A method for detecting the oscillation in control loops based on variational mode decomposition

Nowadays, the plant performance is a big issue in process control. One of the major factors to indicate the plant performance is the oscillation in control loops. The oscillation detection should be applied first before implementing the plant performance improvement methods. This paper presents a new method to detect the oscillation in control loops. This method is based on variational mode decomposition (VMD). VMD is used because it can decompose the signal accurately. In this research, VMD is combined with the autocorrelation approaches to analyze the character of the oscillation. Four data sets from the Tennessee Eastman problem simulations are used to evaluate the performance of this method. The evaluation is provided in four different conditions, i.e. normal condition, abnormal conditions due to sticking valves, external process disturbances and mistuned controllers. The results show that this method can characterize the oscillation in control loops. It can define the oscillatory process variable accurately.