The modelling and design of a mechanism for micro-force measurement

Abstract

The null balance method is used for precision force measurement in the precision industry in order to overcome the limitations of the load cell. The performance of any micro-weighing device is determined by the design of the precision mechanism. Such a device should be designed for high reproducibility, large measurement range with high resolution and fast response characteristics. The device consists of a displacement amplification mechanism and a parallel spring. The mechanism proposed here is analysed against the design specifications. The mechanism was designed for a resolution of 0.1 mg, a range of over 100 gf and a settling time of less than 1 s. The results of this design were verified by simulation and by experiment.