Study Of Model Predictive Control Method On Electric Vehicle’s Regenerative Braking Process

Safety and environmental protection is key development direction and hot topicsin research field of nowadays automobile industry. More pressure was put ontransportation, resource and environment with the increasing of automobile productionand ownership. In recent years, electric vehicle (EV) has been the focus of globalautomobile industry under the pressure of resource and environment. EV with in-wheelmotor (IWM) drive shows vast potential of development with less structure and higherefficiency. In addition, driving and braking on each wheel could be controlledrespectively, and this makes IWM electric vehicle an ideal object for modern controltechnology development and better dynamics performance and fuel economyexploration.In the past, most research on braking process was based on linearized model, butnonlinear properties exist in each subsystem of vehicle and there are strong-coupledcharacteristics among several subsystems. With the development of modern automobile,higher and higher requirement of driving and energy saving makes it difficult to ensurevehicle’s performance with linear model. To reach the target of accuracy control andenergy optimization of vehicle a nonlinear and coupled system, better nonlinearcontrol method should be built with higher accuracy and faster operating speed.For the braking process of IWM electric vehicle, a nonlinear control strategy wasproposed for the goal of ensuring vehicle’s stability, improving control accuracy andRB efficiency. A series of work including model establishing, nonlinear propertiesanalysis, and control method improvement and simulation platform development weredone for the goal which could be summarized as follows:Model Building. Models involved with the RB process were established includingwheel model, motor model and suspension model. Full vehicle models were built forseveral control targets.Based on the IMW electric vehicle, nonlinear properties in each subsystem andcoupling properties among them were analyzed to obtain the principle of vehicle’sstability.For the fast nonlinear system, a control method based on nonlinear modelpredictive control (NMPC) was proposed for the control targets and higher operatingspeed. A controller based on the proposed control method was built for the RB process ofIMW electric vehicle. Optimal interval of weights on each goal were discussed bycertain RB processes to verify the rationality and feasibility of the control method.