Skating motion analysis of the amphibious quadruped mother robot

Biomimetic underwater robots are of great interest for underwater monitoring operations, such as pollution detection and video mapping. However, in some restricted underwater environments, regular sized robots are not suitable for real applications. Therefore, we designed several novel types of bio-inspired microrobots, using ionic polymer metal composite (IPMC) and shape memory alloy (SMA) actuators. These microrobots possess some attributes of compact structure, multi-functionality, flexibility, and precise positioning. However, for real-world applications, they lacked the attributes of long endurance, high stable speed, and large load capacity. To implement these characteristics, we proposed a mother-son robot system, which includes several microrobots as sons and a newly designed amphibious spherical robot as the mother. Inspired by the amphibious turtle, the mother robot was designed with a spherical body and four legs. It was actuated by four water-jet propellers and ten servomotors, capable of walking motion on land and three directional moving motions in the underwater environment. We developed a prototype of the amphibious spherical robot and evaluated its walking and swimming motions experimentally. To improve the walking velocity on level or comparatively smooth terrain, we added four passive wheels on four legs with lightweight. The skating trajectory was investigated to implement high terrain adaptability of the mother robot.