Design Research On Electric Driving And Braking Electric Wheel

With the increasingly serious impact of fuel cars on the shortage of oil resources and environmental pollution,electric vehicles with the advantages of energy saving and environmental protection have become the development direction of the automotive industry,electric-wheel vehicles have the advantages of higher transmission efficiency and better dynamic controllability.The electro-mechanical brake(EMB)system is provided with torque by the motor,which is transmitted to the brake disc by several times through the mechanical transmission mechanism,which can provide a larger braking torque.In addition,the braking response time of EMB is shorter,and the braking force can be adjusted accurately,meet the high-performance requirements of electric-wheel vehicles for braking systems.Therefore,the electric driving and braking electric wheel integrated with the in-wheel motor and EMB system has higher dynamic performance and braking performance.After the electric driving and braking electric wheel integrates the in-wheel motor and the EMB system,the unsprung mass is greatly increased,which leads to the deterioration of the ride comfort of the whole vehicle.It is necessary to optimize the structure of the electric driving and braking electric wheel,and optimize the parameters of the suspension system of the electric wheel with the goal of reducing the unsprung mass and improve vehicle ride comfort.The article conducts research from the following aspects:(1)Based on the parameters and dynamic performance indicators of electric-wheel vehicles,the in-wheel motor and suspension system of the electric driving and braking electric wheel were matched and structured.With the goal of reducing the unsprung mass of the electric wheel and reducing the volume of the brake,a new type of bidirectional synchronous force-boosting EMB actuator was proposed.Based on the maximum demand braking force of the target vehicle under emergency braking conditions,the rotary motor and ball screw were selected.With the goal of ensuring that the clamping force on both sides of the brake disc was equal,the structure design of the EMB actuator was completed.(2)Based on the structure of the in-wheel motor,EMB actuator and Mac Pherson suspension,the integrated design of the electric driving and braking electric wheel was completed,and the three-dimensional model of the electric wheel was established.Under the premise of ensuring the performance and structural strength of the in-wheel motor,lightweight design of the wheel in-wheel motor was carried out.The optimization goal is to equal the boost ratio of the two-stage booster mechanism and the lever booster mechanism,based on the particle swarm algorithm,the booster parameters were optimized.In order to improve the ride comfort and ride comfort of the vehicle as the optimization goal,the parameters of the electric wheel Macpherson suspension system were optimized based on the particle swarm algorithm.(3)Based on the optimized design of the electric driving and braking electric wheel,the force analysis of the key parts of the electric wheel was carried out,under the deceleration belt road conditions and emergency braking conditions,the position and magnitude of the maximum load were determined.Based on ANSYS Workbench,structural statics analysis and modal analysis under assembly constraints were carried out.It was analyzed that the electric driving and braking electric wheel can work reliably and safely under various working conditions without structural damage and resonance.The situation,from the perspective of structural strength,had verified that the design of the electric driving and braking electric wheel meet the requirements.(4)Based on MATLAB/Simulink,the vibration model of the electric driving and braking electric wheel suspension system,the random road input model were built,the influence of the increase of unsprung mass on the ride comfort of the whole vehicle was analyzed.Three verification schemes have been developed,the effects of lightweight design of in-wheel motors and optimization of suspension stiffness and damping parameters on improving the ride comfort of the vehicle were analyzed from both the time domain and the frequency domain.From the perspective of vehicle ride comfort,it was verified that the design of the electric driving and braking electric wheel meet the requirements.(5)Based on the relevant test requirements for the power and braking performance of the electric driving and braking electric wheels in the national standard,a test bench for the performance test of the electric wheels was proposed.The test bench can simulate the driving of the actual vehicle on the road,for the wheel load transfer caused by acceleration,deceleration,the vertical load was applied by the dynamic and static loading device,so that the vertical force of the electric wheel on the test bench is close to the vertical force of the electric wheel when driving on the road.The performance test verifies whether the design of the electric driving and braking electric wheel meets the requirements.