Optimal Magnetorquer Rod Design for Small-Size Satellites using Axiomatic Design Theory and Nanocrystalline Material Core

ABSTRACT

The magnetic torquer rod, also called a magnetorquer, is the most popular actuator for attitude control of satellites in low Earth orbit. In the case of nano and picosatellites, the available inner space is quite limited, as is the maximum power value. An optimal design solution is highly desirable to produce adequate torque while minimizing energy consumption and mass. Based on the axiomatic design theory, a solution was developed by establishing the requirements – wire diameter, magnetic dipole moment, voltage, and solenoid length – and the physical domain variables – number of turns, current, resistance, and wire length. As a result of the modelling, the design system is decoupled. The choice of core material can also contribute to the actuator’s improvement. Two options are proposed in this work: the FINEMET, a nanocrystal composed of various metals and other elements, and the FeNi50 alloy, for comparative performance. In terms of design parameters, four prototypes were developed to evaluate different wiring configurations and two core materials. The test results of the design options reveal a contrasting performance concerning core material: while the utilization of nanocrystalline material yields superior hysteresis characteristics or linearity behavior, the FeNi50 alloy exhibits enhanced magnetization magnitude.

Keywords
Nanosatellites; Attitude control; Magnetorquer rod; Axiomatic design; Design optimization