Data-driven direct control method for coagulation dosing large time-delay process in water works
水厂混凝投药大滞后过程的数据驱动直接控制方法

To deal with the large time-delay in the coagulation dosing process in water works, we, in combining with Smith predictor, propose a novel data-driven direct control method based on the iterative feedback tuning(IFT) method. In considering the characteristics of the large time-delay, we add to the performance index a penalty factor of predictive errors in the controller design. A novel step size setting scheme is proposed in which the rate of descent of the step size is adjustable. Three closed-loop experiments are carried out to perform the gradient descent optimization of the cost function which is computed totally from the I/O data in the close-loop system. The parameters of controller and predictor are automatically tuned for an unknown plant. Simulation studies with a practical coagulation dosing process model are conducted. Results show that the convergence and stability of this algorithm outperform classical IFT in large time-delay applications and with less dependence on the initial parameters. This scheme can be applied to the initial tuning of the controller or for the automatic tuning during the dosing process.