Lateral String Stability for Vehicle Platoons

2026-06-28

AI Summary

This study addresses the safety risks arising from the propagation of lateral path-tracking errors in vehicle platoons by filling a critical gap in lateral string stability research. The authors propose a unified modeling framework based on arc-length parameterization and introduce, for the first time, a path-point-centered definition of lateral string stability, enabling consistent cross-vehicle error analysis. Building on this foundation, two control strategies are developed: one relying solely on onboard sensing and another incorporating a “learning-from-leading-vehicle” mechanism via vehicle-to-vehicle (V2V) communication. Theoretical analysis and simulations demonstrate that purely onboard sensing fails to guarantee error attenuation, whereas integrating V2V communication effectively suppresses error propagation and significantly enhances the lateral safety of the platoon.

Abstract

Connected and automated vehicle (CAV) platooning promises gains in energy efficiency and traffic throughput and, most critically, in safety. These safety benefits hinge on string stability, which determines how disturbances propagate along a platoon. While longitudinal string stability is well studied, lateral string stability, which governs the propagation of path-tracking errors that can lead to unsafe deviations from the intended path, remains underexplored. Its importance is increasing as autonomous vehicles rely more heavily on onboard sensing and map-free navigation, where sensor occlusion and dense formations amplify safety risks. This paper presents a new framework for lateral string stability that directly addresses safety-critical path-relative tracking errors and enables consistent comparison across vehicles following the same road geometry. Central to this framework is an arc-length (Eulerian) viewpoint, a departure from traditional analyses, that clarifies how tracking errors at a given point on the path propagate from one vehicle to the next. A formal definition of lateral string stability is introduced along with two control strategies: an onboard-sensing-only controller and a novel learn-from-predecessor approach utilizing vehicle-to-vehicle (V2V) communication. We show that onboard sensing alone cannot guarantee attenuation of path-tracking errors, imposing a fundamental safety limitation, whereas V2V communication enables true error attenuation.

Problem

• lateral string stability
• vehicle platooning
• path-tracking errors
• connected and automated vehicles
• safety

Innovation

• lateral string stability
• arc-length perspective
• path-tracking error
• vehicle-to-vehicle communication
• platooning control