Localization and mapping using physical features

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Solution Overview

Problem

Current localization and mapping techniques for mobile robots, such as SLAM, face challenges in maintaining accurate pose estimation and map generation due to errors from odometry data, which can lead to reduced confidence and increased uncertainty over time, necessitating efficient re-localization methods without the need for additional specialized sensors.

Innovation Solution

The method involves using conventional sensors like encoders, bumper sensors, gyroscopes, and accelerometers to estimate the robot's pose and confidence, generating data for SLAM by interacting with the environment, and updating maps through template matching and re-localization based on physical landmarks, allowing for efficient data collection and storage while reducing the complexity of the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If SLAM techniques are used for localization and mapping, then the robot can determine its position and build a map of surroundings, but odometry errors accumulate over time leading to reduced pose estimation accuracy

Engineering Contradiction:
Improvepose estimation accuracyVSAvoidtime duration for operation
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The robot performs wall-following behavior in advance to collect path segment data and create a library of reference paths. This preliminary action establishes a baseline for later comparison, allowing the robot to detect when its current position diverges from expected paths due to odometry errors, thereby enabling corrective re-localization actions.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If additional specialized sensors are added to improve localization accuracy, then pose estimation precision can be enhanced, but device complexity and cost increase

Engineering Contradiction:
Improvelocalization accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The robot uses its existing sensors (encoders, bumper sensors, gyroscopes, accelerometers) to perform localization and mapping functions. By leveraging data from sensors already present in the system for navigation and obstacle detection, the robot achieves improved pose estimation accuracy without adding specialized localization sensors, thereby avoiding increased device complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If the robot continuously updates its pose based on odometry data, then localization can be maintained, but computational resources and storage requirements increase

Engineering Contradiction:
Improvelocalization continuityVSAvoiddata storage requirements
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system extracts and stores only essential path segment characteristics (geometric features, length, orientation) in a compressed library format, rather than storing complete raw sensor datasets. When re-localization is needed, the robot compares current odometry-based position against these extracted key features, maintaining localization continuity while minimizing storage requirements through selective data retention.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If the robot performs frequent re-localization to correct pose errors, then localization accuracy can be maintained, but navigation time and productivity decrease

Engineering Contradiction:
Improvepose accuracyVSAvoidnavigation efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The robot implements a feedback mechanism where it periodically compares its odometry-based position against the stored library of reference path segments. When the comparison indicates positional divergence beyond a threshold, the robot triggers re-localization by matching current sensor data against the reference library, thereby correcting pose errors only when necessary and maintaining navigation efficiency.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11960304B2Localization and mapping using physical features
Publication Date: 2024.04.16 IROBOT CORP
  • US11960304B2 patent drawing
  • US11960304B2 patent drawing
  • US11960304B2 patent drawing

AI summary

A method includes maneuvering a robot in (i) a following mode in which the robot is controlled to travel along a path segment adjacent an obstacle, while recording data indicative of the path segment, and (ii) in a coverage mode in which the robot is controlled to traverse an area. The method includes generating data indicative of a layout of the area, updating data indicative of a calculated robot pose based at least on odometry, and calculating a pose confidence level. The method includes, in response to the confidence level being below a confidence limit, maneuvering the robot to a suspected location of the path segment, based on the calculated robot pose and the data indicative of the layout and, in response to detecting the path segment within a distance from the suspected location, updating the data indicative of the calculated pose and/or the layout.