Rail Agent Behavior Prediction Under Track and Signal Constraints

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Solution Overview

Problem

Autonomous vehicles face challenges in accurately predicting the behavior of rail agents due to their unique constraints, such as adherence to tracks and traffic signals, which differ from road agents, leading to suboptimal navigation and resource inefficiency.

Innovation Solution

A control system for autonomous vehicles that detects rail agents, determines their tracks, predicts possible paths based on spatial search and geometry, filters paths using agent characteristics and traffic control factors, and operates the vehicle based on the most probable path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If general path planning methods are used for rail agents, then the system can handle diverse agents, but prediction accuracy for rail agents deteriorates due to their unique constraints

Engineering Contradiction:
Improveability to handle diverse agentsVSAvoidprediction accuracy for rail agents
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system segments path planning into two distinct modules: a general path planning module that handles diverse agent types, and a specialized rail agent path planning module that applies specific constraints for rail agents. This segmentation allows each module to optimize for its specific function, resolving the contradiction between versatility and accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects which path planning module to use based on the detected agent type. When a rail agent is detected, the specialized module is activated; for other agents, the general module is used. This dynamic adaptation allows the system to maintain high prediction accuracy for rail agents while preserving overall versatility.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If specialized path planning for rail agents is implemented, then prediction accuracy improves, but system complexity increases

Engineering Contradiction:
Improveprediction accuracy for rail agentsVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The specialized rail agent path planning is segmented into distinct constraint modules (track adherence, traffic signal compliance, switching point considerations) that can be independently applied. This modular segmentation reduces overall system complexity by allowing each constraint to be handled separately rather than as a monolithic complex system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary detection and classification of rail agents before applying specialized path planning. By identifying rail agents early and preparing their specific constraints in advance, the system avoids complex real-time calculations, thereby reducing computational complexity while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If comprehensive track and path analysis is performed, then navigation safety improves, but computational time increases

Engineering Contradiction:
Improvenavigation safetyVSAvoidcomputational time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system applies partial analysis by focusing computational resources on the most critical constraints for rail agents (track adherence and traffic signals) rather than analyzing all possible path variables. This partial action approach maintains navigation safety by addressing key safety-critical factors while reducing overall computational time.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Track geometry and traffic signal information are preprocessed and stored in accessible formats before path planning occurs. This preliminary preparation allows the system to quickly retrieve and apply constraint information during real-time operation, maintaining high safety standards without excessive computational delays.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12393192B2Behavior prediction for railway agents for autonomous driving system
Publication Date: 2025.08.19 WAYMO LLC
  • US12393192B2 patent drawing
  • US12393192B2 patent drawing
  • US12393192B2 patent drawing

AI summary

To operate an autonomous vehicle, a rail agent is detected in a vicinity of the autonomous vehicle using a detection system. One or more tracks are determined on which the detected rail agent is possibly traveling, and possible paths for the rail agent are predicted based on the determined one or more tracks. One or more motion paths are determined for one or more probable paths from the possible paths, and a likelihood for each of the one or more probable paths is determined based on each motion plan. A path for the autonomous vehicle is then determined based on a most probable path associated with a highest likelihood for the rail agent, and the autonomous vehicle is operated using the determined path.