Design of a magnetic field-based multi degree-of-freedom orientation sensor using the distributed-multiple-pole model

Abstract

Precision control of a tiltable spinning shaft requires real-time measurement of the inclination. Conventional single-axis encoders, though capable of providing high-resolution (linear or angular) measurements, rely on mechanical linkages (that often introduce frictions, backlashes, and singularities) to constrain the device so that the three-DOF motion can be deduced from the individual orthogonal measurements. Vision-based sensors, which have the attractive features of being non-contact, are limited to low speed measurements. We present here an efficient method for designing a magnetic field-based orientation sensor for devices where orientation control of a rotating shaft under the influence of a magnetic field is required. The ability to characterize the magnetic fields and forces in addition to orientation sensing can offer a number of advantages in real-time computation and control.