9 research outputs found
Best-effort Highway Traffic Congestion Control via Variable Speed Limits
International audienceThe problem of controlling the congestion front in a single link road section is considered in this paper. For this purpose, we introduce a new variable-length two-cell lumped model composed of; one congested cell, and another in free flow. This model has the advantage of having few states while preserving the vehicle conservation property. This model is used as a basis to design a simple "best-effort" controller that regulates (at its best) the congestion front to some prespecified value. The control law can be implemented using only information about the congestion front position
Hybrid model predictive control for freeway traffic using discrete speed limit signals
HYCON2 Show day - Traffic modeling, Estimation and Control 13/05/2014 GrenobleIn this paper, two hybrid Model Predictive Control (MPC) approaches for freeway traffic control are proposed considering variable speed limits (VSL) as discrete variables as in current real world implementations. These discrete characteristics of the speed limits values and some necessary constraints for the actual operation of VSL are usually underestimated in the literature, so we propose a way to include them using a macroscopic traffic model within an MPC framework. For obtaining discrete signals, the MPC controller has to solve a highly non-linear optimization problem, including mixed-integer variables. Since solving such a problem is complex and difficult to execute in real-time, we propose some methods to obtain reasonable control actions in a limited computation time. The first two methods (-exhaustive and -genetic discretization) consist of first relaxing the discrete constraints for the VSL inputs; and then, based on this continuous solution and using a genetic or an exhaustive algorithm, to find discrete solutions within a distance of the continuous solution that provide a good performance. The second class of methods split the problem in a continuous optimization for the ramp metering signals and in a discrete optimization for speed limits. The speed limits optimization, which is much more time-consuming than the ramp metering one, is solved by a genetic or an exhaustive algorithm in communication with a non-linear solver for the ramp metering. The proposed methods are tested by simulation, showing not only a good performance, but also keeping the computation time reduced.Unión Europea FP7/2007–201
Best-effort Highway Traffic Congestion Control via Variable Speed Limits
International audience; The problem of controlling the congestion front in a single link road section is considered in this paper. For this purpose, we introduce a new variable-length two-cell lumped model composed of; one congested cell, and another in free flow. This model has the advantage of having few states while preserving the vehicle conservation property. This model is used as a basis to design a simple "best-effort" controller that regulates (at its best) the congestion front to some prespecified value. The control law can be implemented using only information about the congestion front position
Best-effort Highway Traffic Congestion Control via Variable Speed Limits
International audienceThe problem of controlling the congestion front in a single link road section is considered in this paper. For this purpose, we introduce a new variable-length two-cell lumped model composed of; one congested cell, and another in free flow. This model has the advantage of having few states while preserving the vehicle conservation property. This model is used as a basis to design a simple "best-effort" controller that regulates (at its best) the congestion front to some prespecified value. The control law can be implemented using only information about the congestion front position
Best-effort highway traffic congestion control via variable speed limits
International audienceThe problem of controlling the congestion front in a single link road section is considered in this paper. For this purpose, we introduce a new variable-length two-cell lumped model composed of; one congested cell, and another in free flow. This model has the advantage of having few states while preserving the vehicle conservation property. This model is used as a basis to design a simple "best-effort" controller that regulates (at its best) the congestion front to some prespecified value. The control law can be implemented using only information about the congestion front position
Hierarchical Speed Planner for Automated Vehicles: A Framework for Lagrangian Variable Speed Limit in Mixed Autonomy Traffic
This paper introduces a novel control framework for Lagrangian variable speed
limits in hybrid traffic flow environments utilizing automated vehicles (AVs).
The framework was validated using a fleet of 100 connected automated vehicles
as part of the largest coordinated open-road test designed to smooth traffic
flow. The framework includes two main components: a high-level controller
deployed on the server side, named Speed Planner, and low-level controllers
called vehicle controllers deployed on the vehicle side. The Speed Planner
designs and updates target speeds for the vehicle controllers based on
real-time Traffic State Estimation (TSE) [1]. The Speed Planner comprises two
modules: a TSE enhancement module and a target speed design module. The TSE
enhancement module is designed to minimize the effects of inherent latency in
the received traffic information and to improve the spatial and temporal
resolution of the input traffic data. The target speed design module generates
target speed profiles with the goal of improving traffic flow. The vehicle
controllers are designed to track the target speed meanwhile responding to the
surrounding situation. The numerical simulation indicates the performance of
the proposed method: the bottleneck throughput has increased by 5.01%, and the
speed standard deviation has been reduced by a significant 34.36%. We further
showcase an operational study with a description of how the controller was
implemented on a field-test with 100 AVs and its comprehensive effects on the
traffic flow
2nd Symposium on Management of Future motorway and urban Traffic Systems (MFTS 2018): Booklet of abstracts: Ispra, 11-12 June 2018
The Symposium focuses on future traffic management systems, covering the subjects of traffic control, estimation, and modelling of motorway and urban networks, with particular emphasis on the presence of advanced vehicle communication and automation technologies.
As connectivity and automation are being progressively introduced in our transport and mobility systems, there is indeed a growing need to understand the implications and opportunities for an enhanced traffic management as well as to identify innovative ways and tools to optimise traffic efficiency.
In particular the debate on centralised versus decentralised traffic management in the presence of connected and automated vehicles has started attracting the attention of the research community.
In this context, the Symposium provides a remarkable opportunity to share novel ideas and discuss future research directions.JRC.C.4-Sustainable Transpor