Dynamic Receptacle Rate Matching for Material Handling Bottlenecks
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Solution Overview
Problem
In order fulfillment systems, faster operators are idle due to slower operators' inventory receptacles accumulating and recirculating, causing system bottlenecks and reduced throughput, as the system cannot accommodate varied operator rates without additional capacity.
Innovation Solution
A computer-controlled feedback algorithm adjusts the set-point for inventory receptacles at each processing station, using a dual-loop feedback control to dynamically manage the supply based on actual and desired numbers, ensuring optimal inventory levels and preventing bottlenecks by prioritizing faster operators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system supplies inventory receptacles to all processing stations at a uniform rate, then slower operators can keep up with supply, but faster operators become idle and system throughput is reduced
Solution Approach 1:
The patent applies dynamics by making the supply rate adjustable and adaptive rather than fixed. The control system dynamically modifies the supply rate to each processing station based on real-time operator performance data, allowing the system to adapt to varying operator speeds and maintain optimal throughput without sacrificing stability
Solution Approach 2:
The patent changes the parameter of supply rate from a constant value to a variable that can be adjusted based on operator performance. By modifying this parameter dynamically, the system optimizes throughput for each operator's capability while maintaining overall system reliability
2Productivity
If the system increases capacity to accommodate faster operators, then throughput can be maintained at high levels, but system complexity and cost increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring operator performance and using this information to adjust supply rates. This closed-loop feedback mechanism allows the system to maintain high throughput for fast operators without requiring additional physical capacity, as the supply is dynamically matched to actual processing needs
Solution Approach 2:
The control system serves multiple functions: it monitors operator performance, calculates optimal supply rates, and adjusts delivery timing. This multi-functional approach replaces the need for additional physical capacity with an intelligent control mechanism that handles various operator speeds within the same system infrastructure
3Ease of operation
If inventory receptacles are allowed to accumulate at buffers, then operators can work at their own pace, but recirculation fills the sorter and prevents supply to faster operators
Solution Approach 1:
The system performs preliminary action by pre-calculating and pre-positioning inventory receptacles based on predicted operator needs. Rather than allowing random accumulation and recirculation, the system proactively prepares and delivers the right number of receptacles at the right time, preventing both shortages and excessive accumulation
Solution Approach 2:
The patent applies dynamics by making the buffer accumulation level adjustable rather than fixed. The control system dynamically determines the optimal buffer level for each operator based on their performance characteristics, allowing fast operators to have minimal buffer accumulation while slow operators can have larger buffers, thereby preventing sorter congestion while maintaining operator independence
Data Source
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AI summary
A method and apparatus for supplying a unit of work in a material-handling process includes a set-point of work units desired at a material-processing station and an actual measure of work units at the material-processing station. A feedback control algorithm is performed to establish the set point of work units at the material-processing station and an error between the work units at the material-processing station and the set-point of work units at the material-processing station. The feedback control algorithm also determines a desired amount of units that should be supplied to the material-processing station as a function of the error. The feedback control algorithm causes a work unit to be released from the inventory store for a particular processing station when the actual amount of work units supplied to that processing station is less than the amount of work units that should be supplied to that processing station.