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

This paper presents a simulation study on the downscaling of multiple electrodynamic proof \nmass actuators for the implementation of decentralized velocity feedback control loops on a thin \npanel. The system is conceived to reduce the panel response and sound radiation at low \nresonance frequencies. In the first part of the paper, the principal downscaling laws of a single \nproof mass actuator are revisited. In particular, the scaling laws are given for: (a) the \nfundamental natural frequency, (b) the damping factor, (c) the static displacement, (d) the \nmaximum current that can be fed back to the actuator, (e) the maximum stroke of the proof mass \nand (f) the maximum control force that can be produced by the actuator. The second part of the \npaper presents a numerical study concerning the control performance produced by decentralized \ncontrol systems with an increasing number of control units, which are scaled down in such a \nway as to keep the total base surface occupied by the actuators constant. This study shows that \nthe control performance tends to rise as the number of control units is increased. However, this \ntrend is reversed for large arrays of small scale actuators since the gain margin of the feedback \nloops tends to decrease with downscaling and incrementation of the actuators density.