An improved robotic arm constant force control method for forward terrain sensing system on planetary rovers

The traversability of the terrain ahead of planetary rovers significantly impacts the success of their extraterrestrial exploration missions. Accurate perception of the terrain force through a forward wheel-on-limb detection system can provide crucial data for assessing the traversability of the terrain ahead. Existing constant force control methods, largely based on static terra mechanics models, struggle to meet the operational needs of planetary rovers in unknown environments. To address this issue, this paper proposes an improved adaptive impedance control method for robotic arms in unknown soft terrain. First, a dynamic soft terrain model is established to simulate the unknown soft terrain environment. Based on this model, an improved adaptive impedance control method is designed, and its stability is rigorously proven. The proposed method is then comprehensively validated through simulation experiments, hardware-in-the-loop tests, and experiments using a planetary rover model in flat, inclined, and curved terrain scenarios. Experimental results demonstrate the effectiveness of the designed adaptive impedance control method.