Active shape and vibration control of large structures have long been desired for many practical applications. PVDF being one of the most suitable materials for these applications due to its strong piezoelectric properties and availability in thin sheets has been the focal point of most researchers in this area. Most of the research has been done to find an open loop solution, which would be able to shape the structure as per the desired requirements in an ideal atmosphere. Unmodeled dynamics and external disturbances prevent the open loop (no feedback) solution from achieving the desired shape. This research develops a dynamic model of a laminated plate consisting of two layers of PVDF film joined with a layer of epoxy. The orthotropic properties of PVDF have been modeled and the epoxy layer is considered to be isotropic. A general control model is developed, which would work for most boundary conditions and developed for a simply supported beam with patch actuators. The methodology is then extended for a simply supported laminated plate. This model could be used for real time dynamic disturbance rejection and shape and vibration control of the structure.

The main objective of this work is to predict the shape of an antenna subreflector that produces a desired radiation far‐field pattern by utilizing artificial intelligence and other methodologies. In this study the size of the radiation beam is kept constant while it is steered throughout the domain. Three different methodologies or constructs are used to develop this model: Neural networks, batch least squares, and recursive least squares. The accuracy of a method is measured by the sum‐squared error of the training examples. During training the variables inside of the constructs are varied, so that the predicted aperture shape matches the actual shape. The networks predicted the antenna reflector shape at an average accuracy of over 97%, the maximum being 99.78%. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 156–163, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10263

No abstract