Design of a Lightweight, Electrodynamic, Inertial Actuator with Integrated Velocity Sensor for Active Vibration Control of a Thin Lightly-Damped Panel

This paper presents the design study of a lightweight inertial actuator, with integrated velocity sensor, for the implementation of velocity feedback control, i.e. active damping, in lightly-damped panels. The arrangement provides a collocated force actuator and velocity sensor device so that, in principle, an unconditionally stable direct velocity feedback loop could be implemented. However, this property is limited by the fundamental resonance due to the vibration of the inertial mass on the supporting spring. The main design issues are discussed starting from the characterization of the electromagnetic device which has been optimised using a Finite Element Analysis (FEA) to produce the maximum design force of 3N for a given weight of the inertial mass of 20g and input power constraints. The actuator suspension is designed so that important resonance frequencies lie outside the desired control bandwidth of 70Hz to 1kHz. Finally the design predictions are compared to measurements at a built up prototype actuator.