An MRI-compatible force sensor for measuring differential isometric precision grip force.

Abstract

Investigating neural correlates of fine motor control in a magnetically sensitive environment requires special considerations in sensor design. Our application requires measurement of forefinger and thumb forces during precision grip in a relatively low (<; 20 N) force range. This work describes the design, characterization and performance evaluation of an MR-compatible precision grip sensor that independently measures forefinger and thumb forces. We selective laser sintered Nylon 12 into a flexure, measuring deformation using optic fibers which matches our finite element model simulation. We found that the device was capable of measuring forces within the desired range, with some hysteresis at higher frequencies as expected. We conclude that the device performs well compared to specifications.