Gain adjusting device for pid controller for controlling rotational

Abstract

A plurality of characteristic variables concerning the rotational speed are detected so as to be used for inference, and the plurality of characteristic variables are divided into a plurality of sets. Groups of rules each indicating the relationship between the characteristic variable corresponding to each set and an amount of gain adjustment, as well as the relationship between the magnitude of the characteristic variable corresponding to each set and the degree of adoption of the amount of gain adjustment, are stored. When it is determined that each of the characteristic variables cannot be controlled within a permissible range, the relationship between each of the characteristic variables of the groups of rules and the amount of gain adjustment is corrected in such a manner that the permissible range is broadened. The amount of gain adjustment for each set is inferred on the basis of the characteristic variable detected and each group of rules, and the degree of adoption of the amount of gain adjustment is determined for each of the sets in correspondence of the manipulated variable of the respective characteristic variables. On the basis of the result of inference of the amount of gain adjustment and the degree of adoption, an amount of gain to be adjusted is determined by calculating a weighted average value of the result of inference of the amount of gain adjustment with the degree of adoption set as weight. This amount of gain to be adjusted is set in a PID controller.