Robot cleaner and method of operating the same

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Solution Overview

Problem

Existing robot cleaners face inaccuracies in distance measurement due to uneven floors, leading to errors in navigating to exact target points, as their distance measurement methods are indirect and prone to errors when the traveling distance cannot be accurately measured.

Innovation Solution

A robot cleaner equipped with a rotatable sensor unit that can switch between two sensitivity modes for obstacle detection, using light reflection or scattering, with the first mode for navigation and the second mode for locating a recharging base with a reflective sheet, allowing for precise obstacle avoidance and base detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a robot cleaner uses indirect distance measurement based on traveling distance, then the device complexity is reduced, but the measurement precision deteriorates due to floor unevenness errors

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

Solution Approach 1:

The patent replaces the mechanical indirect measurement method (based on traveling distance and wheel rotation) with an optical measurement system. The sensor unit emits light and detects reflected light from obstacles to directly measure distance, eliminating the accumulation errors from floor unevenness that affect mechanical measurement methods.

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

Solution Approach 2:

The patent introduces light as an intermediary medium for distance measurement. The sensor unit emits light that reflects off obstacles and returns to the sensor, allowing distance calculation based on light travel time or phase difference, thereby avoiding direct mechanical contact with the uneven floor surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the sensor unit uses high sensitivity for obstacle detection, then the measurement precision improves, but the reliability deteriorates due to false detection of reflective surfaces

Engineering Contradiction:
Improveobstacle detection accuracyVSAvoiddetection stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements dynamic sensitivity adjustment in the sensor unit. The controller automatically adjusts the sensitivity threshold based on the current operating context - using higher sensitivity when approaching the recharging base (to detect the reflective sheet) and lower sensitivity during general navigation (to avoid false detections from normal reflective surfaces like furniture or floor tiles).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies different detection characteristics to different spatial contexts. The sensor unit uses mode 1 (lower sensitivity) for general area exploration and mode 2 (higher sensitivity) specifically when searching for the recharging base, optimizing detection performance for each local task requirement.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the robot cleaner uses a single sensitivity mode for the sensor unit, then the device complexity is reduced, but the adaptability deteriorates when switching between navigation and base searching tasks

Engineering Contradiction:
Improvesensor control systemVSAvoidtask-specific detection capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic sensitivity adjustment in the sensor unit. The controller automatically adjusts the sensitivity threshold based on the current operating context - using higher sensitivity when approaching the recharging base (to detect the reflective sheet) and lower sensitivity during general navigation (to avoid false detections from normal reflective surfaces like furniture or floor tiles).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent makes the sensor unit multi-functional by enabling it to operate in two sensitivity modes. The same sensor hardware performs both general obstacle detection (mode 1) and recharging base detection (mode 2), eliminating the need for separate sensor systems for different tasks while maintaining high adaptability.

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

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 robot cleaner can accurately and quickly move to target points while avoiding obstacles and locate the recharging base with improved precision, enhancing its navigation and charging efficiency.

Implementation Method 1

a sensor unit that is rotatable to sense an obstacle using light reflected or scattered by the obstacle

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a sensor unit that is rotatable to sense an obstacle using light reflected or scattered by the obstacle

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

the controller controls the robot cleaner to search for the recharging base according to a reflectance of light reflected by a reflective sheet attached to the recharging base and received by the sensor unit

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2781981B1Robot cleaner and method of operating the same
Publication Date: 2020.09.16 LG ELECTRONICS INC
  • EP2781981B1 patent drawingFigure 1
  • EP2781981B1 patent drawingFigure 2
  • EP2781981B1 patent drawingFigure 3

AI summary

A robot cleaner includes a main body, a traveling unit, a cleaning unit, a sensor unit, and a controller. The traveling unit allows the main body to travel. The cleaning unit suctions foreign substances around the main body during the traveling. The sensor unit is rotatable and senses an obstacle using light reflected or scattered by the obstacle. The controller controls the traveling unit so as to travel along a traveling path and controls the cleaning unit so as to perform cleaning. Here, the sensor unit includes a first mode and a second mode that are set to differ from each other in sensitivity with respect to the reflected or scattered light, and the controller changes the sensitivity of the sensor unit according to a traveling mode.