Reinforcement Learning Maintenance Decisions for Failure-Cost Tradeoffs

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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 such as 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 autonomously, optimizing maintenance timing and reducing downtime through explainable AI and historical data analysis without the need for high-fidelity simulators.

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 avoids sudden failures while minimizing unnecessary repairs, thus resolving the contradiction between maintenance cost and reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback loops where the RL agent observes equipment state, receives feedback on maintenance outcomes, and updates its policy accordingly. This feedback mechanism enables the agent to learn from past maintenance decisions and their consequences, optimizing the balance between inspection frequency, maintenance cost, and failure prevention over time

Inventive Principle:
Principle #23Feedback

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 RL agent schedules maintenance actions in advance based on predicted equipment degradation trajectories, performing maintenance only when and where it is truly needed rather than following fixed frequent inspection schedules. This preliminary action approach maintains reliability by preventing failures while avoiding unnecessary maintenance activities that inflate costs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts maintenance parameters such as inspection intervals and maintenance timing based on real-time equipment state and learned patterns. Rather than using fixed frequent inspection schedules, the RL agent adapts inspection and maintenance parameters to actual equipment conditions, reducing unnecessary maintenance while maintaining reliability

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a decision maker model predicts maintenance action based on historical data, then maintenance timing is optimized, but the system requires complex machine learning model training and deployment

Engineering Contradiction:
Improvemaintenance timing optimizationVSAvoidmodel training and deployment complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The reinforcement learning agent is self-training and self-improving through continuous interaction with the equipment environment. The agent learns optimal maintenance policies autonomously from historical data without requiring complex manual model training procedures. Once deployed, it continuously refines its policy through online learning, reducing the burden of model training and deployment complexity while maintaining optimization capability

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4407523A1Reinforcement learning system for maintenance decision making
Publication Date: 2024.07.31 HITACHI LTD
  • EP4407523A1 patent drawingFigure 1
  • EP4407523A1 patent drawingFigure 2
  • EP4407523A1 patent drawingFigure 3

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.