Container Handling Vehicle Routing Using Zone-Based Grid Modeling
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Solution Overview
Problem
Existing methods for determining routes of container handling vehicles in automated storage and retrieval systems are either too slow or inaccurate, particularly when considering the geometry of the grid, and full A* routing algorithms are too time-consuming for real-time processing in large grids.
Innovation Solution
A method and system that represent the rail system as a finite set of non-overlapping rectangular zones, determine overlap information, and use grid position zone information to calculate routes efficiently, allowing for fast and accurate path determination using a control system and model of the rail system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full A* routing algorithm is used for route determination, then route accuracy is improved, but processing time increases making it unsuitable for real-time control
Solution Approach 1:
The patent segments the grid into zones and pre-calculates routing information for each zone and zone pairs. This segmentation allows the system to break down the complex full A* algorithm into smaller, pre-computed components that can be quickly assembled during real-time operation, thereby maintaining route accuracy while reducing processing time.
Solution Approach 2:
The patent performs preliminary actions by pre-calculating routing information, zone overlaps, and path costs before real-time operation. The control system stores this pre-computed data and uses it during real-time route determination, eliminating the need to execute the full A* algorithm during critical real-time control moments.
2Productivity
If traditional routing methods are used, then processing speed is improved, but route accuracy deteriorates particularly when considering grid geometry
Solution Approach 1:
The patent applies local quality by creating zone-specific routing information that accounts for local grid geometry characteristics. Each zone and zone pair has pre-calculated routing data that reflects the specific geometric constraints and optimal paths for that local area, ensuring high route accuracy while maintaining fast processing during real-time operation.
Solution Approach 2:
The patent creates simplified copies of routing information in the form of pre-calculated zone-based path data. Instead of executing the complex A* algorithm in real-time, the system uses these pre-computed copies of routing information that capture the essential geometric constraints and optimal paths, achieving both speed and accuracy.
3Measurement precision
If the rail system is represented as individual grid positions, then routing precision is improved, but system complexity increases for real-time processing
Solution Approach 1:
The patent segments the detailed grid position representation into larger zone units. Each zone encompasses multiple grid positions and has pre-calculated routing information. This segmentation reduces the complexity of real-time processing by working with zone-level data rather than individual grid positions, while still maintaining routing precision through pre-computed zone-to-zone path information.
Solution Approach 2:
The patent transitions from a one-dimensional grid position representation to a two-dimensional zone structure with additional dimensions for zone overlaps and path costs. This dimensional transformation organizes the routing information in a more manageable format that reduces processing complexity while preserving routing precision through the structured zone-based representation.
Data Source
AI summary
System, method, and computer program product for determining a route for a container handling vehicle operating on a rail system of an automatic grid-based storage and retrieval system. The method comprising creating a model of the rail system representing the rail system as a finite set of non-overlapping rectangular first zones in a first direction, and a finite set of non-overlapping rectangular second zones in a second direction, wherein the zones are positioned around grid positions that are not accessible by the container handling vehicle, determining overlap information indicative of one or more regions of the rail system in which there is an overlap between a zone of the finite set of first zones and a zone of the finite set of second zones, determining grid position zone information by, for each grid position determining in which of the finite set of first zones and/or the finite set of second zones the grid position is located, receiving a request for a route for at least one container handling vehicle from a first grid position to a second grid position; and determining the route using the model of the rail system.