Motion control for a multi-joint robotic fish with the pectoral fins assistance

In this paper, we present a novel motion control approach for a multi-joint robotic fish with the pectoral fins assistance. The robotic fish undulates its body and tail to produce the basic swimming patterns that are generated by a general internal model (GIM), while twists its pectoral fins to assist the body to reach the desired direction. The hydrodynamics of the pectoral fin movements is first analyzed. Then the motion control strategies in two basic patterns, namely “cruise” and “C sharp turning”, are explored. Since it is difficult to explicitly formulate the hydrodynamics of the pectoral fin movements, a model-freed fuzzy logic control (FLC) is employed in the robotic fish control system. Finally, the effectiveness of the approach is verified through experiment results.