Intervention criterion and control strategy of active front steering system for emergency rescue vehicle

Abstract

Active front steering (AFS), as an effective active technology, can enhance the handling stability of the emergency rescue vehicle. In order to deal with the shortcomings of full AFS intervention for the vehicle, the intervention criterion and control strategy of AFS system for the emergency rescue vehicle are studied deeply. Based on the phase plane theory, the double-line and yaw rate methods are combined to construct the closed polygonal stable area of the vehicle. Depending on whether the vehicle status is outside the closed polygonal stable area, the AFS intervention criterion is proposed. Taking the yaw rate and the sideslip angle of the vehicle as the control targets, a sliding mode control (SMC) controller for the AFS system of the emergency rescue vehicle is designed based on the variable structure theory, and the extended Kalman filter (EKF) state observer is introduced to estimate the vehicle sideslip angle. Based on Matlab/Simulink software, the intervention criterion and control strategy of AFS system are simulated and analyzed. In addition, the self-developed fire rescue prototype vehicle is selected as the experimental vehicle, and the proposed AFS intervention criterion and control strategy is tested. The simulation and experimental results showed that the proposed AFS control strategy with the intervention criterion is reasonable and effective, and it improves the handling stability of the emergency rescue vehicle.