Robot Positioning via Sensor Fusion of Odometry and Visual Registration

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Solution Overview

Problem

Current robotic scanning and positioning systems face accuracy issues due to reliance on camera-to-robot calibration and nominal kinematics, particularly in feature-less or feature-sparse scenes, leading to distance drift and challenges in real-time synchronization between camera image acquisition and robot position reading.

Innovation Solution

A method that combines robot position measurement (robot odometry) with image registration (visual odometry) to automate camera-to-robot calibration, using sensor fusion to increase positioning accuracy by recording and synchronizing camera and robot position coordinates with timestamps, and estimating camera tool center points and scene work objects across different scan regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If camera-to-robot calibration and nominal kinematics are used for positioning, then the system structure remains simple, but positioning accuracy deteriorates due to distance drift and error accumulation

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines robot odometry (measured robot positions) with visual odometry (image registration methods) into a unified sensor fusion approach. This merging allows the system to leverage the advantages of both methods while compensating for their individual weaknesses, thereby improving positioning accuracy without requiring complex separate calibration systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs automated camera-to-robot calibration by utilizing the robot's own motion data and captured images. The calibration process is self-contained, using the robot's measured positions and visual features from the environment to automatically determine the camera tool center point, eliminating the need for external calibration equipment or procedures

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If image registration methods are used alone, then calibration equipment is not needed, but positioning accuracy deteriorates in feature-less or feature-sparse scenes

Engineering Contradiction:
Improvecalibration simplicityVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent merges robot odometry data with visual odometry results, creating a hybrid positioning system. The robot's measured positions provide reliable distance information that compensates for the weaknesses of image registration in feature-sparse environments, while visual features help correct drift in the odometry data

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an automated calibration process as an intermediary that connects the robot's motion data with the visual navigation system. This calibration mediator translates between the robot's coordinate system and the camera's coordinate system, enabling accurate positioning without requiring external calibration equipment

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If separate calibration steps are performed, then camera-to-robot relation is established, but time consumption increases and real-time synchronization becomes challenging

Engineering Contradiction:
Improvecamera-to-robot calibration accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs self-calibration by utilizing data already collected during normal operation. The robot's measured positions and captured images are used to automatically determine the camera tool center point, eliminating the need for separate calibration steps and enabling real-time calibration without external equipment

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs calibration continuously in the background during normal operation rather than requiring a separate preliminary calibration step. By accumulating and processing data as the robot moves, the system prepares the calibration information in advance, enabling real-time synchronization without interrupting the robot's workflow

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3377948B1Facilitating robot positioning
Publication Date: 2021.01.06 ABB (SCHWEIZ) AG
  • EP3377948B1 patent drawingFigure 1~2
  • EP3377948B1 patent drawingFigure 3
  • EP3377948B1 patent drawingFigure 4

AI summary

Robot positioning is facilitated by obtaining, for each time of a first sampling schedule, a respective indication of a pose of a camera system of a robot relative to a reference coordinate frame, the respective indication of the pose of the camera system being based on a comparison of multiple three-dimensional images of a scene of an environment, the obtaining providing a plurality of indications of poses of the camera system; obtaining, for each time of a second sampling schedule, a respective indication of a pose of the robot, the obtaining providing a plurality of indications of poses of the robot; and determining, using the plurality of indications of poses of the camera system and the plurality of indications of poses of the robot, an indication of the reference coordinate frame and an indication of a reference point of the camera system relative to pose of the robot.