An Electrohydraulic Actuation Scheme Using Novel Piezoelectrically-Actuated Nozzle Flapper Valve

This paper proposes a new electro hydraulic proportional actuation scheme, in which a piezoelectric ring bender actuating a nozzle flapper valve is adopted to directly control a single-ended actuator. The piezoelectric ring bender is a less complex, lighter and more reliable alternative to a conventional torque motor. The nozzle flapper valve is used as the only hydraulic control component, rather than a first stage amplifier in traditional servovalves, which allows the whole actuation system to response faster. Due to the lack of flapper displacement feedback, the valve used here is a proportional valve instead of a servovalve in this actuation system. In order to evaluate the performance of the actuator, a system-level mathematical model was built, where the piezoelectric hysteresis effect and the position of the ring bender on the flapper are considered. An analytical solution was implemented by using Matlab/Simulink. Results show that the actuation system proposed in this paper exhibits fast response, good controllability and linearity. A virtual prototype of the actuator is designed to analyze the arrangement. This has potential for use in situations where min load, fast response and high reliability actuation are required.