Digital Twin RL Training for Pallet Routing Bottlenecks

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Solution Overview

Problem

Training reinforcement learning systems to control pallets in manufacturing environments is resource-intensive and tedious, particularly in preventing bottlenecks and satisfying production constraints.

Innovation Solution

A method and system that utilize a digital twin to simulate pallet routing, obtain state information from sensors, determine actions such as merging or splitting operations, calculate transient and steady-state production values based on objective functions, and adjust reinforcement parameters to optimize pallet movement and inhibit bottlenecks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If reinforcement learning system is used to control pallet routing, then autonomous control and bottleneck prevention are improved, but training resource consumption and complexity increase

Engineering Contradiction:
Improveautonomous controlVSAvoidtraining complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by pre-defining multiple predefined paths for pallets between workstations and pre-configuring routing control locations. This allows the reinforcement learning system to learn from structured scenarios rather than unstructured environments, reducing training complexity while maintaining autonomous control capabilities.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The manufacturing environment is segmented into discrete routing control locations and predefined paths, with pallets controlled individually at each location. This segmentation transforms the complex continuous control problem into manageable discrete decisions at each routing point, reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

2Productivity

If reinforcement learning system is trained to satisfy production constraints, then manufacturing efficiency is improved, but training time and computational resources increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidtraining time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system changes parameters by adjusting the complexity and number of predefined paths, the number of routing control locations, and the specific production constraints during training. This allows progressive training from simpler to more complex scenarios, reducing overall training time while achieving high manufacturing efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses digital twins to create virtual copies of the manufacturing environment for training purposes. This allows extensive training to occur in the virtual copy without affecting real production, enabling the system to learn optimal control strategies without time loss in the actual manufacturing environment.

Inventive Principle:
Principle #26Copying

3Measurement precision

If multiple sensors are deployed for state information collection, then control precision is improved, but system complexity and cost increase

Engineering Contradiction:
Improvestate information accuracyVSAvoidsensor layout complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Sensors at routing control locations are designed to detect multiple types of pallets and various state conditions simultaneously. This multi-functionality allows a single sensor to provide comprehensive state information, reducing the total number of sensors needed while maintaining high measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges sensor functions by consolidating detection capabilities at routing control locations, where sensors monitor pallet presence, type, and routing decisions in unified locations. This merging reduces overall system complexity while maintaining comprehensive state information collection.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS11860592B2Systems and methods for training a reinforcement learning system for pallet routing in a manufacturing environment
Publication Date: 2024.01.02 FORD GLOBAL TECH LLC
  • US11860592B2 patent drawing
  • US11860592B2 patent drawing
  • US11860592B2 patent drawing

AI summary

A method includes obtaining state information from one or more sensors of a digital twin. The method includes determining an action at the first routing control location based on the state information, where the action includes one of a pallet merging operation and a pallet splitting operation, and determining a consequence state based on the action. The method includes calculating a transient production value based on the consequence state and a transient objective function, calculating a steady state production value based on the consequence state and a steady state objective function, and selectively adjusting one or more reinforcement parameters of the reinforcement learning system based on the transient production value and the steady state production value.