A behavior-based approach to multiple spacecraft formation flying
Multiple spacecraft flying in tight formation can be used to measure light from a distant star to reconstruct the star's image. This approach will be used to achieve imaging resolutions much finer than current technology permits. Several measurements must be taken from many different formation orientations and sizes. Crucial to the success of formation flying missions is the ability to navigate the spacecraft through several maneuvers while maintaining formation.
There are several approaches to the spacecraft formation flying problem. These include leader-following, behavior-based and virtual structure approaches. In the behavior-based approach the control laws that govern the motion of each spacecraft are derived by weighting the importance of several desired behaviors including formation keeping and goal seeking. However, the degree to which behavior-based approaches achieve goal seeking and formation keeping have never been analyzed. No sufficient conditions have been derived to ensure convergence for behavior-based approaches. Moreover, behavior-based strategies have never been applied to the coordination of spacecraft attitude. The main contribution of this dissertation is the development of the coupled dynamics approach to formation flying, a behavior-based control strategy. This approach is structured such that the control input to each spacecraft is influenced by the position and orientation of every other spacecraft. This establishes a notion of feedback missing from other formation flying strategies. In addition, the control laws are decentralized and can be implemented with limited communication.
We prove convergence to the final formation goal and provide a bound on the average pairwise formation keeping error for each maneuver. Furthermore, we implement similar output feedback control laws using passivity-based ideas.
0538: Aerospace materials