Research On Optimization Of Surface Quality For Ultraprecision Machining Of Pure Sn Materials

Miniature intelligent ammunition has the characteristics of good concealment,difficulty in interception,low explosive power,and high precision.It has gradually became an important material basis for building a powerful modern new army.As the actuator in the intelligent ammunition control system,the steering gear system directly affects the maneuverability and dynamic quality of the intelligent ammunition.In order to meet the development requirements of miniature intelligent ammunition,it is necessary to research,develop and apply new principles,new materials,and new structures of rudder surface driving devices.To meet the miniaturization and intelligence requirements of the miniature intelligent ammunition for the steering gear system,based on the variable width post-buckling pre-compression piezoelectric bimorph actuator,this paper studies its static and dynamic characteristics,and designs a control system for the hysteresis and creep nonlinearity of piezoelectric materials.The main research contents of this paper are summarized as follows:In this paper,the inverse piezoelectric effect of piezoelectric materials was used to study the structure and driving principle of piezoelectric bimorphs.Appropriate piezoelectric ceramic materials were selected and a finite element model of piezoelectric bimorphs was established to verify the correctness and effectiveness of the simulation model.Based on the assumption of classical laminates and piezoelectric constitutive equation,the static characteristics of bimorphs were studied by energy method.The dynamic characteristics of bimorphs were studied by finite element method.The piezoelectric bimorph with variable width was proposed to reduce the mass and volume of the steering gear.The finite element simulation obtained the reliable output performance of the variable width piezoelectric driver.The driving scheme of the rudder actuator and the rotatable,folding and unfolding rudder surface mechanism reduced the volume and mass of the launcher,making it easy to carry in a single soldier’s backpack.The overall structure of the micro smart ammunition steering system was designed to meet the requirements of miniature intelligent ammunition for the miniaturization of the steering gear system.The bouc-Wen hysteresis model was established.Combined with the least square method,the parameters in the model were identified and an effective hysteresis model was obtained.The logarithmic creep model and the superposition model of basic creep operator are established respectively,and the accurate creep model was obtained.In order to describe the hysteresis nonlinearity and creep nonlinearity of piezoelectric bimorphs at the same time,a hybrid hysteresis creep model of piezoelectric ceramics was established.In this paper,the hysteresis displacement observer of the hysteresis model and the inverse model of the creep model were respectively established.The inverse compensation controller was designed.Considering the hysteresis and creep characteristics,the overall inverse control system was designed.The ability of the controller to suppress hysteresis and creep was analyzed through simulation.So as to meet the requirements of miniature intelligent ammunition for linearity and intelligence of the steering gear system.