An experiment to stabilize an electromechanical continuum

An experiment is presented which demonstrates the stabilization of a distributed electromechanical interaction by means of feedback. A conducting elastic "string," stressed by a transverse electric field, is shown to exhibit a threshold electric pressure for instability. The transverse displacements of the spring are sampled and these signals used to induce a feedback field which tends to retain the static equilibrium. Open loop measurements are used to determine the distributed parameters. The experimental and theoretical stability limits of a two station system are compared. Using two sampling stations, the electric pressure consistent with stability is increased by a factor of five. The experiment has implication for the stabilization of more complicated electrostatic levitation devices and for the stabilization of certain hydromagnetic equilibria.