Research And Design Of The Electro-Mechanical Brake-by-Wire System Based On Wedge Transmission

Intellectualization and electrification require that every executive system of the car can respond quickly and accurately according to the command of the central controller,so as to obtain higher intelligent control performance,that is,by wire.The automobile braking system is the key of the current line control.The traditional automobile braking system does not have the complete line control function,and has the problems of long response time and poor function of independent decoupling control of each wheel.In this paper,the passenger car by wire brake system is taken as the research object,the electronic mechanical brake configuration and control method are taken as the research core,the brake response performance is taken as the goal,and the MATLAB/Simulink Adams joint simulation platform is taken as the design and verification means.The main work is as follows:Firstly,the structure and control method of the electro-hydraulic and electro-mechanical control system are taken as the starting point.The development of the outgoing line control system is not mature,especially the problems of large axial size,weak pressure maintaining performance and poor safety exist in the electro-mechanical control system,and the importance of the small volume,high response and pressure maintaining electro-mechanical braking system is introduced ?Secondly,taking the electro-mechanical line control system as the research object,the paper puts forward the structure of the floating wedge-shaped driving force augmentation;based on the braking demand of the whole vehicle braking system,the structure of the rear wheel brake assembly is designed,and an optimal solution method is proposed for the selection of the optimal wedge-shaped driving angle;the strength analysis and structural optimization of the key components are carried out,so that the maximum stress of the caliper body is reduced by 14.2%,and the maximum stress is reduced The strain decreased by 34.5%.Then,based on the above configuration,the dynamic model of the electro-mechanical braking system is deduced,and a virtual prototype is built by using ADAMS multi-body dynamics software and MATLAB / SIMULINK for joint simulation and performance analysis.Compared with the traditional electro-hydraulic line control system,the coordination time of the braking force of the system is shortened by 16.67%,the steady-state time is shortened by 7.4%,the unloading time of the braking force is shortened by 30.77%,and the electric power is shortened by 7.4% The maximum steady-state error of the braking force is 1.94%,and the tracking error is less than 2.9% under the condition of rapid pressure regulation.The comprehensive performance is excellent,but the unloading of the braking force is still incomplete.Furthermore,the influence of friction,damping,mass and other parameters on the performance of the system is analyzed,which proves the design effectiveness of the parameters of the system,and points out the key factors to be considered in the design and selection of the brake;at the same time,through detailed analysis,it points out that the fit clearance between the piston and the caliper body will affect the response performance.At last,aiming at the problems of bad piston clamping and incomplete unloading,the system is optimized from two aspects of structure and control respectively: the eccentric matching method of piston caliper is put forward,which can reduce the piston sliding friction by 54.98% at the initial stage of loading,reduce the steady-state time of braking force by 48%,and shorten the unloading time by 26%;the double closed-loop control method of pressure position is adopted to eliminate the residual braking force and make the system live The plug and caliper body are reset to the initial position,and the reset deviation is less than 0.05 mm.