On the computation of the maximal structured singular value for aeronautical applications

This paper considers the necessary transformations and the computational issues associated with the determination of the maximal structured singular value, μ_max without the use of a frequency gridding strategy. It is shown that, for the case of purely real model perturbations, convergence difficulties exist in determining bounds on μ_max using existing Matlab software. A new computational scheme is presented which improves on existing methods for the computation of the worst case combination of real uncertain parameters. This scheme easily outperforms regularisation type solutions, which have been suggested as one way of improving the convergence properties of a strictly real robustness analysis. The improvement is illustrated on a well known civil aircraft robustness analysis example.