LQG/GA design of active noise controllers for a collocated acoustic duct system

Active noise control of an acoustic duct system is studied by a real state- space model in this paper. The linear quadratic Gaussian (LQG) method is ch osen to design an active noise controller in order to reject noise in a col located duct system subject to a disturbance source at one end, Robustness property of the designed controller with respect to the uncertainty of a co mplex-valued acoustic impedance at the other end is validated through compu ter simulations. A nominal real-valued acoustic impedance is therefore used to design reduced order controllers. The design parameters of the LQG meth od are automatically adjusted by using a simple genetic algorithm (SGA) to achieve a better global control effect. This adjustment is guided by a fitn ess function of SGA specified by a control objective. Results from computer simulation demonstrate the global effectiveness of the active noise contro llers. Results of experiments also support the feasibility of the proposed design method. (C) 1999 Academic Press.