Moving Robot Grid Mapping for Unsearched Boundary Path Planning

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Solution Overview

Problem

Existing moving robots face challenges in accurately distinguishing between searched and unsearched regions, particularly in environments with few features, leading to inefficient path planning and map creation.

Innovation Solution

The use of LiDAR, ultrasonic, and 3D sensors, along with image processing, to create a cell-based grid map and identify optimal boundary lines between searched and unsearched areas, enabling efficient path planning and map updating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If feature points are extracted from images to create search paths, then the robot can navigate the environment, but in environments with few features, uncertainty remains high leading to redundant searching

Engineering Contradiction:
Improvesearch efficiencyVSAvoidlocation recognition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the environment into a grid map with discrete cells, where each cell is marked as searched or unsearched. This segmentation allows the robot to systematically track which areas have been explored and which remain, eliminating redundant searching in already-explored regions while maintaining navigation capability in feature-poor environments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation from continuous feature point coordinates to discrete grid cell states (searched/unsearched). This parameter transformation enables the robot to maintain location awareness and plan paths based on grid map information rather than relying on feature point extraction, thereby improving both search efficiency and location recognition accuracy.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If grid map is used for search traveling, then the robot can systematically explore the environment, but the boundary between searched and unsearched regions cannot be accurately extracted

Engineering Contradiction:
Improvemap creation efficiencyVSAvoidboundary extraction accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses visual color coding to represent different grid cell states: white for searched regions and black for unsearched regions. This visual differentiation enables accurate boundary extraction between searched and unsearched areas, allowing the robot to precisely identify and navigate to boundaries for efficient map creation.

Inventive Principle:
Principle #32Color changes

3Measurement precision

If the robot continuously searches based on high uncertainty feature points, then location accuracy may be improved, but time is wasted searching the same region repeatedly

Engineering Contradiction:
Improveself-location recognition accuracyVSAvoidredundant search time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements feedback through the grid map that records which cells have been searched. This feedback mechanism prevents the robot from revisiting and re-searching already-explored regions, thereby eliminating redundant search time while maintaining accurate self-location recognition through grid map-based positioning rather than feature point uncertainty.

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

This approach allows for accurate recognition of unsearched regions and efficient path planning, reducing redundant searches and improving map creation robustness in changing environments.

Implementation Method 1

a sensor unit configured to create LiDAR data regarding an external geometry, a distance to an object, and the like through a LIDAR sensor

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

a sensor unit configured to create LiDAR data regarding an external geometry, a distance to an object, and the like through a LIDAR sensor, an ultrasonic sensor

Methodology Applied
Scientific EffectEcho: Echo

Data Source

PatentEP3993961B1Moving robot and control method thereof
Publication Date: 2024.10.16 LG ELECTRONICS INC
  • EP3993961B1 patent drawingFigure 1A~1B
  • EP3993961B1 patent drawingFigure 1C~1D
  • EP3993961B1 patent drawingFigure 2~3

AI summary

Creating a map of a moving robot includes: receiving sensor data regarding a distance to an external object through a distance measurement sensor; creating a cell-based grid map based on the sensor data; performing image processing to distinguish between regions in the grid map and create a boundary line between the regions; selecting an optimal boundary line if one or more boundary lines exist; planning a path to the optimal boundary line; and updating the grid map, while moving along the path, whereby a map may be automatically created.