A new momentum management controller for the Space Station

Multibody Dynamics and Nonlinear Control of Flexible Space Structures

“…They have also provided a compensation scheme to decouple roll and yaw dynamics so that roll, pitch, and yaw controllers can be designed independently. Wie et al (1988) incorporated "cyclic-disturbance rejection filters" in an integrated attitude/momentum controller. The inclusion of such filters is motivated by the fact that the spacecraft with articulated solar arrays in near-Earth orbits are subjected to torque disturbances at multiples of the orbit frequency.…”

“…However, they do not suppress roll attitude or yaw momentum at orbital frequency, nor do they suppress constant attitude offsets. Sunkel and Shieh (1990), using the controller architecture in Wie et al (1988), have proposed the matrix sign scheme for placing the closed-loop poles in a prescribed sector of the left-half plane. This method has an advantage over the LQR procedure since, for non-autonomous systems, it does not require time consuming iterations to determine the optimal gain matrices for the cost-function.…”

Multistage design of an optimal momentum management controller for the Space Station

“…The nonlinear equations of motion in terms of components along the body-fixed control axes can be written as follows 4 : space station dynamics (/</ = /// for i (4) where (1,2,3) are the roll, pitch, and yaw control axes whose origin is fixed at the mass center, with roll axis in the flight direction, the pitch perpendicular to the orbit plane, and the yaw toward the Earth; (0 lf 0 2 , #3) the roll, pitch, and yaw Euler angles of the central ( body) axes with respect to LVLH axes that rotate with the orbital angular velocity n; (o>i, o) 2 , o) 3 Equations (5-7) can be put together and written following state-space form: where /represents the inertia matrix with elements /# and Id 3 is an identity matrix of dimension 3. The external disturbances (aerodynamic disturbances) w/ are modeled as bias plus cyclic terms in the body-fixed control axes: w/(0 = bias+A n sin(nt + <£")+A 2n sin(2nt + </> 2n ) (10) The cyclic component at orbital rate is due to the diurnal bulge effect, whereas the cyclic torque at twice the orbital rate is caused by the rotating solar panels.…”