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arXiv · 2105.13799

Inaccuracy matters: accounting for solution accuracy in event-triggered nonlinear model predictive control

Abstract

We consider the effect of using approximate system predictions in event-triggered control schemes. Such approximations may result from using numerical transcription methods for solving continuous-time optimal control problems. Mesh refinement can guarantee upper bounds on the error in the differential equations which model the system dynamics. With the accuracy guarantees of a mesh refinement scheme, we show that the proposed event-triggering scheme -- which compares the measured system with approximate state predictions -- can be used with a guaranteed strictly positive inter-update time. We show that if we have knowledge of the employed transcription scheme or the approximation errors, then we can obtain better online estimates of inter-update times. We additionally detail a method of tightening constraints on the approximate system trajectory used in the nonlinear programming problem to guarantee constraint satisfaction of the continuous-time system. This is the first work to incorporate prediction accuracy in triggering metrics. Using the solution accuracy we can guarantee reliable lower bounds for inter-update times and perform solution dependent constraint tightening.

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BibTeXRIS

Omar J. Faqir, Eric C. Kerrigan. 2021-05-28. Inaccuracy matters: accounting for solution accuracy in event-triggered nonlinear model predictive control. https://arxiv.org/abs/2105.13799

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