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Die konventionelle Realisierung von Abtastreglern für elektrohydraulische Flugsteuerungsaktuatoren zeigt erhebliche Schwächen bezüglich der Wahl der Abtastzeit, der Zahlendarstellung endlicher Wortlänge und Signalquantisierung. Eine deutliche Verbesserung verspricht die Verwendung der modifizierten Beschreibungsform auf der Basis des d–Operators. Dieses wird anhand verschiedener Überlegungen plausibilisiert und durch Prüfstandsversuche belegt., The traditional realization of sampled–data controllers for electrohydraulic flight control actuators shows considerable weakness concerning the choice of sampling period, finite word length effects and signal quantization. A remarkable improvement is expected by using the description form based on the d–operator. These considerations follow from different arguments and are prooved by real tests.

Regarding the regulation of weakly damped aeroelastic structures by means of the primary flight controls (PFC), the present contribution focusses on a sophisticated robust controller design method, to achieve the required functionality. Generally, the outlined approach is premised on eigenstructure assignment. Enhancements promise effective integration of miscellaneous potentially competing objective specifications either in time or frequency domain as well as parametric requirements. Due to the infinitive set of flight conditions and fuel configurations the underlying aeroservoelastic plant consists of a linear multivariable multi–model system. Technical feasibility, parametric and dynamic uncertainties as well as architectural constraints, e.g. the number of available sensors lead to a robust output feedback controller. Principally the proposed method is well known from flight control design and modal decoupling. But in contrast, the constrained simultaneous robust eigenvalue stabilisation represents the primary objective at the current application. Since the intrinsic controller calculation is implemented as multiobjective optimisation task, proper optimisation criteria are defined, which incorporate the aeroservoelastic performance specifications into the design procedure. The suitability of the resulting low–order static output controller is verified by real time simulation for a completely normal and degraded configuration covering a real PFC actuation system hardware–in–the– loop.

Analyzing the structure of an aircraft’s electrohydraulic actuation system, the traditional realization of the closed–loop system shows a considerable limitation of dynamics. Enhanced control concepts like state control enable a remarkable improvement. Gradually, the outlined descriptive design procedure leads to a robust sampled–data controller, which automatically manages the parameter uncertainties and finite wordlength effects, occuring in low hardware performances or with rapid sampling. These considerations are verified by extensive simulations and real tests. Finally, a conceivable application is presented regarding to the interaction of actuator dynamics and the flexible structure of an airfoil.

Analyzing the structure of an aircraft’s electrohydraulic actuation system, the traditional realization of the closed–loop system shows a considerable limitation of dynamics. Enhanced control concepts like state control enable a remarkable improvement. Gradually, the outlined descriptive design procedure leads to a robust sampled–data controller, which automatically manages the parameter uncertainties and finite wordlength effects, occuring in low hardware performances or with rapid sampling. These considerations are verified by extensive simulations and real tests. Finally, a conceivable application is presented regarding to the interaction of actuator dynamics and the flexible structure of an airfoil.