J Intell Robot Syst (2012) 65:457–471 DOI 10.1007/s10846-011-9589-x Quad-Tilting Rotor Convertible MAV: Modeling and Real-Time Hover Flight Control Gerardo Ramon Flores · Juan Escareño · Rogelio Lozano · Sergio Salazar Received: 16 February 2011 / Accepted: 18 April 2011 / Published online: 6 September 2011 © Springer Science+Business Media B.V. 2011 Abstract This paper describes the modeling, con- trol and hardware implementation of an exper- imental tilt-rotor aircraft. This vehicle combines the high-speed cruise capabilities of a conven- tional airplane with the hovering capabilities of a helicopter by tilting their four rotors. Changing between cruise and hover flight modes in mid- air is referred to transition. Dynamic model of the vehicle is derived both for vertical and hor- izontal flight modes using Newtonian approach. Two nonlinear control strategies are presented and evaluated at simulation level to control, the vertical and horizontal flight dynamics of the ve- hicle in the longitudinal plane. An experimental prototype named Quad-plane was developed to perform the vertical flight. A low-cost DSP-based Embedded Flight Control System (EFCS) was de- This work was partially supported by the Institute for Science & Technology of Mexico City (ICyTDF) and the French National Centre for Scientific Research (CNRS). G. R. Flores (B ) · J. Escareño · R. Lozano Heudiasyc Laboratory, University of Technology of Compiègne, CNRS 6599, 60205 Compiègne, France e-mail: gfloresc@hds.utc.fr S. Salazar French-Mexican Laboratory on Computer Science and Control, CINVESTAV, Mexico City, Mexico signed and built to achieve autonomous attitude- stabilized flight. Keywords Quad-plane UAV · Operational transition · Inner-outer loop control · Backstepping · Embedded control system · Convertible MAVs 1 Introduction The applications of mini Unmanned Aerial Ve- hicles (UAVs) have widely diversified during the last years. They comprise both military and civil- ian, though the latter has had a lower develop- ment rate. The key feature of UAVs is to provide a mobile extension of human perceptions allowing not only the security of the user (soldier, police- man, cameraman, volcanologist) but also gather- ing information such as images or video, locations coordinates, weather conditions, etc., for either online or offline analysis. As a result, the use of aerial robots, specially miniature (mini and micro) UAVs (MAVs), has enhanced activities such as surveillance of sensible areas (borders, harbors, prisons), wildlife study, natural disasters assess- ment, traffic surveillance, pollution monitoring, just to mention a few. However, there are missions whose scope is beyond the capabilities of conventional MAVs