Decentralized Vibration Active Control Of Smart Constrained Layer Damping Structure

The lightening of automobile bodies is particularly important for improving the fuel economy of automobiles.The body lightening is often at the cost of thinning the body structure and reducing the stiffness of the body.This will inevitably cause the deterioration of the dynamic performance and NVH performance of the body structure,the most prominent of which is the low-frequency vibration problem.Smart constrained layer damping is a new active control technology that combines passive damping and active control.It has the advantages of simple structure,fast response,wide controllable frequency,and good low-frequency vibration suppression effect.For the vibration suppression of large and complex flexible structures such as car bodies,solar panels and ships,centralized vibration active control has the disadvantages of large number of sensors/actuators,large amount of measurement information and complicated controller design.Decentralized vibration control technology can make up for the shortcomings of centralized vibration control technology in the vibration suppression of large flexible structures,and provide a new solution to the low-frequency vibration problem of automobile bodies.In this paper,the clamped-clamped thin plate structure with partial the smart constrained layer damping treatment is taken as the research object.Based on the decentralized control method,the related research on the vibration active control of the thin plate structure is carried out.First,the dynamic model of SCLD structure is established according to the finite element method.The GHM model is introduced to describe the damping characteristics of viscoelastic materials to improve the damping accuracy of model.Second,the optimization criterion of controllability is adopted to optimizes the position of the actuators corresponding to each subsystem.For the problem that the dynamic model has a large degree of freedom,the combined reduction method of internal balance reduction and state space complex modal truncation is used to obtain low-dimensional subsystem model;Then,the stabilization method of local state feedback is used to solve the stabilization problem of decentralized system.The local state feedback controller with an observer is designed according to the optimal pole placement method,and the low output feedback between each subsystem is used to make the decentralized closed-loop large system have good dynamic performance and global stability;Finally,a hardware-in-the-loop experimental platform is established to verify the vibration control effect of the decentralized closed-loop system under the excitation of different external disturbance signals.The research results show that the introduction of GHM model and base plate damping can make the established theoretical model closer to the modal experimental results;the adopted combined reduction method can effectively reduce the order of high-dimensional models,and the low-order inherent characteristics of the structure remain basically unchanged before and after the order reduction.The hardware-in-the-loop experimental verification under different external disturbance signal excitations has shown that vibration control has achieved good effects.Under the excitation of the first-order natural frequency(32Hz)sinusoidal signal and the composite periodic signals(32Hz,53 Hz,93Hz)superimposed,the amplitude of the vibration response is attenuated by 48% and 35%,respectively.The root mean square of the amplitude of the vibration response decreased by 28% under the excitation of 20～200Hz gauss white noise signal.At the same time,the vibration response signal after the control is relatively stable.