Tactile Sensing Skin for Robotic Object Manipulation

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Solution Overview

Problem

Current robotics systems lack sufficient tactile sensing resolution and integration capabilities to effectively manipulate and interact with objects in various settings, including consumer and industrial applications, due to limitations in sensitivity, dynamic range, and robustness across different environments.

Innovation Solution

A conductive tactile sensing skin made of polymeric materials, such as rubber doped with carbon-containing materials, integrated with a vision system for enhanced sensing and manipulation capabilities, allowing for flexible form factors and scalable applications. This skin includes an array of electrodes for boundary-based tomographic units and can detect position-orientation, force-torque, and pressure distributions, combined with software for state estimation and situational awareness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional tactile sensing systems are used, then sensing capability is provided, but sensing resolution and sensitivity are insufficient for effective object manipulation

Engineering Contradiction:
Improvesensing resolutionVSAvoidsensing performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The tactile sensing surface is divided into multiple discrete sensing elements (e.g., capacitive sensors, piezoresistive elements) arranged in arrays or matrices. This segmentation allows each element to independently measure local pressure, force, or touch characteristics, thereby achieving high spatial resolution while maintaining reliable sensing across the entire surface through coordinated operation of multiple elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional single-dimensional or two-dimensional pressure sensing to three-dimensional force-torque sensing capabilities. By incorporating sensor configurations that can detect force vectors in multiple directions and calculate torque moments, the system achieves comprehensive six-degree-of-freedom tactile measurement, significantly improving sensing resolution and reliability for complex manipulation tasks.

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

2Measurement precision

If complex sensing systems are integrated, then sensing capability is enhanced, but system complexity and integration difficulty increase

Engineering Contradiction:
Improvesensing capabilityVSAvoidintegration capability
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple sensing modalities (capacitive, piezoresistive, flexural sensors) are merged into a single integrated tactile sensing surface or skin. This combination allows the system to simultaneously measure different physical quantities (pressure, force, touch, strain) using a unified sensor array, enhancing sensing capability while reducing the complexity associated with integrating separate sensor systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The tactile sensing system is designed with universal sensor elements that can detect multiple types of mechanical stimuli (normal force, shear force, torque, vibration) using the same physical platform. This multi-functionality is achieved through sensor configurations that respond to various stimulus types, thereby enhancing sensing capability without requiring separate specialized sensors for each measurement type.

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

3Adaptability or versatility

If robust sensing systems are deployed across different environments, then environmental adaptability is improved, but sensitivity and dynamic range are compromised

Engineering Contradiction:
Improveenvironmental robustnessVSAvoidsensitivity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The tactile sensing system incorporates dynamic calibration and adaptation mechanisms that allow sensor characteristics to be adjusted in real-time based on environmental conditions. This includes temperature compensation algorithms, adaptive threshold settings, and dynamic range adjustment that maintain high sensitivity across varying environmental conditions, thereby achieving both environmental robustness and measurement precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs sensor materials and configurations whose physical parameters (electrical conductivity, mechanical stiffness, piezoresistive coefficients) can be modified or selected to optimize performance for specific environmental conditions. By changing material parameters or sensor operating parameters based on environmental requirements, the system maintains high sensitivity and measurement precision across different temperatures, humidities, and atmospheric conditions.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a cost-effective, easily calibrated tactile and vision system that improves robotic ability to identify and manipulate objects, enhancing interaction with unstructured environments and reducing setup times for new production runs.

Implementation Method 1

a conductive skin formed of a polymeric material (e.g., rubber) that can be doped with a chemically inert material, such as a carbon-containing material

Methodology Applied
Scientific EffectElectrical conduction through carbon doping: Conduction (electrical)

Implementation Method 2

the non-metallic sensing electrodes are adapted to sense changes in electrical impedance when disposed at or in proximity to the object

Methodology Applied
Scientific EffectElectrical impedance sensing: Electrical Impedance Tomography

Data Source

PatentEP3007867B1Systems and methods for sensing objects
Publication Date: 2020.10.21 ONROBOT AS
  • EP3007867B1 patent drawingFigure 1A~1B
  • EP3007867B1 patent drawingFigure 1C~1D
  • EP3007867B1 patent drawingFigure 2

AI summary

Disclosed is a tactile sensing and integrated vision system that surmounts problems of existing systems. The tactile sensing skin can be formed into any shape, size, or form factor, including large areas. Computer-implemented algorithms can detect position-orientation and force-torque at landmark points for a given object set. The result is a modular sensing system that is highly scalable in terms of price, quantity, size and applications. Such skin technology and associated software can comprise a sensing package that integrates tactile and visual data with accompanying software for state estimation, situational awareness, and automatic control of machinery. The addition of tactile data can serve to constrain and/or augment visual pose estimation methods as well as provide pose estimation to visually occluded objects.