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On-line parameter tracking is often an attractive option for advanced FDD/FTC systems that require a global monitoring in contrast with a local (component) one. This is the case for impaired aircraft, but also for under-equipped vehicles (UAVs, small airplanes), since an updated model is a prerequisite for many indirect adaptive or reconfigurable control algorithms. Many schemes have been proposed...
An adaptive gain-scheduled flight control law is designed for a transport aircraft, within the context of the European project RECONFIGURE. A primary concern being on-line implementation, a recursive frequency domain estimator of the linearized aerodynamic model is developed, with a low on-line computational burden and the capability to track time-varying parameters. Next, an LFT flight controller...
In this paper, the realization-free model approximation problem, as stated in [1], [2], is revisited in the case where the interpolating model might be time-delay dependent. To this aim, the Loewner framework, initially settled for delay-free realization, is firstly generalized to the single delay case. Secondly, the (infinite) model approximation ℋ2 optimality conditions are established through the...
In this paper, the problem of determining the approximate stability regions of large-scale time-delay systems (LS TDS) is solved using model approximation techniques. To achieve this, an ℋ2-oriented approximation algorithm, referred to as TF-IRKA [1], is considered. This algorithm has been shown to be well suited for the approximation of infinite-dimensional systems into finite-dimensional ones. We...
Introduction of fly-by-wire and increasing levels of automation significantly improve the safety of civil aircraft, and result in advanced capabilities for detecting, protecting and optimizing A/C guidance and control. However, this higher complexity requires the availability of some key flight parameters to be extended. Hence, the monitoring and consolidation of those signals is a significant issue,...
The works presented in this paper are a part of research studies which aim at evaluating new concepts for the control and guidance of future A/C, focusing on the augmentation of control laws' availability. The main purpose is to improve the monitoring and the consolidation of the key parameters used by these latter and by the flight envelope protections. Model-based FDD techniques, that make a global...
Introduction of Fly-By-Wire and increasing levels of automation improve the safety of civil aircraft significantly, and result in advanced capabilities for detecting, protecting and optimizing A/C guidance and control. However, this higher complexity requires the availability of some key flight parameters to be extended, to keep for a nominal behaviour of the flight control systems. Hence, the monitoring...
Timely deletion of a large number of stale sessions monitored by Internet routers, particularly in the presence of SYN floods, is critical to prevent flow table explosion. We investigate two frameworks for purging of stale sessions: "opportunistic" purging that employs a free-list of pointers to memory and "deterministic purging" involving logical swapping of a 1-bit flow enable...
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