Energy-saving and stability-enhancing control for unmanned distributed drive electric plant protection vehicle based on active torque distribution

The distributed drive electric plant protection vehicle (DDEPPV), equipped with a unique four-wheel independent drive system, demonstrates excellent path-tracking capability and dynamic performance in agricultural environments. However, during actual field operations, issues such as severe tire slip, poor driving stability, high rollover risk, and excessive energy consumption often arise due to improper torque distribution. This study proposes an energy-efficient and stability-enhancing control method based on active torque distribution, aiming to improve both operational safety and system efficiency. A hierarchical control architecture is adopted: the upper-level controller employs a nonlinear model predictive control (NMPC) to achieve coordinated control of steering and yaw moment, enhancing lateral stability and ensuring operational safety. The lower-level controller implements a direct torque allocation method based on an adaptive-weight multi-objective twin delayed deep deterministic policy gradient (AW-MO-TD3) algorithm, enabling joint optimization of tire slip ratio and energy consumption. Real-vehicle tests were conducted under two typical field conditions, and the results show that compared with conventional methods, the proposed strategy significantly improves key performance metrics including tracking accuracy, vehicle stability, and energy efficiency. Specifically, stability was enhanced by 29.1 % and 41.4 %, while energy consumption was reduced by 19.8 % and 21.1 % under dry plowed terrain and muddy rice field conditions, respectively. This research provides technical support for the intelligent control of distributed drive electric agricultural vehicles. • A hierarchical control strategy is proposed for unmanned distributed drive electric plant protection vehicle systems. • NMPC ensures lateral stability via coordinated steering and yaw control. • TD3-based torque allocation optimizes slip ratio and energy efficiency. • Field tests show improvements in stability (↑41.4 %) and energy use (↓21 %).