Airacuda’s waterproof head houses all the electronic and pneumatic components. The hull has an internal balance tank that can be flooded with either water or air, depending on whether there is a need to sink or rise towards the water’s surface. This is determined by a pressure sensor, which evaluated the depth in which the fish is swimming. An air bladder allows the Airacuda to remain balanced.
The Airacuda is capable of maneuvering by using four actuators. Two fluidic muscles are used to steer the fish, while two other muscles actuate the tail fin in an S-shaped pattern. Festo’s fluidic muscles feature qualities similar to those of real muscles. The artificial muscles are constructed out of a
flexible hose made from rubber and embedded aramid fibres. The muscles expand and contract when inflated with pressurized air, releasing a powerful force.
Air is distributed to the Fluidic Muscles via electronically steered valves that make them contract, setting off the structural motion. Pressurized air is stored in a bottle at 300 bar. Another great feature of the Airacuda is called the Fin Ray Effect, and was developed by Leif Kniese. The Fin Ray Effect is a fin consisting of an alternating traction and pressure edge, which are connected via frames. When one flank is put under pressure, the structure automatically bends in the opposite direction, allowing Airacuda to display the full swinging power of its fins when swimming. In Airacuda, this concept is used once within a passive structural element in the tail fin, and again in an active structural component inside the fish’s hull.
“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 – it strikes us with an unlimited number of solutions showing uncompromisingly optimized features developed over the course of the evolutionary process. Various innovations can be derived from nature – and visions come true,” states Festo.
TFOT has covered two other projects created by Festo. One is the “Air ray”, a remote-controlled ballonet filled with helium and constructed with a flapping-wing drive mechanism, which allows it to “swim” freely in the air, just like the Manta ray in the water. The other is “Airic’s Arm”, a novel mechanical arm incorporating highly advanced techniques in automated movement.