Inflatable actuator with two stable states

Here is the latest iteration of the macro bistable actuator. We inflated two air pockets to make this 3-D printed plastic beam contort into an S-shape; this shape is an important step on the way to “snap-through” of our small and large bistable beams. The work continues Fidel Tewolde’s earlier project and makes good use of the materials and techniques in this excellent tutorial.

Watching the fins on the beam, you can see where we need to exert compressive stress (fins get farther apart) or tensile stress (fins get closer together) in order to make the beam bend. The visible fins provide some insight into our thermally-driven micro-beams, where it is a little harder to see what’s going on.