Discrete and distributed sensor and actuator design for intelligent structures

Mehmet Sunar, Purdue University

Abstract

This dissertation addresses the problems of structural and control design for intelligent structures using modern control techniques. Two major topics are considered. The first topic deals with the discrete control design for flexible structures. The sensors and actuators are assumed to be collocated at some discrete nodal points of structures. Two substructural control techniques are developed: Generalized and periodic substructural control techniques. The substructural control techniques are important in the active control of flexible (intelligent) structures, since they allow the design of controllers at component level. The generalized substructural control technique reduces the spillover problem and is proven to be accurate and numerically efficient for the control design of large flexible structures. This technique is further presented with two multiobjective control optimization problems which are constructed to optimize structure and control objective functions and to meet the prespecified stability and performance bounds along with other constraints. The periodic substructural control technique is developed for the control design of flexible structures with identically repeating arrays which are often encountered in the large structure control design studies. The second major topic involves the distributed sensor and actuator design of intelligent structures. These structures are the new-generation high-performance structures with intelligent adaptive capabilities. Piezoelectric sensors and actuators are used for the distributed sensing and actuation and the effect of the location of piezolectric actuators is investigated. It is numerically found for cantilevered beam structures that the piezoelectric controllers closer to the fixed end are more efficient than those which are farther away from the fixed end in dampening out the structural vibrations. The distributed piezoelectric control system is designed to sense and reject thermal disturbance (thermopiezoelectric sensor and actuator design) in addition to other mechanical disturbances present in the environment.

Degree

Ph.D.

Advisors

Rao, Purdue University.

Subject Area

Mechanical engineering

COinS