Model predictive steering control law for double gimbal scissored pairs of control moment gyros Academic Article in Scopus uri icon

abstract

  • Copyright © 2019 by the International Astronautical Federation (IAF). All rights reserved.Because the control-moment gyro (CMG) singularities are in an inconvenient state for attitude control, significant efforts have been devoted to overcoming the singularity problem of CMGs systems. Notwithstanding these efforts, the following problems remain to be addressed: (1) The use of six (or more) single-gimbal CMGs is unsuitable as these add more weight to spacecraft. (2) In variable-speed CMG(VSCMG), the reaction speed of torque generation resulting from the change in the wheel speed is slow. As the angular momentum decreases, the large torque generating function, which is a feature of CMG, is impaired. (3) The gimbal control law becomes complicated, and verification of many cases is required. Also, methods for generating perturbation torque make it difficult to realize ground observation requiring highly accurate attitude tracking control owing to the generated perturbation torque. To overcome these issues, this study proposes a newly configured CMG system called ¿double-gimbal scissor-paired control-moment gyros (DGSPCMG).¿ Because the proposed system is a hybrid system combining a scissor-paired and double-gimbal CMGs, it has no inner singularities, except for the origin and the line along the x-axis. Furthermore, the outer singularities in this system (saturation singularities) can be escaped by steering the scissored-pair gimbals. Therefore, the singularity avoidance steering law, which generates perturbation torque, is unnecessary. In this study, model-predictive control based steering laws are designed for this system by using objective functions: fast maneuver type, minimum control energy type, and a hybrid of these two types. Finally, the control performances of these three laws are compared through numerical simulations.

publication date

  • January 1, 2019