Multimodal Cross-Domain Motion of Terrestrial-Aerial Amphibious Robots: Planning, Control, and Experiments

Terrestrial-aerial amphibious robots (TAARs), due to their flexibility, efficiency, and strong adaptability, are widely applied in practical engineering. However, the multidimensional, staged motion, and transitions between different modals pose significant challenges to the cross-domain motion planning of TAARs. In addition, TAARs integrating both terrestrial and aerial motion systems, characterized by complex nonlinearity, strong coupling, and uncertainties, present difficulties in achieving stable and precise control. To address these issues, this article proposes a multimodal cross-domain motion planning and control method. Specifically, an energy-optimal cross-domain obstacle avoidance planning scheme is first proposed to generate a path, which aligns with the characteristics of TAARs and ensures fast convergence. Then, a smooth modal-switching control scheme is proposed to ensure the stability and safety of the modal-switching process during aerial operation. In addition, a trajectory tracking control method is developed to improve tracking performance. Based on this, the nonlinear uncertain term is described through a fuzzy logic system and approximated by the proposed update law. The asymptotic stability of closed-loop systems is proven by Lyapunov methods. As far as we know, this is the first time that the precise modal-switching control of TAARs has been achieved, with stability guaranteed through strict theoretical analysis. Finally, the effectiveness of the aforementioned methods is validated by experiments on the self-built experimental platform.