Design of a Strain Gauge-Based Force Sensor With Three Ranges Based on Compliant Mechanisms

This article presents a strain gauge-based force sensor with three ranges based on compliant mechanisms. Different from the traditional force sensors with rigid mechanisms, the force sensor based on compliant mechanisms proposed in this article realizes the transformation of three ranges through the change of stiffness. The force sensor mainly consists of corrugated flexure beams, a strain gauge, semicircular flexure beams, and guide beams. The corrugated flexure beams are used to adjust the accuracy and range of the presented sensor by changing the stiffness. A strain gauge is stuck to the semicircular flexure beams and used to acquire the corresponding strain. The guide beams are used to avoid the generation of parasitic displacements. The force sensor is theoretically modeled by the compliance matrix method and Mohr’s integral method. In addition, a series of simulations and experiments are carried out to determine the working performance of the force sensor and to verify the accuracy of the modeling. The experimental results indicate that the force sensor can be adjusted in three ranges and achieve a maximum sensitivity of <tex-math notation="LaTeX">89.82~mV· N⁻¹ </tex-math>, an accuracy of 1 mN, and a maximum range of up to 25 N.