A Novel Yawing Suppression Model and Control of Robotic Fish via Stable Point

This paper proposes a dynamic model and control for the four-joint biomimetic robotic fish with yawing suppression. The robotic fish is composed of fusiform head, flexible body and wide caudal fin which can produce a fish body wave through the swinging of the body and tail in order to push itself forward. It is shown that the stable point, based on the classical function by Lighthill, is presented to control the yawing amplitude of robotic fish. Thus, the dynamic model and the influence for the position of stable point on the swimming speed of the robotic fish can be improved. The nonlinear central pattern generators (CPGs) are then used to control the coordinated movement of the four joints for our robotic fish. Experimental results are presented in support of the effectiveness of stable point to suppress the yawing amplitude of the robotic fish.