Maneuver-Based Cross-Validation Approach for Angle-of-Attack Estimation

The estimation of the Angle of Attack (AOA) and Angle of Sideslip (AOS) is crucial for flight monitoring and control. However, a gap has been identified on the data selection technique for the class of estimators based on data-driven methods, such as the synthetic sensor based on Neural Network (NN). This paper proposes a Cross Validation (CV) technique applied on a manoeuver-based partitioning method to provide evidence that a given selection of data can lead to better estimation performance, with the final aim of providing a list of manoeuvers suitable for the training phase of the estimator. Results are shown using simulated data related to the CleanSky 2 project MIDAS

Structural and Aerodynamics Analysis on Different Architectures for the Elettra Twin Flyer Prototype

In this paper, the authors analyze and compare two airship configurations for the Elettra Twin Flyer prototype, an innovative airship concept which is remotely-controlled and intended for monitoring, surveillance, exploration and reconnaissance missions. The aim of the comparison is to determine the most appropriate solution in terms of performance, cost and maneuvering capabilities. In particular two potential solutions are analyzed: the first consists of a double-hull configuration, characterized by the presence of a primary support structure connected to a couple of twin inflatable hulls. The second architecture is a soap-shaped exoskeleton configuration which features a single inflated section, incorporating two separate elements, which are held internally by a system of ribs

Flight control system rapid prototyping for the remotely-controlled elettra-twin-flyer airship

Nautilus S.p. A. is a small company investing in the design and development of a low-cost multipurpose multi-mission platform, known as Elettra-Twin-Flyer, which is a very innovative radio-controled airship, equipped with high precision sensors and telecommunication devices. In the prototype phase, Nautilus policy is oriented towards a massive employment of external collaborators to reduce the development costs. The crucial problem of this kind of management is the harmonious integration of all the teams involved on the project. This paper describes the integration process of the PC-104 on-board computer with the avionic devices, which are electronic systems characterized by complex communication protocols. Attention is focused on the testing, verification, validation and final translation of the embedded control software into the on-board computer, through techniques derived from the automatic code generation, such as Rapid Prototyping and Hardware-In-the-Loop. Copyright © 2006 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved

Multi-objective and multi-phase 4d trajectory optimization for climate mitigation-oriented flight planning

Aviation contribution to global warming and anthropogenic climate change is increasing every year. To reverse this trend, it is crucial to identify greener alternatives to current aviation technologies and paradigms. Research in aircraft operations can provide a swift response to new environmental requirements, being easier to exploit on current fleets. This paper presents the development of a multi-objective and multi-phase 4D trajectory optimization tool to be integrated within a Flight Management System of a commercial aircraft capable of performing 4D trajectory tracking in a Free Route Airspace context. The optimization algorithm is based on a Chebyshev pseudospectral method, adapted to perform a multi-objective optimization with the two objectives being the Direct Operating Cost and the climate cost of a climb-cruise-descent trajectory. The climate cost function applies the Global Warming Potential metric to derive a comprehensive cost index that includes the climate forcing produced by CO2 and non-CO2 emissions, and by the formation of aircraft-induced clouds. The output of the optimization tool is a set of Pareto-optimal 4D trajectories among which the aircraft operator can choose the best solution that satisfies both its economic and environmental goals

Comparison of Adaptive Control Architectures for Flutter Suppression

A study is conducted to derive and implement a state feedback model reference adaptive control (MRAC) solutions for a 2-D aeroelastic nonlinear system and in evaluating the robustness of different control strategies to damage leading to the deterioration of the structural stiffness characteristics. The standard MRAC, a modified MRAC and the adaptive controller are the three model reference adaptive control solutions analyzed. The standard direct MRAC solution serves as the threshold to assess whether or not the more complex algorithms are an effective improvement to it

Occlusion points identification algorithm

In this paper a very simple and efficient algorithm is proposed, to calculate the invisible regions of a scene, or shadowed side of a body, when it is observed from a pre-set point. This is done by applying a deterministic numerical procedure to the portion of scene in the field of view, after having been projected in the observer reference frame. The great advantage of this approach is its generality and suitability for a wide number of applications. They span from real time renderings, to the simulation of different types of light sources, such as diffused or collimated, or simply to calculate the effective visible surface for a camera mounted on board of an aircraft, in order to optimize its trajectory if remote sensing or aerial mapping task should be carried out. Optimizing the trajectory, by minimizing at any time the occluded surface, is also a powerful solution for a search and rescue mission, because a wider area in a shorter time can be observed, particularly in situations where the time is a critical parameter, such as, during a forest fire or in case of avalanches. For its simplicity of implementation, the algorithm is suitable for real time applications, providing an extremely accurate solution in a fraction of a millisecond. In this paper, the algorithm has been tested by calculating the occluded regions of a very complex mountainous scenario, seen from a gimbal-camera mounted on board of a flying platform

Innovative airplane ground handling system for green operations

The aim of this work is to develop a new concept of taxiing, in order to reduce the pollution in terms of noise and gas emission and to introduce a higher level of safety during ground operations. In the area close to the airport gates, the airplane ground handlings are currently performed through the airplane engines, which have the task of providing the trust necessary to move the airplane to the runway. Pollutant emissions and the noise level near the gates, however, could be drastically reduced by introducing an innovative autonomous tractor called CHAT (Clean Hydrogen Autonomous Tractor), developed from the standard pushback tractor. The ground operations could be basically modified by extending the time in which the airplane engines are idle and the airplane is towed by the tractors powered by renewable energy

Innovative Aircraft Aeroelastic Modelling and Control

The aeroelastic design of innovative aircraft wing configurations imposes the designer to deal with specific phenomena, which are not usually considered in classical aircraft definition. The design process itself, though, gives the designer several indications on how to maintain the safety standards imposed by regulations. The investigation of the basic aeroelastic principles for unconventional wings with high aspect ratios can be extremely interesting as, once introduced in a multidisciplinary design, they can be very effective in giving an early determination of the static and dynamic behaviour of the aircraft, leading to significant improvements in the configuration weight, cost, and overall performance. The paper shows some preliminary results as part of the main objectives of the In.A.Team group (Innovative Aircraft Theoretical-Experimental Aeroelastic Modelling) at Politecnico di Torino, Italy. The In.A.Team Project has the following main objectives: 1) to develop multidisciplinary analysis methods appropriate to unconventional aircrafts (highly flexible, "morphing" vehicles); 2) to develop the capability of illustrating and understanding the effects of uncertainties on the behaviour of an aeroelastic system; 3) to apply the innovative adaptive L1 control techniques to highly flexible wings, 4) to integrate theoretical analysis with commercial structural (FEM) and aerodynamic tools (CFD). 5) to design and manufacture an aeroelastic experimental-test-model. 6) to validate theoretical/numerical results by vibration and aeroelastic wind tunnel tests

PERFORMANCES OF A SMALL HYPERSONIC AIRPLANE (HYPLANE)

In the present work a preliminary performance study regarding a small hypersonic airplane named HyPlane is presented. It is designed for long duration sub-orbital space tourism missions, in the frame of the Space Renaissance (SR) Italia Space Tourism Program. The vehicle is also consistent with a point-to-point medium range hypersonic trip, within the “urgent business travel” market segment. The design of such a hypersonic airplane is based on the concept of integrating available technologies developed for aeronautical and space atmospheric re-entry systems. The vehicle, characterized by high aerodynamic efficiency and low wing loading, is able to provide aerodynamic stability and manoeuvrability along the flight path and to produce a reduced sonic boom during cruise and supersonic descent approach, ensuring a very limited environmental impact. HyPlane, powered by Turbine Based Combined Cycle (TBCC) engines plus a throtteable Rocket, is able to perform Horizontal Takeoff and Horizontal Landing (HTHL) on runways. Aerodynamic and propulsive performances for the different flight regimes encountered during the missions are studied. Aerodynamic heating effects are analyzed, in order to identify suitable structures and materials design to sustain the hypersonic flight conditions. Different flight paths are also investigated, including hypersonic cruise and sub-orbital parabolic trajectories, which provide Space tourists with the opportunity of long duration missions, offering short and repeated periods of low-gravity, in the high stratosphere where a large view of the Earth is ensured