Research on active safety control for heavy multi-axle vehicles under steering system failure

Heavy multi-axle vehicles with long bodies, large loads, and many steering axles are prone to one stuck axle with its steering system failed, which leads to a sharp drop in vehicle safety. Modulating the steering angles of the remaining non-faulty axles for compensation control can significantly improve the safety of the vehicle. Therefore, this paper proposes a method based on multi-axle steering compensation, which solves the large trajectory error, and instability of heavy multi-axle vehicles caused by the failure of one-axle steering system. Firstly, based on the Lyapunov method, and nonlinear model, the critical steering angle of the faulty axle leading to vehicle instability under the failure of one-axle steering system is clarified, which provides a quantitative index for vehicle stability evaluation. Then, a two-level controller is designed to maintain stability and reduce trajectory error of the faulty vehicle. The upper dual-input dual-output (DIDO) sliding mode controller (SMC) compensates for the faulty vehicle’s lateral force and yaw moment. And the lower controller distributes the non-faulty axles’ steering angles through a strategy considering tire workload and slip energy dissipation. Finally, a seven-axle vehicle model in the Trucksim and a Trucksim-Simulink co-simulation are used to verify the effectiveness of the proposed method. The results illustrate that the proposed method can maintain vehicle stability and reduce the lateral trajectory error by about 22%–91% in the failure of one-axle steering system. It proves that this method can provide a new scheme for active safety control of heavy multi-axle vehicles.