Research on Control Strategies for High Center of Gravity, High Curvature 4WS Vehicles on Non-Rigid Pavements

Abstract Autonomous driving technology is not only widely used for open vehicles on municipal roads but also for special equipment in low-speed scenarios such as logistics distribution, sanitation cleaning, sightseeing shuttles, and smart farming. However, in the unique scenarios of farmland and the special structure of unmanned agricultural machinery, autonomous vehicles still face complex control issues such as high curvature steering, non-rigid road surfaces, and high centers of gravity, which severely affect the tracking and stability performance of the vehicles. To address these problems, this paper proposes a path tracking stability control strategy that considers the tracking performance of vehicles during high curvature steering at medium and low speeds, as well as the impact on vehicle stability caused by vehicle tilting due to a high center of gravity and the tendency of vehicles to sink in farmland scenarios. By integrating the Model Predictive Control (MPC) algorithm and improving the fuzzy control algorithm, a 4WS vehicle kinematic model and a lateral stability model under non-rigid road conditions were established. A comprehensive control method that considers vehicle stability and turning path tracking accuracy was proposed. Simulation comparisons using Simulink show that the 4WS vehicle control strategy proposed in this paper has better tracking performance and stability compared to traditional 2W tracking control methods. Experiments conducted on an intelligent driving soil sampling vehicle validated the advantages of the proposed control strategy in terms of high center of gravity, high curvature steering control accuracy, and stability.