Structure Design Of Piezoelectric Hydraulic Actuator Based On Simulation Analysis

Morphing aircraft is a new type of deformable aircraft based on intelligent materials.During the flight,the morphing aircraft can actively change the shape and structural parameters of the wing's sweep angle,wingspan,and wing area.It has the best flight performance under different flight missions and flight environments,which can effectively improve the combat performance and safety of the aircraft.The adaptive change of the structural shape of the intelligent morphing aircraft requires high-performance drives with high power density to realize the driving.As a new type of drive,the piezoelectric hydraulic driver combines the advantages of high displacement resolution,good linearity,convenient control,and fast response speed of the piezoelectric ceramic with the advantages of smooth and stepless speed regulation of the hydraulic transmission and the ability to provide great output force.The combination has both advantages.It is the most ideal driver when the wing of the morphing aircraft is deformed.This article mainly completed the structural design of piezoelectric hydraulic actuator,component simulation and design,internal flow field simulation optimization,fluid-structure coupling simulation,and test content.First,the relationship between the output force of the piezoelectric ceramic stack and the deformation of the piezoelectric ceramic under the action of voltage(also called displacement stroke)is derived.The working stages and working modes of the piezoelectric hydraulic driver during operation are analyzed.Then,the output performance of the driver is theoretically analyzed and calculated,and the function image is drawn and analyzed.Then,the overall structure design of the piezoelectric hydraulic actuator and the simulation of each component.Including check valves,actuator housings,seals and hydraulic lines,simulation and design.Finally,during the internal flow field simulation of the piezoelectric hydraulic actuator,the working cavity of the actuator and the structure of the one-way valve were simulated and optimized,including the internal flow field simulation of the two types of actuators.For the first type of driver,consider the effect of different cavity heights on the pressure loss;observe the eddy current through the velocity vector diagram;In the two cases with or without an accumulator,the fluid flowstate inside the cavity can be judged by the velocity cloud diagram,pressure cloud diagram,velocity vector diagram and streamline diagram.In the test part,the output pressure test of piezoelectric hydraulic actuators with different valve sizes is carried out in this paper.It is concluded that the valve plate performance is improved when the rigidity of the valve plate is larger due to the larger area size,but the optimal driving frequency will also be reduced,and the reduction of the driving frequency will cause the flow rate to decrease.There is also an external one-way valve to suppress the backflow test.The external one-way valve can well protect the vibration reed of the one-way valve,keep the pressure at both ends of the driver,and realize self-locking.Finally,the pressure at the outlet end of the driver was increased to 6MPa compared to the inlet end.Under the condition of the pre-charge pressure of 3MPa,the outlet pressure reached 9MPa,and the driver achieved stable self-locking performance.