Design On Precision Rotary Drive Mechanism Driven By Piezoelectric Actuator

In the equipments of spatial laser communication and high-resolution earth observation,precise rotation mechanism is used to control the beam pointing precisely,compensate for beam deflection and imaging noise caused by atmospheric disturbances and carrier vibration.With the characteristics of small size,light weight,small volume,compact structure,high resolution,high stability accuracy and high servo bandwidth,it has been the important part of these equipments.Based on the background of the National Natural Science Foundation(NSFC)key project,"the basic research of large scale sub-micro-arc level precision drive and transmission",the rotary mechanism acted as the research object,the flexible support structure design,precision angle measurement,check of PZT,electromechanical simulation analysis and non-linear control were carried out.The specific contents are as follows:Firstly,according to the background of the application of the subject,the typical fine parts of coarse-fine dual-stage at home and abroad were studied.The main control methods and these characteristics of the existing PZT drive mechanism were researched.The significance of the research was illustrated through the application requirement.Secondly,according to the research results and the connection way of coarse-fine dual-stage,the integral design scheme of rotary mechanism was taken.The performance parameters were analyzed and determined according to the application background.The whole three-dimensional model of the rotary mechanism was formed,and its working principle and movement mode were introduced in detail.Thirdly,as support guide part,flexible support is closely related to the trip,stiffness,dynamic performance of structure.In order to solve the design problems of flexible support,the stiffness and natural frequency of rotary mechanism were studied by two methods,which were theoretical calculation and simulation analysis.The results of two methods is consistent.Fourthly,the PZT was checked and analyzed,and a preloading method was applied for the PZT.With a PZT drive power supply,the experiments of the PZT was carried out,the linearity,stroke and open loop frequency characteristics of PZT were obtained.The element of precision angle measurement was selected and the method of precision angle measurement was analyzed.The accuracy of angle measurement was improved by coefficient calibration.Fifthly,in order to achieve ideal control performance,the linearization electromechanical simulation model was established by concentrated parameter method and finite element simulation method.The dynamic model with hysteresis was established,and it consisted of the Hammerstein model and Bouc-Wen hysteresis operator.The genetic algorithm and sin-sweep method were used to identify the model parameters.Based on this model,non-linear control method was studied.Sixthly,the experiment platform was built.The basic characteristics of the rotary mechanism were tested.The results show that the travel range is 675.9?rad,the resolution is better than 1?rad,the sinusoidal signal tracking error of 150 Hz and 100?rad is less than 8?rad,and the resonance frequency is about 1KHz which verified the correctness of theoretical and simulation methods.At the same time,the effect of non-linear control method was verified through the experiment.The results all meet the design goal.