Digitalization of DLR unmanned aerial system platform PROTEUS for simulation of morphing and flight mechanics

Abstract

Nowadays aircraft efficiency needs to be improved in order reduce the ecological footprint due to the high number of transported persons per day. The quantification of the benefit of a novel system within a complete aircraft is challenging due to the high complexity. One approach to increase aerodynamic efficiency in off design conditions is the implementation of morphing systems. These systems allow on the one hand the control of the outer shape, but they have on the other hand impact on mass and power offtake. The testing of different morphing approaches cannot be done in a proper timeframe for a transport aircraft. Therefore, an unmanned aerial system (UAS) can be a first starting point for benefit quantification. An off the shelf UAS is procured as a new platform under the name PROTEUS within the German Aerospace Center to test morphing systems in flight tests. The prediction of the impact is also vital and therefore a digital model is required. This digital model includes on the one hand the geometry of the UAS for simulations and on the other hand the mechanical properties for the flight dynamic model. The procedure of acquiring the data for the digital model will be presented and the divergence between measurements and existing data for the geometry will be shown. The data will include the complete outer surface of the UAS with wing, fuselage and empennage. This is vital, because the manufacturer modified the model to an updated version and the tolerances are relatively high in UAS manufacturing. Proper geometry data are necessary for the aerodynamic and the structural simulations in order to have a proper prediction and a set of data for a reference configuration. After measurement the data need to be post processed, because the wing e.g. has already decals, which can be resolved by the camera measurement system. Such surface divergences will not have a major influence on the simulation and they will only increase the effort for proper mesh. Also, the aerodynamic simulation needs sharp edges, which are not present in the surface scan. A proper method is required to model edges out of the data. The determination of the mechanical properties like center of gravity or moments of inertia is definitely required, because of an individual flight test instrumentation. These data will be used in the flight computer for a flight dynamic model. This model will be capable to include an artificial intelligence to test an efficiency improvement with the morphing system in future flight tests.