Velocity-based method for controlling an electrohydraulic proportional control valve

摘要

An actuator (16) is part of a hydraulic circuit branch that has a first electrohydraulic proportional valve (21) connecting the actuator to a supply line containing pressurized fluid and a second electrohydraulic proportional valve connecting the actuator to a tank return line (24). A method for operating the valves includes requesting a desired velocity for the hydraulic actuator (16) and sensing a parameter which varies with changes of a force on the actuator. The desired velocity and the parameter are used to derive an equivalent flow coefficient which characterizes fluid flow in the hydraulic circuit. From the equivalent flow coefficient, first and second valve flow coefficient are derived and then employed to activate each of the first and second electrohydraulic proportional valves (21,24). The coefficients may characterize either conductance or restriction in the respective part of the hydraulic system (10).