Least Square Support Vector Machines Laguerre Hammerstein Model Identification and Non-linear Model Predictive Controller Design for pH Neutralization Process

Authors : Akshaykumar NAREGALKAR, Subbulekshmi D

Pages : 80-94

Doi:10.35378/gujs.798451

View : 21 | Download : 11

Publication Date : 2023-03-01

Article Type : Research Paper

Abstract :The ability to describe the nonlinear process dynamics is an essential feature of the Hammerstein model that paved more research and application studies in system identification and control. Using the Hammerstein model, this study shows an alternative approach to identify and control the highly nonlinear pH neutralization process. This Hammerstein model called Laguerre Least Square Support Vector Machines insert ignore into journalissuearticles values(LLSSVM); models the static nonlinearity with LSSVM and the linear part with Laguerre filter. The identified LLSSVM Hammerstein model performance evaluation with Mean Squared Error insert ignore into journalissuearticles values(MSE); and Variance Accounted For insert ignore into journalissuearticles values(VAF); is better than the Linear Laguerre model. We apply the identified LLSSVM Hammerstein model to implement a Nonlinear Model Predictive Controller insert ignore into journalissuearticles values(NMPC); to control the pH neutralization process. Then evaluated NMPC performance in terms of Integral Squared Error insert ignore into journalissuearticles values(ISE);, Integral Absolute Error insert ignore into journalissuearticles values(IAE);, and Total Variation insert ignore into journalissuearticles values(TV); and Control Effort insert ignore into journalissuearticles values(CE); parameters to verify its effectiveness in set-point tracking and disturbance rejection problems. The comparison of the NMPC with the Linear Laguerre Model-based Predictive Controller insert ignore into journalissuearticles values(LMPC); shows better performance of the NMPC than the LMPC. Results show that the LLSSVM Hammerstein model replicates the pH neutralization process well than the Linear Laguerre model. Also, the identified LLSSVM Hammerstein model provides an efficient NMPC than the LMPC for the pH neutralization process.
Keywords : Hammerstein model, Non linear System, Identification Control, Laguerre filter, LSSVM pH neutralization