Adaptive Underactuated Orbit/Attitude Control for Space Debris Rendezvous

This paper investigates the problem of rendezvousing with a tumbling space debris with unknown mass properties using a CubeSat-based approach. The Deorbiter CubeSat is equipped with a single-axis ion thruster, and thus considered as an underactuated system. Further, in most practical situations the information about the exact values of mass and inertial properties of the target is not available a priori. The paper proposes an inner-outer loop structure for concurrent orbit/attitude control of an underactuated CubeSat. The adaptive controller developed for the orbital tracking uses a norm-estimation-based method to obtain instantaneous values of the target's moment of inertia tensor, and handles the target's mass as part of the system disturbance. In addition, a second-order low-pass filter is utilized to generate the desired attitude trajectories. The stability of the entire orbit/attitude controller is analyzed using a Lyapunov function, where the actuator saturation problem is also taken into account. Finally, a simulation study is conducted, using the cataloged COMPTSAT-l defunct satellite, to examine the performance of the controller considering some realistic perturbations.