Design, study and achievement of a fiber optic amplitude modulation sensor for angular position detection: Application to an automotive steering system

摘要

The reliable, accurate and low cost measurement of angular position is an important challenge for numerous industries such as aerospace or automotive industries. We propose a new optical fiber angular position sensor connected to an automotive power steering column. This sensor allows the measurement of the angular position of a car steering wheel over a large range (± 3 turns of wheel). The wheel rotation induces micro-bending in the transducer part of the optical fiber sensing system. This system operates as an amplitude modulation sensor based on mode coupling in the transducing fiber in the case when all the modes are equally excited. We study the sensor's response both theoretically and experimentally with a multimode step index optical fiber [Rf (fiber radius) = 300μm; r_c (core radius) = 50μm; n_c (core index) = 1,457; N.A. = 0, 22 and the wavelength is 632, 8 nm at the ambient Temperature (20℃)]. This sensor has been tested between (-3×360) and (+3×360) degrees with 0,147 sensitivity. We show that the sensitivity can be controlled as a function of the sensor's length and the study of the sensor's output power as a function of the angular position has been achieved. We compare modeling and experimental validation and we conclude by a perspective of what could be soon an industrial sensor.