Abstract: The variable pump makes the open loop gain change and decrease , the tracking control accuracy is difficult to be achieved by traditional feedback control A/O cascade control. Effective compensation to the change of open loop gain can be achieved with micro-controller and compound control methods. Using the MCS-96 chip technology, feedback control, feed- forward control and adaptive control principles, The chip computer feed-forward adaptive controller is developed, and the adaptive digital control to the system is realized and tested. The tests results show that the controller is the effective control method for the variable pump & valve controlled system.

Key words: Adaptive control, Digital control Feed-forward control, Electro-hydraulic servo system