Study On Yaw Moment Control And Torque Distribution For Distributed Drive Electric Vehicles

Under the pressure of limited energy and increasing environmental pollution problems,it is believed that developing electric vehicles (EVs) can effectively mitigate thisphenomenon. Therefore, all countries in the world are actively involved in research on EVs,and committed to its promotion to the market. The distributed drive EVs are valued bynational research scholars and become a hot topic due to its special structure andperformance characteristics. Distributed drive EVs and conventional cars have greatdifferences in the structure. For distributed drive EVs, traditional internal combustion engineand transmission systems were substituted by motor battery system. Each wheel can becontrolled independently, so the handling and stability dynamics in motion of the distributeddrive EVs are different from the conventional vehicles. And it is necessary to study thestability control problems in the process of moving. This paper aims to research on yawstability control and torque distribution problem, which based on the characteristics of thedistributed drive EV.This paper selects four in-wheel motor to drive each wheel, and builds vehicledynamics modeling. Through the various subsystems of the vehicle modular modeling, itincludes body dynamic model, UniTire tire model, the wheel dynamic model, driver model,hub motor model. Then we integrate these subsystems integration for distributed simulationplatform to EV.And then this paper used a hierarchical control architecture system to develop controlsystem. It is divided into upper motion controller and lower control distributor. Enter theupper controller for vehicles in the process of state parameters. Therefore, it is essential toacquire the real time status of the vehicle parameters on the vehicle stability control, When the vehicle in the process of driving. However, some parameters of the vehicle are not easyto be directly measured, so we need an accurate estimate of the vehicle state parameters.This paper develops reduced-order sliding mode observer to estimate the state of the vehiclein real time accurately. And the results show that the proposed development of reduced-ordersliding mode observer is able to achieve the desired effect estimate.Then starting from the analysis of the controllability of the vehicle systems, this paperanalyzes the relationship between the state and the driving stability of the vehicle. Thesideslip angle was seen as the control target. Through controlling the vehicle sideslip angle,we expected it can follow two degrees of freedom linear vehicle model. In the uppercontroller, the desired yaw moment is calculated through dynamic surface control. In thelower controller, through the optimized allocation algorithm, the desired yaw moment isoptimally allocated to each motor actuator in some constraints. Driving or braking torque ofeach motor is applied to each hub motor. That completed the optimal all-wheel torquedistribution. As a result, the distributed drive EV can keep driving stability. The simulationresults show that this double-layered development of distributed control systems for electricvehicle driving stability control has a good effect.Finally, building the driver-in-loop real-time simulation platform to test upper controlalgorithm. The results show that the DSCDYC system has a good effect on vehicle forimproving the handling and stability when the distributed drive EV on complex conditions.