Road Magnetic Marker Layout for Low-Surface Force Detection
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Solution Overview
Problem
Conventional magnetic marker detection systems for vehicles face issues with strong magnetic forces attracting metallic substances like nails or bolts, leading to potential vehicle damage, such as flat tires.
Innovation Solution
A magnetic marker system with a reduced magnetic force, achieved by optimizing the magnetism reach ratio Gh/Gs to ensure detectability by a magnetic sensor attached to the vehicle's underside, using plastic or rubber magnets with a controlled magnetic flux density, and employing sensitive magnetic sensors like MI, fluxgate, or TMR sensors to detect the reduced surface magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic force of the magnetic marker is increased to ensure detectability by the magnetic sensor, then the detection reliability is improved, but the risk of attracting metallic substances such as nails or bolts increases
Solution Approach 1:
The patent changes the magnetic field distribution parameters by optimizing the magnetism reach ratio Gh/Gs to be equal to or larger than 0.5%. This parameter change allows the magnetic flux density at the surface to be reduced to 1/200 or less of the magnetic flux density at 250mm height, resolving the contradiction between detection reliability and harmful attraction of metallic substances
Solution Approach 2:
The patent introduces a new dimensional perspective by defining the magnetism reach ratio in the vertical dimension (from surface at 0mm to 250mm height). This dimensional approach allows optimization of magnetic field distribution in the vertical direction, enabling reliable detection at vehicle height while minimizing surface magnetic force that attracts metallic objects
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 system effectively reduces the risk of attracting metallic substances while maintaining reliable detection, allowing for various driving support controls like automatic steering and lane departure warnings without causing vehicle damage.
Implementation Method 1
a magnetic marker laid on a road surface so as to be detectable by a magnetic sensor attached to a bottom surface side of a vehicle... magnetism generated from a magnetic marker laid on road surface is detected by a magnetic sensor
Data Source
AI summary
Provided are a magnetic marker and a magnetic marker detection system with a reduced magnetic force. The magnetic marker detection system (1S) in which magnetism generated from the magnetic marker (1) laid on a road surface (53) is detected by a magnetic sensor (2) attached to a vehicle's body floor (50) of a vehicle (5) is a system with the magnetic marker (1) and the magnetic sensor (2) in combination, the magnetic marker having a magnetism reach ratio Gh/Gs, which is a ratio of a magnetic flux density Gh at a position at a height of 250 mm with respect to a magnetic flux density Gs of a surface, being equal to or larger than 0.5% and the magnetic sensor using a magneto-impedance element including a magneto-sensitive body with impedance changing in accordance with an external magnetic field.