Optimization of Measuring Magnetic Fields for Position and Orientation Tracking

This paper presents an optimized method of measuring magnetic fields to estimate orientation and/or position of a moving object including a magnet in 3-D space. Existing position/orientation sensors (commercially available in the market), though capable of providing linear or angular high-resolution measurements, rely on mechanical linkages that often introduce frictions, backlashes, and singularities to constrain the device so that the system becomes bulky and complicated. In addition, multidegree-of-freedom motion should be deduced from the individual orthogonal measurements. To overcome such difficulties, the proposed method aims to develop an efficient method for designing a magnetic field-based orientation sensor system. The method utilizes a distributed multiple pole model to accurately characterize the magnetic field of a magnet. The field information is then approximated in a closed form to efficiently configure system parameters and fully utilize sensor capacity and performance of measurement. The simulation and experimental results show the effectiveness of the method along with its ability to characterize the magnetic fields and compute position/orientation, which can offer a number of advantages in real-time measurement and control applications.