Observer-Free Output Feedback Attitude Control

Most aerospace tasks require satellites to perform large-angle attitude tracking maneuvers [1, 2]. Many investigations on large-angle attitude controller design have been reported to accomplish these maneuvers. The work in [3] was an earlier attempt to achieve this objective. An adaptive attitude controller was presented. However, modeling error was not handled; moreover, a linearized model was used, even though this model may not fully and well characterize the satellite dynamics. A simple controller demanding minimum onboard computations was presented in [4] for large pitch-angle maneuver without considering any modeling error. To address the problem of fast and large-angle attitude control, a robust control law was developed for flexible satellites [5]. In [6], the robust large-angle attitude control problem with modeling error due to external disturbance and delayed control inputs was investigated. In [7], a model predictive controller was designed for satellites to perform the large-angle attitude maneuvers with input-to-state stability ensured. To the authors’ best knowledge, few studies are seen on angular velocity observer-free attitude control design for satellites with modeling error due to external disturbances [8]. Although this was achieved in [9] with the attitude stabilized with good accuracy, the structure of the controller was complicated.