Concentric Strain Gauge Layout for Torque and Rotation Sensing
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Solution Overview
Problem
Conventional speed reducers with strain gauges attached to flexible external gears face challenges due to periodic flexural deformation, leading to error components in torque measurement that vary with rotation angle, necessitating the minimization of space for resistance lines to detect rotation angle.
Innovation Solution
A sensor design featuring first and second resistance lines arranged concentrically on a base, with each resistance line constituting a single region along the circumferential and radial directions, allowing for accurate detection of rotation angle and torque while minimizing occupied space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistance line is provided in the strain gauge to detect rotation angle, then torque measurement accuracy is improved by subtracting error components, but the device complexity and space occupation increase
Solution Approach 1:
The resistance line is divided into multiple regions (first region and second region) with different orientations. The first region extends in the circumferential direction to detect rotation angle, while the second region extends in the radial direction to detect torque. This segmentation allows each region to specialize in detecting specific parameters, improving measurement accuracy while organizing the complex resistance line structure into manageable functional segments.
Solution Approach 2:
Different regions of the resistance line are assigned different functional qualities based on their orientation and position. The first region (circumferential) is optimized for rotation angle detection, while the second region (radial) is optimized for torque detection. This local differentiation of quality allows the resistance line to perform multiple measurement functions simultaneously with enhanced precision for each parameter.
2Measurement precision
If resistance lines are arranged to detect both torque and rotation angle, then measurement accuracy is improved, but the area occupied by the resistance lines increases
Solution Approach 1:
The strain gauge integrates both torque detection and rotation angle detection functions into a single unified structure. The resistance line is configured with multiple regions that simultaneously perform both measurement functions, eliminating the need for separate detection systems and reducing the total space required while maintaining high measurement precision for both parameters.
Solution Approach 2:
The resistance line is designed as a multi-functional element that can detect both torque and rotation angle within the same gauge structure. By incorporating regions with different orientations (circumferential and radial), the single resistance line performs multiple measurement functions, reducing the need for additional separate sensors and minimizing the overall space occupation.
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
The sensor effectively detects the rotation angle and torque applied to the flexible external gear, correcting for error components caused by periodic deformation, thereby enhancing measurement accuracy and reducing the required space for the resistance lines.
Implementation Method 1
a strain gauge is attached to a flexible external gear that rotates at a rotational frequency after deceleration. This enables detection of torque applied to the flexible external gear.
Data Source
AI summary
A sensor includes a base, and first and second resistance lines. The base extends in a direction intersecting with a central axis. The first resistance lines are arrayed in a circumferential direction on a surface of the base. The second resistance lines are arranged concentrically with the first resistance lines and between the first resistance lines in the circumferential direction on the surface of the base. In the first resistance lines, the number of regions of the resistance line along the circumferential direction is one or less, and the number of regions of the resistance line along a radial direction is one or less. The sensor is able to provide improved detection accuracy.