Palm-Mounted Optical Sensing for Robotic Grasp Evaluation
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Solution Overview
Problem
Existing robotic grippers, particularly underactuated ones, face challenges in accurately determining grasp success and quality due to limited control inputs and reliance on force-based sensors, which can be unreliable and complex, and integrating sensors within digits complicates manufacturing and maintenance.
Innovation Solution
Equipping robotic gripping devices with non-contact sensors such as time-of-flight sensors and infrared cameras on the palm, allowing for multiple sensing modalities to provide accurate grasp evaluation using an object-in-hand classifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force-based sensors are used to determine grasp success, then measurement capability is improved, but device complexity and reliability worsen due to sensor integration complexity and unreliability
Solution Approach 1:
The patent removes force-based sensors from the digit structures and extracts the sensing function to a separate camera system positioned externally. This eliminates the complexity of integrating force sensors within the mechanical digits while maintaining grasp detection capability through visual feedback from the camera observing the gripper's closing action.
Solution Approach 2:
The patent replaces mechanical force-based sensing with an optical measurement system. Instead of using force sensors to detect contact forces, the system uses a camera to visually monitor the gripper's operation and infer grasp success from the observed motion and positioning, substituting mechanical sensing with optical detection.
2Measurement precision
If force-based sensors are integrated within digits, then grasp quality measurement is improved, but ease of manufacture and maintenance worsen
Solution Approach 1:
The patent segments the sensing function from the mechanical gripping structure. The digits are designed as simple mechanical components without embedded sensors, while the sensing capability is provided by a separate camera system. This segmentation allows the mechanical digits to be manufactured independently using standard techniques while the sensing system is added as a separate module.
Solution Approach 2:
The patent introduces a camera as an intermediary sensing device that observes the gripper's operation from an external position. This intermediary approach allows grasp quality evaluation without requiring direct integration of sensors into the digit structures, simplifying manufacturing while maintaining measurement capability through visual observation of the gripping process.
3Measurement precision
If multiple sensor modalities are integrated on the palm, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a camera system that serves multiple functions: it captures images for grasp success detection, provides visual feedback for control, and can potentially be used for object recognition and positioning. This multi-functionality allows a single sensor modality to perform multiple tasks that would otherwise require different specialized sensors, reducing overall system complexity while maintaining measurement precision.
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
Enhances grasp success determination with high accuracy and simplicity by minimizing hardware and computational overhead, suitable for underactuated grippers with interchangeable digits.
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
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
Data Source
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.