A loop transfer recovery approach to h∞ design for the coupled mass benchmark problem

This paper presents two robust fixed order dynamic compensator designs for the coupled mass benchmark problem. The design technique uses a method for Loop Transfer Recovery at the plant input to approximately recover the transfer properties of a reduced parameter sensitivity full state H_∞ controller. The recovery is accomplished by the unique selection of quadratic performance index weighting matrices in a standard optimal output feedback formulation for fixed order compensation. An observer canonical form is used to represent the compensator dynamics. The first design addresses Problem ^#1, where only the spring stiffness is uncertain. The second design focuses on Problem ^#2, which has three uncertain parameters.