An optimal control framework for estimating autopilot safety margins

This paper presents an optimal control framework to determine a collection of open-loop command signals that mathematically guarantees operation of an aircraft within certain prescribed state constraints. The framework is specifically applied to estimate margins for the reference command inputs of aircraft autopilot systems, so that safe...

A Hybrid Sensor Based Backstepping Control Approach with its Application to Fault-Tolerant Flight Control

Recently, an incremental type sensor based backstepping (SBB) control approach, based on singular perturbation theory and Tikhonov’s theorem, has been proposed. This Lyapunov function based method uses measurements of control variables and less model knowledge, and it is not susceptible to the model uncertainty caused by fault scenarios. In this...

Some aspects of aircraft response to atmospheric turbulence

Aspects of the requirements for and the calculation of design loads due to atmospheric disturbances are discussed. Special attention has been paid to the relation between discrete gusts and continuous turbulence. It is recommended that a worst case gust model, as described in this report, be further developed.

The layered safety concept, an integrated approach to the design and validation of air traffic management enhancements

The expected growth of air traffic asks for large enhancements in continental Air Traffic Management (ATM) to increase capacity. From a technology point of view a multitude of 'solutions' are available, such as introducing air-ground datalink, providing better support to the ATCo (Air Traffic Controller), introducing 4D air traffic control,...

Loads and damage tolerance for helicopters

This report reviews the applicability of damage tolerance concepts to helicopter structures. After a general discussion of the damage tolerance concept, attention is paid to the specific aspects of the helicopter loading environment. Examples are presented of damage tolerant design, both in metal and in composite structures. However, it is felt...

Reliability aspects of software for digital avionics

Modern commercial transport aircraft contain digital avionics systems for more and more safety critical functions. The reliability and safety of those new systems depend on the hardware reliability and on the reliability of the embedded software. In this report, an overview is given of available methods and techniques to develop reliable...