Active Vibration Control Of Smart Constrained Layer Damping Thin Plate Based On Piezoelectric Intelligent Structure

In order to achieve the purpose of energy saving and emission reduction,lightweight automobile body has become one of the important means to solve this problem.The lightweight body design often results in the deterioration of low-frequency vibration,which can not be solved by the traditional NVH suppression technology.In order to meet the increasingly demanding requirements of comfort,the development of active vibration control technology provides a new way to solve this problem.Smart constrained layer damping(SCLD)technique,combination of the dual advantages of passive constrained damping technique and active control technique,can maintain high damping characteristic over a wide frequency range,especially good control effect in low frequency.In this paper,some studies of the active vibration control are done based on a clamped-clamped plate with partially covered SCLD as the research object.The piezoelectric ceramics(PZT)is used as sensor to endow the control object with the ability of self-perception.Firstly,using piezoelectric equation to describe the motion and sensing characteristics of piezoelectric materials,the dynamic model of SCLD laminated structure was established by the finite element method and the damping properties of viscoelastic materials is described by GHM model.The correctness of the model was verified by the modal experiment.Secondly,based on the observability Gramian matrix,and considering the influence of the residual modal,the master modal observability optimization criterion function is constructed.And the positions of piezoelectric sensors are optimized by genetic algorithm.The optimal objective function of the actuators,considering the residual mode,is constructed by using the 2H norm of the system And the ergodic method is used to determine the positions of the actuators based on the fixed location of piezoelectric sensor.Preparing for subsequent dynamic response analysis and controller design,a joint reduction method,combining of the internal balanced order reduction method and state space complex modal truncation method,was presented to solve the problem of huge degree of freedom of coupling system dynamics model.The correctness of the theoretical model of plate with partially covered SCLD was verified by modal experiment and the damping is modified by adjusting ratio coefficients.Then,according to the characteristics of piezoelectric sensor,a control strategy combining the modal control and optimal control was selected and designed.And the state observer was designed to meet the needs for the state feedback.Lastly,the active vibration control simulation and experiment of the structure with local coverage SCLD were studied based on the simulation software and hardware in the loop experiment platform.The results show that the presented method can accurately express its intelligent characteristics of sensing,passive control and active control.A small number of PZT sensors/actuators can be used to achieve good observability/controllability in the control frequency range,and it can avoid the influence of improper position on the follow-up control process.The control simulation and hardware in the loop experiment both achieved good control effect.In the hardware in the loop experiment,the amplitude of the vibration response is attenuated by about 55% under the excitation of the first order natural frequency sinusoidal signal.When the external incentive is complicated periodic signal,the amplitude of vibration response is reduced about 45%.And the root mean square value of vibration response amplitude is decreased by 26% under the excitation of limited bandwidth Gauss white noise.