Robotic Cleaner Cliff Detection Using Image Distance Comparison
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Solution Overview
Problem
Existing robotic cleaning devices face challenges in detecting cliffs, such as stairs, which can lead to damage when not detected in time, as they often rely on proximity sensors that only detect obstacles as they are encountered, making it difficult to plan cleaning paths effectively.
Innovation Solution
A method and device that use a light source to illuminate the surface, capture images with a camera, and compare distances to detect cliffs by identifying a predetermined increase in distance between objects, allowing for early detection and inclusion in the device's navigation and cleaning path planning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reflective infrared proximity cliff sensors are used to detect cliffs, then the robot can detect cliffs when encountered, but the robot cannot plan cleaning paths in advance effectively
Solution Approach 1:
The patent applies preliminary action by using a camera to capture images of the surface ahead of the robot, allowing cliff detection before the robot actually encounters the cliff. This enables advance path planning by identifying cliffs in captured images and calculating their distances, so the robot can plan cleaning paths around detected cliffs before reaching them, resolving the contradiction between reliable cliff detection and effective advance path planning.
2Productivity
If the robot moves at higher speed, then productivity increases, but the risk of missing cliff detection increases
Solution Approach 1:
The camera captures images of the surface in advance of the robot's position, creating a time buffer that allows the robot to detect cliffs and adjust its path before reaching them. This preliminary detection capability enables the robot to maintain higher speeds while preserving cliff detection reliability, as the system has already identified hazards before the robot arrives at those locations.
Solution Approach 2:
The patent introduces an intermediary processing system that captures images, processes them to detect cliffs, calculates distances to detected features, and generates path planning information. This intermediary system between the physical robot and the environment allows for slower image processing at higher robot speeds, maintaining detection reliability while enabling faster overall operation.
3Device complexity
If proximity sensors detect cliffs only when encountered, then device complexity is low, but the robot cannot safely navigate around cliffs
Solution Approach 1:
The patent replaces the mechanical/proximity-based sensor system with an optical system (camera) that captures images of the surface. This substitution allows the robot to detect cliffs from a distance by analyzing image features and calculating distances, enabling safe navigation around cliffs while maintaining relatively simple device complexity through software-based image processing rather than complex sensor arrays.
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
Enables the robotic cleaning device to detect cliffs before encountering them, allowing for safe navigation and efficient cleaning path planning, reducing the risk of damage and enabling higher speed operation.
Implementation Method 1
illuminating the surface with at least one light source, capturing an image of the surface
Data Source
Figure 1~2b
Figure 3a~3b
Figure 4
AI summary
The invention relates to a robotic cleaning device and a method at the robotic cleaning device of performing cliff detection along a surface over which the robotic cleaning device moves. In an aspect of the invention a method for a robotic cleaning device (100) of performing cliff detection along a surface (31) over which the robotic cleaning device (100) moves is provided. The method comprises illuminating (S101) the surface (31) with at least one light source (127), capturing (S102) an image (40b) of the surface, detecting (S103) at least one illuminated section (30b') in the captured image, and determining (S104) distance to objects in the at least one illuminated section (30b') of the captured image (40b). Further the method comprises comparing (S105) at least two of the determined distances and detecting (S106) an object in the captured image (40b) as a cliff when cliff when a relation between the at least two compared determined distances complies with a predetermined increase criterion.