Steady spiraling motion of gliding robotic fish

A gliding robotic fish is developed for promising applications in aquatic environment monitoring. The design concept combines the strengths of both underwater gliders and robotic fish, featuring long operation duration and high maneuverability. This paper presents both analytical and experimental results for the three-dimension spiraling motion, an essential working pattern of the gliding fish for detecting pollution in a water column. A dynamic model of the gliding robotic fish with actuated tail is established. Then the steady-state spiraling equations are derived and solved recursively using Newton's method. The gliding fish prototype is tested in experiments. Both model prediction and experimental results show that the spiraling motion has very low energy consumption, and the gliding fish can achieve high maneuverability with a turning radius less than 1 m, 2.5% of the reported turning radius of a typical underwater glider.