Design of self-repairing digital PID controllers for non-square multivariable plants

The complexity of today's multivariable plants gives rise to the need for sophisticated controlsystems to ensure high-performance operation whilst maintaining high system integrity. Theintegrity of such systems is to be interpreted as the sensitivity of high-performance controlsystems to failure and their capability for reconfiguration if necessary. Thus, the issue ofself-repairing control systems becomes practically very important. Indeed, besides simplicityand practical realism, the associated controller of the self-repairing control system shouldavoid the need for detailed mathematical models of the plant and should utilise only dataobtained from direct input-output measurements. Moreover, the self-repairing controllershould have the capability of altering its control law to promote plant survivability in theface of severe plant-parameter variations characterised by actuator failure.It is accordingly shown in this thesis that self-repairing digital control systems can bedesigned by extending the domain of applicability of the digital PID controller introducedby Porter et al (1985) so as to incorporate non-square plants subject to actuator failure.This demonstration is effected by classifying the time-domain characteristics of non-squarelinear multivariable plants using step-response matrices. These characteristics are used firstlyto design non-adaptive signal-following systems for non-square linear multivariable plants,and then to design non-adaptive model-folio wing systems for such plants. In order toproduce self-repairing controllers, these non-adaptive controllers are then rendered adaptiveso that actuator failures can be tolerated.The effectiveness of such self-repairing digital controllers is illustrated by designing digitalPID controllers for a three-input/two-output gas turbine, the three-input/two-output X-29technology demonstrator aircraft, and a four-input/two-output two-link manipulator subjectto actuator failure.

Level dc:type.qualificationlevel

Doctoral (Level 8)

Year dc:date.issued

1989

Author dc:creator

• Othman, MZ

Language dc:language

en

Identifier

oai:salford-repository.worktribe.com:1339113

OAI identifier oai:identifier

oai:salford-repository.worktribe.com:1339113