Meet the Festo BionicFinWave: an underwater robot with a unique fin drive to maneuver through acrylic glass pipe systems. This autonomous underwater robot moves with undulating fin movement. It can transmit data to the outside world wirelessly.
The BionicFinWave has fins cast from silicone, so they are flexible and can exhibit fluid wave movements. As the makers explain:
the two fins on the left and right are each fastened to nine small lever arms. These in turn are driven by two servo motors located in the body of the underwater robot. Two attached crankshafts transfer the force to the levers in such a way that the two fins can move individually.