Octorotor UAVs for radar applications: Modeling and analysis for control design

In the context of radar applications using small UAVs (Unmanned Aerial Vehicles), this paper focuses on the dynamic modeling and the analysis of an octorotor in view of control design. As part of a research and educational project aiming at designing a VTOL (vertical take-off and landing) flying robot with an embedded radar system, this paper presents a complete multivariable nonlinear model of the rigid body motion of a commercially available octorotor, fully parametrized considering the geometry and mass properties of the octorotor and the load. This model is completed to take into account the effects of air drag due to the friction between the drone and the air. To meet the control objectives for radar applications, a PID (Proportional Integral Derivative) controller for altitude and attitude control, then a Linear Quadratic controller for trajectory tracking are designed. The proposed control laws are validated through simulation results and exhibit effective performance.