PATH

Lateral Control of Commuter Buses

Hingwe, Pushkar
Tomizuka, Masayoshi
1995

This report presents two approaches to the design of the lateral controllers for commuter buses based on Sliding Mode Control (SMC). The objective of the control is to track the lane centerline. The first controller uses the sensor output which is a combination of yaw and lateral error. The second controller achieves tracking objective by providing a yaw rate to the vehicle so as to keep the lateral error dynamics stable. The two controllers are compared by performing simulations for a range of parameters.

ITS Information and Services to Enhance the Mobility of Disabled Travelers

Chen, Wan-hui
Uwaine, Rochelle
Klaver, Kelley
Kurani, Ken
Jovanis, Paul P.
1998

This study examined the potential of advanced information systems to increase the mobility of disabled travelers using public transportation. A stated preference survey inquired as to whether subjects would make more trips by transit, paratransit, and/or real-time paratransit if kiosk, on-board, in-home, and/or personal information systems were available. The results show that these systems do have the potential to increase the use of public transportation by disabled travelers, as they allow for more trip flexibility that what is currently available. Regression and log-linear models show...

Issues in Fault Tolerant Control of Vehicle Follower Systems

Hedrick, J. K.
Garg, V.
1994

The aim of this report is to study issues concerning fault detection and identification in vehicle follower control. The report discusses various potential fault modes among sensors, and actuators used in the vehicle following experiments in cars. It deals with issues of fault detection of sensors and actuators for vehicle following applications.

Investigation of an Optical Method to Determine the Presence of Ice on Road Surfaces

Misener, James
1998

This report presents a review of alternative techniques to determine the presence of ice on road surfaces. It examines techniques ranging from passive, in-pavement technologies, to different remote sensing techniques. The author presents the Polarized Reflectance Infrared Signature Method (PRISM) technique which uses differences in measured near infrared reflectance between ice, water and dry road due to absorption, in addition to the effect of polarization to discount the contribution of specutacular reflectance off the front surface.

Investigating Intelligent Transportation Systems Strategies on the Santa Monica Freeway Corridor: Technical Appendix

Bacon, Jr., V.
Windover, J.
May, A.
1995

This document contains the technical appendices to the report on Investigating Intelligent Transportation Systems Strategies on the Santa Monica Freeway Corridor (see PATH Database record no. 8800.)

Intelligent Sensor Validation and Sensor Fusion for Reliability and Safety Enhancement in Vehicle Control

Agogino, Alice
Goebel, Kai
Alag, Sanam
1995

This research project is concerned with sensor validation and sensor fusion as part of a five module hierarchical architecture for supervisory control. The goal is to enhance reliability and safety of the Intelligent Vehicle Highway System (IVHS) by taking into consideration the uncertainty of sensors and the system. Potential hazards are detected and feasible maneuvers are recommended within the upper modules of the architecture.

Intelligent Sensor Validation and Fusion for Vehicle Guidance Using Probabilistic and Fuzzy Methods

Agogino, Alice
Goebel, Kai
Alag, Sanam
1997

This study reports on a method to accomplish sensor validation and fusion in Intelligent Transportation Systems (ITS). The method is based on probabilistic and fuzzy techniques that express a confidence in the sensor data and take into account environmental factors and the state of the system. Sensor data fusion uses the confidence assigned to each sensor reading and integrates them into one reading. Noise and failure are filtered from the data and lead to a safety improvement in ITS.

Intelligent Diagnosis Based on Validated and Fused Data for Reliability and Safety Enhancement of Automated Vehicles in an IVHS

Agogino, Alice
Chao, Susan
Goebel, Kai
Alag, Satnam
Cammon, Bradly
Wang, Jiangxin
1998

Vehicles in an IVHS system rely heavily on information obtained from sensors. So far, most control systems make the implicit assumption that sensor information is always correct. However, in reality, sensor information is always corrupted to some degree by noise which varies with operating conditions, environmental conditions, and other factors. In addition, sensors can fail due to a variety of reasons. To overcome these shortcomings, sensor validation is needed to assess the integrity of the sensor information and adjust or correct as appropriate. In the presence of redundant information...

Intelligent Cruise Control Systems and Traffic Flow Stability

Darbha, Swaroop
Rajagopal, K.r.
1998

In analogy to the flow of fluids, it is expected that the aggregate density and the velocity of vehicles in a section of a freeway adequately describe the traffic flow dynamics. The conservation of mass equation together with the aggregation of the vehicle following dynamics of controlled vehicles describes the evolution of the traffic density and the aggregate speed of a traffic flow. There are two kinds of stability associated with traffic flow problems - string stability (or car-following stability) and traffic flow stability. We make a clear distinction between traffic flow stability...

Intelligent Vehicle/Highway System Safety: Multiple Collisions in Automated Highway Systems

Hitchcock, Anthony
1995

In this report, a comparison is drawn between the casualty rates per failure on an automated highway system (AHS) according to the longitudinal control configuration used. The comparison is drawn between closed-spaced platooning, vehicle following of the types used in Autonomous Intelligent Cruise Control (AICC) and Cooperative Intelligent Cruise Control, and a point-following configuration (PFC). The model used permits evaluation of the consequences of a failure, allowing for the multiple collisions that usually ensue.