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.

Related Articles


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 January 28, 2015 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 January 28, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Wednesday, January 28, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boeing's Profit Soars

Boeing's Profit Soars

Reuters - Business Video Online (Jan. 28, 2015) Boeing delivered more commercial planes, especially 737s and 787s, fueling profit. But it issued a mixed outlook. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Robot Replacements for Foxconn's Workers

Robot Replacements for Foxconn's Workers

Reuters - Business Video Online (Jan. 28, 2015) Foxconn parent Hon Hai Precision Industry is looking to automation to keep productivity up without the rising costs of human labor. Meg Teckman reports. Video provided by Reuters
Powered by NewsLook.com
More Guns Found in Carry-on Bags at US Airports

More Guns Found in Carry-on Bags at US Airports

AP (Jan. 27, 2015) The Transportation Security Administration says officers discovered 2,212 firearms during safety screenings last year, a 22 percent jump over 2013. (Jan. 27) Video provided by AP
Powered by NewsLook.com
Cablevision Enters Wi-Fi Phone Fray

Cablevision Enters Wi-Fi Phone Fray

Reuters - Business Video Online (Jan. 26, 2015) The entry by Cablevision and Google could intensify the already heated price wars for mobile phone service. Fred Katayama reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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