A temperature-compensated force sensor based on a cascaded FPI for needle force sensing

Abstract

In order to solve problems of puncture force sensing error and delay caused by the change of temperature, a cascaded Fabry–Perot interference (FPI) sensing structure consisting of an air cavity and a silica cavity was proposed, and force–temperature dual-parameter sensing and decoupling models were established. The puncture experiments of hard silica gel and soft silica gel at room temperature show that the cascaded FPI has high force resolution and can effectively perceive the small changes of cutting force during the puncture process. The puncture experiment of hard silica gel after increasing the temperature shows that the cascaded FPI can simultaneously measure the cutting force and temperature at the tip of a flexible needle, and effectively eliminate the pseudo-force caused by temperature during the puncture process.