Control of a Reverse Osmosis plant by using a robust PID design based on multi-objective optimization

Normally, Reverse Osmosis desalination plants (RO plants) include one or two PID (Proportional, Integral, and Derivative) controllers. These controllers usually are not optimally tuned because models are not constant for a long time due to the fact that plant parameters change often. In the current work, the PID controller of the flow rate control loop for permeate is designed by using multi-objective parametric optimization so that the control loop is less sensitive to parameter changes of the plant. Simulation results on a model of a real plant show that the proposed method yields satisfactory performance for wide range of operation conditions.