• Inertia tensor
• Output error method
• Parameter estimation
• Pendular motion
• Small-size aerial vehicle

In this paper, a procedure for estimating the inertial properties of small size aerial vehicle is illustrated. It has been developed an identification algorithm that, starting from experimental data, estimates the parameters of physical model describing the pendular motion of a rigid body. The attitude time histories of a structure (“cage”), carrying the object whose inertial properties have to be evaluated, are the experimental data and they are obtained through a measurement unit attached to the cage itself. The cage, designed in order to facilitate the assembly issues, is put in pendular motion thanks to a pivot needle shaped, placed to the cage-top and leaning against a beam. Before proceeding to the identification of aerial vehicle inertial properties, the performance of the identification algorithm has been evaluated by performing several tests. A preliminary effectiveness of the algorithm has been tested via simulation environment, by artificially creating “virtual” time histories. Next, the algorithm has been validated experimentally by loading the cage with a proof mass of known inertial characteristics. In this case, the algorithm errors have been evaluated by comparing the obtained results with the inertial properties predicted by a 3D CAD software where both the cage and the proof mass have been modeled. During these experimental tests, specific attention has been focused on the effect of the cage on the inertial properties estimate. In particular, it has been identified a range of initial attitudes that guarantee n opportune compromise between having cage wide oscillations, needed for a correct identification, and negligible aerodynamic effects that haven’t been considered in physical model. After this algorithm test phase, the developed methodology has been applied to a small rotorcraft vehicle in order to evaluate its inertial properties.