Robust stability analysis method for vibration systems by using virtual perturbations

In this paper, a robust stability analysis problem for mechanical vibration systems is considered. As well known, μ-analysis is a useful tool in order to guarantee stability robustness, but obtained results by conventional procedures are sometimes conservative. It is caused by weakness of valuation tools of perturbations. For example, a specified weighting function whose gain covers all of the gains of unstructured perturbations requires tolerating wider perturbations than realistic ones. On the other hand, to guarantee stability robustness of active control system is extremely important and tight evaluation methods are required. In this paper, a new robust stability analysis method for mechanical vibration systems by using virtual parametric perturbations is proposed. The effectiveness of the proposed method is verified by a mechanical vibration system example and the proposed method can guarantee the stability robustness with reducing conservativeness in comparison with conventional methods.