Thesis-2005-Dai.pdf (4.57 MB)
Remote maintenance of real time controller software over the internet
thesis
posted on 2013-06-12, 13:23 authored by Chengwei DaiThe aim of the work reported in this thesis is to investigate how to establish a standard
platform for remote maintenance of controller software, which provides remote
monitoring, remote fault identification and remote performance recovery services for
geographically distributed controller software over the Internet.
A Linear Quadratic Gaussian (LQG) controller is used as the benchmark for the control
performance assessment; the LQG benchmark variances are estimated based on the
Lyapunov equation and subspace matrices. The LQG controller is also utilized as the
reference model of the actual controller to detect the controller failures. Discrepancies
between control signals of the LQG and the actual controller are employed to a General
Likelihood Ratio (GLR) test and the controller failure detection is characterized to
detect sudden jumping points in the mean or variance of the discrepancies. To restore
the degraded control performance caused by the controller failures, a compensator is
designed and inserted into the post-fault control loop, which serially links with the
faulty controller and recovers the degraded control performance into an acceptable
range.
Techniques of controller performance monitoring, controller failure detection and
maintenance are extended into the Internet environment. An Internet-based
maintenance system for controller software is developed, which provides remote
control performance assessment and recovery services, and remote fault identification
service over the Internet for the geographically distributed controller software. The
integration between the mobile agent technology and the controller software
maintenance is investigated. A mobile agent based controller software maintenance
system is established; the mobile agent structure is designed to be flexible and the
travelling agents can be remotely updated over the Internet. Also, the issue of heavy data process and transfer over the Internet is probed and a novel data process and
transfer scheme is introduced. All the proposed techniques are tested on sirnulations or
a process control unit. Simulation and experimental results illustrate the effectiveness
of the proposed techniques.
History
School
- Science
Department
- Computer Science
Publisher
© Chengwei DaiPublication date
2005Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.429832Language
- en