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.