Robust ... Control of Uncertain Systems with Structured Uncertainty

This paper considers a problem of absolute stabilization with a specified level of disturbance attenuation for a class of uncertain systems in which the uncertainty is structured and satisfies a certain integral quadratic constraint. The paper shows that an uncertain system is absolutely stabilizable with a specified level of disturbance attenuation if and only if there exists a solution to a corresponding H 1 control problem. The paper also shows that if an uncertain system can be absolutely stabilized with a specified level of disturbance attenuation via nonlinear output feedback control, then it can be absolutely stabilized with a specified level of disturbance attenuation via linear output feedback control. Key words: robust H 1 control, absolute stabilizability, uncertain systems, integral quadratic constraint, structured uncertainty, nonlinear control AMS Subject Classifications: 93B36 1 Introduction An important idea to emerge in recent years is the connection between t..