Six-degree of freedom micro force-moment sensor for application in geophysics

This paper presents the design concept, fabrication and calibration of a six-degree of freedom (6-DOF) turbulent flow micro sensor utilizing the piezoresistive effects in silicon. The proposed sensor can independently detect six components of force and moment on a test particle in a turbulent flow. By combining p-type conventional and shear piezoresistors in Si (111), and arranging them suitably on the sensing area, the total number of piezoresistors used in this sensing chip is only eighteen, much fewer than the forty eight piezoresistors of the prior art piezoresistive 6-DOF force sensor [1]. Calibration for six components of force versus output voltages was carried out. The sensitivities are linear, close to the design values, and high enough to measure the forces and moments expected to act on the particles in turbulent flow in geophysics.