In order to solve the problem,the dynamic equation of the stator is solved with the structural perturbation theory,then a method is found by resolving the equation,thus adjusting the two modal f.

The robust stability of time_lag systems with structural perturbation is investigated.

Although LQG(LinearQuadraticGaussian) method has been much used in robust control of a structural perturbation system, we found that improvement could be achieved by making the eigenvector of closeloop control system as closely orthogonal as possible to two matrices to be named later.

Presents the sufficient conditions for asymptotic stability of systems respectively when uncertain parts are unconstructed perturbations and highly constructed perturbations, using the transcendental inequality and the matrix measure and the matrix norm, illustrates the conservatism of the conditions given than that given in the literature with a numerical example.

Presents the sufficient conditions for asymptotic stability of systems respectively when uncertain parts are unconstructed perturbations and highly constructed perturbations, using the transcendental inequality and the matrix measure and the matrix norm, illustrates the conservatism of the conditions given than that given in the literature with a numerical example.

Given a family of polynomials with structured perturbations,and a stability region in the complex plane,whether the family has invariant root numbers with respect to the interior,the boundary and the exterior of the region? The peper answers the so-called invariant inertia question.