Percorrer por autor "Parafita, Ricardo"
A mostrar 1 - 4 de 4
Resultados por página
Opções de ordenação
- Intelligent traffic management at intersections supported by V2V and V2I communicationsPublication . Conde Bento, Luis; Parafita, Ricardo; Nunes, UrbanoThis paper describes an intelligent traffic management system applied to road intersections, namely round-about and crossroads. A microscopic traffic simulator was developed to study intelligent traffic management techniques and evaluate their performance. The intelligent management techniques are aimed to minimize accidents, traffic congestion and consequently the environmental costs of road traffic. Each vehicle is modeled by an agent and each agent provides information depending on its vehicle sensors. Two intersection types, roundabout and crossroads, were simulated each using its intelligent traffic management system. Both intersections use an algorithm based on a spatio-temporal reservation scheme. The envisioned intelligent traffic management algorithm is supported by vehicle-to-vehicle and vehicle-to-infrastructure communications, allowing the exchange of information between vehicles and the intersection intelligent traffic management system. The developed intelligent traffic management system is very well suited for autonomous vehicles, it can also be used by human drivers if they follow accurately the proposed speed profile along the path.
- Intelligent traffic management at intersections: Legacy mode for vehicles not equipped with V2V and V2I communicationsPublication . Bento, Luís Conde; Parafita, Ricardo; Santos, Sergio; Nunes, UrbanoThis paper describes a legacy algorithm for an intelligent traffic management system applied to automatic regulation of traffic at intersections. The application of the legacy algorithm enables the intelligent intersection to accommodate vehicles, in a low percentage, not equipped or with faulty V2V and V2I communications. The developed intelligent traffic management techniques, which are based on a spatiotemporal reservation scheme, aim to minimize accidents, traffic congestion and consequently the environmental costs of road traffic. The performance of three intelligent traffic management algorithms applied to road intersections, roundabouts and crossroads, are analyzed. Compared with traditional traffic management techniques, simulation results using the developed intelligent traffic management techniques, show that the traffic output flux can be increased, traffic flow rate can be higher and the average time to cross intersections can be significantly reduced. This reduction is more pronounced when the traffic flow is heavy. The conducted studies show that the inclusion of a low percentage of vehicles, not equipped or with faulty V2V and V2I communications, in intelligent intersections using the legacy algorithm, have a low impact on the traffic flow. © 2013 IEEE.
- Inter-vehicle sensor fusion for accurate vehicle localization supported by V2V and V2I communicationsPublication . Conde Bento, Luis; Parafita, Ricardo; Nunes, UrbanoCooperative driving system techniques aim to minimize accidents, traffic congestion and consequently the environmental costs of road traffic. An accurate vehicle's pose is of extreme importance for the inner working of the traffic management systems. An agent based traffic simulator was developed integrating typical automotive sensors, vehicle-tovehicle (V2V) and vehicle-to-infrastructure (V2I) communications, vehicle's agent and infrastructure agent. In this paper, we propose to further enhance a multi-sensor localization algorithm in environments where V2V and V2I communication is possible. This paper describes an inter-vehicle sensor fusion for an accurate vehicle positioning, where each vehicle is modeled by an agent, and each agent provides information depending on its vehicle sensors. In the first fusion stage, data from four wheel encoders and one steering encoder are fused by means of an EKF, providing robust odometric information, namely in face of undesirable effects of wheels slippage. Next, a second fusion stage is processed for integrating odometric and inter-vehicle absolute positioning data.
- A study of the environmental impacts of intelligent automated vehicle control at intersections via V2V and V2I communicationsPublication . Bento, Luís Conde; Parafita, Ricardo; Rakha, Hesham A.; Nunes, Urbano J.This article presents a novel intersection traffic management system for automated vehicles and quantifies its impact on fuel consumption and greenhouse gas emissions of CO2 relative to traditional traffic signal and roundabout intersection control. The developed intelligent traffic management (ITM) techniques, which are based on a spatiotemporal reservation scheme, ensure that vehicles proceed through the intersection without colliding with other vehicles while at the same time reducing the intersection delay and environmental impacts. Specifically, the spatiotemporal reservation scheme provides each vehicle a collision-free path that is decomposed into a speed profile along with navigational instructions. The integration of the developed microscopic traffic simulator with instantaneous emission model, provides improved assessments of the environmental impact of traffic control strategies at intersections. The simulator architecture integrates several ITM algorithms, vehicle sensors, V2V/V2I communications, and emission and fuel consumption models. Each vehicle is modeled by an agent and each agent provides information depending on the specific vehicle sensors. The ITM system is supported by V2V and V2I communications, allowing the exchange of information among vehicles and infrastructure. The data include the estimated vehicle position and speed. Compared with traditional traffic management techniques, the simulation results prove that the proposed ITM system reduces CO2 emissions significantly. The research also shows that these reductions are more significant when the traffic flow increases.