QFT-type design methodology for guaranteed performance in uncertain multivariable systems subjected to a disturbance

Presented in this paper is a controller design methodology for a class of uncertain, stable, multivariable systems with the objective of maintaining operating conditions within specified tolerances despite both hardware limitations and external disturbances. It is a frequency domain technique that closely parallels Quantitative Feedback Theory. The distinguishing feature of the proposed methodology is that it incorporates controller constraints such as bandwidth limitations and saturation as well as hard time domain constraints on the outputs. The synthesis can be reduced to a series of SISO loop shaping problems with well defined regions confining some nominal loop transfer function at different frequencies. Demonstrating the methodology will be the controller design for a highly ignorant multivariable system.