Stability control system for an automatic control system

A stability control system for use in an automatic control system comprising:

• a controlled system;
• response characteristic measuring means for measuring a response characteristic of said controlled system;
• frequency response computing means for processing the response characteristic measured by said response characteristic measuring means to obtain a standard frequency transfer function having a standard frequency characteristic, and a varied frequency transfer function having a frequency characteristic with a permissive variation to the standard frequency transfer function;
• band division means for dividing the standard frequency transfer function and the varied frequency transfer function obtained by said frequency response computing means into a plurality of bands, respectively;
• modeling means for mathematically approximating the standard frequency transfer function for each band divided by said band division means to obtain a standard approximate model for each band, and mathematically approximating the varied frequency transfer function for each band to obtain a varied approximate model for each band, respectively;
• variation computing means for computing a variation of the varied approximate model to the standard approximate model for each band;
• modern controller setting means for setting a modern controller for the variation in each band computed by said variation computing means, respectively, to provide a plurality of modern controllers;
• parallel processing means for processing the plurality of modern controllers in parallel with each other;
• and
• actuating means for actuating said controlled system according to a result processed by said parallel processing means.