Fuzzy control of a new type of piezoelectric direct drive electro-hydraulic servo valve

A new type of piezoelectric direct drive electro-hydraulic servo valve is developed in this paper. Multilayer piezoelectric actuator is used as the electricity-machine converter in this new electro-hydraulic servo valve, which makes the electro-hydraulic servo valve system have higher dynamic and steady performance. Because the system exists complicated nonlinearity and uncertainty, the conventional control method cannot meet the speed and precise requirements for positioning. An improved fuzzy control method with self-adjusted function is designed and implemented. Because of eliminating the undesirable nonlinear effects, the proposed method demonstrates substantial improvements in the dynamic and steady characteristics of the system. The experimental results illustrate the effectiveness of the proposed control method.