A study on information propagation structure and formation maintenance control

In formation flying missions, the spacecrafts should keep particular formation, so it is very important to control the relative positions between them. Although there have been many researches on the relative position control, most of them assumes that each satellite use the absolute information about its position and velocity. However, in order to keep the formation strictly and to avoid the collisions, the feedback control with the relative information between the members is effective. In such formation maintenance control, 1) the local control law (control gain, etc.) of each spacecraft and 2) "whose relative information can each spacecraft acquire" (we call this "the information propagation structure") determine the behavior of the formation. Especially, the information propagation structure significantly influences the behavior of the formation. However there are few researches about the information propagation structure. In this study, the information propagation structure of the formation is focused on and how the information propagation structure influences the behavior of the formation is investigated. First, we express the information propagation structure of the formation by a matrix and derive the transfer function matrix of the whole system. Next, from this transfer function matrix, we clarify the relation between the information propagation structure and the stability, the steady-state error and the reactivity of the formation and derive the indexes of these control performances. Finally the method for constructing the information propagation structure by optimizing these indexes is shown.