On a Bio-inspired Amphibious Robot Capable of Multimodal Motion

This paper addresses the system design and locomotion control for a versatile amphibious robot, AmphiRobot-II, inspired by various amphibian principles in the animal kingdom. In terms of the propulsion features of existing amphibians, a novel hybrid propulsive mechanism coupled with wheel-propeller-fin movements is proposed that integrates fish- or dolphin-like swimming and wheel-based crawling. The robot is able not only to implement flexible wheel-based movements on land, but also to perform steady and efficient fish- or dolphin-like swimming under water and can further switch between these two patterns via a specialized swivel device. To achieve multimodal motions, a body deformation steering approach is proposed for the turning locomotion on land with minimum turning radius obtained accordingly. A central pattern generator inspired underwater locomotion control is also implemented and tested on the physical robot. Based on the aforementioned design, the AmphiRobot-II prototype has been built and has successfully demonstrated to confirm the effectiveness of the hybrid propulsive scheme and the amphibious control approaches.