Palm-Mounted Optical Sensing for Underactuated Robotic Grippers

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Solution Overview

Problem

Robotic grippers with underactuated digits face challenges in determining grasp success and quality due to limited control inputs and the complexity of integrating sensors within the digits, particularly when handling varied objects like paper and plastic cups, where force-based solutions are unreliable.

Innovation Solution

Incorporating a combination of a time-of-flight sensor and an infrared camera on the palm of the gripper, which generates time-of-flight distance and grayscale image data, respectively, to provide accurate sensor information about the region between the digits, allowing for effective grasp control and success determination using an object-in-hand classifier that combines multiple sensing modalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If force-based sensors are integrated within the digits to determine grasp success, then grasp quality detection is improved, but device complexity and manufacturing difficulty increase significantly

Engineering Contradiction:
Improvegrasp success detection accuracyVSAvoidsensor integration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the sensing function from the digits and relocates it to the palm of the gripper. By placing time-of-flight sensors and infrared cameras in the palm rather than integrating force sensors within each digit, the system achieves grasp detection capability while significantly reducing device complexity and manufacturing difficulty.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical force-based sensing with optical sensing methods. Time-of-flight sensors and infrared cameras use light-based measurement rather than mechanical force detection, enabling grasp success determination through optical data about the region between digits without requiring complex force sensor integration.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If multiple sensor types are integrated into the gripper to handle varied objects, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improveability to handle varied objectsVSAvoidsensor combination complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by using time-of-flight sensors and infrared cameras positioned in the palm to perform multiple sensing tasks simultaneously. These sensors provide depth information, surface detection, and material characterization that work across diverse object types including paper, plastic cups, and other varied materials, achieving universality without requiring separate specialized sensors for each object type.

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

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

This solution enhances the accuracy of grasp success detection and quality evaluation, even with underactuated grippers, by providing reliable distance and reflectance data, and image-based information, improving the robotic system's ability to handle diverse objects without the need for complex force sensors.

Implementation Method 1

a time-of-flight sensor arranged on the palm such that the time-of-flight sensor is configured to generate time-of-flight distance data

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

an infrared camera, comprising an infrared illumination source, where the infrared camera is arranged on the palm such that the infrared camera is configured to generate grayscale image data

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentEP4039422B1Sensorized robotic gripping device
Publication Date: 2024.05.15 GOOGLE LLC
  • EP4039422B1 patent drawingFigure 1
  • EP4039422B1 patent drawingFigure 2
  • EP4039422B1 patent drawingFigure 3

AI summary

A robotic gripping device is provided. The robotic gripping device includes a palm and a plurality of digits coupled to the palm. The robotic gripping device also includes a time-of-flight sensor arranged on the palm such that the time-of-flight sensor is configured to generate time-of-flight distance data in a direction between the plurality of digits. The robotic gripping device additionally includes an infrared camera, including an infrared illumination source, where the infrared camera is arranged on the palm such that the infrared camera is configured to generate grayscale image data in the direction between the plurality of digits.