Robot Cleaner Sensor Module With Light Shielding for False Obstacle Detection
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Solution Overview
Problem
Robot cleaners often inaccurately sense obstacles due to light reflected from the inner surface of their sensor windows being incident on the light receiving unit, leading to erroneous detection of obstacles that are not actually present.
Innovation Solution
A sensor module with a light shielding portion between the light emitting device and the light receiving reflector to prevent light emitted from being reflected from the inner surface of the sensor window, combined with a step portion on the upper frame to enhance obstacle detection at closer distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transparent sensor window is provided to allow light transmission for obstacle sensing, then the robot cleaner can sense obstacles through the sensor window, but light emitted from the light emitting unit may be reflected from the inner surface of the sensor window and incident on the light receiving unit, causing erroneous obstacle detection
Solution Approach 1:
A light shielding portion is introduced as an intermediary element between the light emitting unit and the light receiving unit. This light shielding portion selectively blocks reflected light from the sensor window inner surface from reaching the light receiving unit, while allowing direct light from obstacles to reach the sensor. This resolves the contradiction by mediating between the need for light transmission (for sensing) and the need to block harmful reflected light (for accuracy).
Solution Approach 2:
The sensor module is segmented into distinct functional regions: a light emitting unit, a light receiving unit, and a light shielding portion. The light shielding portion is specifically positioned to segment and block only the reflected light path from the sensor window inner surface, while maintaining the light transmission path for actual obstacle detection. This segmentation allows the system to simultaneously achieve both light transmission and error prevention.
2Adaptability or versatility
If the light receiving unit is positioned to receive reflected light from obstacles, then obstacle detection is enabled, but reflected light from the sensor window inner surface is also received, leading to false obstacle detection
Solution Approach 1:
The light shielding portion serves as a mediator that selectively filters light paths. It allows the light receiving unit to maintain its ability to detect reflected light from obstacles (adaptability) while blocking the harmful reflected light from the sensor window inner surface (reliability). This intermediary element enables the system to be both versatile in detection and reliable in accuracy.
Solution Approach 2:
The light shielding portion is strategically positioned to provide localized light blocking only in the specific region where reflected light from the sensor window inner surface would reach the light receiving unit. This local quality approach allows the light receiving unit to continue receiving valid reflected light from obstacles while blocking only the erroneous reflected light, thus maintaining detection capability while improving reliability.
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 prevents erroneous obstacle sensing and allows the robot cleaner to accurately detect objects, improving its navigation and cleaning efficiency by ensuring that only valid obstacle reflections are detected.
Implementation Method 1
a light emitting device to emit light outside through the sensor window
Implementation Method 2
a light receiving reflector on which light emitted from the light emitting device and reflected from the obstacle is incident
Data Source
AI summary
A sensor module and a robot cleaner including the sensor module may provide accurate sensing of an obstacle and prevent an erroneous sensing of an obstacle. The robot cleaner may include a body including a cleaning unit to remove foreign substances from a surface of a floor, a cover to cover an upper portion of the body, a sensor module including an obstacle sensor mounted to sense an obstacle, and a sensor window provided at one side of the sensor module. The sensor module may include a light emitting device to emit light through the sensor window, a light receiving reflector on which light reflected from the obstacle is incident, and a light shielding portion interposed between the light emitting device and the light receiving reflector to block the light emitted from the light emitting device from being incident upon the light receiving reflector.