Vukobratović M., Stojic R. Modern Aircraft Flight Control

Berlin: Springer, 1988. — 293 p. — ISBN: 3-540-19119-4.Flight dynamics and automatic flight control represent an extensively studied field of technical sciences. This research area has doubtlessly stimulated the development of many aspects of automatic control and systems theory in general. A salient feature of flight control systems is that the requirements imposed are often conflicting, i.e., a highly complex problem must be solved using the simplest possible control algorithms and appropriate control laws which need to be implemented on a reliable control system of relatively small dimensions.
The problem of flight control is exceptionally complex because of the high complexity of the object, the forces acting on it and the ambient in which the flight process takes place. The mathematical model of the object (aircraft) is an inherently non-linear system which can encompass additional d.o.f, in comparison with the number of d.o.f, of the aircraft as a rigid body, if the elastic shapes of the structure are taken into account.
This textbook considers a class of aircraft whose behaviour can be described adequately by the model of a six-d.o.f, rigid body under the assumption of a quasistationary aerodynamic flow field. Aeroelastic and nonstationnary effects will be accepted as second-order influence and will be considered as known or unknown perturbations. Even this, from the theoretical standpoint, simplified model is far too complex for implementation by conventional engineering procedures for the synthesis of flight control systems.