The bionic penguins are designed as autonomous underwater vehicles (AUVs) that independently orient themselves and navigate through the water basin and develop differentiated, variable behaviour patterns in group operation.
The penguins’ hydrodynamic body contours and elegant wing propulsion principle were adopted from their natural archetypes. The wings comprise a skeleton of spring steel elements embedded in an elastic matrix of silicon that gives them their profile; they can thus twist to an optimal angle in interaction with the hydrodynamic forces in each stroke, whereby the pitch angle can also be regulated interactively. The robotic penguins can thus manoeuvre in cramped spatial conditions, turn on the spot when necessary and – unlike their biological archetypes – even swim backwards.
An entirely new feature in robotics is the torso that can move in any direction. To make such an “organic” change of shape possible, the head, neck and tail segments were based on a new 3D Fin Ray® structure. This structure, derived from the tail fin of a fish, has thus been extended into three-dimensional space for the first time. In the realisation selected here, the bending structure consists of flexible longitudinal struts with circumferential connecting elements that maintain the shape of the elastic skin. Steering is effected via the longitudinal struts and mechanically linked draw lines, with small actuators for horizontal and vertical movement. The actuators and control electronics are housed in the dry chamber of the torso.
The shoulder joints are spherical; the wing axes pass through the joints and are also fitted with separately rotatable bearings within the sphere. The additional axis of rotation is controlled by one actuator per wing, which adjusts the wings’ pitch angles. This mechanism is used for steering in various manoeuvring situations. A special flapping mechanism acts on the wing axes directed toward the torso, in order to operate the two wings synchronously
and to provide the strong up-and-down motion for propulsion.