Roadmap Lane Annotation for Deadlock-Free Multi-Robot Navigation
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Solution Overview
Problem
Multi-agent planning in environments with multiple robots often results in deadlocks where robots cannot make progress due to simultaneous attempts to occupy the same intersection or conflict regions, leading to collisions and inefficient route planning.
Innovation Solution
A method involving a computing device that annotates a roadmap with unidirectional lanes ending sufficiently distant from conflict regions, assigns priorities to robots, and alters routes to prevent blocking, ensuring higher-priority robots can pass through conflict regions while lower-priority robots wait or take detours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If route planning allows robots to use any path through the environment, then route flexibility is improved, but deadlock risk increases due to simultaneous occupation of conflict regions
Solution Approach 1:
The patent segments the environment into distinct lanes and conflict regions. Lanes are unidirectional paths that robots follow, while conflict regions are specific areas where multiple lanes intersect or converge. This segmentation allows robots to have flexible routing options through different lane combinations while ensuring that conflict regions are managed through priority-based access control, preventing deadlocks.
Solution Approach 2:
The patent introduces an intermediary priority assignment mechanism that mediates access to conflict regions. Each robot is assigned a priority level, and this priority acts as an intermediary control that determines which robot can enter or pass through a conflict region first. This mediation resolves the deadlock problem by ensuring orderly access without restricting overall route flexibility.
2Productivity
If robots are allowed to traverse conflict regions simultaneously, then navigation efficiency is improved, but collision risk increases
Solution Approach 1:
The patent applies preliminary action by assigning priorities to robots before they enter conflict regions. This priority assignment is done in advance, allowing the system to pre-determine the order in which robots will access conflict regions. By establishing this order beforehand, the system maintains navigation efficiency through planned simultaneous traversals while preventing collisions through predetermined access sequences.
Solution Approach 2:
The patent changes the parameter of robot access to conflict regions from simultaneous to sequential based on priority levels. By modifying the temporal parameter of access (when robots can enter conflict regions), the system allows multiple robots to navigate efficiently through different paths while ensuring that conflict regions are accessed in a controlled, collision-free manner through priority-based timing.
3Reliability
If lower-priority robots wait for higher-priority robots to pass, then deadlock prevention is improved, but navigation time increases
Solution Approach 1:
The patent applies local quality by making priority-based waiting behavior localized to conflict regions rather than applying it globally to all navigation. Robots maintain their assigned priorities specifically when accessing conflict regions, allowing them to wait only where necessary (at conflict region boundaries) while moving freely along non-conflicting portions of their routes. This minimizes the time loss from waiting while ensuring deadlock prevention at critical locations.
Data Source
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AI summary
Apparatus and methods related to routing robots are provided. A roadmap of an environment that includes first and second robots can be received. The roadmap can be annotated with unidirectional lanes connecting conflict regions, where each lane ends so to avoid blocking a conflict region. First and second routes for the respective uses of the first and second robots can be determined, where both the first and second routes include a first lane connected to a first conflict region. A first, higher priority and a second, lower priority can be assigned to the respective first and second robots. It can be determined that the second robot following the second route will block the first robot on the first lane. Based on the first priority being higher than the second priority, the computing device can alter the second route to prevent the second robot from blocking the first robot.