Threshold Model of Micro-Fluidic Inertial Switch Based on Orthogonal Regression Design

The micro-fluidic inertial switch with liquid metal droplet moving under the action of acceleration has overcome the disadvantages of contact bounce, arcing and welding, as are found in the traditional inertial switch. Micro-fluidic inertial switches have no moving parts, a small contact resistance, a long service life and a large current capability. In this paper, we present a micro-fluidic inertial switch that is composed of two-stage micro-valves. This design facilitates tuning of the threshold by adjusting the mercury volume, and so provides better switching performance. Numerical simulation of an orthogonal experiment is used to identify the semi-analytical model of the switch threshold. Results show that the identified model is in accordance with simulation results. Switch prototypes are fabricated by micro-machining techniques including ICP dry etching, sputtering technology and anodic bonding. Centripetal test results show that the switch threshold can be tuned by the careful adjustment of mercury volume.