Fractional order sliding model control of active four-wheel steering vehicles

Considering that the vehicle state error derives from the different initial states and parameters between the real vehicle model and the reference model, fractional sliding model control is proposed for the active four-wheel steering vehicle. Optimal control is adopted to design the sliding mode in order to eliminate the state error caused by the different initial states. On this basis, fractional sliding mode control is designed to eliminate the state error caused by the different parameters. And the simulation results show that the fractional sliding mode control can make the 4WS to track the reference model very quickly, although the parameters between the 4WS and the reference model mismatch. And the conclusion can be drawn that the fractional sliding mode control is effective.