Satellite micro-launcher control: An integrated adaptive-robust and nonlinear approach

Abstract

In this paper, a composite and multi-technique-based controller for a three-stage micro-launcher is presented. The proposed control law consists in a linear robust component, obtained for the rigid motion using mixed-sensitivity and normalized coprime factor loopshaping, an adaptive command gain, used to compensate the effects of the flexible motion, and a nonlinear component, used for roll control and payload insertion. Moreover, robust stability is ensured in the presence of parametric uncertainty, while also guaranteeing a set of disk margins which accommodate the adaptive gain. Finally, robust performance is validated via structured singular value analysis at successive instants along the trajectory, while the control scheme is tested in simulation upon the micro-launcher’s nonlinear and uncertain dynamics.