A Survey of Automatic Control Techniques for Large Space Structures

Abstract

The control of large space structures has attracted much attention recently with the advent of the Space Transportion System (STS) in the 1980s and hence the real possiblity of erecting large structures in space. The fundamental and challenging issues in the control of large space structures are those which arise from the flexible characteristics of the structure or the distributed nature of the systems's energy.Modeling errors are inevitable due to the complexity of large space structures and the necessary model simplifications of the distributed parameter system. Model parameters will also change as a function of time and depending on whether the large space structure is on earth, in deep space, or in orbit. To complicate the control problems further, large space structures will tend to have low natural frequencies and very little natural damping, resulting in part from desired mass restrictions. It is therefore non-trivial to design a robust controller for a distributed parameter system with modeling errors and parameter variations, which simultaneously guarantees stability and meets performance requirements.This paper presents a survey of the state of the art in the areas of attitude control, vibration control, and figure control as they apply to large space structures.