A Magnetic Sensor Calibration System Based on a Closed-Loop Tri-Axial Field Simulator

Magnetism is an omnipresent phenomenon with potential applications in various fields. Immense research has gone into the ways by which magnetism can be put to use for practical applications. Apart from day-to-day applications such as mobile phones, laptops, railways, etc., it also finds applications in the aerospace sector for interplanetary studies, navigation, and space robotics. Accurate magnetic field sensing is essential for these applications, for which efficient magnetic sensors are used. To ensure accuracy, precise calibration of these sensors to quantify various parameters and associated uncertainties is necessary. For this, a field simulator that can generate a highly accurate and controlled magnetic field is essential. The design and development of a Tri-axis Helmholtz coil field simulator based on Model Reference Adaptive Controller (MRAC) is presented here. It provides a simple, compact, cost-effective solution for aerospace magnetic sensor calibration. The proposed system offers a uniform magnetic field with 0.1% uniformity within a cubic volume space of 3375cm
³
. The intensity of the magnetic field can be varied within the full-scale range of
$200~\mu \text{T}$
with a resolution of
$0.01~\mu \text{T}$
by appropriate current control. The MRAC scheme was finalized after a detailed analysis with various types of controllers such as basic proportional-integral (PI), proportional-integral-derivative (PID) and Linear Quadratic Integral (LQI) as it provides precise closed-loop control and field stability, which is of paramount importance for aerospace magnetic sensor calibration. It exhibits lesser computational complexity, lower settling time, better adaptability to external field disturbances and higher phase margin, indicating better closed-loop stability compared to other controllers.