@article{oai:tokyo-metro-u.repo.nii.ac.jp:00006598,
 author = {コジマ, ヒロヒサ and 小島, 広久 and Kojima, Hirohisa},
 issue = {1},
 journal = {Acta Astronautica},
 month = {Nov},
 note = {There exists a singularity problem in control moment gyros (CMGs). CMG singularities are classified
into two types: hyperbolic and elliptic. Several gimbal steering control methods have been presented to
avoid CMG singularities. Hyperbolic singularities can be avoided by null motion, but elliptic singularities
cannot. The existing steering control methods are rarely designed by explicitly taking the singularity type
into account. In order to effectively avoid elliptic singularities by perturbing gimbal angles, it is desirable
to calculate and record the boundaries between elliptic and hyperbolic singularities in advance so that
the determined boundaries can be utilized for developing model predictive steering control. To this end,
the boundaries between elliptic and hyperbolic singularities of CMGs are calculated and represented in
the form of fitted curves. Several numerical examples are presented to determine the perturbation gimbal
angles for avoiding elliptic singularities without using singular value decomposition., Journal Article},
 pages = {33--44},
 title = {Calculation and Fitting of Boundaries between Elliptic and Hyperbolic Singularities of Pyramid-type Control Moment Gyros},
 volume = {103},
 year = {2004}
}