Mobile Robot Obstacle Sensing With Inclination Compensation

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Solution Overview

Problem

Conventional mobile robots face challenges in accurately detecting obstacles due to errors in distance measurement caused by uneven floors and interference from light or sound, limiting their ability to recognize three-dimensional shapes and navigate effectively, especially when inclined or encountering thresholds.

Innovation Solution

A mobile robot equipped with a sensor unit for inclination detection, first and second pattern emission units for emitting light patterns up and down, and an image acquirer to capture these patterns, allowing the controller to perform inclination compensation and re-determine obstacles for accurate navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single light source emits light at a predetermined angle, then the device complexity is reduced, but the obstacle detection range and three-dimensional shape recognition capability are limited

Engineering Contradiction:
Improvelight source configurationVSAvoidobstacle detection range
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The single light source is divided into multiple light sources (first and second light sources) positioned at different locations. Each light source emits light in a specific direction to cover different areas, thereby expanding the overall obstacle detection range while maintaining manageable device complexity through modular segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-angle light emission to multi-dimensional light emission by positioning light sources at different heights and angles. The first light source emits toward the lower side while the second light source emits toward the upper side, creating a three-dimensional light coverage pattern that enables detection of obstacles with various heights and shapes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the mobile robot uses infrared rays or ultrasonic waves for distance measurement, then the measurement method is simple, but a large amount of light or sound is scattered by obstacles causing significant measurement errors

Engineering Contradiction:
Improvedistance measurement methodVSAvoiddistance measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces infrared or ultrasonic distance measurement with a visual recognition system using cameras and light patterns. Instead of measuring distance through scattered light or sound waves, the system captures images of light patterns reflected from obstacles and calculates distances based on pattern recognition and geometric relationships, eliminating scattering-induced measurement errors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses colored or patterned light emission and corresponding image capture to identify obstacles. By emitting structured light patterns and analyzing their reflection through image processing, the system achieves accurate distance and shape measurement without the scattering problems inherent in traditional infrared or ultrasonic methods.

Inventive Principle:
Principle #32Color changes

3Productivity

If the mobile robot body is inclined when encountering a threshold or obstacle, then the robot can physically overcome the obstacle, but the robot incorrectly determines them as obstacles or cliffs and stops driving

Engineering Contradiction:
Improvedriving continuityVSAvoidobstacle recognition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary inclination detection using sensors before the obstacle recognition process. By detecting the robot's inclination state in advance, the system can adjust or compensate for the effects of inclination during obstacle detection, preventing false obstacle or cliff identification and maintaining driving continuity when the inclination is within acceptable ranges.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where inclination sensor data is continuously monitored and fed back to the obstacle recognition system. This feedback allows the system to distinguish between actual obstacles and apparent obstacles caused by robot inclination, enabling correct judgment and continuous driving operation.

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

The solution enables the mobile robot to accurately detect obstacles and navigate through various areas by compensating for inclination, reducing errors and extending the cleaning area, allowing it to avoid obstacles effectively without being confined by them.

Implementation Method 1

a sensor unit for detecting inclination of the body and inputting a detection signal

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

a first pattern emission unit disposed on a front surface of the body and for emitting first pattern light toward a lower side of a front side of the body, a second pattern emission unit disposed on the front surface of the body, disposed below the first pattern emission unit, and for emitting second pattern light toward an upper side of the front side of the body

Methodology Applied
Scientific EffectLight: Light

Implementation Method 3

an image acquirer disposed on the front surface of the body and for acquiring an image of the front side of the body

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3459690B1Mobile robot and control method therefor
Publication Date: 2023.08.09 LG ELECTRONICS INC
  • EP3459690B1 patent drawingFigure 1a
  • EP3459690B1 patent drawingFigure 1b
  • EP3459690B1 patent drawingFigure 2

AI summary

A mobile robot emits first pattern light toward a floor in a cleaning area in front of the body, emits second pattern light upward, determines an obstacle through an image obtained by emitting of each emitted pattern light to the obstacle, and detects inclination of the body to perform inclination compensation, and thus, the obstacle is capable of accurately determining the obstacle, whether the mobile robot is capable of being driven is re-determined through the inclination compensation to allow the mobile robot to pass or avoid the obstacle, and thus, the mobile robot is capable of entering various areas to extend an area to be cleaned, is capable of rapidly performing determination and operations, and is capable being effectively driven to avoid the obstacle without being confined by the obstacle.