Decentralised feedback control of sound and vibration
Professor Steve J Elliot
Institute of Sound and Vibration Research, University of Southampton, UK
In order to control random sound or vibration fields over large areas it is necessary to use multiple actuators and sensors, which are generally positioned to make the modes of the system controllable and observable and fully connected with a MIMO feedback controller. Alternatively a larger number of actuators and sensors can sometimes be positioned in closely-located pairs, and local feedback loops used to achieve control with a decentralised strategy. This has the potential advantage that each actuator/sensor/local controller system could be mass-produced and used as a cost-effective module in larger control systems.
With ideal force actuators and velocity sensors the plant response is passive and such decentralised control is unconditionally stable. When using practical transducers, including reactive force or strain actuators, the plant response is found to be close to being passive and this closeness can conveniently be quantified using the characteristic loci.
In this seminar examples of decentralised control will be discussed in several applications of the active control of sound and vibration. These will include active vibration isolation systems and active vibro-acoustic control of panels.
