Patent ID: 7092770

Claim:
A feedback control method of performing disturbance recovery control by giving a manipulated variable to a controlled system so as to make a controlled variable recover to a set point at the time of application of a disturbance, comprising: dividing a response process of disturbance recovery control into three stages including a follow-up phase, a convergence phase, and a stable phase; a first phase switching step of switching to the follow-up phase at a disturbance application detection time point as a start time point of the follow-up phase; the follow-up phase manipulated variable determination step of continuously outputting a manipulated variable which makes the controlled variable follow up the set point in the follow-up phase; the second phase switching step of switching to the convergence phase at a disturbance recovery control elapsed time point, as a start time point of the convergence phase, at which the controlled variable does not exceed the set point in the follow-up phase; the convergence phase manipulated variable determination step of continuously outputting a manipulated variable which makes the controlled variable converge near the set point in the convergence phase so as to prevent a control response waveform from being disturbed before and after a switching time point between the follow-up phase and the stable phase; the third phase switching step of switching to the stable phase at a time point, as a start time point of the stable phase, at which a preset state is reached in the convergence phase; and the stable phase manipulated variable determination step of continuously outputting a manipulated variable which makes the controlled variable stable at the set point in the stable phase.