Abstract: On the basis of an intelligent pipe bundle-shaping machine developed by Zhejiang University, a nonlinear control algorithm with two steps is presented to address the motion synchronization problem for a two-cylinder electro-hydraulic (EH) system. The outer loop of this approach is a linear MIMO robust control controller which is used to get desired pressure for synchronization motion control of two cylinders. The inner loop controller consists of two SISO pressure controllers de-signed by nonlinear perturbation observer theory which are used to track desired pressure under system disturbances. Ex-perimental results indicate this new approach is better than conventional PID and can effectively synchronize two actuators motion.

Key words: Electro-hydraulic proportional control, Motion synchronization, Nonlinear control, Pipe bundle intelligent shaping, Robust control