Control of nonlinear steam generation processes using H∞ design

While the theoretical aspects of H_∞ optimal control have received widespread attention, the nontrivial application issues of this methodology are not often elaborated on. In this paper we detail our experience with H_∞ optimal control as applied to a central heating plant boiler model which exhibits nonlinearities, instability, non-minimum phase behavior, and colored noise disturbances. Descriptions of each step of the design are provided and motivated by features of the model which present problems. The performance of the controller is evaluated by simulation using the boiler model. The H_∞ design is suggested as the foundation for a general method to design control systems for smooth nonlinear plants via gain scheduling.