portfolio: development of ghost knifefish robot

client: Malcolm MacIver, Northwestern University

the ghost knifefish (Apteronotidae) propel themselves forward and back by an undulating wave along their dorsal ribbon fin. Professor Malcolm MacIver contracted Kinea Design to build a submersible model of the ribbon fin propulsor, fully functional with 32 independent fin rays to actuate it. The model is to be used for fluid dynamics measurements with full control of the waveform along the ribbon fin.

kinea's approach in developing the mechanical and electronic hardware for the device was one of pursuing a stackable "fish-steak" actuator design. Each segment (fish-steak) contains a motor, drive-train and custom designed motor controller into a single module. The modules connect with one another with a stack-through connector which runs along the spine of the fish and carry power and CAN bus signals. Each fish-steak is individually addressable by an external master controller. The device is also equipped with electrosense electrodes for mimicking reallife behaviors.

the final design resulted in an easily configurable neutrally buoyant ghostBot.

gallery

videos:

of the real ghost knifefish

• for video of a Black Ghost Knife fish in an acquarium, click here.
• New Scientist report on the Ghost Knife Fish, click here (minutes 1:09 through 1:55).

• for a video of the GhostBot demo, click here.
• for a another video of the GhostBot demo, (side view), click here.

photos:

the pictures and videos below show the components of the knifefish inspired GhostBot device.