Stability robustness of nonlinear dynamic inversion based controller

This paper presents an analysis on stability robustness of the widely used nonlinear dynamic inversion algorithm. By using nonlinear dynamic inversion algorithm, the multiple-inputs-multiple-outputs affine nonlinear system which has bounded uncertainty and disturbances is transformed into a linear time varying system with special structure. Thus the stability robustness issues of nonlinear dynamic inversion based controller are formulated as the stability problem of linear time varying differential equation and solved by linear time varying system theory. Sufficient conditions of stability and tracking error bound for the closed loop system are given and an illustrative example is also presented.