Airacuda
Bionic Objectwith fin drive

' Festo AG & Co. KG Festo AG & Co. KG

Airacuda is a remote controlled and pneumatically driven fish that consistently harnesses bionic principles. Bionic, as we define it, is about translating biological operating modes into technical applications as closely as possible. Nature serves as a source of inspiration.

The Airacuda mimics a fish concerning its function, structural design, as well as shape. Airacuda’s kinematical concept closely resembles the one deployed in its biological role model—propulsion is achieved through a mechanical fin drive.
In terms of structural design the fin drive is modeled based on tail fins found in many fish; also, it applies a Fluidic Muscle showing qualities very similar to real muscles. The structure itself consists of two alternating pressure and tension flanks connected by a vertical frame. This concept is called Fin Ray Effect® and was originally developed by Leif Kniese.

The Fluidic Muscle is a Festo product basically consisting of a flexible hose made from rubber and embedded aramid fibres. When inflated with pressurized air, the Fluidic Muscle expands in diameter and at the same time contracts longitudinally.

As a matter of fact, balancing the Airacuda when waterborne is also modeled after its natural archetype—that is, using an air bladder. To do so, the hull has an internal cavity, which can be flooded with water or filled with air, respectively. A pressure sensor evaluates depth and sends a corresponding signal to the electronic components, which then regulates the valves for either vacuum or compressed air to enter the air chamber.

To provide for a light but powerful energy supply, pressurized air is stored in a bottle at 300 bar. Operating Airacuda for approximately 35 minutes requires roughly 400 liters of compressed air. The air is distributed to the Fluidic Muscles in a controlled manner by means of the electronically steered valves. When inflated with compressed air at 6 bar the muscles contract by about 20 percent, and thus set off the structural motion.

All electronic as well as pneumatic components are housed waterproof inside the head. The entire structure is coated with silicon film. Both tail fin and head are designed and manufactured using the latest technology, which is CAD and related numeric controlled equipment. The complex form was generated using only highly sophisticated laser-sintering technology without any manual labor.

Specifications
Length: 100 cm—Width: 28 cm—Height: 45 cm—Weight: approx. 4 kg
Material used for head, structure and tail fin: laser-sintered polyamide
Material used for skin: silicone
Propulsion system: 4 Fluidic Muscle, ø 5 mm (prototype, not commercially available yet)
Compressed air storage: 1.5 litre bottle, 300 bar

Project partners
Project initiator: Dr. Wilfried Stoll, Chairman of the Supervisory Board, Festo AG
Project team: Dipl.-Des. Elias Maria Knubben, Festo AG & Co. KG
Dipl.-Ing. (FH) Markus Fischer, Festo AG & Co. KG
Membrane Technology: Bernd Lorenz, Dipl.-Ing. (FH) Achim Schanze, Walter Harrer, Festo AG & Co. KG
Hardware design, electronics: Dipl.-Ing. (FH) Walter Suchy, Dr.-Ing. Otto Szenn, Festo AG & Co. KG
Model: Christoph Altekamp, Matthias Kübler, Stuttgart, Germany
Fin Ray Effect®: Leif Kniese, Evologics GmbH, Berlin, Germany