Development Diary of the PF-600

from conception to manufacturing

Koichi Hirata, updated on Jan 25, 2000

October 1998, Conception

I start to consider the design and manufacturing of the experimental fish robot. I refer the experience and experimental results the model fish robots which is made in former times. In the first conception, the shape of the fish robot is decided based the feature of the pike.

July 1999, Drawings of the first plan

The first assembling plan is drawn. But many amendments are needed when the parts are manufactured and they are assembling.

September 1999, Discussion of the link mechanism

What is better mechanism in order to realize the smooth locomotion like the real fish? I discuss the link mechanism of the joints.

November 1999, Drawings of the plans

I start to draw detail parts plans, and manufacture several parts.

November 17, 1999, Manufacture of the body

The right photographs shows the situation to manufacture the body by the lathe.

The link mechanism part is processed using a four-nail chacking.

Shaving in the body. It needs enough time because inner diameter is 138 mm, depth is 176 mm.

Final thickness is 5 mm. The vibration is kept off by rubber band.

At last, the body is completed.

November 19, 1999, Start to assemble

Almost of the parts are completed. We start to assemble.

December 14, 1999, The complete is near!

The servo motor assembly is completed almostly. The assembly shown in the left photograph is inserted in the body.

December 17, 1999, The complete is near!

The link mechanism is completed. We must adjust between the gravitation and buoyancy, and reform the seal devices.

December 24, 1999, First swimming

At last, the fish robot, PF-600 has started to swim. From a simple measurement, it can swim about 0.3 m/s speed at 2.2 Hz frequency.

January 6, 2000, Start experiment!?

Three types of the tail fin have prepared. From left, pike-type, tuna-type (same area of the pike-type) and tuna-type (same ratio of the real tuna).

[Experimental Fish Robot, PF-600]
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Koichi Hirata
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