Localization and mapping using physical features

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Solution Overview

Problem

Current localization and mapping techniques for autonomous 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 based on physical interactions, allowing for re-localization by matching sensor data with stored templates of path segments and landmarks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If SLAM techniques are used to build maps and localize robots using odometry and sensors, then the robot can navigate autonomously, but errors accumulate over time leading to reduced pose estimation accuracy

Engineering Contradiction:
Improveautonomous navigation capabilityVSAvoidpose estimation accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The system continuously monitors pose confidence levels and uses sensor data feedback to detect when odometry errors exceed acceptable thresholds. This triggers re-localization events where the robot compares current sensor readings against stored map features to correct accumulated pose errors, maintaining accuracy over extended operation periods.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The robot pre-processes sensor data during initial exploration to build a detailed map of physical features and path segments. This preliminary mapping enables later re-localization operations, where the robot can quickly compare current sensor readings against the pre-stored feature database to correct pose errors without extensive real-time computation.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If specialized sensors are added to improve localization accuracy, then pose estimation precision improves, but system 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 (cameras, odometry systems, basic range finders) to perform dual functions: both navigation and re-localization. By processing sensor data through confidence monitoring and feature matching algorithms, the system achieves accurate re-localization without requiring specialized localization sensors, making the existing sensor suite serve multiple purposes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The sensor system is designed to perform multiple functions: odometry for pose estimation, cameras for feature detection, and range finders for obstacle detection. The same sensors used for basic navigation are leveraged for re-localization by comparing readings against the stored map, eliminating the need for dedicated localization sensors and reducing overall system complexity.

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

3Measurement precision

If detailed map data is stored to improve re-localization accuracy, then localization precision improves, but storage requirements and data processing complexity increase

Engineering Contradiction:
Improvere-localization accuracyVSAvoiddata storage requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system extracts and stores only the essential re-localization features from the complete environmental map, such as distinctive path segments, landmark positions, and physical feature characteristics. This selective extraction reduces the volume of stored data while maintaining sufficient information for accurate re-localization, as only critical features are retained in the database.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The map data is segmented into discrete, manageable path segments and feature descriptors rather than storing continuous complete map representations. Each segment contains only the necessary geometric and visual characteristics needed for matching, enabling efficient storage and faster comparison operations during re-localization while preserving localization accuracy.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10500722B2Localization and mapping using physical features
Publication Date: 2019.12.10 IROBOT CORP
  • US10500722B2 patent drawing
  • US10500722B2 patent drawing
  • US10500722B2 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.