Determination of All Stabilizing PID Controllers for Time Delay Systems With Smith Predictors

Time delays in the control loop complicate the analysis and design of controllers. The use of a Smith predictor is a well-known technique for dealing with delays in stable systems. This paper presents a method for finding all stabilizing Proportional Integral Derivative (PID) controllers when the Smith predictor is used. This paper introduces a general method to determine all achievable PID controllers even when there is a mismatch between the plant and Smith predictor model. A key advantage of this approach is that it requires only the frequency response of the plant.