Using laser sensor for floor type detection
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Solution Overview
Problem
Existing robotic vacuum cleaners lack the ability to effectively detect the type of surface they are operating on, which affects dust pickup capacity and navigation, as current methods like accelerometers and brush roll current measurements are unreliable.
Innovation Solution
A robotic cleaning device equipped with a method that illuminates the surface with structured vertical light, captures images, and determines the surface structure from the appearance of luminous sections, using a camera and controller to differentiate between surfaces like hard floors, carpets, and rugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometer or gyro is used to detect surface bumps, then surface structure detection is enabled, but detection reliability is poor due to difficulty in distinguishing brush roll vibrations from surface vibrations
Solution Approach 1:
The patent replaces mechanical vibration detection (accelerometer/gyro) with optical detection (laser sensor). The laser projects structured light onto the surface and the camera captures the reflected light pattern. Surface structure is determined by analyzing distortions in the reflected light pattern, eliminating the problem of mechanical vibrations from the brush roll interfering with surface vibration detection.
Solution Approach 2:
The patent introduces an intermediary optical system (laser projection and camera capture) between the robotic device and the surface. Instead of directly measuring surface vibrations with accelerometers, the system uses structured light projection and optical pattern analysis as an intermediary to indirectly detect surface structure with higher reliability.
2Measurement precision
If brush roll current is used to detect carpet thickness, then carpet detection is enabled, but detection speed is slow due to random current variations requiring low-pass filtering
Solution Approach 1:
The patent replaces electrical measurement (brush roll current monitoring) with optical measurement (laser reflection pattern analysis). The structured light projection and camera capture provide immediate visual feedback about surface texture and carpet thickness without suffering from random electrical noise, eliminating the need for time-consuming low-pass filtering.
Solution Approach 2:
The patent changes the detection parameter from electrical current (prone to random variations) to optical reflection patterns (stable and immediately captureable). By projecting structured light and analyzing the reflected light pattern, the system obtains stable measurements that directly reflect surface structure and carpet thickness without temporal filtering requirements.
3Productivity
If no surface type detection is implemented, then device complexity is low, but dust pickup capacity and navigation performance are suboptimal
Solution Approach 1:
The patent uses a multi-functional approach where the laser projection system and camera (already potentially useful for navigation and obstacle detection) are also employed for surface type detection. This single optical system serves multiple purposes: navigation, obstacle avoidance, and surface structure identification, minimizing additional complexity while maximizing productivity benefits.
Solution Approach 2:
The robotic device uses its own optical components (laser and camera) to detect surface type, enabling the system to self-adapt its cleaning parameters (fan speed, brush speed) and navigation strategy based on detected surface conditions without requiring external intervention or complex additional sensors.
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
Improves dust pickup capacity by adapting fan and brush speeds and enhances navigation by accurately identifying surface types, reducing slipping and improving cleaning efficiency.
Implementation Method 1
at least one light source arranged to illuminate the surface with structured vertical light
Implementation Method 2
capturing an image of the surface, detecting at least one luminous section in the captured image
Data Source
AI summary
A robotic cleaning device and a method for operating the robotic cleaning device to detect a structure of a surface over which the robotic cleaning device moves. The method includes illuminating the surface with structured vertical light, capturing an image of the surface, detecting at least one luminous section in the captured image, and determining, from an appearance of the at least one luminous section, the structure of the surface.