A Simple High-Resolution Absolute Rotary Angular Sensor with Nonlinear Transparent Disc

Abstract

This paper has described a simple absolute rotary angular sensor with a nonlinear transparent disc. This sensor consists of five elements: light-source, a shaft coupled nonlinear transparent optical disc, a lens, a pair of light-dependent resistors (LDR) and a signal processing circuit. This absolute rotary angular sensor is of non-contact potentiometer based on a characteristic of resistance via irradiance. It has the advantage of fabricating efficiently as the disc is made with fiber glass and a self-adhesive tape of which transparency is nonlinearly changed in a range of 0-360^◦. Also, this sensor has good linearity of R²=0.99999, good repeatability of maximum characteristic drift around ±0.1⁰ and measurement error below ±0.5⁰. And measurement stability is ±0.1⁰ within its operating range from 0° to 360°.