Adaptive Filter Vibration Control Of Piezoelectric Flexible Plate Structure

Flexible thin wall structures are more and more widely used nowadays in the appendagesof aircrafts and spacecrafts to reduce the total mass and energy loss of the whole structure.Since thin wall structures have the characteristics of low stiffness, low quality, etc. Whenspacecrafts are excited by persistent disturbances or aerospace vehicles fly at supersonicspeed, resonant vibration and panel flutter may easily be excited. As a result, structural fatigueand damage of the whole structure may be caused. Therefore, the research on active vibrationand flutter control of flexible structure is absolutely necessary. A clamped-clamped plate isdesigned for the simulation of the actual panel flutter phenomenon. Finite element modeling(FEM) and active vibration control of the system are also studied.The dynamics model of the system is the basis for research. First of all, a kind ofrectangle thin plate element is used for FEM of the clamped-clamped plate. The optimalplacement of the sensor/actuator and simulation of control algorithms are based on thedynamics equation.An improved H2norm optimizing index for optimal placement of sensor/actuator is usedbased on the finite element model of the clamped-clamped plate. The index not onlymaximizes the norms of the controlled modes, but also minimizes the norms of thenon-controlled modes to ensure better controllability and observability of the system. Geneticalgorithm (GA) and enumeration method are both used for optimal placement of thesensor/actuator to compare with each other. The dynamic model of the piezoelectric flexibleplate is built for characteristic analysis of the system. And ANSYS software is used forcomparison.Then, numerical simulations of the classic PD feedback control algorithm, the adaptivefiltered-X LMS (Least Mean Square) feedforward control algorithm and the adaptivefiltered-U LMS feedforward control algorithm are carried out to suppress the resonantvibration of the clamped-clamped piezoelectric flexible plate under persistent excitation,respectively.Finally, an active vibration control system of a clamped-clamped flexible plate isdeveloped according to the previous theoretical and simulation analyses. The control pathidentification is carried out. Experiments of different control algorithms PD, FXLMS,FULMS on resonant vibration suppression of the piezoelectric flexible plate are conducted forcomparative analysis.The feasibility of the improved H2norm index for optimal placement of sensors/actuators is validated. The simulation and experimental results demonstrate that thePD feedback control algorithm and adaptive filtering feedforward control algorithms cansuppress resonant vibration of flexible structure under persistent excitation effectively.Besides, the resonant vibration under persistent excitation of first-order modal frequency canbe suppressed to very small amplitudes by using the FXLMS and FULMS feedforwardcontrol algorithm after a long time of the self regulating process. This is the main advantageof the feedforward algorithms compared with feedback algorithms.