Pick Walk Optimization via Greedy Tote Reduction and Min Trolley Loop

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Solution Overview

Problem

Existing pick walk optimization systems, such as ant colony optimization, are time and processing power intensive due to the need to calculate savings among all possible combinations, making them cumbersome and inefficient, especially as the number of optimizations increases with the rise of eCommerce and in-store pick-up services, and advancements in computer processing power have plateaued.

Innovation Solution

A system utilizing a combination of algorithms, including a greedy incremental batcher loop, randomized tote local search, and update min trolley loop, to optimize pick walks by reducing the number of totes needed for orders, merging picklists, swapping totes between lists, and combining picklists to minimize costs and processing burdens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ant colony optimization is used to optimize pick walks, then satisfactory solutions are achieved, but processing time and computational power requirements increase significantly

Engineering Contradiction:
Improvequality of pick walk optimizationVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the pick walk optimization problem into multiple independent pick lists that can be processed separately. Instead of optimizing all picks simultaneously (which would require evaluating all possible combinations), the system divides the order into multiple pick lists, each containing a subset of picks. This segmentation allows parallel processing and reduces the computational complexity from factorial to polynomial time, while still achieving satisfactory optimization results for each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial optimization by focusing on optimizing individual pick lists rather than the entire order at once. The system generates an initial pick walk, identifies clusters of picks that can be optimized together, and applies optimization algorithms only to these specific clusters. This partial action approach reduces the overall computational burden while maintaining acceptable quality of optimization for the most critical segments.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If optimization calculations are performed for all possible combinations, then optimal pick walk solutions are achieved, but computational burden increases

Engineering Contradiction:
Improveoptimization qualityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by using different optimization strategies for different portions of the pick walk. Instead of applying a single complex optimization algorithm uniformly to all picks, the system identifies specific clusters or groups of picks that benefit from optimization and applies targeted optimization techniques to those local regions. This allows the system to achieve good results where needed while avoiding unnecessary computational complexity in areas where simple routing suffices.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameters of the optimization problem by transforming it from a global optimization problem (optimizing all picks simultaneously) into multiple local optimization problems (optimizing individual pick lists or clusters). This parameter change involves modifying the scope, granularity, and structure of the optimization inputs, allowing the use of simpler algorithms that run faster while still producing satisfactory results.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12067514B2Systems and methods for optimization of pick walks
Publication Date: 2024.08.20 WALMART APOLLO LLC
  • US12067514B2 patent drawing
  • US12067514B2 patent drawing
  • US12067514B2 patent drawing

AI summary

A system includes one or more processors and one or more non-transitory computer-readable media storing computing instructions that, when executed on the one or more processors, cause the one or more processors to perform: selecting, by a greedy tote reduction algorithm within an infeasible totes loop, items that have a highest volume restriction and a highest weight restriction for each of a plurality of respective totes; iteratively executing a swap of the items; iteratively searching for candidate solutions until a solution of picklists for the plurality of respective totes containing the items, as swapped, is found; executing a minimum trolley loop algorithm on the solution of picklists to create combined picklists; and displaying to a picker on an interface of a computing device, turn-by-turn directions within a pick walk for the combined picklists. Other embodiments are disclosed herein.