NMPC-based Path Tracking Control Strategy for 4WID Autonomous Vehicle Considering Handling Stability Under Extreme Conditions

Path tracking for autonomous vehicles may encounter vehicle stability problem under extreme conditions. To tackle this challenge, this paper proposes a control strategy considering the path tracking and handling stability comprehensively. An NMPC controller is designed for path tracking, in which the tire vertical load transfer is taken into consideration to reduce model mismatch. Orthogonal collocation discretization method is adopted to enhance the solving of NMPC problem. In the stability controller, active rear-wheel steering is applied to avoid the excessive increase of sideslip angle of vehicle and ensure handling stability. The proposed controller is verified in a high-speed and low-adhesion road scene by CarSim/Simulink co-simulation. The results demonstrate the effectiveness of the proposed controller in enhancing path tracking performance and maintaining handling stability even under extreme conditions.