Position control of hydraulic cylinder using constant pressure system

Abstract

The position control of a hydraulic cylinder using a constant pressure system is studied. A hydraulic transformer based on a FFC pump/motor is used as a control component to drive the cylinder with a load. The transfer function from displacement of the variable displacement pump/motor to the cylinder position is derived and a feedback controller and feedforward controller are designed and implemented. With these controllers the friction torque and the leakage of the transformer can be compensated for and sufficient accuracy of positioning is achieved.