Mission function control for deployment and retrieval of a subsatellite

Abstract

This paper presents a new control algorithm applied to the problem of deployment and retrieval of a subsatellite connected through a tether to the main body. From control theory an idea of the is introduced, which is an index used to describe the concept of the mission. The mission function is defined to be positive-definite, and to be zero when the given mission is completed. The deployment and retrieval is thus controlled to decrease the mission function. The control law is totally different from the control laws that have been presented in the literature; linearity and simple open-loop control are not assumed. In addition, the present theory can be applied equally to both the deployment and the retrieval cases. A simplified model is used to clarify the fundamentals of the problem, only in-plane motion is treated, and neither flexibility nor air drag is included. Results of numerical simulation show an excellent controlled behavior.