Abstract:A compact giant magnetostrictive actuator with bowtype amplifier structure was designed to meet the driving needs of largeflow electrohydraulic servo valve. Based on mechanics and vibration theory, the static and dynamic models of this structure were established. The influence of the dimensional parameters towards its static and dynamic performance was analyzed, and it was concluded that its static and dynamic properties were mutually restrictive. Combining with the application requirements of giant magnetostrictive actuator in electrohydraulic servo valve, the multiobjective optimization design was conducted for the bowtype structure, and then the static and dynamic models were validated by the finite element analysis. Finally, the giant magnetostrictive actuator with bowtype displacement amplifier structure was prototyped to test its static and dynamic properties. The results showed that the amplification ratio of this structure was fluctuated from 8.13 to 8.72, the maximum output displacement was 107.9μm, and the natural frequency reached 168Hz. The results were basically in consistent with the theoretical models. Compared with the performance before optimization, the natural frequency was increased by 55.6% when the requirement of the static magnification was met. The actuator designed can basically meet the driving requirements of servo valve, which proved that the optimized design method was effective.