Revisit of first order unstable time delay systems with P and PI controllers: A digital control approach

We consider the control of first order unstable systems with time delays in this paper. Explicit tuning formulae are derived for Proportional (P) and Proportional-Integral (PI) controllers, based on the digitized open loop systems. Stability range is also discussed for the feedback systems with delays. Compared with existing results, the present method significantly improves the accuracy and simplifies the tuning process. Numerical examples are given to illustrate this algorithm, where several relevant methods are also compared.