Stacked Package Detection Using Primary-Secondary Sorter Feedback
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Solution Overview
Problem
Existing sorting systems face issues with stacked or overlapping packages, leading to incorrect sorting due to unreadable tags and inefficient recirculation, particularly in unmanned secondary sorters.
Innovation Solution
Implementing primary and secondary recirculation systems to handle unidentifiable or stacked packages, using identification and sizing systems to detect and re-route packages to appropriate infeed conveyors, with a controller managing the sorting process to ensure accurate destination assignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If packages are sorted through unmanned secondary sorters using automated identification systems, then sorting speed and automation are improved, but sorting accuracy deteriorates when packages are stacked or overlapping causing unreadable tags
Solution Approach 1:
The system performs preliminary identification and sizing measurements at the primary sorter before packages are distributed to secondary sorters. This advance detection allows the system to flag potentially problematic packages (those with unreadable tags or abnormal dimensions) before they reach unmanned secondary sorters, where automated systems cannot correct errors. Packages identified as problematic are routed through recirculation conveyors back to the primary infeed for reprocessing with human oversight.
Solution Approach 2:
The system implements a feedback mechanism where identification and sizing data from primary sorters is used to control recirculation conveyors. When packages are detected as stacked, overlapping, or having unreadable tags, the feedback signal activates recirculation to return these packages to the primary infeed conveyor. This closed-loop control ensures that packages problematic for automated sorting receive additional processing opportunities with human operators present.
2Reliability
If recirculation systems are implemented to handle unidentifiable or stacked packages, then sorting accuracy is improved, but system complexity and processing time increase
Solution Approach 1:
The recirculation system is segmented into distinct functional components: identification systems at primary sorters, sizing measurement systems, control systems that process identification data, and recirculation conveyors that physically redirect packages. Each segment performs a specific function, making the overall complex system manageable through modular design. The identification and sizing systems are separate from the recirculation mechanism, allowing independent optimization and maintenance of each component.
3Measurement precision
If packages are recirculated back to primary infeed for reprocessing, then identification accuracy is improved, but processing time and productivity decrease
Solution Approach 1:
The system applies different processing qualities to different packages based on their identification results. Packages with successfully read tags and normal dimensions proceed directly through the sorting system at high speed. Only packages with unreadable tags, abnormal dimensions, or suspected stacking are diverted to recirculation for additional processing. This localized application of enhanced processing to only problematic packages minimizes the impact on overall system throughput while maintaining high identification accuracy for the majority of packages.
Data Source
AI summary
A stacked-package detection system for a matrix sorter detects stacked packages by comparing weight or dimension measurements on primary sorters from those measurements on secondary sorters. Weight or dimension increases for a package on a secondary sorter indicate a stack of packages. A recirculation system diverts packages identified on the secondary sorters as stacked packages back into bulk flow to be reprocessed by the primary or secondary sorters.