Process control structure screening by steady-state multiple disturbance sensitivity analysis

Control structures with poor steady-state disturbance rejection characteristics are screened from further consideration in the control design stage using steady-state multiple disturbance sensitivity analysis of the nonlinear process models. The procedure deals with the general case where an unequal number of manipulated and controlled variables are employed. A quadratic objective function that defines the relative importance of the control objectives and the manipulated variables governs the behaviour of the system. Continuation methods trace the optimal solution set under the influence of multiple disturbances and parameter variations. The method handles saturation of manipulated variables, control loop failures and hard bounds on the controlled variables efficiently.