DEVELOPMENT OF A DYNAMIC OUTPUT-FEEDBACK REGULATOR FOR STABILIZATION AND TRACKING OF NON-SQUARE MULTI-INPUT MULTI-OUTPUT SYSTEMS
DEVELOPMENT OF A DYNAMIC OUTPUT-FEEDBACK REGULATOR FOR STABILIZATION AND TRACKING OF NON-SQUARE MULTI-INPUT MULTI-OUTPUT SYSTEMS
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Date
2018-03
Authors
OVIE, Ese Oghene
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Abstract
This research work is aimed at the development of an observer-based dynamic output feedback
controller for stabilization and tracking of nonlinear systems. The developed controller is
designed after the immersion-invariance and internal model principle (IMP) frameworks and targets
non-square systems such as rotational-translational actuator (RTAC), cart-driven inverted pendulum
(CIP) and quadrotor unmanned aerial vehicle (UAV). However non-square multiple-input
multiple-output (MIMO) systems such as the UAV represented the principal system of choice for
their structural properties. Non-square MIMO systems are systems that have more inputs than
outputs (over-actuated) or vice-versa (under-actuated) and reflect the structures of many real world
systems. The developed immersion invariance error feedback control law(IIEFCL) is used to solve
stabilization and robust tracking problems of non-square MIMO non-linear systems. The output
feedback internal model based observer is developed and tested with the RTAC, CIP and UAV
while the immersion invariance stabilizing controller is developed and tested on the RTAC system.
The output feedback controller showed good stability response on the selected models while the
immersion invariance method displayed a good transient phase stability and tracking results with
the addition of a robust state feedback feature to the underlying controller. The obtained settling
times for the output feedback stabilization results were 2.7s, 1.113s and 0.6435s respectively for the
three systems. The immersion-invariance control law acting as a robustifier to another controller
produced zero percent overshoot and tracking error. The results showed attainment of desired
stability and tracking and also quick convergence, disturbance rejection and handling of transient
oscillations such as finite time escape or transient instability phenomena, from which many nonlinear
systems do not recover after they occur. The IIEFCL was developed for the Quadrotor UAV
and the results obtained were compared with some other standard nonlinear controllers that have
been used in QUAV control. The metric for comparison was the integral of the squared control
input (ISCI) signal. Results obtained compared favourably with existing nonlinear control laws.
The IIEFCL showed the most improvement of 92.92% improvement over the backstepping conviii
trol law, it had a 72.92% improvement over the feedback linearization control law and the least
improvement was with respect to the sliding mode control law where only 66.225% improvement
was recorded. Simulations were made using Matlab/Simulink and embedded C++ tools.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA.
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF A
DOCTOR OF PHILOSOPHY (PhD.) DEGREE IN CONTROL ENGINEERING.
DEPARTMENT OF COMPUTER ENGINEERING, FACULTY OF ENGINEERING,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
Keywords
DEVELOPMENT,, DYNAMIC OUTPUT-FEEDBACK REGULATOR,, STABILIZATION,, TRACKING,, NON-SQUARE MULTI-INPUT,, MULTI-OUTPUT SYSTEMS