Linear Fractional Transformation Modeling of Multibody Dynamics Around Parameter-Dependent Equilibrium

This brief proposes a new linear fractional transformation (LFT) modeling approach for uncertain parameter-varying (LPV) multibody systems with parameter-dependent equilibrium. Traditional approaches, which consist of building the nonlinear model whole structure and linearizing it around equilibrium after numerical trimming, do not allow to isolate parametric variations LFT form. Although additional techniques, such as polynomial fitting or symbolic linearization, can provide an model, they may be time-consuming miss worst case configurations. The proposed relies on trimming linearization equations at substructure level, before assembly structure, allows only perform operations that preserve form throughout process. Since physical origin parameters is retained, linearized LFT-LPV exactly covers all plants, in single without introducing conservatism errors. An application robotic arm proposed; its nominal configuration, obtained matches provided by software Simscape Multibody, but enhanced form; robust LPV synthesis performed using MATLAB control toolbox illustrate capacity design.