Research On Active Vibration Control Based On Piezoelectric Intelligent Flexible Structures

Space flexible manipulator has the dynamic characteristics of light weight,non-linearity and low damping.Under the influence of excitation,it is easy to produce low-frequency elastic vibration,and the vibration attenuation time is longer.Contin-uous vibration may lead to resonance,which may cause system damage and failure,reduce the service life,and is not conducive to the normal operation of space missions.Therefore,the research on vibration control of space flexible manipulator has im-portant theoretical value and practical significance.Taking Euler-Bernoulli cantilever beam as controlled structure,the differential equation of vibration is deduced and simplified.Based on the constitutive equation of piezoelectric material,the piezoelectric coupling equation is established.The model-ing of flexible beams is studied from the point of view of system identification.Non-parametric identification and parameter identification are used to identify the flexible beam system.The results show that the matching degree between the theoretical model and the actual model obtained by the two identification methods is higher than 95%.Based on linear quadratic optimal control(LQR)theory,aiming at the key prob-lem that weighted matrix is difficult to analyse,genetic algorithm is applied to the de-sign of controller,and the weighted matrix is optimized.In order to verify the good performance of the controller after optimizing the parameters,a fuzzy logic controller is designed for the vibration control of the piezoelectric flexible arm.Based on the system model identified by experiments and the designed controller,simulation ex-periments were carried out on SIMULINK platform.The simulation results show that the designed linear quadratic optimal controller and the fuzzy logic controller can ef-fectively suppress the vibration response of the flexible beam,and the linear quadratic optimal control based on genetic algorithm is better.On the basis of the above theoretical research,a hardware experimental platform for vibration control of piezoelectric flexible manipulator is built,and a software measurement and control program is compiled.The functions of data acquisition and storage,vibration control algorithm and off-line spectrum of signals are realized.Based on the platform,experimental studies on vibration control of flexible manipu-lators driven by piezoelectric actuators and robots are carried out.The experimental results show that the two control algorithms have better suppression effect on the vi-bration of flexible arm,and the linear quadratic optimal control based on genetic al-gorithm has better control effect.