Control of the relative movement of hydraulically driven linear moving parts

In this paper a control strategy is designed to control the relative movement of two linear moving parts on a reallife application driven by a hydraulic circuit. The hydraulic circuit has two motors in series configuration, each bypassed by a direct current controlled cartridge valve. On the output side, the speed of the linear moving parts and the time at which they reach a fixed endposition is measured. First, identification of the valves is done on an experimental basis. Second, these models are validated and a controller for the phase difference between the two linear moving parts is designed. The controller consists of a combination of PI and PID controllers for both speed and position synchronization.