中文摘要：

The robust stability of systems under both plant and controller perturbations is analyzed, with anemphasis on additive norm-bounded perturbation. Choosing the interconnection matrix M makes Δ（s） blockdiagonal matrices and absorbing any matrix makes ||Δ（s）||_∞【1, the problem can be recast into a smallstructured singular value （μ） problem. If 2S+F≤3, μ（M）=inf σ(DMD^-1). In this paper, the main