Abstract: A vehicle control surface, such as an aircraft horizontal stabilizer, is hydraulically controlled using solenoid operated valves (SOVs) controlling directional control valves and/or rate control valves with small numbers of ports, e.g. a four port three position directional control value and/or a four port two position rate control valve.

Abstract: A hydraulic system (e.g., of an aircraft or other vehicle) includes a pump, a pressure line coupled to the pump and configured to distribute pressurized hydraulic fluid, and a return line configured to return hydraulic fluid to a reservoir. The hydraulic system also includes an auxiliary leakage valve coupled to the pressure line, to the return line, and to an actuator. The auxiliary leakage valve is configured to receive a control signal and, based on the control signal, selectively open a restricted fluid path. The restricted fluid path couples the pressure line to the return line to allow a restricted amount of the hydraulic fluid to flow from the pressure line to the return line.

Abstract: A hydraulic system (e.g., of an aircraft or other vehicle) includes a pump, a pressure line coupled to the pump and configured to distribute pressurized hydraulic fluid, and a return line configured to return hydraulic fluid to a reservoir. The hydraulic system also includes an auxiliary leakage valve coupled to the pressure line, to the return line, and to an actuator. The auxiliary leakage valve is configured to receive a control signal and, based on the control signal, selectively open a restricted fluid path. The restricted fluid path couples the pressure line to the return line to allow a restricted amount of the hydraulic fluid to flow from the pressure line to the return line.

Abstract: Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces. The HSTA operate responsive to commands issued by the pilot and/or by a controller and may include hydraulic architecture that minimizes the probability of an un-commanded movement or movement in the opposite direction of such commands.

Abstract: Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces. The HSTA operate responsive to commands issued by the pilot and/or by a controller and may include hydraulic architecture that minimizes the probability of an un-commanded movement or movement in the opposite direction of such commands.