Multi-axis force sensor reducing axial-torque crosstalk
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Solution Overview
Problem
Multi-axis force sensors face decreased sensing accuracy due to crosstalk phenomena caused by axial forces and torques, as most sensors are planar, leading to interference between different axial directions.
Innovation Solution
A multi-axis force sensor design featuring a central portion, an outer ring portion, and sensing portions with distinct elements and strain gauges, where the first element is connected to the central portion and the second element to the outer ring, optimizing strain and twist angles to minimize the influence of axial forces on torque measurements and vice versa through differential design of areas and area moments of inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a planar multi-axis force sensor is used, then the device complexity is reduced and manufacturing is simplified, but the sensing accuracy deteriorates due to crosstalk between axial force and torque measurements
Solution Approach 1:
The sensor is divided into multiple independent sensing elements (first element and second element) with distinct sensing regions. Each element is specifically designed to detect either axial force or torque, preventing crosstalk by segmenting the measurement functions spatially and structurally.
Solution Approach 2:
Different regions of the sensor structure are optimized for different measurement functions. The first sensing region is designed with properties optimized for torque detection, while the second sensing region is optimized for axial force detection, ensuring each local region performs its specific measurement function with high accuracy.
2Measurement precision
If the first sensing region has high sensitivity to torque, then the torque measurement precision is improved, but the influence of axial force on torque measurement increases
Solution Approach 1:
The sensor structure segments the torque sensing function into the first element with the first sensing region, which is specifically designed to be sensitive to torque while being less sensitive to axial force. This segmentation allows high torque measurement precision while isolating the measurement from axial force interference.
Solution Approach 2:
The first element and second element are designed with asymmetric structural properties relative to the measurement axes. The first element has geometric characteristics that make it predominantly responsive to torque, while the second element is configured to be predominantly responsive to axial force, reducing cross-sensitivity through asymmetric design.
3Measurement precision
If the second sensing region has high sensitivity to axial force, then the axial force measurement precision is improved, but the influence of torque on axial force measurement increases
Solution Approach 1:
The axial force sensing function is segmented into the second element with the second sensing region, which is specifically designed to detect axial force with high sensitivity. The structural segmentation ensures that torque effects are isolated from the axial force measurement path, maintaining high precision while minimizing torque interference.
Solution Approach 2:
The second element is designed with asymmetric structural properties that make it predominantly responsive to axial force while being less responsive to torque. This asymmetric configuration optimizes axial force measurement precision while reducing the harmful effect of torque on the measurement.
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 design effectively reduces the impact of axial forces on torque measurements and torques on axial force measurements, enhancing the accuracy and sensitivity of the sensor by leveraging the differences in strain and twist angles between the sensing regions.
Implementation Method 1
at least one first strain gauge and at least one second strain gauge... The first strain gauge is disposed in the first sensing region, and the second strain gauge is disposed in the second sensing region
Data Source
AI summary
A multi-axis force sensor including a central portion, an outer ring portion, and at least one sensing portion disposed along an axial direction of an axis is provided. The sensing portion includes a first and a second elements connected with each other, and at least one first and at least one second strain gauges. A first end surface of the first element is connected to the central portion, and a second end surface of the second element is connected to the outer ring portion. A normal vector of the first end surface is parallel to the axis and the axis passes through a centroid of the first end surface. When the first end surface is subjected to an axial force, a first strain of a first sensing region of the first element in the axial direction is smaller than a second strain of a second sensing region of the second element in the axial direction. When the first end surface is subjected to a first torque with respect to the axis, a first twist angle of the first sensing region with respect to the axis is greater than a second twist angle of the second sensing region with respect to the axis.