Web Registration Control via PI Feed Velocity Adjustment

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Solution Overview

Problem

Manufacturing machines, particularly those used in producing disposable absorbent articles, face challenges in consistently registering pre-produced webs due to variations in pitch length and phase position, leading to inconsistent product positioning and requiring unique controller settings for each machine setup.

Innovation Solution

A continuous registration system using a PI controller to adjust the feed velocity of the controlled web, synchronizing pitch length and phase positions, and applying tension transients to maintain web integrity, allowing consistent registration across different operation speeds and machine configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a machine uses a control system to send registration signals to moving parts for alignment, then the registration process can be automated and precise positioning can be achieved, but the machine may respond to registration signals differently at different operation speeds, leading to inconsistent registration

Engineering Contradiction:

Improveregistration precisionVSAvoidresponse consistency

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The control system dynamically adjusts the response to registration signals based on the current operation speed. The patent implements speed-dependent response characteristics where the machine's moving parts are controlled to respond appropriately to registration signals regardless of whether the machine is operating at high or low speeds, thereby maintaining consistent registration precision across varying operational conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes control parameters based on operation speed. By monitoring the current speed and adjusting the response characteristics of the moving parts accordingly, the control system ensures that registration precision is maintained across different speed ranges, resolving the inconsistency between speed variations and registration reliability

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If machines are configured with different mechanical settings for different product sizes, then they can accommodate various production requirements, but they may respond to registration signals in different ways, requiring unique controller settings for each machine setup

Engineering Contradiction:

Improveproduct size accommodationVSAvoidcontroller configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system is designed with universal response characteristics that work across different machine configurations and product sizes. By implementing a standardized interpretation of registration signals that accounts for mechanical differences, the system allows multiple machines with varying configurations to respond consistently to the same registration signals, eliminating the need for unique controller settings for each machine

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system pre-configures response characteristics for different machine types and product sizes. Before operation, the control system is programmed with the specific mechanical characteristics of each machine configuration, allowing it to automatically adjust its response to registration signals based on the detected machine type and product size, thereby simplifying operation without requiring complex unique settings

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the control system adjusts moving parts rapidly to respond to registration signals, then registration can be achieved quickly, but web tension may vary causing pitch length variations and registration errors

Engineering Contradiction:

Improveregistration speedVSAvoidpitch length consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The control system applies periodic adjustments to web tension during the registration process. By rhythmically modulating the tension in synchronization with the registration signal processing, the system maintains pitch length consistency even while making rapid positioning adjustments, thereby achieving both fast registration and precise pitch control

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system applies preliminary tension stabilization before processing registration signals. By pre-establishing a stable tension baseline and using feedback control to maintain it during rapid adjustments, the system cushions against tension variations that would otherwise cause pitch length changes, enabling fast response without sacrificing precision

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2475604B1Systems and methods for registering a controlled web to a pitched unit operation

Publication Date: 2016.07.13 PROCTER & GAMBLE CO

Figure 1~2A
Figure 2B~2C
Figure 3

AI summary

Systems and methods for registering a web to an on-line pitched unit operation. A PI controller is used to modify the feed velocity of the controlled web to allow for variations in controlled web pitch and phase differences between the controlled web and a pitched unit operation. The integral term of the registration control system may be proportional to a sum of error signals taken over previously measured pre-produced objects.