Electric Press Bend-Point Detection Using Load Slope Smoothing

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Solution Overview

Problem

Conventional methods for detecting bend points in press-fitting operations using electric presses face challenges in precision due to variations in slope values and local vibrations, making it difficult to accurately determine the bend point, especially when speed variations occur.

Innovation Solution

An electric press system with a detection unit, input/storage unit, data-row calculation unit, slope calculation unit, and bend-point determination unit that calculates the slope of the load at a constant distance interval using a regression line and smoothing techniques to determine the bend point by exceeding a set reference value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the slope of the load is calculated using simple second-order differences, then the bend point can be detected, but local vibrations are picked up and determination becomes difficult

Engineering Contradiction:
Improvebend point detection precisionVSAvoidnoise interference from local vibrations
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing smoothing processing on the load values before calculating the second-order differences. This preprocessing step removes local vibrations and noise from the data, ensuring that the subsequent differential calculations are based on clean, reliable data. The smoothing is done in advance to prevent noise amplification during the differential operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary element in the form of a smoothing filter that mediates between the raw load data and the differential calculation. This intermediary processing step transforms the noisy raw data into smoothed data, which then serves as the input for calculating second-order differences, thereby preventing noise interference from affecting the bend point detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the slope calculation is performed on actual detected load values, then the calculation can be carried out, but the values are buried in noise and significant values are difficult to obtain

Engineering Contradiction:
Improvecalculation efficiencyVSAvoidsignal significance
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing smoothing processing on the load values before calculating the second-order differences. This preprocessing step removes local vibrations and noise from the data, ensuring that the subsequent differential calculations are based on clean, reliable data. The smoothing is done in advance to prevent noise amplification during the differential operation.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a fixed slope threshold is used for bend point determination, then the detection method is simple, but the bend point cannot be precisely detected when slope values vary individually

Engineering Contradiction:
Improvedetection method simplicityVSAvoidbend point detection precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the determination threshold dynamic rather than fixed. The threshold is calculated based on the statistical properties (standard deviation) of the second-order difference values, allowing it to adapt to different operating conditions and individual part variations. This dynamic threshold maintains detection simplicity while improving precision across varying slope conditions.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If the amount of change in position is extremely small, then the slope calculation can be performed, but the divided values do not have significance

Engineering Contradiction:
Improveposition measurement precisionVSAvoidslope calculation significance
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing smoothing processing on the load values before calculating the second-order differences. This preprocessing step removes local vibrations and noise from the data, ensuring that the subsequent differential calculations are based on clean, reliable data. The smoothing is done in advance to prevent noise amplification during the differential operation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10173385B2Electric press, bend-point detection method, and program
Publication Date: 2019.01.08 JANOME CORP
  • US10173385B2 patent drawing
  • US10173385B2 patent drawing
  • US10173385B2 patent drawing

AI summary

A detection unit for detecting a data row of a press position and a load at the press position; an input/storage unit for inputting and storing a value serving as a reference for determining a bend point in a relation between the press position and the load at the press position; a data-row calculation unit for calculating a data row of a press position and a load at a constant distance interval based on the data row of the press position and the load detected; a slope calculation unit for calculating a slope of the load based on the press position and the load at the press position detected; and a bend-point determination unit for determining a point, at which the calculated slope of the load exceeds the value serving as the reference for determining the bend point, as the bend point are provided.