Inverse-Kinematics Steering Laws for Double-Gimbal Scissored-Pair Control Moment Gyros

Abstract

The generalized singularity robust inverse steering law (GSRISL) is widely used to avoid singularity problems in control moment gyroscopes (CMGs). However, GSRISL tends to generate perturbation torques near singularities, which hinder highly accurate attitude tracking control. Model predictive steering control can eliminate the necessity of considering singularities, but its implementation in satellites remains challenging because of its high computational cost. Therefore, the development of a steering law that avoids explicit consideration of internal singularities and costly calculations is critical. The inverse-kinematics steering law (IKSL) is one such law removing the need for the calculation of the inverse matrix. The double-gimbal scissored-pair CMG (DGSPCMG) addresses the singularity problem as it does not have internal singularities except along the outer gimbal axis. To enhance the attitude control by removing the need for the calculation of the inverse matrix, this study proposes the combining of IKSL with DGSPCMG. Additionally, to mitigate the risk of gimbal mechanical failure, the IKSL for inner or outer gimbal axes failure was designed by relaxing the identical steering constraint of the scissored-pair gimbal angles. Numerical simulations were performed to evaluate the effectiveness of the combination of IKSL and DGSPCMG in terms of settling time and maneuvering axis accuracy.