Machine Learning PID Control for Tool Life in Machining

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Solution Overview

Problem

The existing smart adaptive control techniques for machining using machine tools require manual adjustment of PID control parameters, which is time-consuming and labor-intensive, and the effect of parameter modification on tool life can only be confirmed after the tool reaches the end of its life, leading to inefficient optimization.

Innovation Solution

A machine learning device is integrated into the controller to learn and determine PID control parameters based on machining conditions and environment, automating the parameter adjustment process and extending tool life without significantly increasing cycle time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If manual adjustment of PID control parameters is performed to extend tool life, then tool life is extended, but operator workload increases and optimization time is excessive

Engineering Contradiction:
Improvetool lifeVSAvoidoperator workload
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The system performs self-learning by automatically acquiring machining data, evaluating tool life, and optimizing PID parameters without requiring manual operator intervention. The learning unit continuously improves control parameters based on accumulated data, making the system self-sufficient in parameter optimization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical adjustment of PID parameters with an automated learning system that uses machine learning algorithms to determine optimal parameters. This substitution eliminates the need for operators to manually tweak parameters based on experience.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Duration of action of stationary object

If PID control parameters are adjusted to extend tool life, then tool life is extended, but the effect cannot be confirmed until the tool reaches end of life

Engineering Contradiction:
Improvetool lifeVSAvoidoptimization time
Core Design Contradiction:
Duration of action of stationary objectVSLoss of time

Solution Approach 1:

The system implements continuous feedback by monitoring machining data and tool condition in real-time. The learning unit uses this feedback to evaluate the effectiveness of PID parameter adjustments and continuously optimize parameters based on actual tool life data, allowing for mid-process corrections rather than waiting until tool failure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary learning and parameter optimization by analyzing accumulated machining data before tool failure occurs. The learning unit prepares optimal PID parameters in advance based on patterns recognized from historical data, enabling proactive rather than reactive parameter adjustment.

Inventive Principle:
Principle #10Preliminary action

3Extent of automation

If machine learning device is introduced to automatically determine PID parameters, then operator workload is reduced and optimization is accelerated, but device complexity increases

Engineering Contradiction:
Improveparameter determination automationVSAvoidcontroller complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The learning unit is designed to perform multiple functions: acquiring machining data, evaluating tool life, determining PID parameters, and controlling the machine tool. This multi-functionality consolidates what could be separate complex systems into a single integrated unit, reducing overall system complexity.

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

Solution Approach 2:

The patent merges the PID control function with the machine learning function into a single integrated controller. The learning unit combines data acquisition, parameter optimization, and control execution in one system, eliminating the need for separate manual intervention systems and reducing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS10895852B2Controller and machine learning device
Publication Date: 2021.01.19 FANUC LTD
  • US10895852B2 patent drawing
  • US10895852B2 patent drawing
  • US10895852B2 patent drawing

AI summary

A machine learning includes a state observation unit that observes, as state variables representing a current state of an environment, PID control parameter data indicating the a parameter of the PID control during machining, machining condition data indicating a machining condition of the machining, and machining environment data relating to a machining environment of the machining, a determination data acquisition unit that acquires, as determination data, tool life determination data indicating an appropriateness determination result relating to depletion of the life of a tool during the machining, and cycle time determination data indicating an appropriateness determination result relating to the cycle time of the machining, and a learning unit that learns the machining condition and the machining environment of the machining, and the parameter of the PID control in association with each other.