Warehouse Robot Routing to Minimize Operator Wait Dwell Time
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Solution Overview
Problem
In warehouse order fulfillment operations, autonomous mobile robots often experience delays when waiting for human operators to assist with item retrieval, leading to inefficiencies that can significantly impact overall warehouse productivity.
Innovation Solution
The method involves a robot determining if it has been paused at a location for longer than a maximum dwell time without operator assistance, causing it to leave that location and proceed to another item in the order, selecting the next item based on factors like robot/operator density or active location population to minimize dwell time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robots wait for operator assistance at each item location, then item retrieval can be completed with human help, but robot dwell time increases and warehouse efficiency decreases
Solution Approach 1:
The system dynamically adjusts robot behavior based on real-time conditions. Robots monitor dwell time thresholds and operator availability, switching between waiting for operators and autonomously proceeding to next items based on current warehouse state, making the system adaptable rather than static
Solution Approach 2:
The system implements continuous feedback loops where robots report their status and dwell time to the WMS, which monitors operator locations and availability. This feedback mechanism enables real-time decision-making about whether to wait or proceed, optimizing the balance between completion reliability and time efficiency
2Productivity
If robots proceed to next item without operator assistance when dwell time exceeds threshold, then overall dwell time decreases and efficiency improves, but some items may not be retrieved
Solution Approach 1:
The system performs preliminary actions by having robots skip items with excessive dwell times and continue with other items in the order. This allows progress on fulfillable items while setting up for subsequent recovery actions, rather than stalling at problematic locations
Solution Approach 2:
The system maintains continuity of useful action by enabling robots to continue retrieving items that can be fulfilled even when some items require operator assistance. The robot doesn't stop the entire fulfillment process but continues with available items, maximizing productive activity
3Productivity
If multiple robots operate with limited operators, then robot utilization increases, but operator availability decreases leading to longer dwell times
Solution Approach 1:
The system segments the warehouse into zones and divides orders among multiple robots operating in parallel. This segmentation allows robots to independently manage their own item sequences, reducing dependency on centralized operator coordination and minimizing wait times
Solution Approach 2:
The system changes operational parameters dynamically by adjusting dwell time thresholds based on robot density, operator availability, and order characteristics. This allows optimization of robot behavior parameters to match current system load and resource availability
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A method for executing an order with a plurality of items assigned to a first robot of a plurality of robots operating in a warehouse with the assistance of a plurality of operators. The method includes navigating the first robot to a first location in the warehouse proximate a location of a first item in the order and pausing for an operator of to assist the first robot to execute a function. The method includes determining if the first robot has been paused for greater than a maximum dwell time without being assisted by an operator. If it has been, the method causes the first robot to leave the first location without completing the function on the first item and causing the first robot to proceed to a second location proximate a storage a second item to execute a function.