Cooperative Adaptive Cruise Control with Variable Time Headway for Graceful Degradation under Fluctuating Network Quality of Service

TL;DR

This paper introduces a control method for Cooperative Adaptive Cruise Control that adaptively adjusts inter-vehicle distances based on network quality, ensuring stability and safety during fluctuating network conditions.

Contribution

It presents a novel online distance adaptation algorithm with a control design that guarantees robust stability using IQC framework, validated through simulations and experiments.

Findings

The control algorithm maintains stable vehicle platooning under variable network QoS.

Simulation and experimental results confirm effective graceful degradation.

The IQC framework ensures robustness of the adaptive control system.

Abstract

This paper proposes a dynamic distance adaptation for Cooperative Adaptive Cruise Control (CACC) under time-varying network conditions. When the Quality of Service (QoS) drops below a level required to maintain desired inter-vehicle distances, an online adaptation of the reference distances, reflected by a change of the time headway factor, becomes necessary. We present a control design algorithm realizing a graceful degradation, for which a distance control to a virtual preceding vehicle is introduced. Furthermore, the Integral Quadratic Constraints (IQC) framework is applied to guarantee robust stability of the time-varying system. The concept is validated in simulation and experimentally using small-scale test vehicles.