A method of driving an hydraulic actuator by means of a pressure-controlled proportioning solenoid valve

摘要

A method of driving a hydraulic actuator (13) provided with a pressure-controlled proportioning solenoid valve (21); the method includes the steps of: determining a first open-loop contribution (I p ) according to a pressurized oil flow rate (Q FF ) which crosses the proportioning solenoid valve (21) and according to the desired load pressure (P load ) inside the actuation chamber (20); determining a second open-loop contribution (I QFF ) according to the desired position (X SpoolRef ) of the spool (29) of the proportioning solenoid valve (21); determining a third closed-loop contribution (I QCL ) according to the difference (µ X ) between a desired value (X REF ) of the position of the mobile piston (22) and a real value (X) of the position of the mobile piston (22); and calculating a desired electric driving current value (I TOT ) of the proportioning solenoid valve (21) by means of an algebraic sum of the three contributions (I P , I QFF , I QCL ).