Strain Wave Gear Torque Sensing With Strain Gauge Self-Check
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Solution Overview
Problem
Existing methods for measuring torque in strain wave gearings do not adequately account for defects in strain gauges, leading to potential inaccuracies in torque measurement.
Innovation Solution
A method involving an assembly of at least three strain gauges on the elastic transmission element of a strain wave gearing, which self-examines by predicting output signals from measured values and issuing an error message if deviations exceed a predetermined tolerance, without requiring additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are used to measure torque in strain wave gearings, then torque measurement is enabled, but defects in strain gauges can lead to measurement inaccuracies
Solution Approach 1:
The system performs preliminary self-examination of strain gauge defects by comparing measured output signals with predicted output signals before torque measurement. This preliminary check identifies defective strain gauges that would otherwise compromise measurement accuracy, resolving the contradiction between enabling torque measurement and preventing measurement inaccuracies from defects
Solution Approach 2:
The system implements feedback by continuously monitoring strain gauge output signals and comparing them against predicted values based on elastic transmission element deformation. This feedback mechanism detects deviations indicating defects, allowing the system to maintain measurement precision by identifying and flagging unreliable strain gauges
2Reliability
If additional sensors are added to detect strain gauge defects, then defect detection capability is improved, but device complexity increases
Solution Approach 1:
The existing strain gauge assembly performs dual functions: measuring torque through output signals and self-examining for defects by comparing measured signals with predicted signals. This multi-functionality eliminates the need for separate defect detection sensors, resolving the contradiction between improving reliability and reducing device complexity
Solution Approach 2:
The strain gauge assembly performs self-diagnosis by autonomously comparing its own output signals against predicted values. This self-service capability enables defect detection without external monitoring sensors, maintaining reliability improvement while avoiding increased device complexity
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
Enables detection of gauge defects with minimal effort, ensuring accurate torque measurement by verifying the consistency of strain gauge outputs within a tolerance range, thereby maintaining measurement precision.
Implementation Method 1
The strain gauges are placed on the elastic transmission element to measure a mechanical stress of the elastic transmission element
Implementation Method 2
The elastic transmission element is also referred to as a flex spline and has an outer toothing
Data Source
AI summary
An assembly includes at least three strain gauges and is attached to an elastic transmission element of a strain wave gearing. The assembly is designed to measure a torque acting on the elastic transmission element. Output signals from each of the strain gauges are measured. The output signal of one of the strain gauges is predicted from the measured output signals of the other strain gauges. An error message is output based on the predicted output signal deviating from the respective measured output signal by more than a predetermined tolerance.