title: Orthogonal adaptation for multichannel feedforward control.
abstract: In active noise control, it is desired to generate destructive interference by model-independent control. This is possible for single-channel systems to which a recently proposed method, called orthogonal adaptation, is applicable. In this study, the new method is extended to multichannel systems. An important issue is how to optimize a feedforward controller in the minimum H2 norm sense. In practice, secondary paths of some multichannel systems may be nonminimum phase. It is a difficult problem to design H2 feedforward controllers for multichannel systems with nonminimum phase secondary paths. The problem is solved analytically here with the best achievable, a practical and an economical solution. A recursive least squares algorithm is presented for online identification of multiple paths without persistent excitations. These solutions make it possible to implement noninvasive mode-independent controllers for multichannel systems. Experiment results are presented to verify the analytical results.
authors.affiliation: Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong. mmjyuan@polyu.edu.hk
authors.forename: Jing
authors.initials: J
authors.lastname: Yuan