Robust control apparatus responsive against disturbance

Abstract

A process control apparatus comprises a main controller having a first integrator for integrating a difference signal between a set point and an output of a process and a PD (proportional-derivative) arithmetic operating unit for executing the PD arithmetic operation for the output of the process. The main controller obtains a control signal on the basis of an I-PD (integral-poroportional-derivative) control method and supplying this control signal to the process. A robust controller, connected to the output of the process, comprises a high-order differentiator for high-order differentiating the output of the process, a second integrator for integrating the difference signal between the set point and the output of the process, a subtractor for subtracting an output of the second integrator from an output of the high-order differentiator, and an amplifier for amplifying an output of the subtractor and feeding back this amplified output to the control signal.

Dependencies are inferred from the claim text.