Research On Stability Control And Energy Consumption Optimization Strategy Of Hub Motor-driven Vehicle

In recent years,people in various countries have paid more attention to environmental protection issues year by year.At the same time,countries have formulated increasingly stringent emission standards,which has enabled the rapid development of electric vehicles.The research object of the article is a four-wheel drive electric vehicle with in-wheel motors.The four power units are independent and accurately controllable,which is of great significance to improving the handling stability and economy of electric vehicles.The article aims to improve vehicle driving stability and energy consumption optimization,and studies the stability control and energy consumption optimization strategies of four-wheel in-wheel motor-driven electric vehicles.First,based on the main analyzation of main control objectives,a three-degree-of-freedom vehicle reference model for obtaining control reference values is established by simplifying the six-degree-of-freedom vehicle theoretical model.For the research object,a four-wheel hub motor-driven vehicle model was established through software joint modeling.Secondly,the main influencing factors of stability control and energy consumption optimization are analyzed.In terms of stability control,the relationship between the stability of the vehicle and the yaw rate and the slip angle is analyzed,and the phase plane of the center of mass slip angle is determined as the basis for determining stability;in terms of energy consumption optimization,the wheel hub motor drive is analyzed.The main energy loss sources of automobiles,and a model of the main energy loss sources hub motor energy consumption and tire slip loss has been established.Based on the above analysis,the hierarchical control structure of stability and energy consumption optimization control is determined.Then a speed tracking controller based on PID control algorithm is established to determine the generalized longitudinal moment.The stability boundary of the phase plane under different conditions is discussed.On this basis,the sliding mode control is designed for the yaw rate and the center of mass side slip angle error.The control mode is switched based on the stable phase plane state,the results of the sliding mode controller are weighted to obtain the additional yaw moment,and the generalized yaw moment is further obtained,completing the establishment of the upper-level controller.Then,a lower-level control model based on solving the torque optimal distribution problem is established.The optimization goals are motor energy consumption,tire slip loss,and tire margin.The generalized torque obtained by the upper-level controller is an equation constraint.Taking the motor energy limit and attachment conditions as inequality constraints,the optimization problem is solved by the NSGA-II algorithm,and the optimal torque distribution scheme is obtained,and the establishment of the lower-level controller is completed.Finally,based on the four-wheel hub motor-driven vehicle model and the controller model,a combined simulation platform was established.Through the simulation of the sinusoidal input working condition and the double-shifting working condition,the effectiveness of the upper-level stability controller was verified.Condition simulation verifies the energy consumption optimization effect of the lower-level controller.And through the in-wheel motor experiment platform to carry out simulation tests,further verify the energy consumption optimization effect of the control strategy.