Research Of The Integrate Control On Vehicle Longitude Force And Lateral Force

Vehicle stability receives more and more attention from users as the driving speed of the vehicle become increasingly higher in modern vehicle. And there exist lots of control subsystems in vehicle chassis stability control field, but the functions of many subsystems may same or have conflicts between then. So, when all of these subsystems were equipped on the vehicle, it may not exert the performance of these subsystems and it is a way of waste. As the longitude force and lateral force of each tire can be controlled independently on the vehicle which steering and braking/driving independently for four wheels, there exist huge potential to improve vehicle stability. This paper conducts a integrate control of the longitude force and lateral force of each tire research that is aim to enhance the driving stability of the vehicle which can steering, braking/driving independently for each tire.This paper applied CarSim to have virtual tests for the tire to get the slip data and corner data of the tire. Then obtained tire’s pure slip, pure corner, combine slip with corner force characteristic of the tire through analysis these tire data and fitting a four-dimension inverse tire model based on tire data which was obtained through virtual tire test. On the other hand, combining the tire force characters with functions of subsystems among vehicle stability control system to analysis the coupling and conflicting between control subsystems among vehicle stability control system, and it can provide a theory basis for vehicle stability integrate control strategy.This paper propose a control strategy that integrate control the longitude force and lateral force of the vehicle which can steering, braking/driving independently for each wheel. Set the ideal vehicle model’s outputs which were based on driver’s input as the control target, and figures out the errors between control target and actual output of vehicle, then adopts the errors as input and figured by sliding mode to figure out how much total longitude force, total lateral force and yaw moment should supplied to vehicle. And allocates the total longitude force, total lateral force, yaw moment of vehicle to each tire through an optimal allocation method which has considered tire force constraint factors, then we can know we should supply how much longitude force and lateral force to each tire. At last figure out each tire’s slip rate and slip angle through tire inverse model, and control the steering and braking/driving with PID control which were set the slip rate and slip angle as the feedback.The integrate control of longitude force and lateral force has been validated thorough many simulation conditions in this paper. And the result shows that:the integrate control strategy can keep vehicle driving according to driver’s willing, and always maintain the vehicle slip angle is zero, the yaw rate is driver’s expect value.