What are the advantages and disadvantages of different PID tuning methods?

1 Manual tuning

Manual tuning is the simplest and most intuitive method to adjust the PID gains. You start with zero values for all gains and then increase the proportional gain until you get a steady oscillation. Then, you reduce the proportional gain by half and add some integral gain to eliminate the steady-state error. Finally, you add some derivative gain to reduce the overshoot and improve the response time. The advantage of manual tuning is that you can see the effects of each gain on the system and fine-tune them according to your preferences. The disadvantage is that manual tuning can be tedious, trial-and-error based, and sensitive to noise and disturbances.

2 Ziegler-Nichols method

Ziegler-Nichols method is a systematic and analytical method to determine the PID gains based on the frequency response of the system. You first obtain the ultimate gain and the ultimate period of the system by increasing the proportional gain until you get a sustained oscillation. Then, you use these values to calculate the PID gains using some empirical formulas. The advantage of Ziegler-Nichols method is that it provides a quick and easy way to find the PID gains without requiring a mathematical model of the system. The disadvantage is that it may result in a large overshoot, a long settling time, or an unstable system if the system is nonlinear, time-varying, or has significant dead time.

3 Cohen-Coon method

Cohen-Coon method is another analytical method to determine the PID gains based on the step response of the system. You first obtain the process gain, the time constant, and the dead time of the system by fitting a first-order plus dead time model to the step response data. Then, you use these values to calculate the PID gains using some empirical formulas. The advantage of Cohen-Coon method is that it provides a more accurate and robust way to find the PID gains than Ziegler-Nichols method, especially for systems with large dead time. The disadvantage is that it requires a well-defined step response and may not work well for systems with higher-order dynamics, nonlinearities, or disturbances.

4 Software-based tuning

Software-based tuning is a modern and advanced method to optimize the PID gains using computer algorithms and simulations. You can use various software tools, such as MATLAB, Simulink, or LabVIEW, to design, test, and implement your PID controller. You can also use different optimization techniques, such as genetic algorithms, particle swarm optimization, or fuzzy logic, to find the best PID gains for your system. The advantage of software-based tuning is that it can handle complex and nonlinear systems, reduce the human error and effort, and achieve better performance and stability than other methods. The disadvantage is that it may require more computational resources, technical skills, and knowledge of the system model and parameters.