LASER POINTING FOR ORBITAL DEBRIS MITIGATION USING HIGHER ORDER SLIDING MODE CONTROL AND OBSERVATION TECHNIQUES

摘要

This paper explores the use of a space-based laser to clean up small orbital debris from near Earth space. This system's challenge is to quickly and precisely aim the laser beam at very small (＜1cm) and distant (＜10km) moving orbital debris in the presence of parametric uncertainties and external disturbances. A structure of the laser-based debris tracking system that consists of the debris position sensors, a Fast Steering Mirror, and a telescope is proposed, and its mathematical model is derived. A Kalman Filter is designed to accurately track the orbital debris and generate a command signal for the controller. A second order (specifically, super-twisting) sliding mode controller is designed to follow the command signal in the presence of the parametric uncertainties and external disturbances. A higher order sliding mode differentiator is used to facilitate the proposed super-twisting controller. The efficacy of the proposed control system is assessed via simulations.