Sliding mode path tracking control for fish-robot under ocean current perturbation
Nonlinear equations of motion for fish-robot have been derived based on three basic motion behaviors, swimming, orientating, and driving. By incorporating the fish-tail mechanism, 2-DOF barycenter mechanism, and autonomous underwater vehicle-like dynamics model, the fish robot motion and maneuverability are considered in north-east-down frame. A sliding mode controller for swimming, orientating, and tracking control of a fish robot in three-dimensional motion is designed. Simulation results demonstrate excellent maneuverability and tracking performance of the fish-robot in three-dimensional swimming, which shows effectiveness of the controller against modeling uncertainty and ocean's current turbulence.