Sliding Mode Controller and Hierarchical Perturbation Compensator in a UAV Quadrotor

The commercial small Unmanned Aerial Vehicle (UAV) quadrotor is very sensitive to perturbation due to its relatively small size and because of being an under-actuated system. In general, some non-modeled parameters, wind disturbance, sensor noise and miscellaneous uncertainties cannot be easily quantified in UAV quadrotor systems. Changes of mass and inertia parameters for pick and place operations add more uncertainties to the system. Traditional controllers might not be robust enough to handle all aforementioned perturbation types. This arises the need of some perturbation compensation for guidance and stability. In this article, the complete system is synthesized as a combination of Hierarchical Perturbation Compensator (HPC) and a Sliding Mode Controller (SMC). With this compensation system, better tracking performance is demonstrated through analysis and simulation. The simulation response shows enhanced performance compared with other conventional methods.