Patent ID: 8291925
Filing Date: 2012-10-23
Classification: F15B,Y10T

Abstract:
1. A method for operating a hydraulic actuation system during a pressure sensor malfunction, the hydraulic actuation system including: a pressure source arranged to supply fluid flow in response to a fluid flow demand, a reservoir arranged to hold fluid, a first work-port and a second work-port, wherein the pressure source is in fluid communication with the reservoir and the first and second work-ports; a valve system capable of controlling fluid flow having a first orifice arranged between the pressure source and the first work-port, a second orifice arranged between the pressure source and the second work-port, a third orifice arranged between the first work-port and the reservoir, and a fourth orifice arranged between the second work-port and the reservoir; a pressure sensor system capable of sensing pressure (Ps) of the fluid supplied by the pressure source, pressure (Pa) of the fluid supplied to the first work-port, and pressure (Pb) of the fluid supplied to the second work-port; and a controller arranged to regulate the pressure source and the valve system based on the fluid flow demand and on determined differences between Ps, Pa, Pb, and pressure (Pt) of the fluid returned to the reservoir; the method comprising: detecting a malfunction of solely a sensor arranged to sense Pa; closing the second and third orifices; regulating the pressure source to generate fluid flow corresponding to a maximum Ps; assigning a value for the difference between Ps and Pa that is equivalent to a value within an attainable range for the difference between Ps and Pa; regulating the first orifice in response to the fluid flow demand; and regulating the fourth orifice in response to the fluid flow demand, such that the system continues to operate despite the malfunction of the sensor arranged to sense Pa.