Modeling and control of a single axis tilting quadcopter

In this paper, the dynamic model of a tilting rotor quadcopter, i.e., a quad-rotor aerial vehicle with rotors that can tilt along one of its axes, is presented. The tilting rotor quadcopter provides the added advantage in terms of additional stable configurations, made possible by additional actuated controls, as compared to a traditional quadcopter without titling rotors. The tilting rotor quadcopter design is accomplished by using an additional motor for each rotor that enables the rotor to rotate along the axis of the quadcopter arm. This turns the traditional quadcopter into an over-actuated flying vehicle allowing us to have complete control over its position and the orientation. In this paper, a dynamic model of the tilting rotor quadcopter vehicle is derived for flying and hovering modes. The model includes the relationship between vehicle orientation angle and rotor tilt-angle. Furthermore, a PD controller is designed to achieve the hovering and navigation capability at any desired pitch or roll angle. The dynamic model and the control design is verified with the help of numerical studies.