A Torque Distribution Strategy for the Six-Wheeled Lunar Rover

As a crucial tool for lunar exploration, lunar rovers are highly susceptible to instability due to the rough lunar terrain, making control of driving stability essential during operation. This paper focuses on a six-wheel lunar rover and develops a torque distribution strategy to improve vehicle handling stability. Based on a layered control structure, firstly, the strategy establishes a two-degree-of-freedom single-track model with front and rear axle steering at the state reference layer to compute the ideal yaw rate and center of gravity side slip angle. In the desired torque decision layer, a sliding mode control-based strategy is used to calculate the desired total driving torque. In the torque distribution layer, optimal control allocation is employed to maximize tire stability margins. Finally, a multi-body dynamics model of the six-wheel lunar rover is built using the open-source multi-physics simulation engine Chrono, exploring its dynamic behavior on soft terrain. Various operating scenarios are tested to verify the effectiveness, reliability, and safety of the designed control strategy. This research provides a reference for the design and control of lunar rovers in future lunar exploration missions. It offers guidance for the design and motion control of extraterrestrial planetary surface exploration vehicles.