Disturbance attenuation property for random disturbances in two-degree-of freedom optimal servo control systems

The two-degrees-of-freedom optimal servo control systems have advantages that the integral gain can be tuned for improving feedback properties such as disturbance attenuation properties, while tracking property is independently designed of feedback properties using nominal controlled process model. However, the earlier works have not studied the effect of the integral. This paper considers the effect of the integral gain in the two-degrees-of-freedom optimal servo control systems in the presence of random disturbances. From the simulation study, there exist a tradeoff relation between the tracking property and output variance depression.