Capacitive Sensor Layout for Six-DOF Force and Torque Sensing

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Solution Overview

Problem

Existing mechanical and electromechanical systems face challenges in accurately measuring force and torque along multiple axes due to limited space and placement constraints, making it difficult to incorporate multiple sensors for multi-degree of freedom applications.

Innovation Solution

A capacitive sensor design featuring alternating non-patterned and patterned conductive regions on opposing surfaces, capable of measuring up to six degrees of freedom by detecting relative axial and lateral displacements and rotations, utilizing both non-patterned and patterned conductive regions for precise capacitance measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple separate sensors are used to measure force and torque in multiple degrees of freedom, then measurement coverage is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvemeasurement coverageVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensing functions into a single capacitive sensor device that can measure forces and torques across multiple degrees of freedom simultaneously. The sensor integrates multiple conductive regions (patterned and non-patterned) on opposing surfaces that work together to detect various mechanical parameters, eliminating the need for multiple separate sensors and reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The capacitive sensor is designed with universal functionality to measure multiple parameters including forces in three directions and torques in three directions (six degrees of freedom). The same sensor structure with its array of conductive regions can detect different types of mechanical stimuli, making it a multi-functional device that replaces several specialized sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple separate sensors are used to measure force and torque in multiple degrees of freedom, then measurement accuracy is improved, but available space requirements increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidavailable space
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent merges multiple sensing capabilities into a single compact sensor assembly. The sensor uses two opposing surfaces with multiple conductive regions that can simultaneously measure forces and torques in multiple directions, significantly reducing the space required compared to using multiple separate sensors distributed throughout the system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor utilizes a three-dimensional capacitive measurement approach by placing conductive regions on opposing surfaces with spacing between them. This dimensional arrangement allows the sensor to detect forces and torques in multiple directions simultaneously within a compact volume, effectively using spatial dimensionality to achieve multi-degree-of-freedom measurement without requiring large planar area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If patterned conductive regions are used to measure lateral displacement and rotation, then measurement precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvelateral displacement measurement precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The conductive regions are segmented into patterned and non-patterned areas on each surface. The patterned regions are specifically designed with conductive traces arranged in patterns that enhance sensitivity to lateral displacement and rotational measurements. This segmentation allows different regions to serve different measurement functions while maintaining manufacturability through standardized fabrication processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor implements local quality by creating patterned conductive regions in specific locations where enhanced measurement capability is needed. The patterned regions are strategically placed and configured to provide superior sensitivity for lateral displacement and rotation detection, while non-patterned regions provide complementary measurement capabilities, optimizing overall performance.

Inventive Principle:
Principle #3Local quality

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 capacitive sensor provides simultaneous, accurate, and precise measurements of force and torque in multiple degrees of freedom in a compact form, suitable for systems with space and weight restrictions, enhancing the functionality of robotic systems.

Implementation Method 1

The capacitive sensor may measure relative axial displacement between the first and second surfaces based at least partially on gap distance between at least one of the first plurality of non-patterned conductive regions and at least one of the second plurality of non-patterned conductive regions

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the capacitive sensor may measure relative lateral translation and/or relative rotation between the first and second surfaces based at least partially on area of overlap between the first and second pluralities of patterned conductive regions

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3513300B1Multi-degree of freedom sensor
Publication Date: 2025.11.12 VERB SURGICAL INC
  • EP3513300B1 patent drawingFigure 1~2
  • EP3513300B1 patent drawingFigure 3A~3C
  • EP3513300B1 patent drawingFigure 4A~4B

AI summary

A capacitive sensor for characterizing force or torque includes a first plurality of non-patterned conductive regions and a first plurality of patterned conductive regions, and a second plurality of non-patterned conductive regions and a second plurality of patterned conductive regions. The first and second pluralities of non-patterned conductive regions are facing and the first and second pluralities of patterned conductive regions are facing.