نوع مقاله : علمی پژوهشی
عنوان مقاله English
نویسندگان English
With the growing reliance on space-based technologies in daily applications, space missions have gained strategic significance. Missions such as orbital inspection, space station assembly, debris removal, and in-orbit refueling now represent critical operational priorities. Consequently, simultaneous control of relative position and attitude in spacecraft systems has attracted increasing research interest. This study presents a nonlinear control strategy for rendezvous and proximity operations between two non-cooperative spacecraft. The 6-degree-of-freedom relative motion dynamics are modeled by coupling translational and rotational motions into a set of second-order nonlinear equations. An integral nonsingular terminal sliding mode control method is proposed to enhance tracking performance during both transient and steady-state phases. To estimate aggregated uncertainties—including external disturbances and parametric variations-and accurately reconstruct velocity states, a third-order sliding-mode observer is designed. This observer ensures finite-time convergence and delivers high-precision estimation of system states and uncertainties. Simulation results, compared with prior methods, confirm the proposed control system's superior tracking accuracy, rapid response, reduced chattering, robustness against system uncertainties, and accelerated convergence to the sliding manifold. These findings validate the control system’s effectiveness for high-precision orbital rendezvous and proximity operations under non-cooperative conditions.
کلیدواژهها English
