SAMPLED DATA CONTROL OF NON LINEAR SYSTEMS USING EXTENDED

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.