CENTRAL FLOW-CONTROL IN SEWER NETWORKS

Control methods are applied to sewer network flow in the aim of reduci ng pollution of receiving waters. A multilayer control structure consi sting of an adaptation, an optimization, and a direct control layer ma y be used for the solution of the complex control problem. Several app roaches have been proposed with regard to the optimization layer. This paper focuses on the comparison of two methods, the nonlinear optimal control and the multivariable feedback control. For the numerical sol ution of the nonlinear optimal control problem a feasible direction al gorithm is used, and for the design of the linear multivariable feedba ck regulator a linear-quadratic approach is applied. A detailed study of the central control problem for a particular sewer network is prese nted using these two methods and comparing their respective efficiency . Results indicate a slight superiority in terms of efficiency of the nonlinear optimal control approach for the price of an increased, but real-time, feasible computational effort.