Speed Controller Web Break Detection via Drive Data Analysis

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Solution Overview

Problem

High-speed web material processing machines face issues with uncontrolled breaks leading to machine downtime, contamination, and damage due to the limitations of existing optical sensor systems, which are prone to dirt and require frequent maintenance, resulting in delayed and imprecise tear detection.

Innovation Solution

A method and device using a speed controller to detect web breaks by analyzing drive data and setpoint values, eliminating the need for optical sensors and enabling faster, more precise detection without maintenance delays, by tapping off signals from existing speed controllers to identify increases in drive data that indicate a tear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optical sensor systems are used to detect web breaks, then detection capability is provided, but the sensors quickly become dirty and require frequent cleaning and readjustment

Engineering Contradiction:
Improvedetection capabilityVSAvoidmaintenance requirement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts the detection function from optical sensors and relocates it to the speed controller by utilizing existing drive data. This removes the optical sensors from the detection process, eliminating their maintenance requirements while preserving break detection capability through analysis of speed controller signals that indicate web tension changes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces drive data from the speed controller as an intermediary medium for detection. Instead of directly observing the web with optical sensors, the system uses speed controller data (torque, speed, power) as a mediator to indirectly detect web breaks, thereby avoiding contamination issues while maintaining detection reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If optical sensors are positioned at certain points on the machine, then device complexity is reduced, but rapid detection and precise localization of tears are prevented

Engineering Contradiction:
Improvesensor arrangementVSAvoiddetection delay
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The invention makes the speed controller multi-functional by adding break detection capability to its existing speed control function. The same speed controller that drives the web processing equipment now also serves as the detection system, eliminating the need for separate optical sensor installations while enabling comprehensive monitoring at all drive locations simultaneously.

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

Solution Approach 2:

The invention merges the detection function with the existing drive control system. By combining break detection with the speed controller's existing functions, the system achieves both reduced device complexity (no separate sensors needed) and improved detection speed (real-time data from all drives), as the speed controller continuously monitors drive parameters throughout the web path.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If optical sensor systems are used for web break detection, then detection is provided, but detection precision is reduced due to torn material preventing detection

Engineering Contradiction:
Improvedetection functionVSAvoidtear localization accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention replaces the optical detection system with a mechanical/electrical parameter-based detection system. Instead of using light beams that can be blocked by torn material, the system uses mechanical drive parameters (torque, speed, power) from the speed controller, which are not affected by visual obstructions and provide precise localization through the specific drive unit showing the anomaly.

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

Data Source

PatentEP2384379B1Method and device for detecting a tear-off of a material web
Publication Date: 2015.07.29 SIEMENS AG
  • EP2384379B1 patent drawingFigure 1
  • EP2384379B1 patent drawingFigure 2
  • EP2384379B1 patent drawingFigure 3

AI summary

The invention relates to a method and to a device for detecting a tear-off of a material web in a machine for producing and/or processing a material web without the necessity of optical sensor systems. The drive data of drive units that have a speed governor and that are provided on the machine are evaluated.