Abstract:
This work is concerned with the design of a pitch-rate-commandattitude-hold Command and Stability Augmentation System in order that
the augmented aircraft meets the Gibson dropback criterion, the Gibson
phase-rate criterion and MIL-F—8785C requirements. The work shows two
methods of design, pole-placement and optimal control, and discusses
the design procedures, the advantages and disadvantages of each
method. The work is also concerned with the redundancy aspect of the
control law design, and so not only a sensor based design but also an
observer-based design are investigated. In order to design the
observer-based control law, a Doyle-Stein observer was implemented.
Two methods showing how to design the observer are discussed and
presented, and the special characteristics of this kind of observer
are also considered. The performance of the observer-based control
law was compared with that of the sensor-based control law. The
failure transients and characteristics of the control law are also
studied and presented. Finally an evaluation of the control law was
carried out with a non-linear model of the B-747 aircraft, and a
simple altitude-hold autopilot was designed to work together with the
stability augmentation control law.
