Mobile Robot Grid Map Accuracy via Feature Point Alignment

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Solution Overview

Problem

Conventional methods for building grid maps by mobile robots are prone to inaccuracies due to sensor errors, leading to distorted maps and inefficient cell decomposition, which hinders the robot's ability to perform tasks accurately and efficiently in wide areas.

Innovation Solution

The method involves obtaining grid points by sensing distances to obstacles, extracting feature points, using SLAM algorithms to update the robot's pose and transform feature points, and updating the grid map with a transform formula to achieve a more accurate representation, followed by cell decomposition based on these feature points and sweep-line angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a robot builds a grid map by autonomously traveling and using sensors to recognize surroundings, then the robot can operate without pre-prepared maps, but sensor errors cause uncertainty and inaccuracies in the built map

Engineering Contradiction:
Improveautonomous map building capabilityVSAvoidmap accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces feature points as intermediary elements that mediate between sensor data and the final grid map. These feature points serve as reference markers that help correct and align the grid map, reducing the impact of sensor errors while maintaining autonomous operation capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the robot repeatedly captures images, extracts feature points, and compares them with previously identified feature points. This feedback loop allows the robot to detect discrepancies caused by sensor errors and correct the grid map accordingly, improving map accuracy while maintaining autonomous operation

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If the robot uses sensors to build a grid map of a limited area, then the robot can recognize the local surroundings, but the overall structure of the completed map becomes distorted and inaccurate

Engineering Contradiction:
Improverecognized area coverageVSAvoidoverall map structure accuracy
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent segments the map building process into multiple stages: capturing images at different positions, extracting feature points from each image, and progressively constructing the grid map. This segmentation allows the robot to build accurate local maps that can be correctly integrated into the overall map structure, preventing distortion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Feature points serve as intermediary reference markers that connect different local areas into a coherent overall map. By using these feature points to align and integrate local maps, the patent maintains accurate overall map structure even as the robot expands its recognized area

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional cell decomposition methods are used on inaccurate grid maps, then the space can be divided into cells, but the decomposition is inefficient and the robot cannot perform tasks accurately

Engineering Contradiction:
Improvetask execution efficiencyVSAvoidposition and orientation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary correction of the grid map using feature points before conducting cell decomposition. By pre-aligning and correcting the map structure, the subsequent cell decomposition and task execution can proceed accurately, improving both productivity and position/orientation accuracy

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8060254B2Method, apparatus, and medium for building grid map in mobile robot and method, apparatus, and medium for cell decomposition that uses grid map
Publication Date: 2011.11.15 SAMSUNG ELECTRONICS CO LTD
  • US8060254B2 patent drawing
  • US8060254B2 patent drawing
  • US8060254B2 patent drawing

AI summary

Provided are a method, apparatus, and medium for building a grid map in a mobile robot and a method, apparatus, and medium for cell decomposition using the grid map building method and apparatus. A mobile robot for building a grid map includes a grid map building unit obtaining grid points by sensing a distance to an external space or obstacle, and building a grid map, a feature point extraction unit extracting feature points from the grid points, a feature point update unit estimating the pose of the robot after the robot moves, and obtaining updated feature points by SLAM (Simultaneous Localization And Map building) algorithm, a transform formula calculation unit calculating a transform formula that transforms feature points extracted by the feature point extraction unit into feature points updated by the feature point update unit, and a grid map update unit updating the grid map according to the obtained formula.