Study On The Vibration Control Of The Car Roof With Piezoelectric Ceramic

Along with the development of the society and the improvement of people's living standard, vehicle has played a more and more important role in the daily life. People require more and more highly ride comfort of the vehicle. The vibration of the vehicle is one of an important sign to measure the ride comfort of the vehicle. Controlling the vibration of the vehicle body when it is on driving is concerted by the experts. Piezoelectric material is a new intelligent material, and it is widely applied in structure active vibration control by its good electromechanical coupling characteristics. This paper centres on the theme of piezoelectric intelligent structure active damping and does a systemic research on the active vibration control technology of the vehicle crest slab based on piezoelectric ceramics from the aspects of piezoelectric patches'selection,dynamic modeling of Body-in-white of vehicles, realizing of optimized method, designing of the control strategy and experiment research. This paper mainly contains:1) According to analyzing the data of the characteristics of different piezoelectric material at home and abroad, electing the piezoelectric ceramics (PZT) as the sensor and actuator.2) The electrical characteristics and mechanical properties of piezoelectric material were introduced. The piezoelectric equation based on electrical characteristics and mechanical properties was introduced also. Using optimum design method based on extraction accuracy criterion by modal coordinates to ascertain the position of pasting piezoelectric patches.3) The basic process of theoretical modal analysis and experimental modal analysis were described. The relationship between them and their characteristics were researched. Theroy of modal parameter identification was reviewed, and the characteristics of three methods were discussed. The finite element model of car body was built. Low order modal analysis is performed based on the model. Meanwhile modal test of prototype vehicle is carried out and verify the reliability of the finite element model.4) Researching the basic principle of the wavelet transform and MALLAT algorithm, and combination of wavelet analysis theory and LMS(Least Mean Square, LMS)algorithm to propose the wavelet adaptive algorithm including two structure forms of decompose LMS algorithm ( Decomposition LMS, D-LMS ) and Decomposition and Reconstruction LMS(Decomposition and Reconstruction LMS, DR-LMS). Then proceeding deeply theoretical research to the two algorithms.5) According to random adaptive control theory, establishing wavelet adaptive controlling system and designing two wavelet adaptive controller using respectively D-LMS algorithm and DR-LMS algorithm. Giving the adaptive adjusted functions of the two controllers parameter matrix and using the Simulink platform to simulate the two controllers.6) Researching the data collecting and controlling technology based on the Simulink/Dspace hardware platform and designing the hardware and software of wavelet adaptive controlling system based on the Simulink/dSPACE hardware platform. Applying the technology to the active vibration control system of the cantilever beam and obtaining a good control effects.7) The above researches are applied to active vibration control of vehicle crest slab based on intelligent structure thought. The controlled object of intelligent structure concept including the actuator and the sensor is established. And the hardware and software design of active vibration control of vehicle crest slab is completed. The experiment results show that the active vibration control system of vehicle crest slab can control the vibration of the vehicle crest slab effectively. So it confirmed the effectiveness of the wavelet adaptive control algorithm and the feasibility of controlling the vibration of the vehicle crest slab using piezoelectric ceramics.