Cohen-Coon PID Tuning Method: A Better Option to Ziegler Nichols-Pid Tuning Method

Abstract

Controller loop tuning is the process of manipulating the parameters (gains) in a proportional-integral-derivative (PID) controller in order to give satisfactory response to the process system. A satisfactory response is one that exhibits the desired speed of response, yet meets the required accuracy and stability criteria. Control processes are generally tuned under operating conditions, as opposed to start-up conditions, so that the process variable is stable at an operating point. In the industry, the PID human tuning method normally applies to machinery tuning is the Ziegler Nichols (ZN) tuning method, known as the ZN-PID tuning method. However, this PID controller tuning method is ineffective in the control of nonlinear and complex system with varied parameters, large inertia and large delay, as it tends to give a very higher overshoot, higher rise time and higher settling time in the system operation. These disturbances, due to the nonlinearity of the system under control cause the controller to produce poor responses at the output, leading to poor system performance. The limitations in this ZN-PID tuning method could be overcome by using Cohen-Coon-PID (CC-PID) tuning method to drive the system plant. In a nutshell, this research work takes a look at the CC-PID tuning method as betterment to the current ZN-PID tuning method being mostly used in the industrial machinery control. This research work finds application in any PID controlled plant.