Ring Heater Control in Continuous Kneading Without PID Retuning

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Solution Overview

Problem

Existing continuous kneading apparatuses for injection and extrusion molding require time-consuming parameter adjustments for PID control, leading to inefficiencies and material waste when process conditions change.

Innovation Solution

A control unit that performs reinforcement learning to determine an optimum action for each ring-shaped heater based on past actions and control errors, updating control conditions to select the best action for the current state, eliminating the need for parameter adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PID control is used for heater control in continuous kneading apparatus, then temperature control stability is improved, but parameter adjustment time increases significantly when process conditions change

Engineering Contradiction:
Improvetemperature control stabilityVSAvoidparameter adjustment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system pre-calculates and stores optimal PID parameters for multiple anticipated process conditions in advance. When a process condition change is detected, the system quickly switches to the pre-prepared parameters corresponding to the new condition, eliminating the need for time-consuming real-time parameter adjustment while maintaining temperature control stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system dynamically selects appropriate PID parameters based on detected process conditions. Instead of using fixed parameters or manual adjustment, the system automatically adapts parameters in real-time by selecting from pre-calculated parameter sets that match current process conditions, enabling both stability and responsiveness.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If traditional feedback control is used for heater control, then temperature measurement accuracy is maintained, but resin material waste increases during parameter adjustment

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidresin material waste
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

Optimal control parameters are pre-calculated and stored for various process conditions before actual production. When process conditions change, the system immediately switches to pre-prepared parameters, eliminating the trial-and-error adjustment period that causes resin material waste while maintaining accurate temperature measurement and control.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system automatically selects and applies appropriate parameters based on detected process conditions without requiring manual intervention or trial production. This self-adjusting capability eliminates resin waste that would otherwise be consumed during manual parameter tuning while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces the time and resin material required for adjustments when process conditions change, enhancing the efficiency of the kneading process by directly updating control conditions through reinforcement learning.

Implementation Method 1

heating the pellets by using a heater

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heating the pellets by using a heater

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS11858175B2Continuous kneading apparatus and its control method
Publication Date: 2024.01.02 THE JAPAN STEEL WORKS LTD
  • US11858175B2 patent drawing
  • US11858175B2 patent drawing
  • US11858175B2 patent drawing

AI summary

In a continuous kneading apparatus according to an embodiment, for each of a plurality of ring-shaped heaters, a control unit determines a current state and a reward for an action selected in the past based on a control error calculated from an acquired temperature; updates a control condition based on the reward, and determines an optimum action corresponding to the current state under the updated control condition, the control condition being a combination of a state and an action; and controls a target ring-shaped heater based on the optimum action.