Active LQR and H2 shunt control of electromagnetic transducers

Electromagnetic transducers have been used extensively for active feedback control of mechanical vibration. In this paper, we demonstrate a new technique where an electrical impedance, connected to the terminals of an electromagnetic actuator, is designed to reduce vibration in the host structure. By measuring the coil terminal voltage and controlling the resultant current or vice-versa the coupled mechanical system can be controlled. The problem is cast as a standard MIMO control objective to facilitate automatic design of the electrical impedance by such means as regular LQR or H₂ controller synthesis. Potential applications include: vehicle suspension systems, vibration isolation platforms, and the control of enclosed-sound fields. Active impedance controllers require no external sensors. The presented techniques are verified experimentally through the application to a single-degree-of-freedom system.