Vibration/noise control system including adaptive digital filters for simulating dynamic characteristics of a vibration/noise source having a rotating member

A vibration/noise control system for controlling vibrations and noises generated with a periodicity or a quasi-periodicity from a vibration/noise source having at least a rotating member, said system comprising:

• timing pulse signal-detecting means for detecting at least one timing pulse signal indicative of a period of vibrations and noises peculiar to at least one component part of said vibration/noise source;
• sine wave-generating means for generating a reference sine wave having a single repetition period dependent upon time intervals of generation of said at least one timing pulse signal;
• delayed sine wave-generating means for generating a delayed sine wave which is delayed by a delay period T of 1/3.gtoreq.T.gtoreq.1/7 relative to said reference sine wave, wherein T is a real number;
• first filter means for generating a control signal for controlling said vibrations and noises from said vibration/noise source, said first filter means comprising an adaptive digital filter including two taps, and said first filter means having an adjustable filter coefficient;
• electromechanical transducer means, arranged in at least one vibration/noise transmission path through which said vibrations and noises from said vibration/noise source are transmitted, for converting said control signal into a driving signal for driving said vibration/noise source;
• error signal-detecting means for detecting an error signal indicative of a difference between said driving signal and a vibration/noise signal indicative of said vibrations and noises from said vibration/noise source;
• second filter means for storing a transfer characteristic of a portion of said at least one vibration/noise transmission path extending between said first filter means and said error signal-detecting means, and for generating a reference signal based on said transfer characteristic and said at least one timing pulse signal, said second filter means also having an adjustable filter coefficient;
• control signal-updating means for updating said filter coefficient of said first filter means so that said first filter means generates said control signal in a manner such that said error signal is minimized, based on said error signal, said reference signal and said filter coefficient of said first filter means;
• first dynamic characteristic-identifying means for simulating a dynamic characteristic of a physical system extending between said first filter means and a predetermined control area;
• second dynamic characteristic-identifying means for simulating a dynamic characteristic of said portion of said at least one vibration/noise transmission path extending between said first filter means and said error signal-detecting means;
• and
• reference signal-updating means for updating said filter coefficient of said second filter means based on a simulation result of said second dynamic characteristic-identifying means;
• wherein each of said first and second dynamic characteristic-identifying means includes an adaptive digital filter having a filter coefficient, and filter coefficient-updating means for updating said filter coefficient of said adaptive digital filter of each of said first and second dynamic characteristic-identifying means;
• and
• wherein said adaptive digital filter of each of said first and second dynamic characteristic means includes two taps.