Development of Implicit-Explicit Control Based Amphibious Centipede-Type Robot and Evaluation of its Mobile Performance

TL;DR

This paper tackles the problem of enabling robust land–water locomotion for multi-legged robots using a unified, simple control scheme. It adopts an implicit-explicit control philosophy combined with open-design principles to design an amphibious centipede-like robot, i-CentiPot-Amphibian, that moves across environments under the same control without environment-specific gait switching. The key contributions include a leg-centric, flexible leg design with three leg shapes (Normal, Fin, Web), a unified control approach with in-phase or opposite-phase leg motion, and a comprehensive experimental evaluation of slip rate and actuator energy across land and water. The findings indicate that Fin-type legs deliver superior terrestrial mobility and competitive aquatic performance, with phase differences playing a crucial role in propulsion, suggesting design guidelines for efficient amphibious locomotion and informing future parameter exploration. The work advances practical amphibious robotics by reducing control complexity and highlighting leg design as a primary lever for cross-environment mobility.

Abstract

Multi-legged mobile robots possess high mobility performance in rough terrain environments, stemming from their high postural stability, joint flexibility, and the redundancy provided by multiple legs. In prior research on navigating between different environments such as land and water, the primary strategy employed involves switching to a controller that generates an appropriate gait for the new environment upon entering it. However, designing appropriate gaits for each complex and diverse environment and accurately determining controller switching for each environment is challenging. Therefore, this research develops a centipede-type mobile robot that navigates both aquatic and terrestrial environments with a simple, unified control scheme, based on the implicit-explicit control philosophy and by ingeniously designing the robot's body structure. In this research, we developed the robot featuring flexible joints and left and right legs on each body segment and focused on the leg structure which has extensive contact with the environment. This paper evaluates the locomotion performance on land and water using the three developed leg structures, using the robot's leg slip rate and actuator energy consumption as evaluation metrics. The experimental results confirmed the existence of an appropriate leg structure capable of navigating both aquatic and terrestrial environments under identical control.

Figures (30)

• Figure 1: Strucuture of Explicit-Implicit Control
• Figure 2: i-CentiPotkinugasa2017developmentosuka2019centipede
• Figure 3: i-AMMRTieng18042025
• Figure 5: Approach of this research
• Figure 6: i-CentiPot-Amphibian