Improving of Characteristics of Rotary Angular Sensor Using Nonlinear Transparent Disc

摘要

As the angular position sensor is a main sensor to measure an accurate position and direction, it plays an important role in various applications such as robotic controller, camera and industrial machines. Recently, lots of angular position sensors such as simple resistive potentiometer, capacitive potentiometer, optical sensor and magnetic sensor are described in several literatures. This paper has described a simple absolute rotary angular sensor with a nonlinear transparent disc. This sensor consists of five elements such as light-source, a shaft coupled nonlinear transparent optical disc, lens, a pair of light dependent resistor (LDR) and a signal processing circuit. This absolute rotary angular sensor is one of non-contact potentiometer based on characteristic of resistance via irradiance and has an advantage to fabricate easily as 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 a good linearity of R~2 = 0.99999, a good repeatability of maximum characteristic drift around 0.1 and measurement error below 0.5. And measurement stability is 0.1 within its full operating range from 0 to 360. The proposed disc assembly and overall results can be helpful to design absolute rotary angular sensor for performance improvement of it. It seems that the proposed method has important practical significance for the development of optical absolute rotary angular sensor.