Extremal gain and phase margins for interval systems
Lee H. Keel, Shankar Prasad Bhattacharyya · Navigation and Control Conference · 1991
A general feedback configuration that consists of two linear time invariant systems is considered. One of which is fixed and the other is uncertain. The uncertain system possesses its uncertainty in the form of parametric uncertainty. This paper considers the case of the parametric uncertainty being represented as upper and lower bounds of coefficients of the numerator and denominator polynomials of the uncertain system transfer function. This type of a system is called an interval system. Using this setup, we develop Bode plots to analyze and design the control systems. The development of Bode plots for an interval system is new and may play an important role in many robust control design and analysis