Application of wavelet transform to control system diagnosis

Process systems are usually implemented feedback control systems such as PID controller for stabilizing the systems. The principle of PID control system is simple and the function is robust if it were well tuned, however, it tends to fall in sustaining oscillation state because of bad tuning in actual plants. By applying wavelet transform to chemical process data, sustaining oscillation was identified and root cause of it was isolated for better tuning.