Pneumatic microactuator powered by the deflagration of sodium azide

This paper details the design, simulation, fabrication, and characterization of two pneumatic microactuators powered by sodium azide or an external pressure source. One was fabricated using traditional manufacturing, while the other used microfabrication techniques. To characterize force output, a microforce gage was also designed, built, and characterized since commercial devices were not available. The azide-based microactuator was successfully actuated numerous times and simulations were then used to predict model characteristics based on system identification techniques. Forces as high as 65 mN and as low as sub milli-Newton were recorded, and displacements in the multi millimeter range were observed. Both the force and displacement magnitudes are in fact limited by the material properties, design geometry, and amount of azide deflagrated. It was demonstrated that a microactuator powered by sodium azide can provide both large forces and displacements simultaneously with the potential of using a small amount of electrical power. No tradeoffs had to be made between force outputs and displacement strokes, as is common to other microactuators. Since only a small amount of electrical power should be necessary in a properly designed battery powered device, the microactuator is poised to be mobile and independent of external power sources.