Trajectory Tracking Control of a Free-Flying Space Manipulator System Mockup: an adaptive robust controller for a real-application case

The growing density of space debris and the need for satellite life-extension have made autonomous In-Orbit Operations (IOO) a critical area of research. However, controlling a robotic manipulator in microgravity presents unique challenges arising from the lack of a fixed base, the dynamic coupling between the manipulator and the spacecraft, and additional disturbances inherent to the space environment. This thesis presents the modeling, control design, and validation of a Seven-Degree-of-Freedom (7-DoF) Space Manipulator System (SMS) mockup operating in free-flying mode. It enables the Earth-based emulation of an actual SMS, intended for research activities related to future space missions. First, a kinematic analysis is performed and a complete dynamic model is derived using the Newton-Euler formulation, capturing the reaction forces exchanged between the robotic arm and the base. To address the trajectory tracking problem, the implementation of a Computed Torque Control (CTC) approach featuring dynamic gain scheduling is considered at first. Then, to tackle actuator saturation, parametric uncertainties and external disturbances in a more targeted way, an Adaptive Integral Sliding Mode Control (AISMC) strategy with saturation compensation is proposed. The proposed architectures are then validated through a high-fidelity simulation environment developed in MATLAB-Simulink. The system is tested under various real-application considerations, including discrete-time execution and sensor noise. Numerical results demonstrate that both control architectures achieve satisfactory tracking accuracy under realistic constraints. However, the proposed AISMC technique exhibits a slightly better performance. This confirms the viability for its actual implementation in the real-world setup.