Vector Magnetometer Pose Tracking System
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tracking systems for object position and orientation in small volumes are either limited to a few dimensions or require expensive infrastructure, and none enable accurate tracking of both position and orientation of a free-hand tool using magnetometers.
Innovation Solution
A system utilizing two or more vector magnetometers mounted in a fixed relationship, along with a user-borne device containing a permanent magnet, to provide six degrees of freedom tracking without external infrastructure, leveraging MEMS technology for small and inexpensive implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometer and gyro are used together to determine orientation and position, then orientation information can be obtained, but gradual drift in calculated position occurs making the system unsuitable for determining pose
Solution Approach 1:
The patent introduces a magnetometer as an intermediary sensor to measure the magnetic field vector, which serves as a stable reference frame. By combining magnetometer data with accelerometer and gyro measurements, the system corrects the drift in position calculation while maintaining orientation information, thus resolving the contradiction between obtaining orientation and maintaining position stability
Solution Approach 2:
The patent changes the measurement parameters by adding magnetic field vector measurements to the existing acceleration and angular velocity measurements. This additional parameter allows the system to distinguish between actual position changes and drift, enabling accurate pose determination without gradual position errors
2Measurement precision
If camera systems are used to track special markers for accurate pose computation, then high precision pose information can be obtained, but the system becomes expensive and requires fixed installations
Solution Approach 1:
The patent replaces the mechanical/optical camera-based tracking system with a magnetic field-based sensing system. Instead of using cameras to visually track markers, the system uses magnetometers to detect the magnetic field vector generated by a magnet in the tool, eliminating the need for fixed camera installations and special markers while achieving comparable pose precision
Solution Approach 2:
The patent makes the tracking system universal by using a magnetometer that can detect the magnetic field from a simple magnet attached to any tool, rather than requiring specific camera installations. This allows the same system to track different tools without reconfiguration, reducing infrastructure complexity while maintaining precision
3Productivity
If accelerometer data is integrated twice to determine relative position, then position information can be calculated, but gradual drift accumulates making the technique unsuitable for determining pose
Solution Approach 1:
The patent implements feedback by continuously measuring the magnetic field vector with the magnetometer and using this information to correct drift in the integrated position calculations. The magnetic field measurements provide a reference that allows the system to detect and correct accumulated errors, maintaining position accuracy over time while preserving the ability to calculate position through integration
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 accurate 5D or greater tracking with high update rates, insensitive to magnetic disturbances, and embedded in everyday tools, offering high precision and cost-effectiveness.
Implementation Method 1
two or more vector magnetometers fixed in a reference frame including the computing device. The position and orientation of the ferromagnetic object is determined by magnetic field strength measurements derived from the two or more vector-magnetometers
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In accordance with various embodiments of the invention, a user-borne computer input device is disclosed including a 5D or greater "mouse" or other tool or object containing or consisting of one or more permanent magnetic presenting permanent magnetic dipoles. The position and orientation of the device are determined by magnetic field strength measurements derived from at least two vector-magnetometers fixed in a reference frame connected to the computing device. The system allows a user to interact with the computing device in at least 5 dimensions by manipulating the position and orientation of the device within a measurement volume, which may be a few cubic meters.