A new control algorithm for turbidity in water plant

Water quality is related to the national economy and a major event,water turbidity after filtering in the water supply system is one of the key indicators of water quality.Against to large inertia,large delay,model parameters time varying and much disturbance of water turbidity control in city supply system,a new control algorithm is proposed to obtain better control results.The specific idea of the algorithm is the double controller:the track controller and the disturbance controller in view of different task.The former adopts a nonlinear compensation PI controller to track the set point,the latter uses a traditional PI controller to restrain the disturbance from the process.The gain K of the nonlinear compensation part is very important to the track controller and adopts expert rules according to the system response.The simulation comparison of the new algorithm and the traditional PID feedback control algorithm,Smith predictive control and dual PI control algorithm has been done in this paper.Finally the new control algorithm is applied to a pilot base.The results of simulation and experiment show that the new control algorithm can overcome disturbance in time,is not sensitive to changes of model parameters and has a strong robustness and a good tracking ability to ensure the stability of water quality.