Quasi-LPV Transformations for Robust Gain Scheduling of Incremental Nonlinear Dynamic Inversion-based Controllers

Nonlinear Dynamic Inversion (NDI) has a long and successful history of research and development. The need for gain scheduling for nominal performance may be alleviated with the NDI method, which is accompanied by developmental benefits in terms of design modularity and transparency. However, the robustness of NDI-based control laws remains dependent on the nature of the open-loop plant. In this paper, a design and analysis framework based on quasi Linear Parameter-Varying (q-LPV) system theory is proposed that systematically considers this aspect across nonlinear operating regimes. The q-LPV model framework is presented in the context of robust hybrid incremental NDI control design, which incorporates inversion error compensation in addition to baseline model predictions. Based on a design case study for a simulated aeroservoelastic system, it is shown how systematic gain scheduling of the related inversion compensation design parameters can be performed with the proposed approach.