To efficiently constitute a high performance digital robust control system suitable for the digital position control of a magnetic disk device of a low dimensional compensator order.
The basic form of a frequency weighting function is set, based on the characteristics of an object 5 to be controlled, and a high order continuous system robust control compensator using the basic form is turned into a low dimensional compensator, and divided into a low frequency band compensator and a high frequency band compensator, and then made discrete so that a low frequency band compensator 2 and a high frequency band compensator 4 can be constituted. Then, a difference between a target value and the present value of the object 5 is inputted through a low speed sampler 1 to the low frequency band compensator 2, and the output is inputted through a high speed sampler 3 to the discrete high frequency band compensator 4, and the output is inputted to the object 5. The sampling rates of the high speed sampler 3 and the low speed sampler 1 are set so that the rate of the output from the high frequency band compensator 4 to the object 5 can be several times as high as the sampling rate at which the present value is obtained.
EJIRI KAKU
WATANABE ICHIRO
