Design and Fabrication of a Miniature Four-Axial Piezoresistive Force/Torque Sensor with MEMS Technology

A novel miniature four-dimensional force/torque piezoresistive force sensor is presented in this paper. The silicon sensor is fabricated using standard MEMS technologies. The cross-beam structure is adopted in this design due to its high mechanical stability. Twelve n-doped silicon piezoresistive strain gauges are located on the different positions of the cross-beams. Finite element simulations assess the stress distribution and help with piezoresistors arrangement. The sensor can simultaneously detect three directions of forces (F
x
, F
y
, and Fz) and a torque M
z
in the plane by four independent Wheatstone bridges. A series of precise gravity masses were used to characterize the sensor performance. Results show the properties of good linearity, high sensitivity, small crosstalk, and highly dynamic response (2ms).