Safe and Operationally Efficient Longitudinal Control of Autonomous Truck Platoons

TL;DR

This paper introduces a hierarchical control system for autonomous truck platoons that ensures safety, stability, and efficiency by combining real-time safety filtering, spacing regulation, and economic optimization.

Contribution

It presents a novel integrated control architecture that guarantees safety and stability while optimizing fuel efficiency in truck platoons.

Findings

The control system guarantees collision avoidance under actuation delays.

It achieves string stability and energy-efficient long-term operation.

Numerical results show improved transient response and fuel savings.

Abstract

This paper presents a hierarchical longitudinal control architecture for autonomous truck platoons that jointly addresses safety, string stability, and economic efficiency. The framework integrates a high-rate safety projection filter, a spacing-regulation layer based on a lag-aware proportional-integral-derivative (PID) controller, and a slow-timescale economic optimizer balancing fuel consumption and travel time. The safety layer guarantees collision avoidance under bounded actuation delays by enforcing forward invariance of a velocity-aware headway constraint through a high-order control barrier function. The regulation layer shapes the spacing-error dynamics into a second-order form with interpretable parameters for damping and natural frequency while explicitly accounting for actuator lag. At the macroscopic level, fuel use is modeled by a tractive-power relation that captures aerodynamic benefits of close spacing, enabling a long-term optimization of speed trajectories subject to comfort and energy trade-offs. We show that the closed-loop dynamics converge to the Optimal Velocity Model with Relative Velocity (OVRV) under undisturbed conditions and derive worst-case upper bounds for platoon stabilization time. Numerical case studies demonstrate the superiority of the proposed design over an canonical baseline controllers in both transient behavior and long-term energy efficiency.