A force transducer to measure individual finger loads during activities of daily living

A new six-degree-of-freedom force transducer has been manufactured, with the sensitivity to measure forces in the range ±100 N and moments of up to ±5 Nm. The transducer incorporates two mechanical components: shear forces and bending moments are measured via a strain-gauged tubular section whilst axial forces are transmitted to a cantilevered load cell. Both components are instrumented with 350 Ω strain gauge full bridge circuits and are temperature compensated. After calibration, measurement errors are less than ±0.3 N for direct forces and ±0.03 Nm for applied moments. In order to measure sub-maximal finger loads during activities of daily living, the transducer has been incorporated into several housings representing objects in domestic use: a jar, a tap, a key in a lock and a jug kettle.