Optimum feedback patterns in multivariable control systems

The following problem is considered: 'Given a multivariable system with nl inputs and r outputs and an external matrix whose non-negative (i, j)th element represents the cost of setting LIP a feedback link from the, jth output to the ith input, find a set of feedback links with minimum total cost, which does not give rise to fixed modes'. Utilizing the graph-theoretic churiicterization of structurally fixed modes, the problem is decomposed into two subproblems. which are then solved by using concepts and results from network theory. A combination of the optimum solutions of the subproblems provides a suboptimal solution to the original problem. © 1989 Taylor & Francis Group, LLC.