Force Sensor with Line-Symmetric Strain Generation Parts
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Solution Overview
Problem
Existing force sensors require complex calculations to detect forces and moments in three-axis orthogonal coordinates, limiting their ability to accurately measure forces other than torque around the central axis.
Innovation Solution
A force sensor design featuring four strain generation parts with specific branch and connection configurations, allowing for line-symmetric and four-fold symmetric arrangements of strain sensors, which enables direct detection of forces and moments in each axial direction without the need for decoupling calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a six-axis force sensor uses multiple strain sensors with decoupling matrix calculations, then it can detect forces and moments in three-axis orthogonal coordinates, but the calculation becomes complicated
Solution Approach 1:
The strain generation part is divided into four separate strain generation parts arranged radially along the first axis and second axis. Each strain generation part independently detects strain in specific directions, segmenting the detection function to eliminate the need for complex decoupling calculations while maintaining six-axis detection capability
Solution Approach 2:
The strain generation parts are configured with asymmetric branching structures (first branch part and second branch part with bent parts) that create line-symmetry when projected perpendicular to the reference plane. This asymmetric design enables direct separation of strain in the direction of applied force without requiring mathematical decoupling
2Measurement precision
If a torque measurement apparatus uses thin-film type strain sensors on a surface perpendicular to the torque central axis, then it can measure torque accurately, but it cannot detect other forces and directions in three-axis orthogonal coordinates
Solution Approach 1:
The force sensor maintains the accurate torque measurement capability of thin-film strain sensors while extending functionality to detect forces in three-axis orthogonal coordinates. The four radially arranged strain generation parts enable the same sensor structure to measure both torque around the central axis and forces in radial directions simultaneously
Solution Approach 2:
The strain generation parts extend radially from the first structure along the first axis and second axis on a reference plane, adding radial detection dimensions to the traditional axial torque measurement. This dimensional extension enables six-axis detection while maintaining the proven accuracy of thin-film strain sensor technology
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 reliable detection of six-axis forces and moments in a balanced manner, improving sensitivity and reducing computational complexity, suitable for applications like robot joints and power transmission systems.
Implementation Method 1
A force sensor for detecting at least one of a force in each axial direction and a moment about each axis... by detecting a strain generated in the strain generation part
Implementation Method 2
thin-film type strain sensors arranged on a surface perpendicular to a torque central axis of the strain generation parts that detect an amount of strain in the strain generation parts
Data Source
AI summary
A force sensor includes a first structure, four strain generation parts, and a second structure connected to the first structure with the strain generation parts interposed therebetween. The strain generation part includes a first connection part connected to the first structure, a first branch part, which is a beam-like part branching into two from the first connection part toward the second structure and extending in directions separating from each other, a second branch part, which is a beam-like part connected to the first branch part with bent parts interposed therebetween and extending in directions approaching each other, and a second connection part where branched parts of the second branch part join and connects to the second structure. The strain generation parts are formed so that the strain generation parts become line-symmetric with respect to the first and second axes when projected in a direction perpendicular to the reference plane.