Determining tuning parameters for a process controller from a robustness map

Abstract

A simulation procedure simulates the response of a process control loop having a controller tuned according to a set of tuning parameters to illustrate, for example, the overshoot, oscillation, response time, etc. of the controller as tuned. As part of the simulation procedure, a robustness map, such as a plot illustrating phase margin versus gain margin or other robustness qualities, is created and the robustness of the simulated control loop may be plotted as a point on the robustness map. During the creation of the robustness map, different sets of tuning parameters for a region in which the process control loop is stable are determined and stored and the corresponding robustness qualities of the loop having a controller tuned according to these tuning parameters are also determined and stored. The robustness map is then displayed to a user showing the stable region. Thereafter, a user may select any point within the stable region on the robustness map and, upon doing so, a set of tuning parameters that will produce a control loop with the selected robustness characteristics will then be determined from the previously calculated sets of tuning parameters and robustness qualities. The simulation routine may then simulate the control loop using these new tuning parameters to enable a user to view the performance characteristics of the resulting control loop.