Authors: Potito Cordisco, Senior Project Manager; Mauro Terraneo, Chief Technical Officer
Nuuva V300 is the new e-VTOL cargo drone developed by the Pipistrel (www.pipistrel-aircraft.com) to autonomously transport 300kg of payload up to 300 km.
Before the maiden hovering flight, Vicoter (www.vicoter.it) was required to perform the Ground Vibration Tests (GVT) of Nuuva’s preliminary configuration, to improve the reliability of the Finite Element dynamic model and to study the transmissibility of vibrations from the eight rotors to the sensors of the flight control units.
Due to the unusual geometry of the aircraft, an extensive pre-test phase, based on the original FE model, was made to identify the most modal-participating locations of the first thirty elastic modes and to guarantee the visual recognition of the modal shapes.
The structure was loaded in various locations/directions and more than 100 accelerometric signals were acquired simultaneously to be sure to well recover all the modes. Modes were identified in terms of frequency, damping, shape and modal mass using a MIMO strategy and the Polymax™ algorithm.
Impact of the dynamic behaviour of the structure at low frequency on the measurements of the gyroscopes installed in the Inertial Navigation System was evaluated too. Specific tests were performed shaking the aircraft from each of the Vertical Thrust Unit (VTU). Accelerometers were installed near the device and, by an ad-hoc spatial differentiation of the translational information, Frequency Response Functions (FRFs) of the rotations were measured.
Vicoter warmly thanks Usua Haizea, Antonio Righetti and Jure Marinko and all the Pipistrel’s staff for all the support provided during the activity.
