A Cooperative Model Predictive Control Technique for Spacecraft Formation Flying

This paper investigates the control problem for a group of cooperative spacecraft with communication constraints. It is assumed that a set of cooperative local controllers corresponding to the individual spacecraft is given which satisfies the desired objectives of the formation. It is to be noted that due to the information exchange between the local controllers, the overall control structure can be considered centralized, in general. However, communication in flight formation is expensive. Thus, it is desired to have some form of decentralization in control structure, which has a lower communication requirement. A decentralized controller is obtained which consists of local estimators inherently, so that each local controller estimates the state of the whole formation. Necessary and sufficient conditions for the stability of the formation under the proposed decentralized controller is attained and its robustness is studied. It is then shown that the resultant decentralized controller can be converted to a decentralized model-predictive controller so that most of the features of its centralized counterpart such as the collision avoidance capability are recovered. The results presented in this paper for stability, robustness and performance evaluation can be envisaged as the extension of recent developments for the relevant problems in the literature.