Path-Following Control via Dorsal Fin of a Biomimetic Underwater Robot and Fuzzy Theory-Based Path Generation

This paper proposes a velocity-type fuzzy proportional–integral–derivative (PID) control system with integral line-of-sight (ILOS) guidance to precisely follow the path of a biomimetic underwater robot equipped with a caudal fin propulsion mechanism, as well as a fuzzy logic algorithm for efficient path generation. This study involves two distinct key parts. First, a precise path-following control system that incorporates the dorsal fin motion characteristics is proposed. The proposed velocity-type fuzzy PID controller is designed to achieve superior transient response and tracking precision compared to conventional PD controllers. In addition, an ILOS guidance algorithm is integrated to provide compensation for cross-track errors caused by ocean currents and external disturbances. Second, a fuzzy theory–based underwater path generation algorithm is proposed. Through a comparative analysis with the conventional A* and deep Q-network algorithms, the superiority of the proposed method is demonstrated in terms of computational efficiency, path smoothness, and obstacle-handling capability. The findings of this study demonstrate that precise path-following for a dorsal fin–based biomimetic robot is achievable even in environments prone to disturbances, while validating the performance of fuzzy theory–based path generation.