Research On Longitudinal Velocity Tracking Control For Electric Vehicle

The surge of car ownership, the severity of energy crisis, the deterioration ofenvironmental pollution and the development of science of technology make intelligenttransportation system the trend of transportation system in the future. Meanwhile, newenergy vehicles are paid more attention due to their excellent environment-friendlyproperty. As one of the key technologies in the intelligent transportation system,longitudinal velocity tracking control has important research value. This paper selectspure electric vehicles as research object, analyzes and discusses the implementationissues of longitudinal velocity tracking control on them.On the basis of constructing the longitudinal velocity tracking control systemmodel, this paper designs controller using model predictive control method, and finallycompletes software and hardware implementations of longitudinal velocity trackingcontrol.In the process of model construction, this paper completes construction work ofvehicle longitudinal dynamics model, motor system model and drivetrain system modelrespectively, simplifies the model under appropriate assumptions, and finally confirmsthe accuracy of these models by using precise comprehensive software for real-timesimulation of vehicle dynamics veDYNA.In the process of controller design, longitudinal velocity tracking control is viewedas a nonlinear control issue with time-varying constraints. Therefore, the paper employsmodel predictive control method in designing the on-line controller, and completes aseries of simulations under multiple scenarios in order to verify its effectiveness. Sinceon-line controller cannot be implemented in the practical vehicles, the paper adoptsmodel predictive control method again to designs explicit controller by the aid ofMatlab multiple parameters toolbox (MPT). The simulation results show that theindividual explicit controller has excellent control performance. However, it reliesheavily on the parameter of front vehicle’s acceleration, which results in its poor robustperformance. In order to solve the problem of individual explicit controller with poorrobust performance, the paper designs multiple explicit controllers for multiple frontvehicle’s acceleration values respectively, chooses appropriate controller by judging therange of the front vehicle’s acceleration.Finally, this paper presents the hardware design and software design solutions forlongitudinal velocity tracking controller, completes the hardware circuit schematic andPCB design, and accomplishes the design and debug of related software.