Method and system for on-line system identification

Claim 1

An active noise or vibration control system with on-line system identification for identifying the response of a physical system, said control system comprising control means producing control signals, said control means including control adaption means responsive to residual signals, test signal generating means for generating test signals, wherein the test signal generating means includes means for delaying or inverting a fixed test signal of length determined by the response time of the physical system, including actuator means and sensing means, said actuation means responsive to a combination of the control signals and the test signals and producing a canceling noise or vibration, one component of which counters or partially counters an unwanted first noise or vibration, said sensing means responsive to the combination of said canceling noise or vibration and said first noise or vibration and producing input signals, compensation filter means responsive to said test signals and producing compensation signals, said compensation filter means including a filter adaption means responsive to said test signals and said residual signals and configured to minimize the correlation between the residual signals and the test signals, signal subtraction means for subtracting said compensation signals from said input signals to produce said residual signals, characterized in that the compensation signals substantially cancel the components of the input signal due to the test signals.