Adaptive Identification of Nonlinear Systems Operating in Closed-loop

点击翻译按钮获取中文摘要

The aim of this research is to present efficient on-line adaptive methods for identification of parameters of time varying linear and nonlinear elements operating in closed-loop systems. The obtained results are summarized as follows : (1) A perfect adaptive acitve noise control scheme has been given first to suppress primary noise at an error microphone without identification of any secondary path dynamics from artificial control loudspeaker to the error, in a situation when there is also an uncertain coupling path from the control loudspeaker to a reference microphone. Its effectiveness has also been validated in active noise attenuation using an air duct. (2) The stable adaptive control algorithm was derived to identify linear and nonlinear friction and damping factors in two-mass motor velocity feedback control systems. (3) Adaptive predistortion schemes have been given to compensate for linear and nonlinear distortions of high power amplifier used in OFDM systems. (4) Direction-of-arrival estimation methods using an array sensor have been developed in of multipath situations, and also applied in cancellation of coupling signals from a transmitter antenna.