PID tuning controller using internal model control method

Abstract

There are three design methods commonly used nowadays for second order systems, the method of state space design, lag/lead filter compensation and finally the Internal Model Control (IMC) method [3, 8, 11]. The latter design is utilised in control of current in DC electrical motors (servo system) and many other second order systems. The internal model control design has capabilities of achieving high performance. The IMC technique, in theory, substitutes the closed loop system with a low-pass filter of the same order as the system itself. In this case the plant (process) under control is always second order, so if an exact representation of the plant (process model) is given, the step response for a change in the reference signal would look as a low-pass filter step response.