Minimizing Rack Visits in Order-Picking Robots

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Solution Overview

Problem

Conventional robot control systems for order-picking robots often result in inefficiencies due to the need to visit an unnecessarily large number of racks, leading to increased time and resource wastage in warehouse environments.

Innovation Solution

The implementation of algorithms that explore a solution space to minimize the number of racks visited by robots, utilizing a greedy algorithm to approximate a global optimum solution within a shorter timeframe, such as the bitmap model and binary tree approaches, to determine a minimized rack set for efficient order fulfillment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If robots transport an unnecessarily large number of racks for packing of associated items, then the robot can fulfill orders, but the total time to completion becomes unacceptably long and time and resources are wasted

Engineering Contradiction:
Improveorder fulfillment speedVSAvoidtime to completion
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary analysis of order requirements and rack contents before robot execution. The optimization algorithm pre-calculates the minimum rack set needed by matching order item requirements against rack inventories, allowing the robot to directly navigate to only the necessary racks rather than transporting unnecessary ones, thus reducing completion time while maintaining order fulfillment capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies partial action by selecting only the subset of racks that contain items actually needed for the current order, rather than transporting all available racks. The optimization algorithm identifies and selects the minimum necessary rack set based on order requirements, eliminating excessive rack transportation and reducing time loss without compromising order completion

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If algorithms explore the complete solution space to find the global optimum solution, then the minimized rack set is achieved, but the computation time becomes excessively long

Engineering Contradiction:
Improverack set optimizationVSAvoidcomputation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary filtering and preprocessing of rack and order data before optimization computation. By pre-organizing rack contents and order requirements, and pre-identifying potential rack candidates, the system reduces the effective solution space that requires exhaustive exploration, enabling faster computation of near-optimal solutions without sacrificing significant optimization quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the optimization parameters by transforming the complex global optimization problem into a series of simpler sub-problems with modified constraints. The algorithm adjusts search parameters and uses heuristic evaluation functions that balance solution quality with computation speed, allowing efficient exploration of the solution space to find minimized rack sets within acceptable timeframes

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10329090B2Robot control system for minimizing a number of racks used for order picking
Publication Date: 2019.06.25 SAP SE
  • US10329090B2 patent drawing
  • US10329090B2 patent drawing
  • US10329090B2 patent drawing

AI summary

Techniques are provided for controlling an order-picking, rack-transporting robot. More specifically, the robot is controlled to select a minimized number of movable racks storing ordered products identified in one or more orders for product deliveries, while still ensuring that all ordered products are included.