The AmphiSTAR high speed amphibious sprawl tuned robot: Design and experiments

This paper details the development, modeling and performance of AmphiSTAR, a novel high-speed amphibious robot. The palm size AmphiSTAR, which belongs to the family of STAR robots, is a "wheeled"robot fitted with propellers at its bottom that allow it to crawl on the ground and run (i.e. hover) on water at high speeds. The AmphiSTAR is inspired by two members of the animal kingdom. It possesses a sprawling mechanism inspired by cockroaches, and it is designed to run on water at high speeds like the Basilisk lizard. We start by presenting the mechanical design of the robot and its control system. Then we model AmphiSTAR when crawling, swimming and running on water. We then report experiments on the robot to measure its lift and thrust forces in its on-water running mode and evaluate its energy consumption. The results show that in the on-water running mode, the lift forces are a function of the work volume of the propellers whereas the thrust forces are a linear function of the propellers' rotating speed. Based on these results, the final version of the 3D printed robot was built and experimentally tested in multiple scenarios. The experimental robot can crawl over the ground with performances similar to the original STAR robot and can attain speeds of 3.6 m/s. The robot can run continuously on water surfaces at speeds of 1.5 m/s. It can also swim (i.e. float while advancing by rotating its propellers) at low speeds and transition from swimming to crawling (see video).