The purpose of this project is to extend and integrate existing results on fault diagnostics and fault management for passenger vehicles used in automated highway systems (AHS). These results have been combined to form a fault diagnostic and management system for the longitudinal and lateral control systems of the automated vehicles which has a hierarchical framework that complements the established PATH control system.  Furthermore, the fault diagnostic module effectively monitors the sensors and actuators required for longitudinal and lateral control, while the fault handling module corrects for any detected faults via controller reconfiguration and degraded modes of operation. “Soft” faults such as tire/road conditions variations have also been investigated in this project. Based on a dynamic friction tire/road model, an emergency braking control law has been developed. Simulation and limited experimental results are provided to validate the design and development.

This project is a continuation of MOU 373.  It concludes ongoing research to extend and integrate existing results on fault diagnostic and fault management research, and develop a comprehensive fault management system. Features include a multi-layer fault diagnostic and management system, diagnosis of faults in the sensors and actuators of the lateral and longitudinal control systems, detection of faults in the most vital sensors and actuators, and development of a systematic methodology for processing diagnostic residues. Experimental implementation and testing of the completed sys-tem is carried out in this project. This work is important because fault diagnostics and management appear to be the most important technical issues remaining to be resolved before vehicle automation can be implemented. “Soft” faults such as tire/road conditions variations have been extended in this project. An analytical model for calculating the longitudinal and lateral traction/braking forces and the self-alignment moment and the effect of wet road conditions on the tire/road friction model have been discussed and developed in this project.

This project was created in order to continue progress toward a future in which vehicle automation technologies are able to improve transportation operations.  In the wake of the termination of the National Automated Highway Systems Consortium (NAHSC) program in 1998, the California Department of Transportation (Caltrans) created The Phoenix Project to bring together the organizations that remained interested in this future vision.  The discussions within The Phoenix Project focused on the opportunities that could be gained from earlier deployment of automation technologies on transit buses and heavy trucks, as compared to passenger cars.  PATH was already doing intensive research and testing on automation of one heavy truck, which provided a starting point for further work.