Robust Control of Spacecraft: Application to an Actuated Simulator

In this article, a hardware-in-the-loop implementation of two robust controllers based on high-order sliding mode and μ -synthesis method are performed and compared in terms of performance and functionality. The spacecraft simulator consists of a free-floating platform hinged on a spherical air-bearing support. The proposed scheme makes full use of adaptive super twisting algorithm to alleviate the chattering effects without increasing the control effort; both controllers are adapted to deal with the saturation of reaction wheels with respect to momentum and its rate of change. The ab-initio simulations compared well with the simulator responses, implying that involved instruments including actuators and sensors have been properly emulated. This also proved that the external disturbances were modeled in a reliable manner. The robustness and effectiveness of the proposed scheme have been validated experimentally under extreme circumstances and uncertainties.