Development of a variable stiffness mechanism and energy-based control to study stiffness modulation

MSc assignment

Birds have the ability to morph and stiffen their wings during flight to adapt their flight behaviour. The change in stiffness results in a different interaction with the air around the wings. Research into robotics currently draws inspiration from these distributed variable stiffness and control methods in nature to create bio-inspired, more energy efficient robots.

In previous work we studied 3D-printed variable stiffness mechanisms and energy-based control methods for beams. Modulating the wing stiffness during flight, however also costs energy. In order to study the fundamentals of variable stiffness mechanisms and control properly, we need to find control methods that can modulate the stiffness with the least amount of energy. For this also an experimental set-up with a variable stiffness mechanism needs to be designed and fabricated.

Within the scope of the PortWings project (, this master thesis assignment focuses on the development of an experimental test set-up for a variable rotational stiffness mechanism to represent the pitching motion of a bird wing. This set-up will then be used to design a controller able to steer the wing to accomplish certain motions (e.g. flapping, maneuvering) while taking into account the energy required for stiffness modulation.