Task-Space Robust Control Framework of Space Manipulators for Tumbling Satellite Capture

The growing need for space debris mitigation and satellite life extension has intensified interest in Space Manipulator Systems (SMS) for Active Debris Removal (ADR) and On-Orbit Servicing (OOS). Among the most critical challenges is the capture of uncooperative, tumbling targets. This work builds on a robust control architecture based on Nonlinear Dynamic Inversion (NDI) and Nonlinear Disturbance Observation (NDO), previously applied in On-Orbit Assembly, and adapts it to the unique dynamics of target capture. We focus on two key challenges: managing uncertainties due to incomplete target knowledge and handling the momentum transfer during postcapture stabilization. To ensure robustness throughout both pre- and post-capture phases, we propose a joint synthesis of control and observer gains using Linear Matrix Inequalities (LMI). The proposed framework is validated in high-fidelity simulations across a range of target inertias and uncertainty sources, demonstrating its effectiveness and feasibility for future ADR and OOS missions.