Research Of Brake Pedal Stroke Simulator And Braking Smoothness Based On Electric-wheel Vehicle

With the increasing of automotive exhaust emissions, the environmental pollutionbecomes more and more serious, and now it is the most outstanding one of the pressingproblems of environmental protection. Because of rising price in oil and less non-renewableresources, the traditional automobile will be replaced by new energy vehicles. Electric wheelvehicle can solve these problems. This article introduces4independently-driving andelectric wheel auto, and systemically studies Braking System. I propose some new ideas andmethods that can solve the ride comfort problem of electric vehicle braking process. Thesame as the traditional vehicle, the braking system of electric wheel vehicle is also the chiefmanoeuvre mechanism. Frequently movements will impact driver’s safety and comfort. Todispose of practical considerations on comfort during brake, I make an exhaustive studyabout switching on brake pedal feel and electric vehicle braking mode, and design the strokesimulator that accords with usual brake feel. During switchover on brake mode,we shouldkeep stability and reduce the brake torque fluctuations during brake.This text aims at electric wheel car, designing without vacuum booster and includingbrake-by-wire system of brake pedal travel simulator,building electric wheel vehicledynamics model with15DOF that can be used for simulation test, using the trajectorytracking control algorithm to control braking feel, analysing the electric wheel car’s brakingprocess, applying dynamic coordinated control method to control braking mode switchingprocess, at last dSPACE hardware in the loop test bench to verify the assumption.Based on the above ideas to expand the study as follows:Firstly, according to the characteristics of the electric wheel car, electric vehicles areanalyzed, including body modules, suspension modules, steering model, tire module, motormodule and hydraulic module, using AMESim software and as a basis to establish accurate15degrees of freedom nonlinear electric wheel automobile dynamics simulation platform.Urban conditions in order to verify the accuracy of the model simulation, the simulationresults show that the accuracy of the model the dynamic simulation requirements. Thesimulation platform module parameters can be modified depending on the model, simulationdegrees of freedom, a relatively high accuracy, the various conditions of the car to simulateelectric wheel drive. Secondly, I will introduce a conventional brake system, analysis of the variouscomponent parts, including the brake pedal, the vacuum booster, active master cylinder andthe brake, etc. to describe the characteristics of the pedal feel of a conventional brake system.Then, based on the traditional brake pedal feel characteristics, using AMESim softwarestroke simulator model and designing the structure of the program. Later, trajectory trackingcontrol method and fuzzy-PID control method for controlling the solenoid valve feedbackbrake pedal brake pedal travel simulator. Offline simulation on the basis of the establishedmodel, the results show that by the above method to achieve with the braking Jiaogan of theconventional braking system similar to the braking system, i.e. adding motor brake still has agood brake pedal feel.Thirdly, the analysis of factors affect car ride, several electric wheel car brake systembrake mode analysis of a typical motor brake control method. Electric wheel car there aretwo braking systems (motor brake and mechanical hydraulic braking) during braking thebraking mode switching is common composite braking system. The proposed control method,consisting of two parts, brake torque management strategy and dynamic coordinated controlalgorithm can solve the braking process Brake mode switching braking torque fluctuations.For braking torque according to the vehicle speed, brake pedal, accelerator pedal, and othersignals identifying the driver, according to the value and the traveling state of the batterySOC, resulting in the adjustment of the braking torque in the brake mode switching and theswitching process. Vehicle dynamics model based on the continuous the switching processsimulation and a condition on the simulation. Simulation results show that, behind dynamiccoordinated control algorithm control braking mode switching process regulation and controlof motor and hydraulic system, to achieve the desired effect, reduced motor brake andmechanical hydraulic brake switch fluctuations, the ride of the braking process.Finally, it introduces the characteristics of the hardware in the loop test platform anddesigned dSPACE real-time platform-based hardware in the loop test rig. The test platformincludes a hardware part and software part and real-time systems, etc. The brake systemvacuum booster of the test with the stroke simulator build the hardware in the loop test standon the brake pedal travel simulator electric vehicle braking mode switching control strategiesfor test and analysis. According to the hardware, results of the loop simulation test can beseen, the design of the pedal travel simulator can be a good analog feel of the brake pedal,meeting the design requirements, through dynamic coordination control algorithmeffectively reduces the braking mode switching process braking torque fluctuations, I ensurethat the ride of the braking process achieving the desired effect.