| 초록 |
The well-known internal model control (IMC) PID rules have the advantage that a clear tradeoff between closed-loop performance and robustness to model inaccuracies is achieved with a single tuning parameter. The reported literatures show that IMC-PID provides good setpoint tracking but very sluggish disturbance response for tuning the process with a small time-delay/time-constant ratio. However, for many process control applications, disturbance rejection is much more important than setpoint tracking. Therefore, controller design that emphasizes disturbance rejection is an important design problem that has received renewed interest recently. Therefore, in this article, we have proposed a modified filter for the unstable processes like first order delay unstable (FODUP) and the second order delay unstable processes (SODUP). The generalized IMC-PID approach is used to obtain the PID parameters for process model by approximating the ideal controller with a Maclaurin series in the Laplace variable. The PID parameters obtained for the unstable process provides better closed-loop responses than those obtained previously for disturbance rejection. |
