Robot Localization Using Distance Sensor Reference Points
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Solution Overview
Problem
Existing methods for semi-autonomous robots to localize themselves in changing environments are hindered by differences between predetermined maps and real-time environment maps, particularly due to non-reference elements like movable objects that change appearance over time.
Innovation Solution
A method using a distance-measuring sensor, such as a laser rangefinder, to identify reference elements by determining the highest distances within defined vertical boundaries, allowing for accurate association of predetermined maps with real-time environment maps and improved path computation in dynamic environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined map is used for robot localization, then the robot can navigate using pre-planned paths, but the map may become outdated due to moved or changed objects in the environment
Solution Approach 1:
The system performs preliminary classification of environment points into reference and non-reference categories before navigation. By pre-identifying which objects are likely to move (non-reference) and which are stable (reference), the system prepares the localization framework in advance to handle environmental changes, allowing the predetermined map to be selectively updated based on object stability characteristics
Solution Approach 2:
The patent applies different treatment to different regions of the environment map based on object characteristics. Reference objects (walls, fixed structures) maintain their original map coordinates, while non-reference objects (movable items) are flagged for potential repositioning. This local differentiation allows the map to maintain stability for reliable navigation while adapting to changes in specific areas
2Area of stationary object
If all environment objects are treated as reference points for localization, then complete environmental coverage is achieved, but computational complexity increases due to processing of movable objects
Solution Approach 1:
The environment is segmented into distinct categories: reference environment points (fixed structures) and non-reference environment points (movable objects). This segmentation allows the system to process only the necessary subset of objects for each localization task, reducing computational complexity while maintaining complete environmental coverage through selective modeling
3Adaptability or versatility
If the robot continuously updates the environment map in real-time, then the map remains current with environmental changes, but the association between predetermined and real-time maps becomes difficult
Solution Approach 1:
The patent extracts and separates non-reference objects from the core reference framework of the environment map. By removing movable objects from the stable reference structure, the system maintains a reliable base map for association with predetermined maps, while still tracking environmental changes through separate monitoring of non-reference objects that does not interfere with map alignment
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
Effectively distinguishes reference from non-reference elements with high probability, enabling better navigation and map association, even in changing environments with movable objects.
Implementation Method 1
a distance-measuring sensor (10) for measuring a set of distances to a plurality of environment points
Data Source
Figure 1~2
Figure 3a
Figure 3b
AI summary
A method for determining reference elements of an environment, the method comprising at least the steps of: providing a ceiling value and a floor value; measuring, using a distance-measuring sensor, a set of environment point positions, each position comprising at least a first coordinate along a first direction and a second coordinate along a second direction non collinear with the first direction; determining reference elements of the environment comprising position of the set of environment point positions whose second coordinate is strictly smaller than the ceiling value and strictly higher than the floor value, and whose distance to the distance-measuring sensor, taken along the first direction, is a highest distance in a set of distances of environment points to the distance-measuring sensor, said distances being taken along the first direction.