Simulation of an under-actuated fish-like robot controlled by an adaptive frequency oscillator inside a Karman Vortex Street

Fish have developed techniques to exploit turbulence from water. They use them in order to economize energy used for locomotion. To learn how to take advantage of these fish strategies with an underwater machine we need to deal with the fluid environment, the robot morphology and the controller behavior, altogether. This paper presents a simulation case of a robot-controller- environment system. A "cheap design" approach has been used to propose an under-actuated robot. As the main characteristic observed in fish exploiting turbulence is the frequency adaptation, we used an Adaptive Frequency Oscillator as main pattern generator for the controller.