@ARTICLE{Urbański_Konrad_Low_2021, author={Urbański, Konrad}, volume={vol. 70}, number={No 4}, journal={Archives of Electrical Engineering}, pages={845-858}, howpublished={online}, year={2021}, publisher={Polish Academy of Sciences}, abstract={The paper presents the results of simulations and experiments in the field of control of the low damping and time delay oscillating system. This system includes a quadcopter hovering at a very low altitude, and the altitude is controlled. The time delay is introduced mainly by the remote control device. In order to handle the quadcopter at low altitudes, a proportional-integral controller with a negative proportional coefficient is used. Such an approach can provide good results in the case of an oscillating, low damped system. This method of steering, which uses a typical radio control transmitter, can be used on any commercially available leisure drone. Feedback is provided by a camera and algorithms of computer vision. The presented results were obtained experimentally using free flight – without a harness. Different types of controllers are used to control horizontal shift and altitude.}, type={Article}, title={Low altitude control for quadcopter using visual feedback}, URL={http://czasopisma.pan.pl/Content/121565/PDF/art08.pdf}, doi={10.24425/aee.2021.138265}, keywords={control, estimation, ground effect, visual servoing}, }