This paper addresses the problem of three-dimensional (3-D) waypoint tracking for a biomimetic underwater vehicle
(BUV) propelled by undulatory fins: RobCutt-II. Based on the specific mechanical design and control system configuration,
the RobCutt-II can perform diversified locomotion patterns, especially submerging or surfacing vertically in the water. For
practical underwater operating procedures, a selective switching control for 3-D waypoint tracking is proposed. This control
scheme contains a depth controller, a waypoint tracking controller, and a selector. When tracking a series of given 3-D
waypoints, the RobCutt-II can switch between two closed-loop locomotion patterns, i.e., the depth control pattern and the
waypoint tracking pattern. Simulations and a comparative experimental study demonstrate the feasibility and effectiveness
of the proposed switching control scheme.