Moving Robot Optical Carpet Detection for Timely Speed Adjustment

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Solution Overview

Problem

Conventional cleaning robots face challenges in accurately identifying plush carpets from a distance, leading to potential misidentification due to high frictional forces and late detection, which can result in inadequate speed adjustments or operations.

Innovation Solution

The implementation of a moving robot equipped with a light projector and image sensor system that projects vertical and horizontal light segments, allowing the processing unit to recognize plush carpets by analyzing the width and vibration intensity of the light segment images, thereby improving detection accuracy and enabling timely speed adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a brush is used to detect plush carpet by measuring frictional force, then the robot can identify carpet surface, but the detection accuracy deteriorates when hairs are twisted round the brush causing false positives

Engineering Contradiction:

Improvecarpet detection accuracyVSAvoiddetection reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical brush-based friction detection system with an optical detection system using light projectors and image sensors. This substitution eliminates the mechanical contact that causes hair entanglement and false positives, while achieving more reliable carpet identification through optical properties of the carpet surface.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light segments as an intermediary medium between the robot and the carpet surface. By projecting vertical and horizontal light segments and analyzing their reflection patterns, the system indirectly detects carpet properties without direct mechanical contact, thus avoiding the hair entanglement problem while maintaining detection accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a brush is used to detect plush carpet, then the robot can identify carpet surface, but the detection distance is limited to very close range only

Engineering Contradiction:

Improvecarpet detection capabilityVSAvoiddetection distance

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent transitions from contact-based detection (zero dimension) to optical field detection (three-dimensional space). By projecting light segments that extend forward from the robot and capturing their reflection patterns at a distance, the system achieves carpet detection in the spatial dimension, enabling identification well before the robot reaches the carpet surface.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The optical detection system performs carpet identification in advance before the robot physically reaches the carpet. The light segments project forward and detect carpet properties at a distance, allowing the robot to prepare appropriate speed adjustments and operational changes beforehand, rather than reacting only upon contact.

Inventive Principle:

Principle #10Preliminary action

3Speed

If plush carpet is detected late, then the robot reacts quickly, but the robot does not have enough time to speed up for climbing

Engineering Contradiction:

Improvereaction speedVSAvoidtime for speed adjustment

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The optical detection system identifies plush carpet at a distance before the robot reaches it, providing advance warning time. This allows the control system to gradually adjust speed and prepare for climbing action in advance, rather than attempting sudden acceleration that would be impossible if detection occurred only at contact point.

Inventive Principle:

Principle #10Preliminary action

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 solution enhances the robot's ability to accurately identify plush carpets from a distance, allowing for timely speed adjustments and appropriate operational changes, such as increased suction force or deactivated brush rotation, to ensure smooth operation.

Implementation Method 1

The light projector is configured to project a vertical light segment toward a moving direction

Methodology Applied

Scientific EffectLight projection: Light

Implementation Method 2

The image sensor is configured to capture an image frame containing a light segment image associated with the vertical light segment

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentUS11809195B2Moving robot with improved identification accuracy of carpet

Publication Date: 2023.11.07 PIXART IMAGING INC

AI summary

There is provided a moving robot including a light projector, an image sensor and a processing unit. The light projector projects a vertical light segment and a horizontal light segment toward a moving direction. The image sensor captures, toward the moving direction, an image frame containing a first light segment image associated with the vertical light segment and a second light segment image associated with the horizontal light segment. The processing unit recognizes a plush carpet in the moving direction when a vibration intensity of the second light segment image is higher than a predetermined threshold, and an obstacle height calculated according to the first light segment image is larger than a height threshold.