抄録
PID control algorithm has been used for several process control systems up to now. However, it is difficult to determine appropriate gains in this control algorithm. For example, we may have excessive overshoot and long settling-time as adjusting gains. Therefore, it is important to determine and adjust PID control gains since control performance depends on these gains. Takahashi has proposed a method to determine PID gains by using characteristics of a step response. However, we may not be able to get a control performance the case of time-variant process control system.
In this paper, in order to overcome these problems we construct a self-tuning PID control system based on the generalized minimumvariance control. We derive a system model from the PID control scheme. By the least squares identification method, the unknown parameters included in the system model are estimated. Using the estimated parameters we obtain prediction values of the system. Letting the prediction values equal a desired signal of the process, we construct a selftuning PID control system. To show the effectiveness of the present self-tuning control system some numerical simulation results are illustrated. Finally, the proposed control method is applied to the pressure control problem for the pressure tank and the quantitative effectiveness is shown.
