In many real world control problems, it is usually desirable to meet specified control goals using controllers with simple structures like as proportional-integral (PI) and proportional-integral derivative (PID) which are useful in industry applications. Since practically, these controllers are commonly tuned based on experiences, classical or trial-and-error approaches, they are incapable of obtaining good dynamical performance to capture design objectives. This paper addresses a systematic method to design robust PIIPID controllers based on H∞ -control technique. First the PIIPID control problem is reduced to an H∞ -static output feedback control synthesis, and then the control parameters are easily carried out using an iterative linear matrix inequalities (ILMI) algorithm. A numerical example and simulations are given to illustrate the proposed methodology.
