Optimizing The Parameters Of Dynamic Vibration Absorber And Researching On The Active Control

The dynamic vibration absorber(DVA) has been an important tool for vibration control in engineering applications. The parameters of a passive DVA can be optimized by using the PQ fixed theory,but when the primary system is damped,it needs other way to optimize the parameter. The passive vibration DVA has a good performance under a narrow band excitation, however it has a poor performance under a wide band excitation. The active DVA can achieve a better vibration attenuation over a frequency band, so studying the active control technology for DVA has important meaning. Parameter Optimizing and active control methods for DVA are studied in this thesis.The thesis includes some aspects as follows:(1) The fundamental of the DVA PQ fixed point theory, as well as the optimization design of the DVA under the condition of the optimum relative tuning are introduced, when primary system is undamped. The vibration amplitude amplification ratio expression of the primary system with a DVA attached is deduced when the primary system is damped,and the performance of the primary system under different mass ratio, natural frequency ratio and damping ratio is investigated.(2) The basic theories and the computing process of some optimal methods, such as simulated annealing(SA), genetic algorithms(GA) and particle swarm optimization(PSO) are discussed to choose the appropriate optimization algorithm.(3) Parameter identification theory of the vibration system’s dynamic parameters such as mass, stiffness and damping ratio is introduced. By using this theory, the parameters of primary system are indentified. For the purpose of minimizing the maximum of the vibration amplitude amplification ratio of the primary system, the parameters of the DVA is optimized by PSO.(4) The model of the active DVA on the primary system is built. The fundamental theory of linear quadratic optimal control is introduced, and a simulation model based on MATLAB/Simulink is built to analyze the vibration reduction performance of the active DVA under shock excitation, white noise excitation and harmonic excitation, as well as the magnitude of active control forces under different weighting matrix.In conclusion,the vibration reduction performance of the DVA can be improved via optimizing DVA’s parameters by minimizing the maximum of the vibration amplitude amplification ratio of the primary system and controlling active DVA by using linear quadratic optimal control.