Design, Dynamic Modeling, and Motion Analysis of a Frog-Inspired Hybrid-Driven Amphibious Robot

To improve the amphibious locomotion capability of robots in aquatic and terrestrial environments, this paper proposes a novel frog-inspired hybrid-driven amphibious robot inspired by the amphibious locomotion characteristics of frogs. Unlike existing frog-inspired robots limited to single-mode jumping or swimming, this robot adopts an innovative hybrid actuation mechanism to simultaneously achieve frog-like swimming and jumping capabilities. On land, it uses a combustion-driven hindlimb propulsion mechanism paired with a linkage-based forelimb posture adjustment mechanism to realize frog-like jumping; in water, it employs a cable-driven linked hindlimb mechanism combined with a controllable soft extension-driven webbed foot to accomplish frog-like swimming. Furthermore, the instantaneous combustion thrust during frog-like jumping and the hydrodynamic thrust during swimming are calculated. The mapping relationships between the take-off attitude angle, hydrogen-oxygen mixture charge, and jumping performance, as well as the motion pattern between hindlimb motion parameters and swimming thrust, are derived. Finally, experimental results demonstrate that the robot achieves a swimming speed of 79 mm/s, a jumping height of 560 mm, and a jumping distance of 1200 mm, while being capable of performing continuous amphibious locomotion.