Active Control Of Automobile Braking Noise Based On Giant Magnetostrictive

With the improvement of people's living standards,the promotion of automobiles'performance is desperately needed.More and more attention has been paid to vehicle NVH performance.The emphasis of current research is the control of automobile brake noise.To enhance the NVH performance of vehicles,noise reduction schemes should be proposed by suppressing the generation of brake noise from the source,and it would lead to a great theoretical and practical value in the development of automobiles and related industries.Based on the practical engineering problems of a domestic brake manufacturer,we mainly focused on the brake noise problem occurred on a specific brake system,and the studies were taken as follows:In this thesis,massive domestic and foreign related literature were referred and the active vibration control was studied(Chapter 1).Based on the principle of magnetostriction,the modeling problem was analyzed from the working principle of giant magnetostrictive actuator.The modeling process was divided into two parts:(1)the hysteresis nonlinear model was established based on the Jiles-Atherton hysteresis theory;(2)based on the verification of the rationality of the displacement dynamic model,the linear dynamic model of giant magnetostrictive actuator was established,which provided the actuator model for the active control of braking noise(Chapter 2).Base on frictional vibration theory,a five-degree-of-freedom brake dynamics model based on Stribeck friction model was established.The simulation of the brake dynamics model under different initial conditions was carried out by Simulink simulation.Three representative working conditions were selected to analyze the brake vibration typical time histories and phase plane trajectories,which provided a model basis for active control of brake noise(Chapter 3).Aiming at the active control of brake noise,an active control scheme for braking noise was proposed,and the analysis was carried out from three aspects:active control technology,active control structure and active control thinking,respectively.Combined with the characteristics of active control of braking noise,an active control model of braking noise based on adaptive fuzzy PID control was established.As shown in the model simulation,the vibration convergence time of the brake pad was decreased:which was reduced from about 3.5 seconds to about 1.5 seconds.The brake high frequency squeal was suppressed by the brake pad(Chapter 4).On the basis of researches above,a new active control scheme for braking noise was proposed,which was based on CMAC cerebellar neural network and adaptive fuzzy PID control.The control scheme further optimized the active control of brake noise under the premise of ensuring system stability.As shown in the model simulation,the vibration convergence time of the brake pad was significantly decreased:which was decreased from about 1.5 seconds to about 0.5 seconds.The brake high frequency squeal was significantly suppressed by the brake pad(Chapter 5).In general,based on CMAC and fuzzy PID parallel control,the generation of brake noise was suppressed by the active vibration control scheme from the source,which enhanced the NVH performance of vehicles.