Tuning of PI, PD, and PID Controllers Based on Fuzzy Logic Using IoT

Abstract

Hydroponic plants require nutrients with a certain concentration according to the type of plant to be cultivated. This study aims to maintain nutrient concentration at a predetermined value. If the concentration measured is below set point, nutrients need to be added. Conversely, water is added as a diluent. PI, PD, and PID controllers are used to adjust servo angle on the water and nutrient valve, then compared to determine the type of controller that provides best response. Controller parameter values ​​​​Kp, Ki, and Kd are then tuned using fuzzy logic. System then uses internet of things (IoT) so that it can be monitored remotely. The variables observed are time required to reach set point and average error generated. Based on testing, PI controller obtained the time to reach set point is t = 50 and the PID controller t = 30. While on PD controller, response did not reach set point during observation. Average error generated on PI controller is 47.95, PD controller 76.55, and PID controller 30.97 where initial concentration value is in range of 70 ppm and target set point is 400 ppm.