Flight Vehicle System Identification: A Time Domain Methodology

Publisher: AIAA, Reston, VA, USA, ISBN: 1-56347-836-6
Source: DLR

ABSTRACT This valuable volume offers a systematic approach to flight vehicle system identification and covers exhaustively the time-domain methodology. It addresses in detail the theoretical and practical aspects of various parameter estimation methods, including those in the stochastic framework and focusing on nonlinear models, cost functions, optimization methods, and residual analysis. A pragmatic and balanced account of pros and cons in each case are provided. The book also presents data gathering and model validation and covers both large-scale systems and high-fidelity modeling.

Real world problems dealing with a variety of flight vehicle applications are addressed and solutions are provided. Examples encompass such problems as estimation of aerodynamics, stability, and control derivatives from flight data, flight path reconstruction, nonlinearities in control surface effectiveness, stall hysteresis, unstable aircraft, and other critical considerations.

Beginners, as well as practicing researchers, engineers, and working professionals who wish to refresh or broaden their knowledge of flight vehicle system identification, will find this book highly beneficial. Based on years of experience, the book also provides recommendations for overcoming problems likely to be faced in developing complex nonlinear and high-fidelity models and can help the novice negotiate the challenges of developing highly accurate mathematical models and aerodynamic databases from experimental flight data.

Software that runs under MATLAB® and sample flight data are provided to assist the reader in reworking the examples presented in the text. The software can also be adapted to the reader’s own interests.

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    ABSTRACT: This article discusses the model selection process taken during parameter estimation of a micro air vehicle using the VICON motion capture system, it shows the accuracy of various aerodynamic models when applied to the same estimation dataset and highlights the inclusion of aerodynamic phenomena that capture the advance and departure of stall condition in any selected models.
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    ABSTRACT: This paper presents some results of the flight test campaign conducted on the Tecnam P2006T aircraft, on the occasion of its certification process. This twin-engine propeller airplane is certified under the normal category CS-23 and FAR 23. A prototype of this light aircraft has been tested in flight for a post-design performance optimization and for the assessment of flight qualities. These experiences have led to the application of two winglets to the original wing. The final configuration has been extensively tested for the achievement of CS-23 certification. The longitudinal and lateral-directional response modes have been assessed and quantified. At the same time the longitudinal airplane model, through a dedicated set of flight maneuvers, has been characterized by means of parameter estimation studies. The aircraft stability derivatives have been estimated from the acquired flight data using the identification technique known as Output Error Method (OEM). Some estimated stability derivatives have been also compared with the corresponding values extracted from leveled flight tests and from wind tunnel tests performed on a scaled model of the aircraft.
    Aerospace Science and Technology 01/2011; 24(1):226-240. · 0.87 Impact Factor
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    ABSTRACT: In this paper we consider the problem of estimating the inertial properties of small-size rotorcraft vehicles. The proposed procedure consists in first subjecting the vehicle to a pendular motion; next, time histories of attitude and angular velocity are obtained by using an inertial measurement unit attached to the vehicle; finally, estimates of the inertia tensor components are obtained by using maximum-likelihood constrained optimization in the time domain. The experimental equipment is extremely simple to realize and of low cost. An important highlight of the proposed approach is that the inertial properties of the vehicle are estimated using specific experimental observations which can be conducted in the laboratory prior to performing flight testing. Hence, flight trials can focus of the sole estimation of the aerodynamic parameters, easing the problem and improving the quality of the estimates. The procedure is first tested in a simulated environment, by artificially creating virtual time histories so as to verify the observability of all parameters. Then, the procedure is validated by using an object of known inertial characteristics. Finally, the document is concluded with the application of the proposed methodology to a small rotorcraft vehicle.
    35th European Rotorcraft Forum, Hamburg, Germany; 09/2009