Robust Control of Uncertain Time-delay Systems

The time delay in transport of material and energy is an inseparable part of many real industrial processes. Unfortunately, the presence of time-delay terms itself almost always brings problems in control and, quite naturally, the situation is even more complicated if this delay is uncertain. The source of the uncertainty can arise e.g. from simplifications during mathematical modelling, changes in physical parameters or various operational conditions. The main aim of the contribution is to show capabilities of robust algorithms designed via an algebraic approach in control of systems with parametrically uncertain time delay. The robust stability of the closed loop is graphically analyzed using the value set concept and the zero exclusion condition.