Linear Control Theory as Applied to Smart Structures

Abstract

This thesis investigates linear control theory as applied to smart structures. Specifically, the problem of active vibration damping in a flexible cantilever beam using piezo-electric ceramic crystals (PZT) as sensors and actuators is addressed.<P>The problem of controlling linear time invariant systems subject to hard input constraints is considered. Some existing methods are reviewed and some new methods are presented.<P>The subject of rapid prototyping and automatic system identification is addressed. Automatic system identification techniques are developed and combined with a commercially available rapid prototyping system to create a test bed which can be used to rapidly model and control existing plants.<P>Closed loop control laws designed to actively damp vibrations in a flexible cantilever beam were tested in various laboratory experiments. The experiments are described, the design of the control laws is discussed, and the results of the experiments are presented.<P>Finally, impact between a flexible robotic arm and a fixed sphere is addressed. A model for the impact forces is developed and compared with experimentally determined impact data. An open loop control law using a neural network is implemented to control the magnitude of the impact force.