3-D positioning tasks for RUAS using switched PVTOL controllers

In this work a switching strategy associated to three PVTOL controllers is proposed to guide a rotorcraft during 3D navigation. The proposal is to orientate the rotorcraft to the desired point (using a Z-PVTOL controller) and then to move it ahead (using a XZ-PVTOL controller), considering the body reference frame. In such goal search, if a lateral displacement error greater than a threshold value is observed an YZ-PVTOL controller is run to minimize it. The stability proof for each of such sub-systems is also included, as well as a strategy to switch between them without affecting the stability of the whole system. Finally, experimental results are presented to validate the proposed approach and its performance during a flight mission is compared to the performance of a controller based on partial nonlinear feedback, proposed to control all degrees of freedom simultaneously.