Stability of autonomous vehicle path tracking with pure delays in the control loop

Authors: Heredia, Guillermo; Ollero, Anibal

Source: Advanced Robotics, Volume 21, Numbers 1-2, 2007 , pp. 23-50(28)

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Abstract:

This paper presents a new method to analyze the stability of a general class of mobile robot path-tracking algorithms taking into account explicitly the computation and communication delays in the control loop. These pure delays are present in autonomous vehicles due to position estimation. The problem is analyzed by solving directly the transcendental characteristic equation that appears when the time delay is considered. The analysis has been done for straight paths and paths of constant curvature. The method has been applied to the pure pursuit path-tracking algorithm, one of the most widely used. The paper presents several tests with two different outdoor autonomous vehicles (ROMEO-3R and a computer controlled HMMWV), in spite of difficulties of practical experiments with real vehicles close to the stability limits. These tests pointed out how the predictions of the stability of the proposed methods obtained by using simple models are verified in practice with two different outdoor vehicles.

Keywords: AUTONOMOUS VEHICLES; MOBILE ROBOTS; PATH TRACKING; STABILITY; TIME DELAY

Document Type: Research article

DOI: http://dx.doi.org/10.1163/156855307779293715

Publication date: 2007-01-01