A six-axis force sensor with three-dimensional cross-shape structure

A six-axis force sensor is described, which has three pairs of elastic elements aligning on three axes which are orthogonal and cross at the center of the sensor. This orthogonal structure is called a three-dimensional cross-shape structure. Each elastic element consists of a pair of thin parallel plates which form the parallel plate structure. From the outputs of strain gauges placed on the elastic elements, the six force components are obtained. The whole characteristic of the sensor is obtainable just by analyzing the force-strain relation of a pair of elastic elements on an axis, making it simpler to design a sensor for a given specification. The cross-coupling between the strain gauge outputs and the six force components can be made small. A prototype sensor has been fabricated and it has been shown that the measured characteristic coincides with the analyses based on beam theory, the cross-coupling is rather small, and the force-strain characteristics in all force directions are uniform