Vehicle Trajectory Control System for Fixed Guideway Networks
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Solution Overview
Problem
Current fixed guideway transportation systems face high construction and operational costs, limiting their reach and convenience, especially for lower density corridors, and struggle to achieve safe operating headways at mass rapid transit speeds while ensuring collision prevention and precise vehicle control on complex track networks.
Innovation Solution
A control system that enforces vehicle movement along a position versus time trajectory using run definition tables, with control equipment on vehicles reporting location every 0.5 seconds, and a central computer calculating tractive effort commands to maintain the desired trajectory, allowing for precise coordination and collision avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fixed guideway systems are built to serve high-density corridors, then passenger capacity is improved, but construction cost increases significantly
Solution Approach 1:
The system segments the guideway infrastructure into modular components that can be deployed in different configurations. Light rail vehicles operate on simpler, less expensive guideways for lower-density areas, while heavy rail provides high-capacity service on major corridors. This segmentation allows each segment to be optimized for its specific density requirements, reducing overall construction costs while maintaining high passenger capacity where needed.
Solution Approach 2:
The system dynamically allocates vehicle capacity and frequency based on real-time demand patterns. Vehicles can adjust their service levels and the system can shift resources between corridors, allowing high passenger capacity to be achieved on-demand rather than requiring permanent heavy infrastructure throughout the entire network.
2Adaptability or versatility
If guideway construction is extended to lower density corridors, then system reach and convenience are improved, but construction cost increases
Solution Approach 1:
The system applies different guideway qualities and vehicle types to different locations based on local density requirements. Lower-density corridors receive lighter, less expensive guideway infrastructure appropriate for their service level, while high-density corridors receive heavy rail infrastructure. This local optimization extends system reach to lower-density areas without uniformly increasing construction costs across the entire network.
Solution Approach 2:
A unified control system and vehicle platform serves multiple functions across different corridor types. The same control architecture manages both light and heavy rail operations, and vehicles can operate on different guideway types, allowing the system to extend reach to diverse locations while maintaining operational efficiency and avoiding duplicate infrastructure investments.
3Productivity
If heavy rail infrastructure is built, then high passenger capacity is achieved, but operational flexibility for different destinations is reduced
Solution Approach 1:
The network is segmented into heavy rail corridors for high-capacity commuter service and light rail branches for local and flexible destination access. This segmentation allows the system to achieve high passenger capacity on major employment centers while simultaneously providing adaptable access to retail, residential, and recreational destinations through the lighter, more flexible light rail segments.
Solution Approach 2:
Light rail vehicles serve as intermediary connectors between heavy rail corridors and local destinations. They pick up and drop off passengers at transfer points, providing flexible access to destinations not directly served by heavy rail, thereby maintaining high overall passenger capacity while expanding destination accessibility.
4Reliability
If automated control systems are implemented for precise trajectory following, then collision prevention is improved, but system complexity increases
Solution Approach 1:
The automated control system continuously receives feedback from vehicle position sensors, speed sensors, and track conditions, adjusting tractive effort in real-time to maintain precise trajectory following. This feedback mechanism ensures collision prevention through constant monitoring and adjustment without requiring overly complex predictive algorithms, balancing reliability with manageable system complexity.
Solution Approach 2:
Vehicles autonomously regulate their own speed and position using onboard controllers that automatically adjust tractive effort based on trajectory requirements and track conditions. This self-service capability reduces the need for complex centralized control while maintaining high reliability for collision prevention through distributed intelligence.
Data Source
AI summary
The invention relates to systems and methods that provide a higher degree of precision and a greater coordination of vehicle movement than is possible in conventional systems. A control system is designed to enforce vehicle movement along a route to a position versus time trajectory. The control system includes control equipment on the vehicle that reports its location on the track periodically. The controlling computer receives the report, and knowing where the vehicle should be and how fast it should be traveling at that point in time via a run definition table prepared for the route, calculates a position and velocity error, then calculates and sends a tractive effort adjustment command to the vehicle that attempts to reduce the position and velocity error. The invention includes a method for providing an estimated force command for a given target velocity and acceleration that can be used in the overall control methodology.