Abstract:
ABSTRACT
A MULTI-INPUT MULTI-OUTPUT SELF TUNING REGULATOR FOR
NONLINEAR HIGH PERFORMANCE AIRCRAFT CONTROL
by
Wilfred L. Ghonsalves
Master of Science in Electrical and Computer Engineering
Electronic Engineering Option
California State University, Chico
Summer 2010
This thesis presents the design and development of an adaptive control scheme
for an application of high performance aircraft control. Traditional flight control design is
based on linearization of an aircraft’s equations of motion around a set of operating
points, and scheduling gains of linear controllers around each of these points to meet performance
specifications. For the complex and aggressive maneuvers carried out by fighter
aircraft, fixed gain or gain scheduled controllers do not guarantee robust performance and
stability throughout the complete flight envelope. Therefore, there is a need for new design
approaches to expand the flight envelope beyond the one achievable by linear controllers,
attenuate failures, and to attain damage adaptation and recovery. Additionally, the
variation in an aircraft dynamics during such aggressive maneuvers is poorly modeled.
Hence, an adaptive control scheme is an ideal solution to overcome such aerodynamics
uncertainties.
In this thesis, a Multi Input Multi Output (MIMO) Self Tuning Regulator
(STR) is proposed for the flight control problem. The approach uses MIMO system identification
to capture process dynamics in the form of a linear model structure. Further,
online design calculations are performed on an identified process model to design an optimal
controller. This automated sequence of system identification and controller design
is performed on each update interval using real-time recursive computations in order to
adapt the controller parameters.
The Proposed control design methodology is applied on a nonlinear 6-DOF
high performance aircraft simulation model to evaluate its performance. Simulation results
show that MIMO STR provides improved performance over linear controllers.
