolating the pressurized hydraulic fluid within the hydraulic supply side and the hydraulic return side so that the pressurized hydraulic fluid leaks from the hydraulic supply side to the hydraulic return side via the bleed restrictor;
• (C) monitoring a pressure over time of the pressurized hydraulic fluid within the hydraulic supply side and/or the hydraulic return side;
• and then
• (D) determining if the pressure over time of the pressurized hydraulic fluid within the hydraulic supply side and/or the hydraulic return side follows a predetermined or expected pattern,
• prior to step (A), detecting a fault in the supply of the pressurized hydraulic fluid to the component during operation, and fluidly disconnecting a first, primary hydraulic supply system of the plurality of hydraulic supply systems from the component;
• and
• identifying a second, backup hydraulic supply system of the plurality of hydraulic supply systems and, before fluidly connecting the second, backup hydraulic supply system, performing steps (A) to (D), wherein the one of the hydraulic supply system referred to in step (A) is the second, backup hydraulic supply system.

A system for controlling a hydraulic component, comprising:

• a hydraulic component comprising a hydraulic supply side and a hydraulic return side, and comprising a controlled leakage between the hydraulic supply side and the hydraulic return side, wherein the controlled leakage comprises a bleed restrictor;
• a plurality of hydraulic supply systems, each configured to selectively supply pressurized hydraulic fluid to the component;
• a device configured to monitor a pressure of the pressurized hydraulic fluid within the hydraulic supply side and/or the hydraulic return side;
• and
• a control system configured to control which of the hydraulic supply systems are fluidly connected to the component using one or more valves,
• wherein the control system is configured to carry out a health check routine on one or more of the hydraulic supply systems, the routine comprising the steps of:
• (A) fluidly connecting one of the hydraulic supply systems with the component until (i) a predetermined pressure is reached on the hydraulic supply side and/or the hydraulic return side, and/or (ii) a predetermined amount of time has passed;
• and then
• (B) isolating the pressurized hydraulic fluid within the hydraulic supply side and the hydraulic return side so that the pressurized hydraulic fluid leaks from the hydraulic supply side to the hydraulic return side via the bleed restrictor;
• (C) monitoring the pressure over time of the pressurized hydraulic fluid within the hydraulic supply side or the hydraulic return side;
• and then
• (D) determining the pressure over time of the pressurized hydraulic fluid within the hydraulic supply side or the hydraulic return side follows a predetermined or expected pattern,
• wherein, following step (D), the control system is configured to carry out the steps of:
• determining whether a hydraulic failure has occurred;
• and
• if the hydraulic failure is detected, determining whether the hydraulic failure was caused by a failure of the one or more valves.

A method of operating a hydraulic component, wherein the hydraulic component comprises a hydraulic supply side and a hydraulic return side, and a controlled leakage is provided between the hydraulic supply side and the hydraulic return side, wherein the controlled leakage comprises a bleed restrictor, the method comprising:

• providing a plurality of hydraulic supply systems, each configured to selectively supply pressurized hydraulic fluid to the component;
• controlling which of the hydraulic supply systems are fluidly connected to the component using one or more valves;
• and the steps of:
• (A) fluidly connecting one of the hydraulic supply systems with the component until (i) a predetermined pressure is reached on the hydraulic supply side and/or the hydraulic return side, and/or (ii) a predetermined amount of time has passed;
• and then
• (B) isolating the pressurized hydraulic fluid within the hydraulic supply side and the hydraulic return side so that the pressurized hydraulic fluid leaks from the hydraulic supply side to the hydraulic return side via the bleed restrictor;
• (C) monitoring a pressure over time of the pressurized hydraulic fluid within the hydraulic supply side and/or the hydraulic return side;
• and then
• (D) determining if the pressure over time of the pressurized hydraulic fluid within the hydraulic supply side and/or the hydraulic return side follows a predetermined or expected pattern,
• the method further comprising:
• following step (D), determining whether a hydraulic failure has occurred;
• and
• if the hydraulic failure is detected, determining whether the hydraulic failure was caused by a failure of the one or more valves.