Featured Research

from universities, journals, and other organizations

Can magnetic fields accurately measure positions of ferromagnetic objects?

Date:
June 23, 2014
Source:
World Scientific
Summary:
Many creatures in nature, including butterflies, newts and mole rats, use Earth's inherent magnetic field lines and field intensity variations to determine their geographical position. The spatial variation of magnetic field around an object can be modeled using just the geometry of the object under consideration. Using this model of magnetic field variation with position and measuring the magnetic field at the sensor's location, the position of the ferromagnetic object is calculated.

The position of a piston inside an engine cylinder can be measured with sub-mm accuracy by using external magnetic sensors and requiring no sensor components at all inside the cylinder. (a) Two axially spaced magnetic sensors are used. (b) The raw magnetic field signals measured by sensors 1 and 2 due to the piston's inherent magnetic field are shown (c) Position estimates from the magnetic sensor and comparison with a LVDT reference sensor are shown. (d) The system does not require pre-calibration and automatically computes algorithm parameters for each individual piston-cylinder combination.
Credit: Image courtesy of World Scientific

Many creatures in nature, including butterflies, newts and mole rats, use Earth's inherent magnetic field lines and field intensity variations to determine their geographical position. A research team at the University of Minnesota has shown that the inherent magnetic fields of ferromagnetic objects can be similarly exploited for accurate position measurements of these objects.

Such position measurement is enabled in this research by showing that the spatial variation of magnetic field around an object can be modeled using just the geometry of the object under consideration. Using this model of magnetic field variation with position and measuring the magnetic field at the sensor's location, the position of the ferromagnetic object is calculated.

A significant challenge is posed by the fact that the parameters of the model would vary from one object to another, even for objects of the same shape. This challenge is addressed by the use of redundant sensors with known inter-sensor distances and associated adaptive estimation algorithms for auto calibration of model parameters.

"The inherent magnetic fields of common ferromagnetic objects have never before been exploited for accurate position measurements of these objects," says Rajesh Rajamani, Ph.D., of the University of Minnesota and the senior author on the paper. Previous magnetic field based sensors require use of embedded magnets and only work over small distances between sensor and magnet. The advantage of the new measurement system is that it enables non-contacting measurement of position over large separation distances and requires neither embedded components nor line-of-sight access.

This means positions of pistons and other internal moving components inside engines, hydraulic cylinders, pneumatic cylinders and other industrial machinery can be measured entirely from external sensors. The researchers have also shown that the measurement system can be used on a car to measure positions of other cars in close proximity, and to thus predict an imminent collision just before the collision occurs.

A key innovation that enables the measurement system to be viable for real-world applications is the ability to automatically compensate for disturbances caused by other ferromagnetic objects. This allows the sensor system to work over larger distances between the object and sensor.


Story Source:

The above story is based on materials provided by World Scientific. Note: Materials may be edited for content and length.


Journal Reference:

  1. Saber Taghvaeeyan, Rajesh Rajamani. Nature-inspired position determination using inherent magnetic fields. TECHNOLOGY, 2014; 02 (02): 161 DOI: 10.1142/S2339547814500149

Cite This Page:

World Scientific. "Can magnetic fields accurately measure positions of ferromagnetic objects?." ScienceDaily. ScienceDaily, 23 June 2014. <www.sciencedaily.com/releases/2014/06/140623120324.htm>.
World Scientific. (2014, June 23). Can magnetic fields accurately measure positions of ferromagnetic objects?. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2014/06/140623120324.htm
World Scientific. "Can magnetic fields accurately measure positions of ferromagnetic objects?." ScienceDaily. www.sciencedaily.com/releases/2014/06/140623120324.htm (accessed July 30, 2014).

Share This




More Matter & Energy News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Stranded Whale Watching Boat Returns to Boston

Stranded Whale Watching Boat Returns to Boston

Reuters - US Online Video (July 29, 2014) Passengers stuck overnight on a whale watching boat return safely to Boston. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Baluchistan Mining Eyes an Uncertain Future

Baluchistan Mining Eyes an Uncertain Future

AFP (July 29, 2014) Coal mining is one of the major industries in Baluchistan but a lack of infrastructure and frequent accidents mean that the area has yet to hit its potential. Duration: 01:58 Video provided by AFP
Powered by NewsLook.com
Easier Nuclear Construction Promises Fall Short

Easier Nuclear Construction Promises Fall Short

AP (July 29, 2014) The U.S. nuclear industry started building its first new plants using prefabricated Lego-like blocks meant to save time and prevent the cost overruns that crippled the sector decades ago. So far, it's not working. (July 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins