Design And Control Of Wheel Motor Drive With Large Steering Angle

In recent years,with the development of the economy,electric vehicles have become an important development direction of the automobile industry,and have received extensive attention from the global automotive industry.As a kind of new energy vehicle,electric vehicles not only show great advantages in energy saving and environmental protection,but also have the advantages of fast torque response and fast acceleration.Therefore,people start to require stability and mobility for electric vehicles.The requirements are also gradually increasing.At present,the car in the form of wheel/hub motor drive can best reflect the superiority of electric vehicle compared with traditional internal combustion engine,including the advantages of high energy utilization and environmental friendliness.However,due to the large size and mass of the wheel motor,it is currently mainly used in large and medium-sized vehicles.Therefore,designing a wheel-drive system that can be applied to and mini-cars improves the diversity of electric vehicles and is conducive to the development of the electric vehicle market.Turning maneuverability is one of the indicators of automobile agility.It has become an important reference indicator of automobile performance over time.At present,the maximum corner of the model wheels on the market generally does not exceed 40 degrees,and the turning maneuverability The outstanding smart model has a minimum turning radius of 6.95 meters,which improves the turning angle of the electric vehicle's steering system,which can improve the turning maneuverability of the electric vehicle,so that the electric vehicle has the characteristics of quick turning and flexibility,which is also an important development direction of the electric vehicle.The main research contents of this paper are as follows:Investigate the types and development status of current electric vehicle drive forms,and analyze the advantages and disadvantages of the wheel drive system.The current form of wheel-side drive is the wheeldrive bridge,and the application environment is mainly for large and medium-sized vehicles.Therefore,designing a wheel-side drive system for mini-cars has certain practical significance and commercial value.Conducted research and analysis of current mainstream steering technologies,including EPS,AFS,AIFS and SBW.Finally,the advantages and disadvantages of various steering technologies were finally obtained.Finally,it was decided to design a steering system that can meet the independent steering of the left and right wheels,and it is proposed to drive by means of wire-controlled steering.Based on the above conclusions and the existing electric vehicle structure,with reference to the vehicle parameters of the existing smart models,a wheel-side drive system is designed with the aid of the dynamic analysis software ADAMS\Car,and the parameters are optimized to satisfy the suspension in the structural design.Kinematic related parameters,and the wheel angle is greater than the limit angle of the traditional car.For the hard point parameters of the built wheel drive system,construct the solid three-dimensional structure,and perform the motion mechanism simulation to ensure the wheel interference and the steering condition,there is no motion interference between the internal parts of the wheel.According to the force under the extreme working conditions of the car,the finite element analysis of the relevant parts is carried out to verify that the strength of the parts is sufficient.According to the magic formula,the tire model is built.The steering control algorithm is built by Matlab/Simulink software.The final result shows that the steering wheel output torque is applied to the wheel and the wheel angle is close to the theoretical value,and the response time meets the national standard.Requirements for steering mechanismsThe model of the whole vehicle is built by Adams software and the previously designed suspension and steering hard point parameters,and the steady-state rotation simulation experiment is run according to the national standard test conditions editing event,and the output result is processed by data and compared with the national standard.Comparing,it is found that the built-in wheel drive system score value meets the national requirements.