Inductive Planar 2-D Displacement Sensor and Its Signal Decoupling Research

To address the high demand for two-dimensional (2-D) precision displacement measurement in high-end manufacturing, this paper proposes a novel measurement model for an inductive planar 2-D displacement sensor based on multi-frequency magnetic field coupling. The sensor comprises a fixed ruler and a moving ruler. By applying high-frequency excitation signals of varying frequencies to the fixed ruler, the moving ruler outputs standing wave induction signals carrying independentXandYdisplacement information. A switch-mixing frequency (SMF) 2-D displacement decoupling scheme based on amplitude discrimination (ADN) of standing wave signals was proposed. Subsequently, electromagnetic field simulation analysis verified the feasibility of this solution, and the sensor structure was further optimized. Finally, a prototype sensor was developed and subjected to performance testing and error analysis. Experimental results demonstrated that the optimized differential structure achieved measurement resolutions of 0.20 μm and 0.25 μm in theXandYdirections. Within the effective measurement range of 130 mm × 130 mm, the measurement accuracies in theXandYdirections, after error compensation correction, were ±14.40 μm and ±14.95 μm, respectively.