Quasi-monolithic planar load cells using built-in resonant strain gauges

摘要

Two load cell designs are presented using resonant strain gauges providing a frequency output. One design is based on a four-point beam deflection jig. It offers high sensitivity, but suffers from robustness and impractical geometries for a broad force range. A modified planar design (typical dimensions 1-10 mm) removes these drawbacks and in addition features built-in force reduction, overload protection and compensation of common mode effects. Load ranges vary from high (1500 N) to very low (0.03 N), with theoretically achievable resolutions as high a 1 part in 107.