Multi-Degree-of-Freedom Hall Measurement System Based on the Kalman Filter for Moving-Magnet Planar Motors

This paper proposes a measurement method to address the challenges of multi-degree-of-freedom (DOF) measurement and noise suppression in magnetic levitation planar motors. The approach incorporates an adaptive Kalman filter (AKF) and phase-locked loop (PLL) technology into traditional Hall measurement techniques. The harmonic model of the mover’s magnetic field in the moving-magnet maglev planar motor (MPM) is derived, providing a foundation for subsequent optimization design. To tackle the issue of low signal-to-noise ratio (SNR), the optimal window parameters for the windowed Kalman filter are investigated. An AKF is designed to operate under conditions of unknown noise variance. Based on the harmonic model of the magnetic field, PLL phase demodulation technology is employed to suppress various interference factors in the magnetic field signals. Finally, experimental results validate the measurement system’s excellent resolution, linearity, and motion repeatability.