Novel Pre-compression Piezoelectric Actuator And Its Integrated Design On Servo System

Flight control actuator determines the performance of flight control system.Piezoelectric bimorphs have the advantages of light weight,low power consumption,simple structure etc.So bimorph is very suitable for actuators used for controlling micro-aircraft and smart ammunition.However,Piezoelectric bimorphs have insufficient displacement output capability and require various amplification mechanisms to amplify their output capability,but at the expense of bimorph output force.To solve the problem,some researchers have put forward the concept of PBP(post-buckled pre-compressed).Applying an axial force on the bimorph to increase the output displacement and force simultaneously.In this paper,Based on the principle of PBP,Theoretical and experimental methods are used to study the structural dynamics of pre-compressed bimorph.The research contents are as follows:1.The structural dynamic model of the axially pre-compressed bimorph was established using analytical mechanics or finite element method.The expressions of static and dynamic characteristics of bimorphs under different axial forces and voltages are given,and the influence of structural stability on the output performance of bimorphs is analyzed.2.Two kinds of piezoelectric flight control actuator scheme are given,and the rigid-flexible coupling dynamic model of the actuator is derived.The angle-torque characteristics,the steady-state response and the transient response of the actuator under different axial forces are analyzed.It is proved theoretically that the increase of the axial force can simultaneously increase the output angle and output force of the rudder.The rudder still has high bandwidth and millisecond response time under the large axial force.Designed and processed the prototype.3.The static and dynamic characteristics of bimorph are studied by experimental method.It is proved that increasing the axial force can significantly improve the displacement and output ability of bimorph,and the bimorph under large axial force still has the advantage of high bandwidth and fast response.4.A four channel piezoelectric actuator was designed.The design scheme of preloading mechanism is given according to the results of theoretical analysis.The experimental platform has been built to verify the feasibility of the single channel rudder.