An Integrative Control Method for Bio-Inspired Dolphin Leaping: Design and Experiments

Abstract

This paper presents the design and implementation of leaping control methods for replicating high-speed dolphin leaping behavior. With full consideration of both mechanical configuration and propulsive principle of a physical robot comprising one neck joint, two propulsive joints, and a pair of two-degrees-of-freedom (2-DOF) mechanical flippers, closed-loop pitch, roll, yaw, and depth control methods are integrated to accomplish precise attitude control. Specifically, two pitch control strategies are proposed to separately satisfy small and large pitch requirements based on the real-time feedback of the pitch angle, while the roll controller is further implemented as a proportional-integral-derivative (PID) loop. A combination of pitch and roll control is utilized to regulate the desired pitch maneuvers. Finally, a parameterized five-phase leaping control algorithm instead of Weihs's three-phase porpoising model is implemented on the self-contained real robot, enabling the examination of biological leaping phenomena which are hard to observe or measure. Latest experimental results reveal that besides high speeds exceeding the minimum exit speeds, the pitch control closely related to pitch angle and submersion depth is another critical factor contributing to effective dolphin leaping.