Electromagnetic Brake Monitoring via Coil Current Sensing

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Solution Overview

Problem

Existing methods for monitoring electromagnetically actuated brakes lack effective means to determine wear and operational state, particularly in identifying deviations from intended behavior and detecting sudden failures, which can lead to unsafe vehicle operation.

Innovation Solution

The method involves detecting the current flowing through the coil and analyzing the current curve to determine the relative position of the solenoid, assessing wear, and monitoring for threshold deviations, using the coil as a sensor to evaluate the brake's engaged or released state, and detecting temperature and ohmic resistance to ensure proper functioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the coil is used as a sensor to determine solenoid position from the current curve, then the measurement precision of brake state is improved, but the device complexity is reduced by eliminating separate sensors

Engineering Contradiction:
Improvebrake state detection accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The coil serves dual functions: as the actuator that generates the magnetic field to move the solenoid, and as a sensor that detects the solenoid position through current curve analysis. This multi-functionality eliminates the need for separate position sensors, reducing device complexity while maintaining measurement precision through the electromagnetic coupling between the coil and solenoid.

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

2Measurement precision

If voltage is increased in time intervals to determine solenoid position, then the measurement precision is improved, but the use of energy by the coil increases

Engineering Contradiction:
Improvesolenoid position detection accuracyVSAvoidcoil energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Voltage is applied to the coil in periodic time intervals rather than continuously, allowing the current curve to be measured at specific moments when position information is needed. This periodic excitation provides sufficient measurement precision for brake state detection while significantly reducing overall energy consumption compared to continuous voltage application.

Inventive Principle:
Principle #19Periodic action

3Reliability

If the brake wear is monitored by determining solenoid position in the engaged state, then the reliability is improved, but the measurement precision requirements increase

Engineering Contradiction:
Improvebrake safety monitoringVSAvoidwear detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system continuously monitors the solenoid position in the engaged state and compares it against reference values to detect wear. When the position deviates from expected ranges, the system provides feedback through warning or error messages. This feedback mechanism enhances reliability by enabling early wear detection while allowing moderate measurement precision thresholds.

Inventive Principle:
Principle #23Feedback

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 allows for simple and effective condition and function monitoring, enabling early detection of wear and potential failures, thereby ensuring safe operation by displaying warnings or error messages when deviations occur.

Implementation Method 1

a brake has a coil whose energization generates a magnetic field, which is intended for electromagnetic actuation

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Implementation Method 2

the current flowing through the coil is detected... the brake coil acts as a sensor. This allows the position of the solenoid to be determined from the current curve

Methodology Applied
Scientific EffectElectromagnetic sensing: Electromagnetic Induction

Data Source

PatentEP3515779B1Method for monitoring an electromagnetically actuatable brake, and vehicle with electromagnetically actuatable brake
Publication Date: 2024.04.10 SEW EURODRIVE GMBH & CO KG
  • EP3515779B1 patent drawingFigure 1
  • EP3515779B1 patent drawingFigure 2
  • EP3515779B1 patent drawingFigure 3

AI summary

The invention relates to a method for monitoring an electromagnetically actuatable brake which has an energizable coil that interacts with a solenoid arranged in a linearly movable manner and to a vehicle with an electromagnetically actuatable brake. The current flowing through the coil is detected, wherein the detected current value is fed to an analysis unit in particular. The voltage applied to the coil is increased during particular periods of time, and the current curve, in particular the curve of the current increase, produced thereby determines the position of the solenoid relative to the coil. In particular, the determined position is used to determine whether the brake is in the engaged state or in the released state. In particular, the solenoid is designed as a permanent magnet or has a permanent magnet.