My theory on Structural Design and Control System of a Caudal Fin Robotic Fish. For nearly 200 years, engineers have been optimizing one way of moving through water, essentially using a propeller. "Fish are very efficient," explained Xiaobo Tan, an assistant professor of electrical and computer engineering. "They can perform very efficient locomotion and maneuvering in the water." Robotic fish - perhaps schools of them operating autonomously for months - could give researchers far more precise data on aquatic conditions, deepening our knowledge of critical water supplies and habitats. There are two types of crescent-shaped caudal fin propulsion: one is the left-right motion of body and caudal fin, such as tuna swordfish and shark; another is the up and down movement of body and caudal, such as whales and dolphins. Both of them have the same principle. Swimming models of fish are various depended on the types and species of the fish i.e. Eel s...