Design of Robust Controller for Tail-Sitter VTOL Aircraft

In this study, a robust controller design using an Integral Sliding Mode Control (ISMC) approach for controlling the roll motion during the Vertical Take-off and Landing of Unmanned Air Vehicles (VTOL-UAV) is introduced. First, the mathematical model of the VTOL-UAV system is derived, and then the ISMC design is carried out via the system's states. The proposed controller design for controlling the VTOL-UAV system comprises two parts. The first handled the nominal term of the system, while the second tackled and mitigated the effects perturbations from the first instant. The computer simulation has been carried out to demonstrate the ISMC's robustness and its ability to reduce the chattering effect in the control signal. Furthermore, a performance comparison between the proposed controller and other controllers in the literature has been conducted.