Development and modeling of biomimetric robotic fish with ionic polymer-metal composite and servo actuators

Abstract

In the last few decades, biomimetic systems have been receiving growing interest relative to bio-inspired design, physics-based modeling, high maneuvering capability, and high energy efficiency. In this research, first a compact-sized biomimetic robotic fish propelled by an ionic polymer-metal composite (IPMC) actuator was developed. This robotic fish contains two pectoral fins to steer and one caudal fin to generate its essential propulsion. Then a new robotic fish propelled by a hybrid tail was developed. In the hybrid tail, an IPMC was used as a soft actuator to change the shape of the caudal fin and provide a responsive turning moment. A traditional servo motor was used as an active joint in the hybrid tail to generate oscillation on the tail, which leads to the main thrust for forward swimming. The robotic fish with the hybrid tail can achieve two-dimensional (2D) maneuvering capability. A 2D dynamic model that incorporates IPMC active beam dynamics, rigid body motion dynamics, and hydrodynamic force acting on the hybrid tail was developed to capture the motion dynamics of the robotic fish. Experiments and simulation data are illustrated to verify the 2D maneuvering capability of the robotic fish.