Numeircal Modelling And Optimization Of Laminated Piezoelectric Smart Structure Active Vibration Control

Piezoelectric materials have been manufactured into thin actuators/sensors because of their ability to transform mechanical energy to electrical energy and vice versa. Laminated piezoelectric smart structures with piezoelectric actuators/sensors bonded on the surface or embedded in host structures have self-detection, self-diagnosis, self-healing and adaptive functions. Application of laminated piezoelectric smart structures in the fields of aerospace, mechanical as well as civil engineering and modern control theory development have greatly promoted the domestic and foreign scholars to poure enthusiasm into their vibration control research. Laminated piezoelectric smart structure is a discrete density distribution, discontinuous material properties and electro-mechanical coupling dynamic model system. Therefore, accurately and effectively analyzing the behavior of piezoelectric material electro-mechanical coupling, exploring the mechanical and electric field coupling action, taking into account of solving efficiency when establishing the accurate dynamic response model of laminated piezoelectric smart structure under disturbance loading, revealing the effect of acturators/sensors distribution location, geometry size as well as compsite material lay-ups on laminated smart structure vibration characteristics, controller parameters and structure configuration impact on system quality and performance, vibration control of smart structures undering moving load are problems to be solved. Investigating active control theory and algorithm of smart structure to improve system stability, optimization of pizeoelectirc actuator/sensor locations, realizing multi target mode vibration control and so on, all these problems mentioned above are also urgent to be solved.In this paper, finit element dyanimc state-space equation of linear elastic piezoelectric is derived from Hamilton principle and electro-mechanical coupling constitutive of piezoelectric materials. Numerical models are established to accurately describe the mechanich-electric coupling field based on ANSYS/APDL parameter language. The variation of natural frequency and mode shape of smart cantilever beam as actuator/sensor location, size and composite material lay-ups changing has been explored. The impact of piezoelectric actuator/sensor location, number and controller parameters on PID closed-loop control system performance is studied. The introduction of advanced PID controller with separated integration, changing rate integration and partial differential effectively settled the divergency and instability appearance of system caused by inappropriate parameters of classic PID controller. The impact of controller parameters and load moving speed on control performance is also analyzed at different vibration stages of laminated piezoelectric smart system under moving load.A self-learning control (SLC) algrothm able to real-time adjust and amend control feedback gain is presented according to system output error. Taking system output error with its variation and the gain of iterative learning as the input and output of fuzzy controller respectively, the fuzzy self-learning control (FSLC) method is also proposed to speed up the convergence of SLC. The numerical simulation results of piezoelectric smart cantilever plate prove that both SLC and FSLC could effectively reduce the vibration response of closed-loop system, and FSLC quality is better than SLC. Based on the idea of combining the linear quadratic optimal control with iterative learning (IL) control, the paper puts forward a new hybrid control strategy which is named linear quadratic iterative learning control to improve the iterative learning control convergence. The numerical model for dynamic analyzing of one-dimensional laminated piezoelectric cantilever beam is created by MATLAB software. And then the classic optimal control and linear quadratic optimal iterative learning hybrid control are achieved, thus the control property is improved.Taking the location parameters of discrete distribution piezoelectric actuators/sensors and the damping ratio of piezoelectric smart structure closed-loop control system as optimization variables and objective function respectively, the actuator/sensor optimization program based on genetic algorithm (GA) is presented. The finite element numerical simulation is conducted to consider the vibration control of cantilever plate exited by transient and harmonic loading at the free end of it. Numerical results show the validity and effectiveness of using GA for searching optimal placement of the actuator /sensor pairs in active structural vibration control.This paper discussed proportional feedback gain and lay-ups effect on the closed-loop system performance of composite laminated piezoelectric beam by numerical simulation method. A simple and easy to implement way to determinate actuator/sensor locations is raised based on distribution of modal strain energy for multi target modes vibration control of laminated smart structures. Numerical results proved the feasibility and correctness of the method metioned above.