Abstract:
Many control design techniques have been established for nonlinear systems using feedback
control. Feedback has fundamental role in stabilizing the linear and nonlinear control system
problem. Most of the results are based on state feedback (SFB) control design. In many cases all
the states variables couldn’t be measured or one is not interested in measuring them due to high
cost or technical reasons, so in these cases observer design arises as the ultimate solution for
estimating the states. This approach of controlling the system is known as output feedback
control. This research work is based on the sampled data OFB control for the stabilization of
nonlinear system.
This thesis deals with the sampled-data control of nonlinear systems using Extended order
High Gain Observer. This dissertation mainly focuses on the stabilization and performance of
non-linear system by using extended order high gain observer (EHGO). Most of work done on
EHGO is in continuous domain, for sampled data output feedback control there is no notable
research work on EHGO. In this thesis extended order High gain observer is designed using
emulation design and Discrete Equivalent Model (DEM) design. Using EHGO which is designed
using both approaches of sampled data control various nonlinear systems are stabilized.
In the emulation approach, observer is designed in continuous domain and then it is
discretized using the Euler forward difference, then that discretized observer is implemented
using sample and hold devices. While in approximate discrete equivalent model approach,
extended order high gain observer is designed in such a way that first system discrete equivalent
model is obtained by discretizing the system using Euler Method and then using that model
DEM observer is designed. Performance of observer based on emulation design and observer
based on approximate discrete equivalent model are compared for different nonlinear systems.
