Offline Reinforcement Learning for Predictive Maintenance Timing

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Solution Overview

Problem

Current predictive maintenance methods for industrial equipment rely on human operators to interpret machine learning outputs, leading to suboptimal timing of maintenance activities and increased costs due to either premature or unexpected failures, and do not efficiently handle constraints like simultaneous equipment repairs.

Innovation Solution

An offline reinforcement learning system that uses a decision maker model, fed with recent observations and actions, to predict and execute maintenance actions, optimizing maintenance timing and reducing downtime through automated decision-making without the need for high-fidelity simulators or online interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If equipment is inspected less often to reduce repair cost, then maintenance cost is reduced, but the probability of sudden failures increases

Engineering Contradiction:
Improvemaintenance costVSAvoidprobability of sudden failures
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The reinforcement learning agent performs preliminary maintenance actions before equipment failure occurs by predicting future equipment states and scheduling maintenance proactively. The agent learns optimal maintenance timing from historical data, executing preventive maintenance that prevents sudden failures while avoiding unnecessary repairs, thus resolving the contradiction between reducing maintenance costs and preventing equipment failures.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the equipment is frequently inspected and repaired, then the risk of unexpected failure is lessened, but the maintenance cost becomes substantial

Engineering Contradiction:
Improverisk of unexpected failureVSAvoidmaintenance cost
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system changes the decision-making parameter from fixed-schedule maintenance to dynamic, state-based maintenance timing. The reinforcement learning agent continuously updates maintenance decisions based on real-time equipment state parameters and predicted future states, optimizing the balance between reliability and maintenance cost by performing maintenance only when and where it is truly needed.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If human operators make maintenance decisions based on model outputs, then flexibility is maintained, but suboptimal timing of maintenance activities occurs

Engineering Contradiction:
Improveoperator flexibilityVSAvoidmaintenance timing optimization
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system implements self-service by enabling the reinforcement learning agent to autonomously make maintenance decisions without human intervention. The agent processes model outputs, evaluates equipment states, and determines optimal maintenance timing automatically, eliminating the suboptimal decisions caused by human operators while maintaining operational flexibility through the learned policy.

Inventive Principle:
Principle #25Self-service

4Productivity

If offline reinforcement learning is used for automated decision-making, then maintenance timing is optimized, but system complexity increases

Engineering Contradiction:
Improvemaintenance timing optimizationVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system uses copying by training the reinforcement learning agent on historical data copies rather than requiring complex real-time simulations. The agent learns from replicated past experiences and scenarios, building a policy that can be deployed with minimal additional complexity. This approach optimizes maintenance timing while avoiding the need for high-fidelity simulators or complex online learning infrastructure.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20240255939A1Reinforcement learning system for maintenance decision making
Publication Date: 2024.08.01 HITACHI LTD
  • US20240255939A1 patent drawing
  • US20240255939A1 patent drawing
  • US20240255939A1 patent drawing

AI summary

A method for predictive maintenance of equipment. The method may include receiving expected future return value as input to a decision maker model, wherein the decision maker model is a machine learning model that predicts maintenance action associated with the equipment; feeding recent observations and recent actions from environment as inputs to the decision maker model; generating a next action as model outputs of the decision maker model, wherein the next action is the predicted maintenance action; and executing the next action in the environment.