Design and Optimization of a Multimode Amphibious Robot With Propeller-Leg

This article describes the design, optimization, and performance evaluation of a novel multimode motion robot named SHOALBOT, which with multimode operations depends on only one type of propulsion device and can work flexibly in the amphibious environment including running on beaches, grasslands, seabed, and swimming in the water. Robots that work in water need to minimize the number of drive components to improve reliability and reduce communication pressure, our unique design enables the robot to rely on a kind of propulsion device named propeller-leg to have the ability to run rapidly in the seaside and seabed, and swim with multi-degrees-of-freedom in the water (such a propulsion system contains only four driving elements), and it can make the robot complete more work content and improve its adaptability to the environment. Running is more stable than swimming and will not disturb the animals in the water, but when the robot encounters a high obstacle with a large area coverage, switching the motion mode to the swimming mode can pass directly over obstacles instead of detouring or giving up work, this can improve work efficiency. We analyzed and optimized propeller-leg by simulation combined with the open water test, the propeller-leg's thrust in the water before and after optimization differs by 400% according to the test results. We optimized the minimum difference between the forward and reverse thrust of the propeller-leg to improve the stability of the robot movement process and optimized the difference from 25% to 3%. This article provides sufficient technical details and completeness, and through a series of performance evaluation experiments validated that the SHOALBOT has excellent movement ability in the amphibious environment compared with other published amphibious robots of the same size.