Aerodynamics and controls design for autonomous micro air vehicles

Due to their small size, micro air vehicles (MAVs) demonstrate intrinsically unsteady behavior with high frequency oscillations, disturbing the usefulness of their applications. An enhanced automatic flight control system is in a great need for the progress of MAV technology. This paper presents an approach for simultaneous aerodynamics and closed-loop control design for MAVs including the determination of stability and control derivatives, simulation of flight dynamics of a vehicle with open- and closed-loop control, and analysis of the telemetry from flight tests of autonomous vehicles. Aerodynamic stability and control derivative coefficients of the MAV were determined for various parameters (angle of attack, roll rate, pitch rate, etc.) using the MAV geometry and airfoil characteristics. These coefficients were integrated with the geometric, mass, and inertial data to produce the longitudinal and lateral equations of motion. Closed-loop control laws were determined via root-locus methods and the closed-loop system simulated. The effects of varying the center of gravity and changing dihedral angle on the stability are discussed in detail. The proposed approach was applied in the development and evaluation of two autonomous micro air vehicles with wingspans of 12 and 23 inches.