A novel flexure-based uniaxial force sensor with large range and high resolution

High performance force sensors often encounter the conflicting requirements of high resolution and large measurement range. To address this problem, this paper presents a conceptual design of a novel uniaxial force sensor with large range and dual-stage force resolutions which enables us to measure forces within a wide range with satisfied resolutions. The newly developed force sensor features an aluminum alloy body with a probe to transfer external forces into the sensing element. It employs an optical linear encoder to detect the displacement of the sensing body. This sensing scheme may immunize outside electromagnetic noises and therefore enhance the performance of the sensor thanks to its digital signal output. In this paper, an accurate, analytical model for calculating the static stiffness and dynamics of the system was developed by using pseudo-rigid-body-model (PRBM) methodology. To optimize the design, finite element simulations were conducted. After a prototype sensor was fabricated, preliminary characterization tests were carried out to verify the accuracy of the theoretical model and demonstrate the effectiveness of the design. The experiment results indicate that the structure of the new sensor is compact, and it has the ability to measure both micro range and macro range forces within one setup, meanwhile keeps very fine resolutions.