Single-loop controller design via IMC principles

In this paper, a new internal model control (IMC)-based single-loop controller design is proposed. The model reduction technique is employed to find the best single-loop controller approximation to the IMC controller. Compared with the existing IMC-based methods, the proposed design is applicable to a wider range of processes, and yields a control system closer to the IMC counterpart. It can be made automatic for on-line tuning. The users have the option to choose between PID and high-order controllers to suit the applications better. It turns out that high-order controllers may be necessary to achieve high performance for essentially high-order processes.