Controller Structure Design for Decentralized Control of Coupled Higher Order Subsystems

Abstract

We address the design of optimally decentralized controllers for linear discrete-time systems. Decentralized controllers are designed that use local measurements and a minimal number of additional measurement links between the subsystems and the controllers. The structure of the decentralized controller, i.e. the additional links between the subsystems and the controllers, is not specified in advance but included into the controller design. We consider state feedback for higher order subsystems and define a pattern matrix to deal with the block structure of the controller. We formulate this problem as a maximization of the degree of decentralization, subject to a given error performance in terms of the H∞-norm between the centralized and the decentralized closed loop. For the resulting non-convex optimization problem, numerically tractable convex relaxations are provided and an example shows the effectiveness of this approach.