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Volvo experimenting with magnets to keep self-driving cars on track

Tests include embedding small ferrite magnets in the roadway and sensors on a vehicle.

By Douglas Newcomb Mar 11, 2014 1:49PM

Volvo magnet research. Image by Volvo.If you liked to play with cars as a kid, one of your first experiences with self-driving vehicles may have been with an HO-scale electric racing set. The tiny vehicles — or “slot cars,” as they're called — are held to the track via the engine's magnets and guided by a pin beneath the chassis that fits into a slot in each lane.


Volvo is testing a similar concept to keep life-sized autonomous cars in their lane, but by using magnets embedded in the roadway rather than slots and guide pins to help keep a self-driving vehicle on track.


“The magnets create an invisible 'railway' that literally paves the way for a positioning inaccuracy of [about 4 inches],” Jonas Ekmark, preventive safety leader for Volvo Car Group, said in a statement. According to Volvo, the benefits of magnet guidance allow self-driving vehicles to be unaffected by poor weather conditions and physical obstacles that can make GPS and camera technologies vulnerable to failure.


And besides making the path of self-driving cars more accurate, guiding a wide range of vehicles via magnets has other advantages.

Volvo pointed to road safety applications from helping to prevent accidents by keeping cars in their lanes on a snow-covered road to guiding maintenance crews or emergency personnel in inclement weather. It added that the use of magnets could also allow for narrower lanes and therefore more efficient use of road space.


In cooperation with the Swedish Transport Administration (Trafikverket), Volvo is testing the magnet concept on a 100-yard track at the automaker’s test facilities outside its headquarters in Gothenburg, Sweden. A research vehicle has several magnetic field sensors installed to detect a pattern of 1.5-inch by 0.5-inch ferrite magnets installed below the track’s surface.


The primary objectives for the research program are to evaluate the technology's reliability, durability, detection sensitivity, cost and how it could affect road maintenance. “We have tested the technology at a variety of speeds and the results so far are promising,” Ekmark said.

“Our experience so far is that ferrite magnets are an efficient, reliable and relatively cheap solution, both when it comes to the infrastructure and on-board sensor technology,” he added. "The next step is to conduct tests in real-life traffic."


If those tests are successful, magnets could someday "pull" us into a potentially safer and more efficient mode of autonomous driving, while also solving other transportation infrastructure challenges.


[Source: Volvo]

Mar 12, 2014 5:03PM
Collect nails and screws! Anyway a lot of cars must already be driving themselves as the drivers seem to be otherwise occupied.
Mar 19, 2014 4:41AM
It's interesting, but regardless of how well it works, cost is going to the major factor in any autonomous car solution. I know they're talking about Sweden, and I don't know the amount of road there, but at least in America, your talking about millions of miles of road. Roads that are already extremely expensive to install and maintain. How can you possibly integrate a magnet grid without ballooning the cost?

Mar 19, 2014 1:55AM
A great idea if you could combine it as a propulsion source, ie battery charging.
Mar 11, 2014 3:48PM
Mar 19, 2014 2:17AM
These comments could be an interesting read if everyone would stop trying to be comedians. 
Mar 19, 2014 7:01AM
How about using the magnets and charging stations and installing resanators as in this story about WiTricity?  Then you have a slef driving car that never needs gas or charging.
Mar 19, 2014 7:19AM
couldn't they use them magnet to propel the cars too.
Mar 29, 2014 4:50AM
The vast majority of drivers have a safe driving record.  But every driver has moments when immediate action is required to avoid or minimize an accident.  Computers, and other devices do NOT have the good record humans do.  No matter how you slice it, computers have a relatively short life, begin to develop glitches, and then fail.  No thank you to "self driving cars".   If there is a failure in the safe operation of the car, I will be responsible.  I have about 3 million miles so far without an accident, so I speak with some credibility.  Will I stake my life on some chinese laptop?  Hell no.
Mar 19, 2014 6:49AM
It's about time, auto industry! This idea jumped at me years ago. Too bad I my degree wasn't in engineering. Use your imagination people - it's the next step. Nice vector leap, Volvo!
Mar 19, 2014 5:37AM
One of the biggest challenges to electric cars in the U.S. is the infrastructure for recharging the vehicles.  Convincing gas stations to convert gas pumps to electric power stations is no small order. We can't even get that completely rolled out.  Now we're going to change the roads to accommodate magnets for self driving cars.  Nice idea but not practical in application.  The roads and highway budgets are already underfunded as it stands today.
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