Precision preview-based stable-inversion for nonlinear nonminimum-phase systems: The VTOL example

This article quantifies the importance of the future desired trajectory in determining the exact-output-tracking input for nonlinear, nonminimum-phase systems by using system inversion techniques. It is intuitive that the effect of the desired output's distant-future values, on the output-tracking input at the current time instant, should be small. Therefore, at a current time instant (tc)(tc), preview information of the desired output in a finite-time window [tc,tc+Tp][tc,tc+Tp] should be sufficient to compute the output-tracking input with an arbitrarily small prescribed error, if the preview time TpTp is sufficiently large. The contribution of this article is the quantification of the needed preview time TpTp by using the benchmark VTOL aircraft model as an example. Additionally, simulation results are presented to evaluate the efficacy of the finite-preview-based stable-inversion approach.