Computer-aided uncertainty modeling of nonlinear parameter-dependent systems. I. Theoretical overview

Robust control system analysis and design is based on an uncertainty description, called a linear fractional transformation (LFT), which separates uncertainties from the nominal system model. These models include both parametric and non-parametric uncertainties for many practical problems. LFT formulation for these “mixed uncertainty” systems involves formulation of a linear parameter varying (LPV) model, construction of a low-order parametric LFT model, and validation of a mixed uncertainty model with respect to measurement data. This paper provides an overview of uncertainty modeling methods and software tools being developed for application to mixed uncertainty systems. These methods and tools provide a computer-aided uncertainty modeling capability that makes current robust and LPV control methods accessible to a broad class of practical problems