In this paper, we present the design of the Omnicopter, a micro aerial vehicle (MAV) with two central counter-rotating coaxial propellers for thrust and yaw control and three perimeter-mounted variable angle ducted fans to control roll and pitch. First, a dynamic model of the robot is established using the Euler-Lagrange formalism. Next, we focus on the attitude control for a special operating case of the Omnicopter with fixed vertical positions of the surrounding ducted fans. A nonlinear model is represented in state space using the quaternion and angular velocity as state variables, which simplifies the system dynamics. Based on this model, a feedback linearization controller is developed, which renders the system linear and controllable from an input-output point of view. The zero dynamics problem is also analyzed. Finally, simulations are carried out and the results illustrate that the attitude stabilization task for the Omnicopter is achieved.
