Drive Train Defect Detection via Drive and Reference Axle Comparison

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Solution Overview

Problem

Existing methods for monitoring drive train defects in vehicles are inadequate for ensuring safe and reliable autonomous driving, as they lack reliable automatic detection capabilities, particularly for conditions like loose wheel nuts that can lead to permanent failure and accidents.

Innovation Solution

A method using sensors to compare the rotational behavior of a drive axle with a reference axle, determining deviations in drive and reference variables to identify defects, such as loose components, by analyzing changes in drive torque transmission and oscillating patterns, leveraging existing sensors like motor speed and wheel speed sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual monitoring of drive train defects is performed by the driver, then detection capability is provided, but reliability is insufficient for autonomous driving and continuous monitoring during trips is not possible

Engineering Contradiction:
Improvereliability of defect detectionVSAvoidautomation of defect detection
Core Design Contradiction:
ReliabilityVSExtent of automation

Solution Approach 1:

The monitoring system performs self-diagnosis by automatically comparing drive variable (from drive axle sensor) with reference variable (from reference axle sensor) to detect defects without driver intervention. The system serves itself by autonomously identifying torque transmission defects through sensor data analysis

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors drive train operation by feeding back sensor signals from both drive and reference axles to the monitoring unit. This closed-loop feedback enables real-time defect detection by comparing actual torque transmission with expected behavior based on reference axle performance

Inventive Principle:
Principle #23Feedback

2Measurement precision

If existing defect detection methods are used, then some fault detection is possible, but measurement precision is insufficient for detecting subtle defects like loose wheel nuts

Engineering Contradiction:
Improveprecision of defect detectionVSAvoidcomplexity of monitoring system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A non-driven reference axle serves as an intermediary reference system. By comparing the drive axle against this stable reference, the system achieves high measurement precision for detecting subtle defects like loose wheel nuts without requiring complex absolute measurement systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The monitoring system segments the drive train into two independent parts: the driven drive axle and the non-driven reference axle. This segmentation allows independent sensing of each axle's rotational behavior, enabling precise defect detection through comparison while keeping individual sensor requirements simple

Inventive Principle:
Principle #1Segmentation

3Reliability

If continuous monitoring of drive torque transmission is implemented, then defect detection capability is improved, but loss of time for data processing and analysis increases

Engineering Contradiction:
Improvecontinuous defect detection capabilityVSAvoidtime for data processing
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system processes only the essential comparison between drive and reference variables rather than analyzing all possible drive train parameters. This partial action approach provides sufficient defect detection capability without excessive data processing time

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The monitoring unit continuously compares drive and reference variables in real-time as they are generated by sensors. This preliminary continuous comparison ensures defects are detected immediately without requiring subsequent batch processing or delayed analysis

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4314757B1Method for determining a defect state of a drive train of a vehicle, monitoring unit and vehicle
Publication Date: 2024.12.18 ZF CV SYST GLOBAL GMBH
  • EP4314757B1 patent drawingFigure 1~2
  • EP4314757B1 patent drawingFigure 3~4
  • EP4314757B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for determining a defect state of a drive train (3) of a vehicle (1), wherein the vehicle (1) has a drive axle (1a) with a drive wheel (11) and a reference axle (1b) with a reference wheel (15), wherein, by means of the drive train (3), a drive torque (MA) generated by a drive (5) can be transmitted to an underlying surface (2) via the drive wheel (11) and the drive torque (MA) of the drive (5) is not transmitted to the underlying surface (2) via the reference wheel (15) of the reference axle (1b), comprising at least the following steps: - reading-in a drive variable (GA), wherein the drive variable (GA) is dependent on a rotation speed (N5) of the drive (5); - reading-in a reference variable (GB), wherein the reference variable (GB) is dependent on a reference wheel rotation speed (N15) of the reference wheel (15); - determining whether there is a deviation between the read-in drive variable (GA) and the read-in reference variable (GB) in order to establish whether the reference wheel rotation speed (N15) of the reference wheel (15) is related to the rotation speed (N5) of the drive (5), wherein it is concluded that there is a defect state of the drive train (3) when there is a deviation; and - outputting a state signal (SD) when there is a defect state of the drive train (3).