Motor speed estimation and failure detection of a small UAV using density of maxima. - Jefferson S. Souza; Moises C. Bezerril; Mateus A. Silva; Frank Cesar Veras; Abel Cavalcante Lima-Filho; Jorge Gabriel Gomes de Souza Ramos; Alisson V. Brito (Frontiers Inf. Technol. Electron. Eng., 2021)