Development of a low-cost system to evaluate coupling forces on real power tool handles

A low cost system based on two rigid thin film pressure sensors located on two sections of the handle between the operator hand and the tool handle is developed to evaluate coupling forces on real power tool handles. The proposed system is made of two custom FlexiForce® sensors from Tekscan Inc. and these sensors act as single distributed force sensors and can be trimmed to the desired shape and size. The sensors with its amplifier were calibrated on a flat surface by applying a force distributed over its entire area. The outputs of the sensor, as a function of the force applied on the pressure sensor on a flat surface, are shown. Linear correlation coefficients slightly above 0.99 are obtained for each of the three trials, confirming the linearity of the sensor. The palm sensor responses are found to be a function of push force applied by one of the subjects for three different trials.