A Novel Process-Reaction Curve Method for Tuning PID Controllers

A novel process-reaction curve method for tuning PID controllers for (possible) higher order processes/models is presented. The proposed method is similar to the Ziegler-Nichols process reaction curve method, viz. only the maximum slope and lag need to be identified from an open loop step response. The relative time delay error (relative delay margin), δ is the tuning parameter. The proposed method is verified through extensive numerical simulations and is found close to optimal in many of the motivated process examples. In order to handle the wide set of process models, two model reduction modes are presented.