Aircraft Parameter Estimation Using Optimal Control Methods

Göttlicher, Christoph; Gnoth, Marcus; Bittner, Matthias; Holzapfel, Florian

doi:10.2514/6.2016-1534

Cited by 6 publications

(2 citation statements)

References 12 publications

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“…One of the main applications of aircraft simulation models is model-based control design as in [9,10]. In order to guarantee a close match to the real aircraft system, identification can be used to improve the accuracy of the models [11,12].…”

Section: Underlying Aircraft Simulation Modelmentioning

confidence: 99%

Required Moment Sets: Enhanced Controllability Analysis for Nonlinear Aircraft Models

et al. 2021

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Attainable moment sets (AMS) are a powerful method to assess aircraft controllability. However, as attainable moment sets only take into account the achievable moment set of the control effectors, they do not assess the required moment set to fulfill the aircraft mission requirements. This paper proposes to calculate a corresponding required moment set (RMS) which defines a set of moments sufficient for fulfilling aircraft controllability requirements in the mission flight envelope. The paper applies the required moment set approach to a nonlinear simulation model of an electric vertical take off vehicle (eVTOL) transition drone in hover. By comparing the required moment set to the AMS of the aircraft model, moment set margins are derived and used to assess the controllability of the considered aircraft. The results indicate that the combined evaluation directly identifies critical moment channels and margins, which is advantageous when compared to a pure AMS-based evaluation. The proposed approach enables the execution of simulation-based assessments in aircraft design and flight control development. In the early stages of aircraft design, required moment sets can support sizing, positioning and tilting of control effectors (e.g., propulsive elements) to fit the AMS to the actual required force and moment set for the specific system.

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Section: Underlying Aircraft Simulation Modelmentioning

confidence: 99%

Required Moment Sets: Enhanced Controllability Analysis for Nonlinear Aircraft Models

et al. 2021

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“…Both Ringerz [20] and Howe-Veenstra [21] developed smooth optimized trajectories following constant IAS or constant Mach number and a constant altitude at cruise with a single, but variable target function considering a temperature deviation of the ISA standard atmosphere. Hargraves [22], Bittner [23] and Gottlicher [24] optimized trajectories as an optimal control problem, which is able to consider conflictive target functions and real weather conditions. The discrete input parameters are approximated by analytically solvable functions.…”

Section: Principle Model Functionsmentioning

confidence: 99%

Untitled

2020

Int J Astronaut Aeronautical Eng

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In line with the objectives of making air transport safer, more efficient, and environmentally friendly through Trajectory Based Operations, a new aircraft performance model has been invented to calculate and optimize free route trajectories considering dynamic weather conditions and multi-criteria target functions. Therefore, the dynamic equation is solved analytically to consider continuous changes in speed and acceleration of this unsteady system. Therewith, the model is based solely on physical functions and calculates only physically possible trajectories. Sixteen aircraft and eighteen engine types are included, the aircraft specific behavior is modeled in detail, and emissions are quantified. Besides a validation, the derivation of several objective functions is shown. Successful trajectory optimization is demonstrated by a variation of the effective variables cruising altitude and target speed. Especially under real weather conditions, aerodynamically derived objective functions cannot be generalized for all aircraft types because in addition to strong wind effects individual aircraft dynamics mainly depend on the drag polar, the maximum Mach number, and the operating empty weight. The model can be used by all participants following Trajectory Based Operations to ensure a continuous recalculation and the exchange of the optimal trajectory in the flight planning phase and during the flight.

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