Design, conception and making of

"Compliant swimming robotic fish" is the title of our project. So we needed a robot with the appearance of a fish, and capable of swimming thanks to a servomotor-actionned tail.

fish2

Material and Software

  • 3D PRINTER
  • Hard filament (Reprapper)
  • Flexible filament (Ninjaflex)
  • FreeCAD version, to conceive
  • Simplify3D version, to prepare for printing

Conceiving and Printing a piece

  1. Conceiving on FreeCAD:

    • The first thing to do is to design the lines of our future object, with precise sizes and dimensions.

    • The next step is to start extruding those drawings (by using the Sweep tool) to get actual solids.


      photo1


    • Once we have the solids, we can for example use one to excavate the other and obtain the object we were looking for.


      photo2


  2. Prepare and print with Simplify3D:

    • Import the .stl ("mesh file") on Simplify3D.
    • Create a process, choosing the right filament and the right filling percentage (30% for example).


      • photo2

    • Export on an SD card, put it in the 3D-Printer.
    • Make sure the printer is loaded with the right filament, then launch the printing (30minutes ~ 2hours).

Robot composition

Our fish is composed of 6 essential parts :
  • The head [a] (soft),


    head


  • The rod's dock [b] (hard).


    socle


  • The body [c] (soft),


    body


  • The tail [d] (soft).

  • The servomotor's dock [e] (hard), that goes inside the head,


    socle


  • The middle piece [f] (hard), which purpose is to fix the servomotor and the tail together,


    middle


  • The servomotor.

Concept and Tail

The way our fish works is actually pretty simple. There's a string running through the tail, and glued at the end of it. The 2 extremities of this string are linked to a cross-shaped solid is in cinjunction with the servomotor. When rotating, this cross pulls one extremity and pushes the other, making the tail move.

drawing

fish1