Grid Track Vehicle Routing to Prevent Congestion Deadlocks

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Solution Overview

Problem

Deadlocks occur in traveling vehicle systems due to congestion on grid-patterned tracks, preventing vehicles from smoothly navigating around congested areas.

Innovation Solution

The system allows vehicles stuck at a cell for a predetermined time to proceed in an alternate direction or to a designated waypoint, adjusting routes to avoid congestion by dynamically reassigning instructions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If exclusive control is applied to blocking sections to prevent collisions, then safety is improved, but deadlock occurs when vehicles are congested and unable to move

Engineering Contradiction:
ImprovesafetyVSAvoidvehicle movement efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the control mode adaptable rather than fixed. The controller dynamically switches between exclusive control mode and non-exclusive control mode based on real-time track conditions. When congestion is detected, the system transitions from rigid exclusive control to flexible non-exclusive control, allowing vehicles to pass through blocking sections without strict permission requirements, thereby resolving deadlock while maintaining safety

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameter from binary (permission granted/not granted) to a dynamic state based on congestion detection. The controller monitors vehicle positions and adjusts the control mode parameter accordingly. When the track section is congested, the control parameter switches to allow free passage, eliminating the deadlock caused by strict permission requirements while preserving safety in normal conditions

Inventive Principle:
Principle #35Parameter changes

2Productivity

If permission requests are changed to alternative directions after predetermined time, then vehicle movement is improved, but vehicles still cannot move sufficiently away from congestion locations

Engineering Contradiction:
Improvevehicle movementVSAvoidtime spent near congestion
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies dimensionality change by introducing a new control dimension (non-exclusive control mode) beyond the traditional permission-based approach. Instead of merely changing direction after time delay, the system operates in a different control dimension where vehicles can move freely through blocking sections when congestion is detected, enabling vehicles to escape congestion areas more effectively and reduce time spent in congested zones

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3985468B1Travel vehicle system and travel vehicle control method
Publication Date: 2025.12.24 MURATA MASCH LTD
  • EP3985468B1 patent drawingFigure 1
  • EP3985468B1 patent drawingFigure 2
  • EP3985468B1 patent drawingFigure 3

AI summary

[Problem] To suppress occurrence of a deadlock by mitigating congestion of traveling vehicles. [Means to Solve Problem] A plurality of traveling vehicles V and a track R provided in a grid pattern, on which the traveling vehicles V can selectively proceed either in a first direction DR1 or in a second direction DR2, are included. A controller TC determines, when a traveling vehicle V that is to proceed in the first direction DR1 from a predetermined cell toward a destination is present, whether or not to grant the traveling vehicle V occupation permission for a cell C adjacent to the predetermined cell C in the first direction DR1. The traveling vehicle V proceeds in the first direction DR1 if occupation permission for the adjacent cell C has been granted from the controller TC, whereas the traveling vehicle V stops at the predetermined cell C if occupation permission has not been granted. The controller TC assigns to the traveling vehicle V a traveling instruction in which a cell C situated at a plurality of cells ahead of the predetermined cell C in the second direction DR2 is designated as a waypoint to the destination if the traveling vehicle V has not obtained occupation permission for the adjacent cell C and has continuously been in a stop state at the predetermined cell C for a predetermined period of time.