Control of microwave-propelled sails using delayed measurements

This paper is concerned with the control of carbon fiber sail structures that are being studied in a series of experiments at the Jet Propulsion Laboratory (JPL) and at the University of California, Irvine. The passive dynamic stability in the one-dimensional (1-D) case was studied in an earlier paper in terms of the fixed points of the trajectories for the governing equations of motion. The simple 1-D model introduced the possibility of controlling a microwave-propelled sail using various nonlinear control strategies, using both position and velocity measurements. In the current paper, we assume that velocity measurements are unavailable, and that the position measurements are delayed (due to the finite speed of light). We then use a novel feedback that employs delayed position measurements only to stabilize the sail about an equilibrium position. The paper will also contain preliminary results on studying the stability of the full 3-D sail model, and potential control strategies.