Research On Electronic Differential And Torque Distribution Control For In-wheel Motor Drive Electric Vehicle

Nowadays energy saving and environmental protection gradually became thedevelopment trend of automotive industry, the development importance ofEV(electric vehicle） is referred to a unprecedented height. In-wheel motor vehicleis an another way of the development of EV, along with the changing of electroniccontrol technology, In-wheel motor drive which has many advantages such as savingspace, brief structure, strong controllability gradually became the research key pointof research institute and automotive enterprise. At present, abroad and domesticresearch is increasing, and won many achievement, such as the US military SUVHummer which equipped with internal combustion engine will change to electric In-wheel drive. But there are many key technologies such as electric differential speedand torque distribution which didn`t make a breakthrough of development. The studyhave a depth research on electric differential speed and torque distribution of electricIn-wheel drive EV.Firstly, this study must confirm the research focus of electric In-wheel drivesystem. In-wheel Motor Drive Electric Vehicle thoroughly change the drive form,leave out the several device of powertrain, shorten the structure of mechanism andtransmission chain, abolish the mechanical connection between the steering wheeland drive wheel. As a result, the degree of freedoms of drive wheel is greatly morethan before, also brought some challenge and development space. Therefore motorcontrol is becoming the key point of overall vehicle control, the torque distributioncontrol of motor turn into the nodus of motor control. Around this topic, the studyhas a research on: Analyzing the difference of steering system between of traditionalvehicle and In-wheel Motor Drive Electric Vehicle, building the simulation model ofelectric differential, and also based on the torque distribution, having a depthresearch on electric differential system of In-wheel Motor Drive Electric Vehicle;Research on active safety system of traditional vehicle, based on traditional hydraulicbraking system, proposing a composite braking ABS scheme of motor and hydraulic.When the vehicle is losing the control of car body, comparing with the traditionalESP strategy which control the yaw moment by longitudinal braking torque, this study achieve a control strategy of active motor torque distribution. Throughcontrolling the drive torque of each In-wheel Motor Drive, realizing the stabilitycontrol of car body, and the control accuracy is better than traditional ESP; Based ontypical cycle condition NEDC and HYZEM-suburban, simulating the distribution ofbraking torque, and then giving a control strategy with high efficiency ofregenerative cobraking energy saving, The most difference between new strategy andtraditional strategy: In-wheel motor cover its whole braking torque to overall brakingtorque, the rest of braking torque demand is compensated by the hydraulic brakingtorque.Summarily, torque distribution control strategy which given by this study couldbe able to improve the longitudinal and lateral stability, and also offer a availableway for regenerative co-braking system of in-wheel motor.