Downscaling of proof mass electrodynamic actuators for decentralized velocity feedbackcontrol on a panel

Abstract

This paper presents a simulation study on the downscaling of multiple electrodynamicproof mass actuators for the implementation of decentralized velocity feedback controlloops on a thin panel. The system is conceived to reduce the panel response andsound radiation at low resonance frequencies. In the first part of the paper, theprincipal downscaling laws of a single proof mass actuator are revisited. In particular,the scaling laws are given for: (a) the fundamental natural frequency, (b) thedamping factor, (c) the static displacement, (d) the maximum current that can befed back to the actuator, (e) the maximum stroke of the proof mass and (f) themaximum control force that can be produced by the actuator. The second part of thepaper presents a numerical study concerning the control performance produced bydecentralized control systems with an increasing number of control units, whichare scaled down in such a way as to keep the total base surface occupied by theactuators constant. This study shows that the control performance tends to riseas the number of control units is increased. However, this trend is reversed forlarge arrays of small scale actuators since the gain margin of the feedback loopstends to decrease with downscaling and incrementation of the actuators density.