Robust Hierarchical Trajectory Tracking Control For Self-driving Four-wheel Independent Drive Electric Vehicles

Autonomous driving is a high-level stage of intelligent vehicle intelligence,and trajectory tracking is the key technology to achieve autonomous driving.Four wheel independent drive electric vehicle(FWID EV)has the characteristics of high transmission efficiency and fast response speed due to their unique structure and driving method.The steer-by-wire provides a hardware basis for improving the security and manipulation stability of the FWID EV.Reasonable torque distribution is the key to ensuring the stability of the FWID EV.Therefore,this dissertation turns to the FWID EV trajectory tracking control and in-depth research on the FWID EV trajectory.The research content is as follows:According to the structure and working principles of the FWID EV system,the integrated trajectory tracking error model,horizontal dynamic model,and line control steering system dynamic model are considered to be established to turn the dynamic characteristics of the executive agency.The non-linear tire model is processed by boundary uncertainty,and the quasi linear parameter varying(LPV)model of the longitudinal speed and non-linear tire model is established when considering the consideration.For the uncertainty,system modeling error,and external disturbance of the FWID EV trajectory tracking the horizontal motion system,the LPV-based robust gain scheduling H_∞status feedback control and torque distribution strategy.First of all,according to the actual driving conditions requirement analysis,the variable parameter changing range is used,and the use of convex decomposition technology will be used to convert the quasi-LPV system into a polycase system combined with a limited polygon convex;In the design of the device,use the second D-stability to obtain a good transient response when the system is relatively small to control the energy;finally,the controller and the linear combination method of each polyphon are designed offline to calculate it.System controller parameters correspond to the variable parameter.The torque distribution layer design is based on the rules-based torque distribution strategy.Aiming at the uncertainty and control of the FWID EV trajectory tracking the horizontal motion system,the problem of driving stability and economic problems in driving stability and economic problems of FWID EV,the LPV-based robust H_∞dynamic output feedback control,and the torque optimization allocation strategy.The control layer design only uses the Modern FWID EV standard sensor measurement signal as the feedback signal-based robust H_∞dynamic output feedback controller.The torque distribution layer comprehensively considers the security and economy during the FWID EV driving process and designs a torque optimization allocation strategy based on economics and stability.Finally,a co-simulation platform is built based on MATLAB/Simulink and Car Sim.In the accelerated lane change scenario,the effectiveness,robustness,and advantages of the trajectory tracking strategy and torque distribution strategy designed in this dissertation are verified by simulation comparison with other control strategies.