Multi-DOF Force Torque Sensor Structure for Decoupled Sensing

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Solution Overview

Problem

Existing force and torque sensors struggle with coupled structural deformations, making it difficult to adjust detection abilities for individual forces and torques without affecting others, and are limited by the sensitivity of strain gauges to unique deformation patterns.

Innovation Solution

A multi-degree of freedom force and torque sensor design using rigid plates and elastic elements with signal pairs to detect relative displacements, allowing independent sensing of forces and torques in multiple directions through adjustable elastic element positions and shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If strain gauges are bonded to local structures to convert deformations into electrical signals, then force and torque can be measured, but each strain gauge is only sensitive to a unique deformation pattern, limiting the sensor's versatility in detecting multiple forces and torques

Engineering Contradiction:
Improvedetection ability for multiple forces and torquesVSAvoidsensor structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sensor is divided into multiple independent sensing units, each equipped with strain gauges oriented in specific directions. Each unit independently measures force or torque components, allowing the sensor to detect multiple forces and torques simultaneously while maintaining a modular structure that doesn't excessively increase complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Strain gauges are strategically bonded to specific local structures where they exhibit maximum sensitivity to particular deformation patterns. By optimizing the placement and orientation of strain gauges at different locations, the sensor achieves enhanced versatility in detecting various force and torque components without requiring a complete redesign of the overall structure.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If transducers are disposed at positions with maximum displacements to sense displacements, then non-contact sensing can be achieved, but structural deformations caused by different forces and torques are seriously coupled, making it difficult to adjust detection ability for individual forces or torques

Engineering Contradiction:
Improvedetection accuracy for individual forces and torquesVSAvoidadjustment capability for different detection requirements
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The sensor structure incorporates adjustable elements that allow the detection characteristics to be dynamically modified. By changing the configuration or positioning of certain components, the sensor can be adjusted to optimize detection for specific force or torque components while maintaining the ability to detect other components, thus achieving both precision and versatility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensor is designed with pre-configured strain gauge orientations and positions that are optimized for detecting specific force and torque components before actual measurement begins. This preliminary arrangement ensures that each strain gauge is positioned to maximize sensitivity to its target deformation pattern, reducing coupling effects and enabling independent adjustment of detection abilities for different forces and torques.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If multiple strain gauges are used to detect different deformation patterns, then more force and torque components can be measured, but the structural deformations are coupled, affecting the independent adjustment of detection ability

Engineering Contradiction:
Improvedetection capability for multiple force and torque componentsVSAvoidindependent detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The sensor structure employs asymmetric design in the arrangement and orientation of strain gauges on different local structures. By creating asymmetric configurations, the coupling between different deformation patterns is reduced, allowing each strain gauge to more independently measure its specific force or torque component with higher precision while maintaining the ability to detect multiple components simultaneously.

Inventive Principle:
Principle #4Asymmetry

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 independent sensing of forces and torques in multiple directions, improving detection accuracy and flexibility in various application scenarios.

Implementation Method 1

a plurality of elastic elements 30 which are connected between the first and second rigid plates 10 and 20

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a plurality of signal pairs are arranged on the first and second rigid plates 10 and 20 to detect relative displacements of the two plates

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP4176239B1Multi-degree of freedom force and torque sensor and robot
Publication Date: 2026.02.11 SHANGHAI FLEXIV ROBOTICS TECH CO LTD
  • EP4176239B1 patent drawingFigure 1~3
  • EP4176239B1 patent drawingFigure 4~6
  • EP4176239B1 patent drawingFigure 7~9

AI summary

A multi-degree of freedom force and torque sensor (100) is provided. The multi-DOF force and torque sensor includes a first rigid plate (10), a second rigid plate (20), multiple elastic elements (30) connected between the first and second rigid plates, and multiple signal pairs arranged between the first and second rigid plates. The signal pairs are used for detecting relative displacements of the first and second rigid plates in multiple directions.