Research on the implementation of average speed for a bionic robotic dolphin

This study proposes an average propulsive speed implementation approach for robotic dolphins theoretically and experimentally. First, it analyzes the motion feature of the robotic dolphin, and finds the strictly corresponding rule between tail's oscillating frequency and propulsive speed of robotic dolphin. A kinetic energy mapping coefficient (KEMC) is defined to extract the motion feature. Then, it establishes a kinematic feature equation based on the KEMC definition. The feature equation takes the KEMC as a feature data, and describes a kinetic energy mapping relation for robotic dolphin's motion. Furthermore, by applying the feature equation and KEMC data, it designs an iterative learning identification and adaptive control solution to adjust automatically the average propulsive speed. Simulations prove the system's convergence and speed adjustment effectiveness. Experiments have been performed in two steps. One, a series of KEMC values are identified through the offline identification, and the distribution of KEMCs is partially known; second, a closed loop control experiment reaches the expected speed target. This study shows that the average speed implementation method based KEMC converts the speed control issue into one kind of pure control problem, and it helps robotic dolphin obtain learning ability and adaptive ability.