Dynamic modeling of a CPG-governed multijoint robotic fish

Abstract

This paper is devoted to the formulation of a dynamic model of a serially connected multijoint robotic fish with a pair of wing-like pectoral fins, in which the whole robot is treated as a moving multilink rigid body in fluids. Considering that the thrust of fish mainly results from the force of trailing vortex, added lateral pressure, and leading edge suction force, the dynamic equations of the swimming fish have been derived by summing up the longitudinal force, lateral force, and yaw moment on each propulsive component in the context of Lagrangian mechanics. Along with the bio-inspired central pattern generators (CPGs) as the locomotor controller, the overall dynamic propulsive characteristics of the swimming robot are then estimated in a mathematical environment (i.e. Mathematica). Finally, simulations and experiments are carried out to validate the effectiveness of the built dynamic model. Results demonstrate that the CPG-coupled dynamic model provides a fairly good guide to seeking pragmatic backward swimming patterns for a carangiform robotic fish.