A Study on Accelerated Motion and Circling Movement of FishBased on Image Analysis

摘要

The shape and swimming method of fish vary in accordance with theirenvironment and fish have high maneuverability in water. It is believed that studies on how fish swim can suggest a new effective propulsion method for underwater vehicles and robots, and that various types of fish type robots using new propulsion methods may contribute to ocean observations, developments and environmental protection. A great deal of research on hydrodynamic performance of fish swimming in a steady state that includes turning and positioning by fins has been carried out (Kumph, 1998; Anderson, 1998), but examination of transient motions such as accelerated motion, stopping motion and unsteady circling movement remains insufficient.These transient fish motions were observed in this paper in the fish‘Carassius auratus’ using a digital video camera. A mathematical model of the fish motion at sudden acceleration was first formulated based on observations. Accuracy of the mathematical model was examined and thrust in the motion was estimated using the model. Next, turning patterns of the fish were proposed based on observations, and a mathematical model of the fish motion at sharp turning is also formulated.