Significance of Low-level Controller for String Stability under Adaptive Cruise Control
Abstract
Current commercial adaptive cruise control (ACC) systems consist of an upper-level planner controller that decides the optimal trajectory that should be followed, and a low-level controller in charge of sending the gas/brake signals to the mechanical system to actually move the vehicle. We find that the low-level controller has a significant impact on the string stability (SS) even if the planner is string stable: (i) a slow controller deteriorates the SS, (ii) slow controllers are common as they arise from insufficient control gains, from a "weak" gas/brake system or both, and (iii) the integral term in a slow controller causes undesired overshooting which affects the SS. Accordingly, we suggest tuning up the proportional/feedforward gain and ensuring the gas/brake is not "weak". The study results are validated both numerically and empirically with data from commercial cars.
Cite
@article{arxiv.2104.07726,
title = {Significance of Low-level Controller for String Stability under Adaptive Cruise Control},
author = {Hao Zhou and Anye Zhou and Tienan Li and Danjue Chen and Srinivas Peeta and Jorge Laval},
journal= {arXiv preprint arXiv:2104.07726},
year = {2021}
}