Development of hydroelectric servo-valve based on piezoelectric elements

In order to improve the performance of servo-valve and reduce its cost, a new type of piezoelectric hydroelectric servo-valve is developed. The electrical-mechanical converter of the servo-valve is constructed by piezoelectric bender, which also functions as baffle of the hydraulic amplifier made by double-nozzles-baffle. Dynamic and static characteristic tests are conducted on the piezoelectric bender developed. In line with the performance of the valve, the dimensions of its components are calculated. The characteristic test system for servo-valve is built and the servo-valve is tested with it. The results show that flux hysteresis loop is less than 2%, resolution is less than 0.5%, nonlinearity is less than 3.5%, and its band width is up to 140Hz. So the new type of piezoelectric servo-valve is characterized by good performance.