pH control using PI control algorithms with automatic tuning method

pH control is quite difficult due to the non-linearity of the neutralizatio n process. In this case, tuning the standard PI controller is a must to ach ieve a stable feedback response. This paper, thus, addresses the applicatio n of an automatically tuned PI algorithm to stabilize the pH-value of a pH neutralization process. The proposed adapted PI algorithm uses a simple mod el for the process to predict the pH closed-loop response and its sensitivi ty to the PI settings. The information obtained is directly used to adjust the PI tuning parameters online in order to produce a pH response that sati sfies a pre-defined time-domain specification. The simulation results of th e proposed method are compared with those obtained by the standard PI, gain scheduling (GS) and globally linearizing (GLC) algorithms. The comparison showed a successful and promising implementation of the proposed strategy.