Research On Roll Stability Control Of Distributed Drive Electric Vehicle

The development of distributed drive electric vehicle can not only alleviate the pressure of resource shortage and environmental pollution,but also make it easier to realize active control of multiple dynamics due to its unique structural.After the elimination of transmission system and the introduction of hub motor,the torque of each wheel can be adjusted independently.The rollover safety of vehicle has always been a hot issue in the field of automobile research.In all traffic accidents,the harm degree of vehicle rollover accident is second only to collision accident,which seriously threatens the safety of human life and property.Therefore,researching the rollover stability of distributed drive electric vehicle in the view of its special structure is the basis and premise of the effective anti-rollover control of this kind of vehicle.It is of great significance to improve the driving safety of this kind of vehicle.In this paper,the distributed drive electric vehicle is taken as the research object to study its roll stability.The main research contents are as follows:(1)The three degree of freedom vehicle model of distributed drive electric vehicle is established.It can reflect main the roll moments of the vehicle when the roll occurs,including the centrifugal moments caused by the excessive lateral acceleration,the roll moments caused by the center of gravity deviation and the roll moments caused by the suspension restraint.For the distributed drive electric vehicle,the roll moment exerted by the suspension to the body includes the influence of the motor reaction moment,which is different from the traditional vehicle.According to the active control of the wheel drive moment,the additional roll moment can be adjusted,so as to achieve the control effect similar to the active suspension and maintain the roll stability of the vehicle.(2)According to the characteristics of the research on the roll stability of the distributed drive electric vehicle,the 18 DOF vehicle dynamics model is established,including the body model,suspension model,motor model,wheel motion model,tire model and brake system model.The model can reflect the additional roll moment of the distributed drive electric vehicle caused by the motor reaction torque on the body.And the simulation of the whole vehicle model in the comparison of Carsim is carried out.The results show that the 18 DOF vehicle model established in this paper can basically reflect the dynamic characteristics of vehicle.(3)In view of the additional roll moment of the distributed drive electric vehicle,the roll and yaw decoupling control strategy is proposed.The yaw stability controller and roll stability controller are designed respectively based on LQR control theory and synovium control theory.And torque distribution control strategy is applied by distributing Compensated yaw moment and roll moment.Finally,the typical simulation verification is carried out and the simulation results show that the anti-roll control strategy proposed in this paper is effective and feasible.(4)In view of the maneuverable rollover caused by excessive lateral acceleration,the anti-rollover control strategy based on differential braking is proposed.By applying braking torque to the front outer wheel,the target of slowing down and changing the steering characteristics of the vehicle is achieved.The simulation verification of typical driving conditions is carried out with the lateral load transfer rate as the main evaluation index.The results show that the anti-rollover control strategy based on differential braking is effective and feasible in view of the distributed drive electric vehicle.