Design and application of a micro-force measuring system based on the principle of torsion balance

Abstract

A micro-force measuring system with a resolution of micro-Newton based on the principle of torsion balance is developed, which consists of micro-force sensor, linear motor, specimen platform and the matching measurement and control software based on LabVIEW. The dynamic method of calibrating the micro-force sensor by in-situ vibration was used to overcome the influence of boundary conditions such as the rod and the clamp, achieving an accurate calibration of the torsional constant. The system was applied to study the process of pressing a slender cylinder imitating the leg of a water strider into the water surface. The results show that the critical interaction force per unit volume of the slender cylinder decreases with the increase of its diameter, showing a significant size effect; the critical depth and critical interaction force can be increased by spraying superhydrophobic silica coating, which greatly improves the hydrophobic performance of the slender cylinder.