Fractional-order PIλDμ control and optimization for vehicle active steering

Active steering is a newly developed technology for passenger cars to enhance vehicle stability and handling performance. A fractional-order PI^lambdaD^mu control strategy is applied on active steering vehicle based on a multi-body vehicle dynamic model in this paper and the active control is expressed as a sum of PI^lambda and PD^mu control. The multi-body vehicle dynamic model using ADAMS can accurately predict the dynamic performance of the vehicle. A new hybrid steering scheme including both active front steering (applying an additional front steering angle besides the driver input) and rear steering is presented to control both yaw velocity and sideslip angle. The parameters of the controller were optimized by a genetic algorithm (GA) and it can adjust both sideslip angle and yaw velocity through the co-simulation between the ADAMS multi-body vehicle dynamic model and Matlab. The co-simulation scenario takes place at high speed with a single-sine steering angle input to validate the effectiveness of active steering system. Simulation result shows that active steering vehicle with fractional-order PI^lambdaD^mu control logic strategy can enhance vehicle stability and handling greatly comparing with classical PID controller and traditional front wheel steering vehicle.