Chaos Behavior Analysis And Control Of Disc Brakes Based On Three-Body Contact

With the increase of car ownership and the continuous deterioration of urban traffic,congestion has become the normal state,and the impossible of braking at low speed is increasing,and the flutter caused by braking has become a hot and difficult issue for professionals in the field.In most of the previous theoretical studies,the friction model is used as the entry point to couple the motion of the brake block and brake disc.This method is simple and easy to operate,but it can only study the influence of some macro parameters,such as friction coefficient,on the braking flutter,which has great limitations and is difficult to deepen the research content.However,the development of tribology brings a glimmer of light to this field: from macroscopic to microscopic,from two-body to three-body,from summarizing the phenomenon to exploring the essence.Based on this,this paper introduces three-body contact into the braking system,and studies the essence of flutter from a microscopic perspective.The main contents are summarized as follows:(1)A three-body contact model including brake pad,brake disc and wear particles was established,and the influence of the average diameter of particles,material hardness,roughness and other parameters on the fluctuation of friction force was analyzed.(2)The torsion dynamics model including brake pad,brake caliper and brake disc was established,and then the motion of the three was coupled with the three-body contact force,and the detailed numerical simulation was carried out.Firstly,the influence of the wear particle size,elastic modulus,hardness and other parameters on the braking chaos was studied.Secondly,the effect of the mass of brake block and brake clamp and the rotary inertia of brake disc on the braking chaos was studied.(3)In order to eliminate stick-slip,bifurcation and chaos,three control methods of braking force response rate suppression,displacement feedback control and velocity feedback control are adopted and simulated.Simulation results show the effectiveness,rapidity and stability of the proposed method.