RESEARCH ON HYDRAULIC CYLINDER POSITION CONTROL USING CONSTANT PRESSURE SYSTEM

Abstract

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