Bio-inspired fluidic thermal angular accelerometer with inherent linear acceleration rejection

Abstract

This paper reports on the design, simulation, fabrication and characterization of a bio-inspired angular accelerometer. The sensor mimics the semicircular canals in mammalian vestibular systems. The device pairs a fluid-filled microtorus with a thermal detection principle based on thermal convection. The microtorus is intersected by a set of heaters surrounded with temperature detectors on either side, which sense a temperature profile asymmetry upon applied angular acceleration. The device fabrication is based on a two-mask process. Proper arrangement of four resistive temperature sensors in a Wheatstone bridge reduces the impact of heater-induced buoyancy effects. The toroidal microchannel results in inherent geometric linear acceleration insensitivity. The sensor demonstrates a sensitivity of 124 μV/deg/s2 for in-plane angular acceleration, two orders of magnitude suppression of cross-axis angular accelerations, three orders of magnitude suppression of linear accelerations, and a test setup limited dynamic range of ±2000 deg/s2 at 1 Hz.