Rotation Angle Sensor Fault Detection in Electric Drive Units

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Solution Overview

Problem

Existing methods for detecting faults in machines, such as those using vibration sensors and electrical measurement variables, often fail to detect damage early enough to prevent costly mechanical damage, leading to unplanned production interruptions and complex repairs.

Innovation Solution

A method that utilizes a rotation angle sensor to emit measurement signals, which are analyzed for abnormalities in the time or frequency domain, allowing for early detection of faults in electric drive units without additional sensor systems, enabling planned maintenance before significant damage occurs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vibration sensors are attached to the machine for fault detection, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefault detection precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The existing rotation angle sensor, which is already part of the electric drive unit for its primary function of controlling rotor position, is utilized for fault detection. The sensor serves dual purposes: controlling the motor operation and monitoring mechanical faults through analysis of its measurement signals, eliminating the need for separate vibration sensors.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The rotation angle sensor is made multi-functional by using it both for its original purpose of providing position feedback for motor control and for the new purpose of detecting mechanical faults. The same sensor hardware and signal processing infrastructure are leveraged for both control and condition monitoring functions.

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

2Reliability

If additional vibration sensors are installed for early fault detection, then reliability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvefault detection reliabilityVSAvoidmachine assembly ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The rotation angle sensor performs self-service by contributing to fault detection functionality without requiring additional sensors or complex installation procedures. The existing sensor infrastructure is repurposed, maintaining ease of manufacture while improving reliability through intelligent signal analysis.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If current intensity monitoring is used for fault detection, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvefault detection simplicityVSAvoidfault detection precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The measurement signal from the rotation angle sensor acts as an intermediary that provides more precise information about mechanical conditions than current monitoring alone. By analyzing variations in this signal caused by mechanical faults, the system achieves both ease of operation (using existing control infrastructure) and improved measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of time

If rotation angle sensor signals are analyzed for fault detection, then loss of time is reduced, but difficulty of detecting and measuring increases

Engineering Contradiction:
Improvefault detection timeVSAvoidsignal analysis complexity
Core Design Contradiction:
Loss of timeVSDifficulty of detecting and measuring

Solution Approach 1:

The measurement signal from the rotation angle sensor provides continuous feedback about the mechanical state of the machine. By monitoring variations in this feedback signal and comparing them against reference values or thresholds, the system can quickly detect faults without complex analysis procedures, reducing detection time while managing complexity through established signal processing techniques.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3120203B1Device and method for detecting errors in machines
Publication Date: 2021.08.11 KHS GMBH
  • EP3120203B1 patent drawingFigure 1~2
  • EP3120203B1 patent drawingFigure 3a~4b
  • EP3120203B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for detecting errors in a machine (1) comprising at least one electric drive unit (3) comprising a rotor, for driving an assembly (2a - 2e) of the machine (1), said drive unit (3) is associated with an rotation angle sensor (7) which is designed to emit a measurement signal (8, 8a, 8b) as the rotor rotates. The measurement signal (8, 8a, 8b) emitted by the rotation angle sensor (7) or a measurement signal derived therefrom is analyzed and evaluated taking into account errors indicating abnormalities.