Equivalent Circuit Modeling of an Induction Reaction Sphere for Microspacecraft Attitude Control

A reaction sphere (RS) is a novel and promising actuator for microspacecraft attitude control systems (ACSs). However, the detection of the motor status, such as the rotating speed of the spherical rotor, is a difficult task. The equivalent circuit can be used to predict the motor status. This article presents an improved multi-layer transfer-matrix method for the equivalent circuit parameters’ calculation. Results compared with a finite element analysis (FEA) show that the proposed analytical model achieves an acceptable accuracy within the operating speed range. Meanwhile, its computation time is 0.072 s, on average, which is only 0.0003% of the FEA.