two-dof magnetic orientation sensor using distributed multipole models for spherical wheel motor

  this paper presents a new method for measuring a two degree-of-freedom (dof) orientation of a permanent magnet (pm) based system using magnetic field measurements. the method exploits distributed multipole (dmp) modeling method to accurately predict a magnetic field, and provides a rational basis to inversely solve for the orientation of the pm from measured data. the pm-based magnetic sensor along with the ability to characterize the magnetic field in real-time offers advantages in sensing and control such as contact-free measurements eliminating frictional wears commonly encountered in existing designs with a combination of single-axis encoders, and high-speed sampling rate thus offering a higher bandwidth than methods based on imaging sensors. this paper demonstrates the efficient method capable of measuring the orientation of the pm by implementing it on a spherical wheel motor (swm), where the two-dof orientation is measured. sensor performance has been studied both analytically and experimentally to validate the dmp-based sensor model. the results can offer valuable insights for optimizing contact-free sensor designs.