Performance Evaluation Using Sim2Real of a Robotic Dolphin With Multi-Link Body Mechanism and CPG-Based Controller

Abstract

Robotic dolphins have the capabilities of both propulsion using fluke and maneuverability using flippers. High propulsion and maneuverability are achieved by attaching multiple motors to the fluke or flipper. However, mechanical designs and control systems to achieve both of these are still difficult. The flexible mechanism increases the number of drive joints and complicates the control system and performance evaluation. In this study, we propose a robotic dolphin with a multi-link body mechanism capable of both propulsion and maneuverability, and its control system in Sim2Real. The proposed robotic dolphin has three axes from the head to the body, four axes from the body to the fluke, and one axis on each flipper. The control system is designed as a central pattern generator (CPG) based locomotion controller and integrates the control of the fluke and flipper. The implementation of an integrated control system using Sim2Real is essential for robotic dolphin with multi-link structures. The control approach using a robotic dolphin with a multi-link body and Sim2Real is expected to contribute the evaluation of algorithms for underwater robots with multi-link mechanism.