18 research outputs found

    A Model-based Dynamic Toll Pricing Strategy for Controlling Highway Traffic

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    A model-based approach to dynamic toll pricing has been developed to provide a systematic method for determining optimal freeway pricing schemes. A novel approach is suggested for alleviating congestion, which utilizes identified models of driver behavior and traffic flow, as well as optimization of the target density to maximize throughput. Real-time traffic information from on-road sensors is integrated with historical information to provide feedback and preview for the dynamic toll price controller. The algorithm developed here provides an opportunity to improve on existing toll policy by guaranteeing minimum speeds for toll lane drivers, maintaining consistent traffic flow for the other drivers, and optimizing the overall traffic throughputthe Ford-MIT Allianc

    Analysis, Design And Evaluation Of Avcs For Heavy-duty Vehicles

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    In this report, the authors develop two new nonlinear spacing policies, variable time headway and variable separation error gain, designed to all but eliminate the undesirable side effect of large steady-state intervehicle spacings. This disadvantage is pronounced in heavy-duty vehicles, which require larger time headways due to their low actuation-to- weight ratio. The first policy significantly reduces the transient errors and allows for the use of much smaller spacings in autonomous platoon operation, while the second one results in smoother and more robust longitudinal control.Trucks--Automatic control, Trucks--Dynamics, Express highways--Automation

    Analysis, Design, And Evaluation Of AVCS For Heavy-duty Vehicles: Phase 1 Report

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    This report addresses the problem of automation of heavy-duty vehicles. After a brief description of the dynamic model used in the design and simulations, the authors develop nonlinear controllers with adaptation, first for speed control and then for vehicle follower longitudinal control. Both autonomous operation as well as intervehicle communication are considered, and the performance of the controllers in several different scenarios through simulation are evaluated.Trucks--Automatic control--Mathematical models, Buses--Automatic control--Mathematical models

    Variable Time Headway for String Stability of Automated Heavy-Duty Vehicles

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    We present adaptive nonlinear schemes for longitudinal control of automated heavy duty vehicles. An important control objective is string stability, which ensures that errors decrease as they propagate downstream through the platoon. It is well known that string stability requires intervehicle communication if a constant spacing policy is adopted. When vehicles operate autonomously, string stability can be achieved if speed-dependent spacing with constant time headway is used. This, however, results in larger steady-state spacings, which increase the platoon length hence decreasing traffic throughput. In this paper we propose a new spacing policy in which the time headway varies linearly with the velocity error. Our simulation results demonstrate that this modification significantly reduces the transient errors and allows us to use much smaller spacings in the autonomous mode of platoon operation. 1 Introduction A widely proposed strategy for effectively increasing traffic throughput ..
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