Mono- and bi-stable planar actuators for stiffness control driven by shape memory alloys

This contribution compares two novel smart, planar actuators driven by shape memory alloys (SMAs) with regard to their potentials and limitations. The principle set-ups, mathematical models and experimental results are described. Both actuators are supposed to control the flexural stiffness in multi-layered beams with variable stiffness. One uses trained SMA wires and buckling springs and possesses one stable active state. The other one uses spiral SMA springs and a bi-stable mechanism to generate two stable, active states.