Torque Sensor Attachment Structure for Symmetric Deformation
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Solution Overview
Problem
Torque sensors attached to robot arms face challenges in maintaining detection accuracy due to asymmetric deformation caused by bending moments and translational forces, which result in asymmetric strain and reduced sensor output quality.
Innovation Solution
A torque sensor attachment structure featuring a first structure with integrated contact portions and a second structure with corresponding contact portions, ensuring symmetrical contact and deformation, thereby reducing interference from non-torque forces and enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the first structure (column) is fitted into the base (cylinder) to align centers of axes, then the centers of axes coincide with each other, but the contact between the column and cylinder occurs at several random points, causing asymmetric deformation and reducing detection accuracy
Solution Approach 1:
The invention divides the contact interface into multiple discrete contact portions (first contact portions on the first structure and second contact portions on the second structure) arranged symmetrically around the central axis. This segmentation ensures that the load is distributed evenly across multiple predetermined contact points rather than occurring at random locations, thereby maintaining symmetric deformation and improving detection accuracy.
2Ease of manufacture
If the first structure and second structure are brought into contact at several random points, then assembly is simple, but asymmetric strain is generated under bending moment and translational force, producing false output signals
Solution Approach 1:
The invention uses symmetric arrangement of contact portions rather than asymmetric random contact. The first and second contact portions are positioned at corresponding locations on opposite sides of the central axis, creating a symmetric load path that eliminates asymmetric strain generation while maintaining ease of assembly through the self-aligning nature of the symmetric structure.
3Measurement precision
If a bridge circuit is configured to output voltage against torque force only, then torque detection is achieved, but asymmetric deformation from non-torque forces generates asymmetric strain at strain sensors, producing false outputs
Solution Approach 1:
The invention converts the potentially harmful asymmetric deformation into beneficial symmetric deformation by carefully positioning the contact portions. The symmetric arrangement ensures that bending moments and translational forces produce equal and opposite strains at corresponding strain gauges, allowing the bridge circuit to reject these forces while maintaining sensitivity to torque, thereby eliminating false outputs.
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 proposed structure ensures balanced deformation of the torque sensor components, suppressing output signals from non-torque forces and improving the detection accuracy of torque measurements.
Implementation Method 1
a plurality of strain gauges serving as sensor elements are arranged on the strain parts. A bridge circuit is constituted by these strain gauges
Data Source
AI summary
A torque sensor includes a first structure, a second structure, a third structure provided between the first structure and the second structure, and at least two sensor units provided between the first structure and the second structure. A plurality of first contact portions having a structure integrated with the first structure is provided inside an outer peripheral portion of the first structure, first distal ends are arranged near the outer peripheral portion, and the first distal ends are in contact with a first attachment portion. A plurality of second contact portions having a structure integrated with the second structure is provided at a part of an inner peripheral portion of the second structure, second distal ends are arranged near the inner peripheral portion, and the second distal ends are in contact with a second attachment portion.