Feedback Control Algorithms for the Dissipation of Traffic Waves with Autonomous Vehicles

Abstract

This article considers the problem of traffic control in which an autonomous vehicle is used to regulate human piloted traffic to dissipate stop and go traffic waves. We first investigate the controllability of well-known microscopic traffic flow models, namely i) the Bando model (also known as the optimal velocity model), ii) the follow-the-leader model, and iii) a combined optimal velocity follow the leader model. Based on the controllability results, we propose three control strategies for an autonomous vehicle to stabilize the other, human-piloted traffic. We subsequently simulate the control effects on the microscopic models of human drivers in numerical experiments to quantify the potential benefits of the controllers. Based on the simulations, finally we conduct a field experiment with 22 human drivers and a fully autonomous-capable vehicle, to assess the feasibility of autonomous vehicle based traffic control on real human piloted traffic. We show that both in simulation and in the field test that an autonomous vehicle is able to dampen waves generated by 22 cars, and that as a consequence, the total fuel consumption of all vehicles is reduced by up to 20%.

Traffic Flow on a Ring With a Single Autonomous Vehicle: An Interconnected Stability Perspective

“…In this work, we extend the existing theories and provide a theoretical framework for the aforementioned experiments by studying both classical and interconnected stability on the ring roadway. Our framework is based on Linear Time Invariant (LTI) systems theory: this choice is consistent with most analytic studies on the topic of mixed traffic [6,10,32,33,35], relying on linearization of the nonlinear vehicle dynamics around the equilibrium flow. Furthermore, LTI systems allow us to work in the frequency domain, in which string stability lends itself to a natural characterization based on the ratio of two transfer functions.…”

“…The weak ring stability notion also completes the currently-known range of possibilities and limitations of traffic control via sparse autonomous vehicle [5]: most notably, it indicates how to design mixed traffic scenarios with improved string stability specifications (dampening any oscillation). Key to this development is studying the AV controller originally proposed in [6], which employs a Proportional Integral (PI) control with saturation: once its limitations are understood, we can propose a novel design that partly overcomes them. Indeed, string stability can be ensured at the price of reducing the sparsity of the autonomous vehicles (Section 5).…”

On a weaker notion of ring stability for mixed traffic with human-driven and autonomous vehicles

“…The AV is the N -th vehicle with preceding vehicle 1. The work [12] proposed a non-linear AV controlleṙ where v target and α are…”

“…Motivated by these experiments, we analyse a linearized version of the control algorithms developed in [12]. First we give a new definition of string stability on the ring (ring stability) motivated by the fact that uniformity in the number of vehicles in the platoon, as required in standard notions, is not appropriate for mixed traffic scenarios (human/automated vehicles).…”

A multiscale model for traffic regulation via autonomous vehicles

“…Despite such achievements, a complete macroscopic theory for control of bulk traffic via AVs is still missing. The need of a macroscopic theory is due to the curse of dimensionality preventing control design for microscopic models [12].…”