Energy Conversion And Control Of Spatial Instability Of Electric Wheel Drive Vehicle On An Uneven Road

The torque and speed of each driving wheel of In-wheel Motor Vehicles?IWMVs?can be adjusted independently,which makes it have excellent dynamic control capabilities such as anti-skip control of driving/braking,active yaw control,differential power steering and body motion attitude control.However,the unspring mass of IWMVs is increased a lot,which results in deterioration of vehicle handling stability,especially under the excitation of uneven road.In order to improve spatial stability of IWMEVs,a multi-objective optimization based on suspension system and chassis coordinated control strategy based on energy method are proposed,which significantly improves dynamics performance of IWMVs.The main contents of this paper is organized as follows:?1?Based on the structural characteristics of the electric wheels,the front and rear suspension system and steering system for the electric wheel drive vehicle are designed,and the virtual prototype assembly is completed.The dynamic model of the vehicle is built in Adams/Car.A prototype electric wheel drive test vehicle was developed and the correctness of the model was verified.?2?Using design of experience?DOE?method,the influences of the structural parameters of the front double pivot suspension and the rear double wishbone suspension are analyzed respectively,and the structural comprehensive contribution coefficient of the suspension parameters is obtained based on the entropy method.The vehicle dynamics model is built,and combines the 2^nd non-dominated genetic algorithm to optimize the parameters that have a great influence on the handing stability to improve the vehicle dynamics.Determine the structural scheme of the front and rear suspension systems,and the optimization effect was verified by simulation and test.?3?According to the structural characteristics of IWMVs,the equations of the kinetic energy,potential energy and dissipated energy in uneven roads are derived.The 18 degree of freedom?DOF?of the vehicle is obtained based on the Lagrange equation and the accuracy of the model is verified.The energy conversion mechanism of vehicle in uneven roads is described and verified.By calculating the vehicle real-time energy reserve and the vehicle instability threshold,a comprehensive multi-factor vehicle stability evaluation index is proposed.?4?The control strategy of spatial stability of IWMVs on uneven road is formulated.With the differential drive and active suspension systems,the coordinated control of yaw motion and roll motion stability is realized.The effectiveness of the control strategy is verified by MATLAB/Simulink.Based on the combination of structural optimization of vehicle suspension system and chassis coordinated control,this paper completes the optimization of handling stability of IWMVs,as well as the space stability control under uneven road,which has theoretical reference value and engineering application significance for related research.