1994 Volume 30 Issue 12 Pages 1474-1483
This paper presents a method for designing decentralized compensators based on coprime factorizations.
The proposed method consists of two steps. The first step is to approximate the given plant to a block-diagonal system, which consists of decoupled subsystems. This paper clarifies the characteristic property of block-diagonal systems, that is, the partial transfer function matrix of the right coprime factorization, corresponding to each sub-system, is not full rank. The approximation of the plant can be obtained by reducing the rank of the transfer functions. In this paper, the gap metric is used to measure the approximation error. An iterative algorithm for the approximation is proposed here.
The second step is to find a decentralized compensator which stabilizes the plant, that is, its approximation with the coprime factor perturbation. Using the μ synthesis, robust stability condition for the local compensators can be derived.
