Connected and Automated Vehicles

The AHS/Street Interface; Effects of Capacity Concentration on System Performance: Phase 1 Final Report

Hall, Randolph
2001

This report provides Phase 1 results for MOU 386, “The AHS/Street Interface, Effects of Capacity Concentration on System Performance.” Additional results from this project can be found in PATH Working Paper 2000-26. Within this paper, strategic issues in Automated Highway Interface design are discussed, including creation of interface components and design alternatives, with emphasis on interchange separation and highway orientation. The report also discusses land use issues associated with interchange construction.

Emergency Vehicle Maneuvers and Control Laws for Automated Highway Systems

Toy, Charmaine
Leung, Kevin
Alvarez, Luis
Horowitz, Roberto
2001

In this report control laws and maneuvers for high priority emergency vehicle transit on automated highways are presented. The work presented is specifically designed for use with the Partners for Automated Transit and Highways (PATH) hierarchical control architecture. The types of control laws that are needed for the different hierarchical layers are examined, and specific maneuvers for the coordination and link layers are presented. Simulations using SmartCAP (a mesoscopic traffic simulator) and SmartAHS (a microscopic traffic simulator) demonstrate the maneuvers' functionality.

A Specification Of An Automated Freeway With Vehicle-borne Intelligence

Hitchcock, Anthony
1992

The focus of this work is to derive a technique of safety analysis for an automated freeway system. To demonstrate the method of safety analysis a procedure called fault tree analysis is applied. The specified freeway operates with vehicles in platoons. The safety criterion used here is that two or more simultaneous faults must occur independently before the hazards can arise.

Safety and Throughput Analysis of Automated Highway Systems

Godbole, Datta N.
Lygeros, John
2000

We investigate the effect of a number of design alternatives on the safety and capacity of an Automated Highway System. Our methodology makes use of two computational tools, designed to highlight the fundamental limitations of the vehicle dynamics, sensing and control strategies and inter-vehicle communication. The first tool produces the minimum spacing necessary for two vehicles not to collide, as a function of their state and capabilities. The second tool investigates the multiple collisions that may occur in a string of vehicles if the spacing requirements of the first tool are...

An Interface Between Continuous And Discrete-event Controllers For Vehicle Automation

Lygeros, John
Godbole, Datta N.
1994

Automation of highways and in particular platooning of vehicles raises a number of control issues. A hierarchical structure is used to address these issues. The work presented here is an attempt at constructing a consistent interface between discrete event and continuous time controllers. The design proposed is a finite state machine that communicates with the discrete controllers by issuing commands that get translated to "jerk" input for the vehicle engine. The operation of the proposed design is tested using COSPAN. By virtue of the fact that the interface touches on both the discrete...

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

Yanakiev, Diana
Kanellakopoulos, Ioannis
1996

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.

Integration Of Fault Detection And Indentification Into A Fault Tolerant Automated Highway System

Douglas, Randal K.
Chung, Walter H.
Malladi, Durga P.
Chen, Robert H.
Speyer, Jason L.
Mingori, D. Lewis
1997

This work focuses on vehicle fault detection and identification. It also describes a vehicle health management approach based on analytic redundancy. It describes a point design of fault detection filters and parity equations that are developed for the vehicle longitudinal mode. A preliminary design of a range sensor fault monitoring system is outlined as an application of a new decentralized fault detection filter. This system combines dynamic state information already generated by the existing filter designs with inter-vehicle analytic redundancy

Vehicle Traction Control And its Applications

Kachroo, Pushkin
Tomizuka, Masayoshi
1994

This paper presents a study of vehicle traction control and discusses its importance in highway automation. A robust control strategy is designed for slip control, which in turn controls the traction. It is shown how traction control can be used to satisfy different objectives of vehicle control. The importance of traction is further emphasized by comparing its performance to passive controllers in a simulation study in which an impulse-like wind disturbance is introduced. The comparative study shows that the system under traction control is stable in the presence of external disturbances...

Message Volumes For Two Examples Of Automated Freeway

Hitchcock, Anthony
1993

In this paper, calculations are made of the volume of messages transmitted between vehicles or between vehicles and the infrastructure, in order to estimate the demand of advanced vehicle control systems (AVCS) for frequency allocations. Two previous conceptual designs for an automated freeway are used to provide a basis for calculations.

A Dynamic Visualization Environment For The Design And Evaluation Of Automatic Vehicle Control Systems

Xu, Z.
1995

This document presents Dynamic Visualization, a project associated with the California PATH Program. The objective of the project is to develop a software which can animate automated highways, visualize the dynamics of automatic vehicles, and help the design and evaluation of automatic vehicle systems. This report summarizes the accomplishments of the project, describes the functions of the developed software, and provides an explanation of how to use the software.