Active Noise and Vibration Control Literature Survey: Controller Technologies

Abstract : This study has been motivated by the need to control noise m naval vessels in order to reduce their delectability and hence vulnerability to enemy attack. In this report, a detailed review of controller technologies, methodologies and algorithms that could be used for active noise, Vibration and structural acoustic control in ship structures has been provided. The review focused on a wide range of controller technologies, methodologies and algorithms such as feedforward control; feedback control; adaptive control; control of tonal noise; control of broadband noise; decentralized control; neural network control; act1ve engine mounts; active noise cancellation; active vibration control and active structural acoustic control. The steps involved in the design of an active control system have been exhaustively rev1ewed and documented. The diesel engine noise problem was the focus of the study and consideration was given to the control of low frequency noise from the engine. All the no1se and vibration transmission paths associated with the engine problems namely, the engine mount, the exhaust stacks and piping systems, the drive shaft, the mechanical couplings and the airborne radiated noise have been considered in the review. Based on factors such as robustness of controller technology, the characteristics of the disturbance, the operating environment and experience in other applications detailed recommendations on controller technologies for the various vibroacoustic paths have been provided. In particular for the engine mounting system, the active vibration control based on adaptive feed forward control technology was recommended. For the drive shafts and coupling, active structural acoustic control that uses the adaptive feedforward control technology has been recommended and an active noise cancellation technique which employs adaptive feedforward control was recommended for the exhausts stack and piping system.