An Improved Magnetic Transduction Scheme and Electronic Processing for Sensing Rotary-Shaft Position Over Full-Circle Range

Abstract

Angular position of a through-shaft is an important measurand whose value needs to be accurately estimated in a number of industrial scenarios. This paper brings forward the design, analysis and hardware-based evaluation of a new magnetic transduction module and associated electronics for through-shaft angle estimation. The proposed transduction module enables non-contact and full-circle operation using an intelligent arrangement of magnetic discs and two Hall sensors. This easy-to-fabricate module is analyzed and its (nonlinear) characteristics are derived. Optimal specifications for the transducer are also ascertained using this analysis. Further, a simple electronic processor, implementing new linearization function, is employed to realize an automated through-shaft sensing system. This system retains all merits of magnetic sensor and reluctance techniques and eliminated many issues of the previous through-shaft sensor systems. A hardware prototype of the transducer and electronic processor is built and tested. Test results show that the developed system can measure through-shaft angle over 360° range with error < 0.8%. The paper, in its final part, discusses the comparison of the developed scheme with prior art as well as the recommendations for fabricating an equivalent industrial model of the proposed system.