Rotating UWB Tag Relative Localization Without Anchors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-robot localization systems face limitations such as limited range of location services, need for central nodes, and requirement for initial calibration, especially in anchor-based methods, while on-board methods like LiDAR and marker-based localization suffer from short effective distances and limited field of view.
Innovation Solution
A method and system using onboard rotating ultra-wideband (UWB) tags, where one robot (leader) has a rotating UWB tag and others have fixed tags, enabling relative localization without external anchors, utilizing a mechanical structure for circular motion and on-board sensors for distance and velocity measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anchor-based localization methods are used, then localization service coverage is provided, but the range of location services is limited and requires central nodes and initial calibration
Solution Approach 1:
The patent extracts the localization function from external anchors and implements it using only on-board sensors and markers. Each robot carries its own localization components (markers and sensors), eliminating the need for external anchor infrastructure and central coordination nodes, thereby reducing system complexity while maintaining localization coverage
Solution Approach 2:
Each robot is equipped with self-contained localization components including markers and sensors that enable it to perform localization autonomously without relying on external anchors or central nodes. The robot uses its own on-board camera to detect markers and calculate its position relative to other robots, achieving self-service localization
2Measurement precision
If on-board sensors like LiDAR and marker-based methods are used, then relative localization is achieved, but the effective distance is short and field of view is limited
Solution Approach 1:
The patent transitions from 2D planar markers to 3D spherical markers with reflective properties. The spherical markers reflect light from multiple directions, enabling detection from various angles and distances, thereby extending the effective localization distance while maintaining measurement precision through multi-dimensional light reflection characteristics
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
Provides scalable, distributed localization services in GNSS-denied environments, eliminating the need for central nodes and initial calibration, and enhancing localization range and accuracy for both stationary and moving robots.
Implementation Method 1
obtaining distance values between the first UWB tag and the second UWB tag
Data Source
AI summary
A method of estimating a relative position of a first robot with respect to a second robot at a current timestamp, wherein a first ultra-wideband (UWB) tag is installed on the first robot, the first UWB tag being a rotating tag configured to move in a circular path about a centre of rotation on the first robot, wherein a second UWB tag is installed on the second robot, the method comprising: receiving an estimate of the relative position of the first robot with respect to the second robot calculated at an earlier timestamp; obtaining rotating tag offset values of the first UWB tag with respect to the first robot at the earlier timestamp and at the current timestamp; obtaining a velocity value of the first robot at the earlier timestamp; obtaining a velocity value of the second robot at the earlier timestamp; obtaining distance values between the first UWB tag and the second UWB tag at the earlier timestamp and at the current timestamp; and calculating the relative position of the first robot with respect to the second robot at the current timestamp according to: the estimate of the relative position calculated at the earlier timestamp, the rotating tag offset values of the first UWB tag with respect to the first robot at the earlier timestamp and at the current timestamp, the velocity values of the first robot at the earlier timestamp, the velocity values of the second robot at the earlier timestamp, and the distance values between the first UWB tag and the second UWB tag at the earlier timestamp and at the current timestamp.