Projectile Spin Axis Tracking via Magnetic Field Sensing
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Solution Overview
Problem
Existing systems for tracking the movement and performance of projectiles in sports games face challenges in accurately determining the direction of a projectile's spin axis and location, particularly due to the complexity and cost of beacon-based systems and the limitations of electronic-compass technology.
Innovation Solution
A method and system that utilize a rotating apparatus equipped with a XYZ-magnetic field sensor to determine the direction of the spin axis by measuring magnetic field values over time, combining these with global magnetic field directions to calculate spin axis angles, and estimating horizontal displacement to locate the projectile relative to a target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beacon-based location systems are used to determine projectile direction and location, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the direction determination function from the complex beacon-based location system and implements it using a simple electronic compass and accelerometer combination within the projectile itself. This eliminates the need for external beacon infrastructure while maintaining the ability to determine projectile heading and trajectory direction.
Solution Approach 2:
The projectile becomes self-sufficient by incorporating its own sensing capabilities (electronic compass and accelerometer) to determine its own direction and location. This eliminates dependence on external beacon systems and allows the projectile to autonomously track its trajectory parameters.
2Device complexity
If electronic-compass is used to determine direction, then device complexity is reduced, but measurement precision deteriorates because e-compass only indicates magnetic field direction not trajectory direction
Solution Approach 1:
The patent merges the electronic compass (for magnetic north reference) with the accelerometer (for motion direction detection) to create a combined navigation system. The electronic compass provides the reference frame while the accelerometer detects the actual motion vector, and their combination enables accurate trajectory direction determination that neither sensor could achieve alone.
3Measurement precision
If multiple sensors are activated continuously to track projectile properties, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic sampling of sensor data at specific event triggers (release detection, impact detection) rather than continuous monitoring. The accelerometer and electronic compass are activated only when needed to capture trajectory parameters, significantly reducing power consumption while maintaining measurement precision for the critical phases of projectile motion.
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
This approach allows for accurate tracking of a projectile's spin axis direction and location without the need for expensive beacon systems, reducing power consumption by activating sensors only during ballistic trajectories, and providing detailed performance analysis for players.
Implementation Method 1
measuring a plurality of magnetic field values as a function of time with the XYZ-magnetic field sensor
Data Source
AI summary
A method for tracking performance of player including determining global direction of magnetic field at first court and computing first court specific data; providing rotation for rotating apparatus about spin axis via player, wherein rotating apparatus comprising XYZ-magnetic field sensor; measuring plurality of magnetic field values as function of time when rotating apparatus is rotating about spin axis; computing magnetic field component of magnetic field in direction of local body co-ordinate of spin axis of rotating apparatus; determining direction of spin axis using computed magnetic field component of magnetic field and determined global direction of magnetic field; determining player specific data comprising angle of spin axis with respect to horizontal ground plane and angle of shot direction with respect to horizontal component of spin axis; and calibrating and storing first court specific data and player specific data to track performance of player at first court.