Mobile Robot Occupancy Mapping With Incident-Angle Validation
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Solution Overview
Problem
Existing simultaneous localization and mapping (SLAM) techniques using laser scanners often inaccurately detect objects due to shallow emission angles, leading to erroneous object absence determinations in maps, particularly in environments with glass and non-diffuse surfaces.
Innovation Solution
An information processing device for mobile robots that includes a detection section, a control section, and a map construction section with a normal line acquirer and validity determinator to assess the validity of detection information based on incident angles, constructing maps that exclude invalid data points to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If laser beams are emitted at shallow angles to detect objects, then the detection range is extended, but the detection accuracy deteriorates due to erroneous determination of object absence
Solution Approach 1:
The patent changes the parameter of beam emission angle and introduces validity determination based on incident angle thresholds. By evaluating whether the incident angle exceeds a predetermined threshold, the system distinguishes between valid object detections and invalid detections caused by shallow angle emissions, thereby maintaining detection range while improving detection accuracy
Solution Approach 2:
The patent introduces an intermediary validity determination mechanism between the laser detection and map construction processes. This intermediary layer evaluates the incident angle of each beam and determines validity, acting as a filter that prevents erroneous detections from being incorporated into the final map, thus resolving the contradiction between detection range and accuracy
2Area of stationary object
If detection information from all beams is used to construct the map, then the map coverage is improved, but the map accuracy deteriorates due to inclusion of erroneous detection data
Solution Approach 1:
The patent changes the parameter of detection information selection by introducing validity flags based on incident angle evaluation. Instead of uniformly using all detection information, the system selectively incorporates only valid detection data into the map construction process, thereby maintaining comprehensive coverage while eliminating accuracy-degrading erroneous data
Solution Approach 2:
The patent applies local quality control by evaluating each detection point individually based on its incident angle. Rather than applying a uniform filtering criterion to all detections, the system assesses each beam's validity locally and incorporates only those meeting the validity threshold, thus preserving map coverage while ensuring local accuracy at each detection point
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 enhances map accuracy by eliminating erroneous object determinations and improving sensing accuracy, particularly in environments with glass and non-diffuse surfaces, by reflecting the validity of detection information in the map construction process.
Implementation Method 1
the laser scanner acquires the presence or absence of the object as the detection information according to return of a laser beam emitted from the laser scanner and reflected on an object surface
Data Source
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AI summary
Provided are an information processing device and a mobile robot capable of reducing erroneous object determination and improving a map accuracy. An information processing device (2) includes a detection section (4) configured to acquire the presence or absence of an object at the periphery of a mobile robot (1) as the detection information, a control section (3) configured to control the detection section (4), and a map construction section (5) configured to construct an occupied map (M2). The map construction section (5) includes a storage (55) configured to store the detection information in chronological order, a map producer (52) configured to produce a map based on the detection information, a normal line acquirer (53) configured to acquire a normal line to each determination point based on the presence or absence of the object at the periphery of each determination point on the temporal map produced by the map producer (52), and a validity determinator (54) configured to determine the validity of the detection information on each determination point based on an angle between each beam and the normal line at each determination point.