Dynamic modeling and control system design for tri-rotor UAV

In this paper, design, dynamics and control allocation of Tri-Rotor UAV are introduced. Tri-Rotor UAV has three rotor axes that are equidistant from its center of gravity. There are two designs of Tri-Rotor introduced in this paper. Single Tri-Rotor UAV has a servo-motor that has been installed on one of the three rotors, which enables a rapid control on its motion and its various attitude changes; unlike a Quad-Rotor UAV, which only depends on rpm of four rotors to control. The other design is called Coaxial Tri-Rotor UAV, which has two rotors installed on each rotor axis. Since Tri-Rotor type UAV has the yawing problem induced from an unpaired rotor's reaction torque, it is required to derive accurate dynamics and design control logics for both Single and Coaxial Tri-Rotors. For that reason, control strategy for each Tri-Rotor type is proposed and nonlinear simulations of altitude, Euler angles, and angular velocity responses have been done by using classical PID controller. Simulation results show that the proposed control strategies are appropriate for the control of Single and Coaxial Tri-Rotor UAV.