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Prototype Fish Robot, PF-550

K. Hirata and K. Sakurai, March 3, 2003

Get a Quick Up -Down Motion!

@We aim to get the quick up -down motion of a fish robot. The Prototype Fish Robot, PF-550 is designed with a new idea for the up -down motion mechanism.

Up -down motions Characteristics
Using of a Float Bad response...
Using of Fins High speed swiming is needed...
With a Vertical Joint Good performance even if slow swiming speed?

Structure of the PF-550

The figure to the right shows the structure of the PF-550. Do you understand the up -down motion mechanism?
Basic Structure

The PF-550 consists of a body case at the central position, a tail peduncle case at the back sided and a battery case at the belows side of the fish. FRP Covers are covers outside of the body and tail peduncle cases.
Joint of the Tail Fin

The photograph shows the mechanical parts of the tail fin. The R/C servomotor in the tail peduncle case moves the tail fin with the rods.
Rotating Mechanism of the Tail

The PF-550 has the special mechanism, which rotates the tail part. The R/C servomotor in the body case rotates the shaft, which is fixed to the battery case. Then, the tail parts with the body case is rotated in the water.
FRP Cover

The body covers and the tail peduncle cover are made by FRP material. The body covers are separated to the side direction, and they are fixed to the battery case strongly.

Swiming Performance of the PF-550

The PF-550 is so fat, then cannot have high speed swiming. The turning performance is so good. The up -down motion performance is not so good yet. When the balance of the weight are adjusted well, it can get often the up -down motion. But it is too difficult to operate the fish with a R/C transmitter, because it is too hard to keep the straight swiming with the vertical position of the joint.

Movie Gallery -Developing Memorys-

The recommended movie!
You can see the unique motion of the PF-550.
MPEG Movie (6.2 MB)
The First Swiming, Jan. 18, 2003
This is the first swiming. A body and a tail fin are not completed.
MPEG Movie (1.2 MB)
Improvement, Part 1, Jan. 19, 2003
The body and the tail fin are completed. The PF-550 is swiming on the water.
MPEG Movie (2.4 MB)
Improvement, Part 2, Jan. 21, 2003
It is difficult to get the up -down motion. We cannot get the success project.
MPEG Movie (1.6 MB)
Turning Performance, Jan. 22, 2003
This is the movie of a turning test. The PF-550 has a good turning performance.
MPEG Movie (1.7 MB)
Up -Down Motion, Feb. 17, 2003
At last, the PF-550 can dive!
But, only one time...
MPEG Movie (2.2 MB)

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