The Coordinated Control Of Active Front Steering And Active Anti-roll Bar For Vehicle

The steering system and the suspension system are important systems of the vehicle.The curve traveling can be realized by the steering system to ensure that the vehicle can be driven according to driver's intention;the force or torque between body and wheels can be transferred by the suspension system to ease the attack of the road.The performance of them directly influences the handling stability,safety and ride performance of vehicle.Recent years,active anti-roll bar control(ARC)and active front steering(AFS)control are all new control syste ms of suspension system and steering system respectively.The roll angle and roll rate can be reduced by the roll torque of active anti-roll bar improving the performance of comfort and safety;steering ratio can be changed in real time by the active front steering system improving the performance of handling stability.The integrated control of suspension system and steering system is an important research direction of the vehicle chassis integrated control;this paper conducts a research about the integrated coordinated control of suspension system and steering system.Firstly,the active anti-roll bar model,vehicle model of 9-DOF and nonlinear tire model are built in the Matlab/Simulink software,the Carsim software is used to test the vehicle model of 9-DOF in this paper.Secondly,considering the roll angle and roll rate are not measured easily,the Kalman filter theory is introduced in this paper,and the Runge-Kutta method is also introduced to discrete the state equation,the roll angle and roll rate are estimated respectively using the unscented Kalman filter algorithm under the two condition: low speed and high speed,the simulation results show the effectiveness of the state estimation method.Additionally,the vehicle roll model and 2-DOF vehicle linear model are built in this paper to design the active roll controller and active yaw controller,and the sliding model control theory is introduced in this paper.The active roll controller and active yaw controller are designed and simulated in the Matlab/Simulink software respectively based on the vehicle roll model and 2-DOF vehicle linear model,using the sliding model control theory,the results show that the accuracy of the active roll controller and active yaw controller.Finally,the influences between the active front steering system and active anti-roll bar system are expounded,the coordinated controller is designed and simulated in Matlab/Simulink software based on the estimated roll angle and estimated roll rate,considering that the lateral acceleration is influenced by the roll and yaw of vehicle,and the results show that the effectiveness of the coordinated controller.