An Integrated Approach to Aircraft Modelling and Flight Control Law Design

Abstract

Control laws as present in the flight control computers of modern aircraft provide the functionality for safe manual and automatic control in flight. The design of flight control laws (FCLs) consists of the actual design phase, followed by a validation phase that involves extensive simulatins, rig tests and, eventually, flight tests. Multi-disciplinary aspects play an important role, since FCLs not only improve aircraft flight dynamics, but also affect structural dynamics, airframe loading, system dynamics, etc. Currently these aspects are not addressed until the validation phase, frequently resulting in late design iterations. In future aircraft design projects interactions between fligth control and other engineering disciplines will become considerably stronger, requiring multi-disciplinary aspects to be addressed from the beginning. This is where this thesis aims to contribute. Three aspects will be addressed in detail: development of integrated multidisciplinary aircraft models to allow a wide range of design criteria to be evaluated and addressed in synthesis of the control laws, development of approaches for handling various types of uncertainty and model variation in tuning of design parameters, and the integration of these methodologies into a design process structure that allows complex control law structures to be handled efficiently and transparently.