Robustness Bounds For Uncertain Sampled Data Systems With Presence of Time Delays

The use of communication networks has increased over the years. Due to many advantages like modularity, system flexibility and ease of maintenance, these networks have made their way into control systems. Today, in majority of applications, real-time networks like CAN (Controller-Area Network), Ethernet, FlexRay, ARINC, etc are used to close the control loop. However, the use of networks leads to communication constraints like transmission delays and packet dropouts. In the thesis, we consider the case of a networked control model wherein the presence of a communication protocol introduces delays in the control input. Additionally, in most of the applications, the plant is in continuous-time domain, whereas the controller is in discrete-time domain. Thus, the choice of sampling rate and the amount of network induced delay play a crucial role in the system stability. Perturbation or modeling errors arise in the nominal system due to parameter variations, un-modeled dynamics, neglected non-linearities or neglected external disturbances. In the thesis, we tackle the perturbations and time delays simultaneously and formulate bounds for stability of uncertain sampled data time delayed systems.The formulation is novel since till now obtaining robust bounds taking uncertainties and time delays simultaneously into consideration has rarely been tackled in the literature. The formulation takes into account the exponential structure of the perturbations due to sampling, the sampling period and time delays arising from the presence of a network in the control loop. Discrete-time Lyapunov stability criterion is used to obtain reasonably sufficient stability margins. Finally, the significance of the problem definition and its effectiveness is illustrated using the distributed turbine engine control case.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Aero/Astro Engineering

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Mulay, Siddharth Pradeep

Contributors dc:contributor

• Yedavalli, Rama

• Aerospace Engineering
• robust control
• sampled data systems
• time delay systems
• robustness bounds
• stability margins

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1365971507

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1365971507