Optimal Control And Design Optimization For Piezoelectric Intelligent Truss

The piezoelectric material is a kind of functional material with electromechanical coupling characteristics,which can make mechanical signals and electric signals exchange with each other under the piezoelectric effect.Piezoelectric materials have been widely used as actuators and sensors in intelligent structures.Active controlling with piezoelectric materials as drivers and sensors for intelligent truss has become one of the hottest issue in engineering vibration control field now.Following is the main contents of this thesis:(1) Based on the large number of references both at home and abroad,the thesis begins with the review of the previous related studies.The history of the development of piezoelectric intelligent structures is also introduced,which lays the theoretical formulas and theoretical foundation for the thesis.The basic theories of optimal control,specially theory of the quadratic optimal control are applied to carry out the analysis and discussion in the thesis;(2) Through a comprehensive analysis of the structure of piezoelectric intelligent truss, electromechanical coupling FEM equation for intelligent truss structure containing piezoelectric actuators can be deduced so as to transform it into vibration control equation for piezoelectric intelligent truss.Thus piezoelectric intelligent truss between the state- space equation and the LQR controller can be established;(3) The finite element analysis of piezoelectric truss structures was carded out in JIFEX, and the optimal control of the stiffness matrix,mass matrix and the voltage control matrix were obtained.Besides,the preparation of the control procedures for solving and JIFEX interface module,using the precise integration method based on high - solver accuracy LQR control procedures piezoelectric intelligent truss of the above state space equation was solved to achieve a piezoelectric smart structure of optimal control;(4) Through the LQR control analysis of space truss for 20 and 72 bars,it is fully shown that the LQR control can realize effective rejection to the vibration of structure.At the same time,the effects of different values of Q,R on structural control are discussed,through the numerous examples,it is proved that the increase in the value of Q can raise the control speed, increase in the value of R can reduce energy consumption;(5) Many studies have shown that on the condition of same number of actuators and the same energy consumption,different locations of the structure have different effects on vibration control,so how to optimize the vibration control actuator / sensor configuration has been a key technical problem for vibration control.In this thesis,based on the theory of genetic algorithm,the optimum design for optimal control of the electromechanical coupling for the structure of intelligent truss is achieved by taking performance index of optimal control as the objective function with the given number of drive bar.