Robust H∞ control for uncertain continuous-time singular systems with circular pole constraints

This paper focuses on the problem of the robust H_∞ control with circular pole constraints in uncertain singular systems. Firstly, the concept of quadratic d stablizability with an H_∞ norm-bound is introduced for the uncertain continuous-time singular system. Secondly, the robust H_∞ control problem is solved in the uncertain continuous-time singular systems, on the basis of circular pole constraints. At last, on the notion of quadratic d stablizability with an H_∞ norm-bound, we gain the state feedback controllers for uncertain singular systems such that the closed-loop singular systems are regular and impulse-free, and the closed-loop poles are located within a preassigned circular region, and the H_∞ norm-bound of the closed-loop transfer function matrix is strictly less than a given positive constant for all admissible uncertainties.