Publications

Deconing controllers are developed for a spinning spacecraft, where the control mechanism is that of axial or radial moving masses that are used to produce intentional, transient principal axis misalignments. A single mass axial controller is used to motivate the concept, and then axial and radial dual mass controllers are described. The two mass problem is of particular interest since spacecraft imbalances can be simultaneously removed with the same control logic. Each controller is tested via simulation for its ability to eliminate existing coning motion for a range of spin rates. Both controllers are developed via a linear-quadratic-regulator synthesis procedure, which is motivated by their multi-input/multi-output nature. The dynamic coupling in the radial two mass control problem introduces some particularly interesting design complications.

Two controllers are developed to provide attitude control of a spinning rocket that has a thrust vectoring capability. The first controller has a single-input/single-output design that ignores the gyroscopic coupling between the control channels. The second controller has a multi-input/multi-output structure that is specifically intended to account for the gyroscopic coupling effects. A performance comparison between the two approached is conducted for a range of roll rates. Each controller is tested for the ability to track step commands, and for the amount of coupling impurity. Both controllers are developed via a linear-quadratic-regulator synthesis procedure, which is motivated by the multi-input/multi-output nature of second controller. Time responses and a singular value analysis are used to evaluate controller performance. This paper describes the development and comparison of two controllers that are designed to provide attitude control of a spinning rocket that is equipped with thrust vector control. 12 refs., 13 figs., 2 tabs.