Collocated attitude and vibrations control for square solar sails with tip vanes

This paper is devoted to developing collocated attitude and vibrations controllers for a square solar sail spacecraft containing four pre-tensioned triangular sails supported by flexible diagonal booms and four reflective control vanes at boom tips. Since the control torques for attitude control are created by the solar radiation pressure forces on the tip vanes, the attitude control problem is effectively non-collocated. The present work identifies collocated sensing for the tip vane forces which furnishes a passive input-output model. Various controllers are developed which furnish attitude and vibrations control. A finite-element-based linear structural model is used to evaluate the developed controllers and examine the controller-structure interactions.