Two-DOF orientation measurement system for a magnet with single magnetic sensor and neural network

Abstract

This paper presents to develop measuring a two degree-of-freedom (DOF) orientation of a permanent magnet with a three dimensional Hall-effect sensor. Using magnetic field of a permanent magnet, the orientation of an object embedded with the magnetic sources can be tracked in real-time. Orientation tracing method based on magnetic field has advantages such as contact-free measurement without any extra mechanics and no requirement of line-of-sight problem. However, it is challenging to calculate orientation from a magnetic field because the field depending on rotational angles is highly nonlinear and has uncertainties with a non-unique solution. In this paper, a cylindrical permanent magnet is used as the excitation source and artificial neural network(ANN) have been applied to compensate the difficulties. In both simulation and experiment, the measurement accuracy according to a motion range is validated. It can be expected to explore various permanent magnet-based systems such as joystick application, spherical motor.