Robust Attitude Tracking of an Uncertain UCAV in a Complex Environment

The chief objective of this paper is to address the problem of robust attitude tracking of an unmanned combat aerial vehicle (UCAV) with uncertain inertia matrix in battlefield environment. As we all known, the environment is complicated due to the combination of lots of unknown external disturbance torques that effects on the UCAV. Thus, for the mathematical model of an unertain UCAV, we carry out this study based on a specific attitude deviation system having input-to-state stable inverse dynamics. This facilitates error-based output feedback controller synthesis by regulation theory based on a nonlinear internal model approach, steering tracking error vanishes asymptotically and guaranteeing precise tracking performance. As a consequence of integral input-to-state stability (iISS) based design, we achieve not only asymptotic attitude tracking with unknown harmonic disturbance rejection, but also robustness property with respect to unknown inertia matrix and unmodeled disturbance. Finally, numerical simulation results are shown for illustration.