Multi-axis MEMS force sensor for measuring friction components involved in dexterous micromanipulation: design and optimisation

摘要

At the nanoscale and for particular applications such as dexterous micro-manipulation, two degrees of freedom nanotribometers are no longer adequate for studying and characterising the contacts. This paper deals with the specifications and working principle of a new multi-axis friction sensor designed for nanotribological testing applied to this purpose in order to extract each contribution independently (i.e., sliding, rolling and spin motion). It is composed of a central platform with a fixed ball and surrounded by a compliant table. Its sensing ability is based on piezoresistivity: four sets of piezoresistors are symmetrically distributed at the root of four central beams. Finite elements method simulations are performed to find the optimal dimensions of the sensor. As results, this sensor could measure independently normal and friction forces in the range of 1 mN and 100 μN, respectively and the three rotation components. Estimated crosstalk is lower than 1% with a good sensitivity.