High-order sliding mode observer-based output feedback control of spacecraft attitude using chattering free full order SMC

This research provides a technique for rigid satellite output feedback control that takes into account dynamic uncertainties and external disturbances without angular velocity measurement. A rigid satellite s dynamics are first expressed using the modified Rodrigues parameter (MRP), and then translated into Lagrangian form to produce the state-space description of the dynamics. Angular velocity data is not always available for practical use due to cost or technological constraints. As a result, angular velocity is thought to be unmeasurable. To avoid additional mathematical computations and design of separate observers to estimate uncertainties and system states, a third order sliding mode (TOSM) state observer was employed to estimate uncertainties and system states concurrently. The primary element of the proposed controller also includes the full order terminal sliding mode approach, which ensures finite-time stability and eliminates chattering. The simulation results of the suggested technique have been provided and compared with the results of methods accessible in the literature, demonstrating the effectiveness of the method described in this study and the improvement of the findings of earlier relevant research.