PID versus MPC Performance for SISO Dead-time Dominant Processes*

Proportional-Integral-Derivative (PID) controllers are used extensively in the process industries for regulating single-input, single output (SISO) processes, with Model Predictive Controllers (MPC) typically being reserved for use on large scale systems. However, in recent years there has been suggestions that MPC may offer benefits when applied to SISO systems at the regulatory level. This paper compares the performance of PID and MPC when they are both applied to first and second order, SISO systems that contain a time delay. From the comparison it can be concluded that improved performance can be achieved by using MPC for, in some cases, very small time delays. Both PID and MPC are shown to be robust to plant-model mismatch.