Attitude Takeover Control of Combined Spacecraft with Actuator Saturation Using Prescribed Performance and Time-Delay Estimation

Abstract In this paper, we propose an attitude takeover control of postcapture combined spacecraft using prescribed performance control (PPC) integrated with time-delay estimation (TDE). In space missions like on-orbit servicing (OOS) and space debris removal (SDR), a service spacecraft and a target form a combined spacecraft in the postcapture phase and it detumbles to achieve a desired orientation. However, model uncertainties such as unknown moment of inertia, center of mass from unknown target, and external disturbances caused by target maneuverability can degrade attitude control performance of the combined spacecraft. To address these challenges, PPC is employed to guarantee control performance in the presence of model uncertainties. In addition, a lumped uncertainty including model uncertainties and external disturbances is estimated using TDE. The proposed method is compared through simulations with conventional model-based PPC, PD control and sliding mode control (SMC). The real-time applicability of the proposed controller was validated through a process-in-the-Loop (PIL) implementation test.