A sequential design methodology for large-scale LBT systems

H₂ and H_∞ based control design methodologies are widely used to deal with multivariable control problems. However, some special problems arise in the case of large-scale systems. On one hand, the complexity (due to the size of the models) of the related H₂ or H_∞, standard problems may be too high to be solved in a classical manner. On the other hand, structure constraints on the controller often exist (use of decentralized processors) and complicate the optimization problem. This paper focuses on the problem of lower block triangular (LBT) H₂ controller design for LBT systems. Based on the principle of sequential design, an algorithm is proposed, attempting to solve iteratively the global H₂ problem. It is finally applied to a particular problem, the control of a platoon of vehicles, and compared with local strategies.