Tire Force And Vehicle Driving State Integrated Estimation Of Four-wheel-independent-driven Electric Vehicle

To cope with the challenge of energy crisis and environmental pollution, maintaining the human sustainable development, the electric vehicle has become a hot spot of global automotive industry research. Among them, the four-wheel independent drive(4WID) electric vehicle are regarded as the future development direction for its many potential and advantages.Drive structure leading to improvements in control degrees of freedom, 4WID electric vehicle is potential in active safety control system.Obtaining current state of the vehicle accurately is the premise of active safety control system. However, on-board sensors of directly measuring vehicle state information are extremely expensive and the signal is strongly influenced by the environment. Therefore, how to accurately estimate vehicle state information which is not easy to measure by the low-cost real-time sensor is the key issues of 4WID electric vehicle in stability control system.In this paper, a variety of state theories and methods are adopted to realize the 4WID electric vehicle integration observation of important status information. The main research work is as follows:Firstly, the development status and technical characteristics of 4WID electric vehicle are introduced. Then, research status and significance about vehicle state observation at home and abroad are described. In addition, mathematical model of 4WID electric vehicle is deduced.The connection relationship between body dynamics and tire model is analyzed. 7DOF vehicle simulation model based on "magic" tires is built and the results are verified by Car Sim vehicle dynamics simulation software. All above lay a foundation for integrating state observation.Secondly, tire longitudinal force observer is designed based on the characteristics of4 WID electric vehicle that the wheel rotation speed and torque of the motor is easy to obtain.The tire lateral force observer and longitudinal velocity observer are built based on random kalman filter algorithm and kalman filter algorithm respectively using low-cost on-board sensors. Moreover, A side-slip angle observer based on neural network left inverse by observations of tire force and the longitudinal velocity is constructed. Then, the integrationstate parameter observer is implemented and the simulations are carried out under the different conditions.Finally, software and hardware test platform for 4WID electric vehicle are constructed,then the feasibility of the tire lateral force observer and longitudinal velocity observer is verified based on hardware-in-the-loop simulation system DS1103. Both the simulation and experimental results show that the integration state observer has a good effect on the linear or nonlinear conditions.