3D Vision-Guided Robotic Grasping in Cluttered Assembly

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Solution Overview

Problem

Current machine-learning approaches for robotic control in manufacturing, such as those used in Industry 4.0, often fail to meet the high precision requirements for recognizing and manipulating small components in cluttered environments, with success rates typically ranging from 90% to 97%, which is insufficient for the 99.9995% accuracy needed in assembly lines.

Innovation Solution

A robotic system incorporating a refinement subsystem that utilizes 3D computer vision with structured-light projection and multi-wavelength illumination, combined with machine-learning techniques like Mask R-CNN for image segmentation and error compensation, to improve the accuracy of robotic arm movements and component grasping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing machine-learning models are used for robotic control, then the system is simple and easy to operate, but the manipulation success rate is insufficient (90-97%) for high-precision assembly tasks

Engineering Contradiction:
Improvemanipulation success rateVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The robotic system is divided into multiple specialized subsystems: a perception subsystem for component detection and pose estimation, a planning subsystem for trajectory generation, and an execution subsystem for precise manipulation. This segmentation allows each subsystem to be optimized independently, achieving high reliability while managing complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A refinement subsystem acts as an intermediary between the basic machine-learning model and the robotic execution. This intermediary layer includes a pose-refinement module that corrects estimation errors and a trajectory-optimization module that adjusts paths in real-time, thereby bridging the gap between approximate detection and precise manipulation without completely redesigning the base system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If basic machine-learning approaches are used, then the device complexity is low, but the precision of component recognition and grasping is insufficient for cluttered environments

Engineering Contradiction:
Improvecomponent recognition precisionVSAvoidvision system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system transitions from 2D image-based recognition to 3D point cloud-based pose estimation by integrating depth sensors and structured light projection. This dimensional enhancement allows the system to accurately perceive component geometry, orientation, and spatial relationships in cluttered environments, achieving high precision without requiring overly complex image processing algorithms

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

Solution Approach 2:

The vision system dynamically adjusts parameters such as lighting conditions, exposure time, and sensor gain based on environmental feedback. A refinement module continuously optimizes pose estimation parameters by comparing detected features with known component models, thereby maintaining high recognition precision across varying conditions without increasing hardware complexity

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If standard robotic control is used, then the system is simple to implement, but it cannot compensate for movement errors to achieve 99.9995% accuracy

Engineering Contradiction:
Improvemovement accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control system implements multi-level feedback mechanisms: sensor feedback from vision and force sensors provides real-time state information, refinement feedback corrects deviations between planned and actual trajectories, and compensation feedback adjusts for systematic errors in actuator performance. This layered feedback architecture achieves high measurement precision while managing control complexity through hierarchical processing

Inventive Principle:
Principle #23Feedback

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 the precision and reliability of robotic manipulation by enabling refined image segmentation, geometric-model-based pose determination, and real-time error compensation, thereby achieving the required high accuracy for assembly tasks in manufacturing.

Implementation Method 1

a structured-light projector to project codified light patterns onto a scene

Methodology Applied
Scientific EffectStructured light: Light

Implementation Method 2

an illumination unit comprising a plurality of single-color light sources of different colors

Methodology Applied
Scientific EffectLight emission: Light

Data Source

PatentUS20230339118A1Reliable robotic manipulation in a cluttered environment
Publication Date: 2023.10.26 EBOTS INC
  • US20230339118A1 patent drawing
  • US20230339118A1 patent drawing
  • US20230339118A1 patent drawing

AI summary

One embodiment can provide a robotic system. The robotic system can include a robotic arm comprising an end-effector, an illumination unit comprising a plurality of single-color light sources of different colors, a structured-light projector to project codified light patterns onto a scene, one or more cameras to capture pseudo-color images of the scene illuminated by the single-color light sources of different colors and images of the scene with the projected codified light patterns, a pose-determination unit to determine a pose of a component based on the pseudo-color images and the images of the scene with the projected codified light patterns, a path-planning unit to generate a motion plan for the end-effector based on the determined pose of the component and a current pose of the end-effector, and a robotic controller to control movement of the end-effector according to the motion plan to allow the end-effector to grasp the component.