Partially decentralized control structure selection and design for a benchmark boiler

Drum boiler is a multivariable nonlinear system with strong interactions and input constraints. Since the boiler involves integral, the general method of selecting control structure is not applicable here. In this paper, a new control structure analysis method based on the open loop shaping is proposed for a benchmark boiler control problem, which is proposed in the IFAC Conference 2012. First a centralized multivariable PID controller based on H_∞ loop-shaping approach is designed as an optimal one, and then reduced it to partially decentralized ones. At last, compared the open loop singular values shapes between the centralized and the partially decentralized ones to obtain the expected partially decentralized structure. Experiment simulations show that the proposed partially decentralized control performs well for the nonlinear boiler system, nearly equivalent to the multivariable control, and they achieve better performance indexes than the reference decentralized one.