A Novel Torsion Instrument for Miniaturized Components Based on the Flexural Pivot

A universal torsion instrument with a broad torque capacity and a high resolution for small-scale components is constructed. A high-sensitivity torque transducer based on the flexural pivot with a wide measurement range is addressed. The torque transducer consists of a cylindrical flexural pivot acting as the elastic element, and an optical angle detector involving dual laser displacement sensors. The instrument can measure the torque accurately using the flexural pivot with a known torsional spring constant. By selecting suitable pivots, it allows for a torque capacity ranging from 1.94 x 10-4 to 1.91 x 10-2 N center dot m, corresponding to a resolution ranging from 1.94 x 10-9 to 1.91 x 10-7N center dot m. The relative uncertainty for the torque measurement is less than 0.8%. Torsion tests on Nylon 6 filaments, copper wires, and soft ribbons were performed with the developed instrument. It shows that the instrument is a helpful tool for characterizing the torsional properties of miniaturized components.