Seat Gear Diagnostics Using Motor Current Frequency Analysis

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Automotive seat assemblies experience performance degradation over time due to repetitive operation and aging, leading to impaired smooth transitions, altered positioning, and unexpected movements, necessitating a system to detect faults before they become noticeable or operational.

Innovation Solution

A method for detecting faults in the gear system of a seat assembly by measuring motor current, analyzing current waveforms, applying continuous wavelet transformation, and monitoring hall effect signals to identify deviations from predetermined thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the gear system operates for extended periods with repetitive operation, then the seat assembly achieves functional positioning, but performance degradation occurs due to aging effects

Engineering Contradiction:

Improveoperational durationVSAvoidsystem reliability

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The system performs preliminary diagnostic actions by continuously monitoring motor current waveforms and calculating power spectrum density to detect early signs of gear degradation before they manifest as noticeable performance issues. This allows preventive maintenance scheduling based on actual gear condition rather than fixed time intervals.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback through continuous monitoring of motor current during operation, analyzing the waveform characteristics and power spectrum density to detect changes in gear mesh conditions. This feedback loop enables real-time assessment of gear health and triggers alerts when degradation thresholds are exceeded.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If the gear train components wear or become damaged, then the seat assembly can still operate, but unexpected movements and positioning errors occur

Engineering Contradiction:

Improveoperational continuityVSAvoidpositioning stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The system replaces mechanical inspection methods with electrical measurement techniques by monitoring motor current waveforms and analyzing power spectrum density. This substitution enables non-intrusive, continuous monitoring of gear condition without requiring physical access to the gear train, maintaining operational continuity while detecting positioning stability issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The motor current waveform serves as an intermediary that indirectly reflects the mechanical condition of the gear train. By analyzing changes in current characteristics and power spectrum density, the system detects gear wear and damage without direct mechanical measurement, enabling early warning of positioning stability degradation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If traditional monitoring methods are used, then the system structure remains simple, but early fault detection capability is insufficient

Engineering Contradiction:

Improvemonitoring system complexityVSAvoidfault detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system transitions from time-domain current measurement to frequency-domain analysis by calculating power spectrum density of the motor current waveform. This dimensional transformation reveals hidden patterns and characteristics of gear meshing that are not apparent in the time domain, significantly improving fault detection precision with minimal additional complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Effectively detects gear system faults, preventing unexpected movements and ensuring smooth operation by identifying and notifying occupants of potential issues.

Implementation Method 1

a gear train operatively coupled to a motor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

measuring a hall effect signal from the drive shaft indicating a rotational position and a rotational speed of the drive shaft

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS12409759B2Systems and methods to monitor seats for diagnostics, prognostics and degradation

Publication Date: 2025.09.09 MAGNA SEATING INC

AI summary

A method is provided for detecting a fault in a gear system for repositioning a seat assembly in an automotive vehicle. The gear system includes a gear train operatively coupled to a motor. The method includes the steps of measuring a current drawn by the motor to reposition the seat assembly, recording the current over time as a current waveform, converting the current waveform into a frequency domain, determining a base frequency of the current waveform based on the converted current waveform, calculating a power spectrum density at the base frequency, calculating a total band power of the power spectrum density, and determining whether the total band power is greater than a predetermined total band power threshold.