Design and Characterization of a Novel T-Shaped Multi-Axis Piezoresistive Force/Moment Sensor

In this paper, a T-shaped piezoresistive multi-axis force sensor fabricated by the semiconductor technology is developed. The sensor's design, simulation, piezoresistors arrangement, and characterization are discussed. Fourteen piezoresistors are arranged on silicon beams and used as independent strain gauges. The three components (F_x, F_y, and F_z) of an applied force and two components of a moment (M_x, and M_y) can be simultaneously resolved from the piezoresistance changes induced by the stresses. The sensor was first characterized using a gravity mass reference test bench. The results show the properties of linearity (0.99), sensitivity (force: 1.5 mN; moment: 0.003 Nmm), and small crosstalk (≈5%) between the dominant force component and other components. The fabricated sensor was also verified against a commercial six degree of freedom load cell, and found to perform reliably with high repeatability, low hysteresis (0.5%), and good dynamic response (4 ms).