Fish Fin Motion


Delicate motion of submersibles is needed to survey complicated seabed terrain and to perform dextrous tasks using manipulators in their free swimming condition. However, it is difficult  for the submersibles developed so far, of which motion is controlled by thrusters and wings, to perform hovering and quick turning as fishes do.
This research deals with experimental analyses of fish fin motion by its observation and by model tests to study the roles of fins in maneuverability performance of fish.
At present, we observe the fin motion of Black Bass. We found the simple rule that the phase angle between lead-lag motion and feathering motion of pectoral fins is only controlled for the various conditions, e.g. advancing, backing, hovering and turning.
We made a model realizing sinusoidal feathering and lead-lag motions of a pectoral fin to measure the the thrust force of the model in a water circulating tank in 1994. In 1995 we made a new model that can be controlled by PC to follow the observed fin motion of Black Bass.
We show here a photograph of the Blackbass Robot and its movie in a pool.@

Movie of Blackbass Robot in Advancing,Hovering and Turning Condition Jan.,1996) (2,465KB " fishmovie2.mpg")

      Length: 2 m, Mass :105.7 Kg
      Actuator : One Pair of 3-Motor-Driven Mechanical Pectoral fins and a thruster
      Sensors: 3-axes gyros, 3-axes inclinometer, 3 CCD cameras, Depth sensor,
      Communication: LAN
      Power : Lead-ascid battery and external power

Movies of swimming performance in a water tank (March 3, 2000)(MPG files)
(1)Ascending in forward direction
(2)Descending in forward direction
(3)Ascending in backward direction
(4)Descending in backward direction
(5)Left turning
(6)Lateral swimming to right hand side

(1)N.Kato,M.Furushima,"Experimental Analyses of Fish Fin Motion",13th Ocean Eng. Symp.(SNAJ),pp.109-116, 1995, in Japanese
(2)N.Kato,M.Furushima,"Pectoral Fin Model for Maneuver of Underwater Vehicles", AUV'96(IEEE ), 1996, June2-6, Monterey,CA
(3)N.Kato,T.Inaba,"Hovering Performance of Fish Robot with Apparatus of Pectoral Fin Motion", 10th Int. Symp. on Unmanned, Untethered Submersible Technology, 1997, September 7-10, New Hampshire
(4)N.Kato, T.Inaba,"Hydrodynamic Characteristics of Apparatus of Pectoral Fin Motion", J. of SNAJ, vol.182, pp.129-139, 1997, in Japanese
(5) N.Kato,T.Inaba,"Control Performance of Fish Robot with Pectoral Fins in Horizontal Plane", Int. Symp. on Underwater Technology, 1998, April 15-17, Tokyo pp.357-362
(6) Kato,N. and Inaba, T.: Guidance and Control of Fish Robot with Apparatus of Pectoral Fin Motion,
Proc. of 1998 IEEE Int. Conf. on Robotics & Automation, pp.446-451
(7) N. Kato, "Research Trend on Aqua-biomechanism," Bulletin of SNJA, No. 830, pp.544-551, 1998, in Japanese
(8) Kato,N, Locomotion by Mechanical Pectoral Fin, J. of Marine Science and Technology(SNAJ), Vol.3, No.3(1998)
(9) Kato,N, Hydrodynamic Characteristics of Mechanical Pectoral Fin, Trans. of ASME, J. of Fluids Engineering, Vol.121, No.3,pp.605-613 (1999)
(10) Kato,N., Three-Motor-Driven Mechanical Pectoral FinAProc. of 11th International Symp. on Unmaned, Untethered Submersible Technology, pp.467-476 (1999)
(11) Kato,N., Application of Swimming Functions of Aquatic Animals to Autonomous Underwater Vehicles, Proc. Of OCEANS'99 (MTS/IEEE) (1999)
(12) Kato,N., "Control Performance in Horizontal Plane of Fish Robot in Mechanical Pectoral Fins", IEEE Journal of Oceanic Engineering, Vol.25,No.1, 2000
(13)N.Kato, Pectoral Fin ControllersAMIT@Press@iNeurotechnology for Biomimetic RobotsAEd. J. Ayersjpp. 325-347, 2002@