Aerodynamic Modelling and Experimental Identification of a Coaxial-Rotor UAV

A comprehensive design of a Gun Launched Micro Air Vehicle (GLMAV) is presented. The GLMAV rotorcraft is a new Micro Air Vehicle (MAV) concept using two-bladed coaxial contra-rotating rotors and a cyclic swashplate. The MAV packaged in a projectile is launched using the energy delivered by a portable weapon. When it reaches the apogee, the projectile is transformed in such a way that the MAV becomes operational over the zone to be observed. A detailed GLMAV nonlinear mathematical model is presented for hover and near-hover flight conditions and identified from experimental load data using a strain-gage aerodynamic balance. Simplifications brought to the aerodynamic submodel have permitted its linearization in the parameter space. The parameter estimation was based on the Kalman filter estimation method applied to the simplified aerodynamic model and using the input-output data from the experiment. The persistently exciting condition is given in terms of physical variables of the GLMAV through two simple expressions. The identification results are presented and validated through comparisons between the model output and real load data.