Photonic Control of a Free-Floating Parabolic Membrane Shell

Communication antennas, optical mirrors, solar/optical reflectors, etc. often have the shape of parabolic shells or shells of revolution, due to their required focusing, aiming, or reflecting performance. In this paper, the wireless control of free-floating flexible parabolic shells using discrete photostrictive actuators is investigated. Parabolic shell of revolution is considered to be one of the most difficult geometry among all shell and non-shell structures. Because of this, an approximate way to estimate the dynamic behavior and light-induced control forces of a photostrictive coupled parabolic shell is presented. Based on the approximate spherical model, the effects of actuator locations as well as membrane and bending components on the control action are analyzed. The results obtained indicate that the control forces are location dependent. It is also shown by analysis that the membrane control action is much more significant than the bending control action. The validation of the approximate model is done by comparing the light-induced control forces of the photostrictive coupled shells obtained by the approximate equivalent spherical shell model and those obtained by the parabolic shell model. From the comparison, it can be concluded that there is only a slight difference between a spherical shell and a parabola for surface with an F/D (focal length to diameter ratio) of 1.00 or larger.Copyright © 2007 by ASME