Highlights from the 2014 LA Auto Show

Experimental EV has four independently-actuated wheels

By

January 24, 2013

The four-wheel independently actuated (FWIA) car (Photo: Junmin Wang, courtesy of Ohio Sta...

The four-wheel independently actuated (FWIA) car (Photo: Junmin Wang, courtesy of Ohio State University)

As any fan of electric cars will tell you, one of the keys to improving their range is getting their weight down. With that in mind, a team of researchers from Ohio State University are currently developing an EV that they claim weighs half as much as a conventional car. Because it’s so light, handling is definitely an issue – that’s why each of its wheels is independently controlled, and contains its own motor and battery pack.

The four-wheel independently actuated (FWIA) car weighs in at just 800 kilograms (1,764 lbs). It was built on the chassis of an existing Big Muddy utility vehicle, with the engine, transmission and differential removed.

Instead, each wheel contains its own 7.5-kW electric motor and 15-kW lithium-ion battery pack. One electrical cable connects all four motors to a central computer. That computer samples data from the steering wheel, gas pedal and brake 100 times a second, then actuates each wheel accordingly for optimum traction and motion control.

As a result, fishtailing is reportedly eliminated via independent control of the left and right sides of the vehicle. Traction is also said to be greatly enhanced, as one or more wheels can brake while others are accelerating. According to lead scientist Junmin Wang, it offers “better control than commercial four-wheel drive.” The computer is essential, however, as the car is “very hard to drive” without it.

When tested on good road conditions, the FWIA car followed within four inches (10 cm) of its driver’s intended path. On a snow-covered parking lot, that figure went up to eight inches (20 cm). Wang states that this is better than what could be managed by a conventional vehicle.

The team is now concentrating on improving the car’s energy efficiency and making it more fault-tolerant, so that it can compensate if one motor, wheel or brake malfunctions. They also plan on optimizing its weight distribution, and creating new algorithms to improve its control system.

Wang estimates that it will be another five to ten years before we see FWIA-enabled cars on the roads.

A paper on the research was recently published in the journal Control Engineering Practice.

Source: Ohio State University

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
9 Comments

"one of the keys to improving their range is getting their weight down" ??? its the batteries that weigh so much. Electric vehicles are novelties and pleasure items. Electric golf carts and RC cars are fine. But sorry no electric vehicle in the next 20 years will be a valid alternative to Hydro carbon (except maybe hydrogen) powered cars. Even fuel cells just don't cut. Until they develop a batter with 10x the energy capacity of LiPo we won't have a valid electric vehicle. I really wish Hydrogen fuel cells could cut it but they just can't.

Michael Mantion
24th January, 2013 @ 04:58 pm PST

I'm thinking that the handling problems are because it is short, narrow, and tall.

Slowburn
24th January, 2013 @ 09:37 pm PST

This is definitely a step in the right direction and these guys have achieved a lot by packing in the battery packs inside the in-hub motors. As the next generation of grounds-up electric vehicles come out, I expect to see more and more in-hub motor technology. These are great results.

Nicolas Zart
25th January, 2013 @ 08:59 am PST

Slowburn, if you actually look at the weight distribution the unit is short, wide and squat. and Michael, with advances in induction charging it is forseeable that an all electric vehicle could have virtually unlimited range in the near future! That or a tow behind generator for the less than 20% of trips the average car owner takes beyond the normal range of the current electrics. Either is eminently do-able.

Max Kennedy
25th January, 2013 @ 09:45 am PST

We have had a 1700 lb EV very similar to this since 2010. It's called a Polaris Ranger EV and it sells for about $11k. It drives and handles extremely well, but if it had lithium batteries it would be much better no doubt. So there actually is a lithium battery kit that that was made recently, but it is very expensive. However, if Polaris offers it as an option in the future it may be more reasonable. Range is always your big problem. Yeah, on a straight flat run you may go over 30 miles, but offroad maybe only 4 or 5 in 4x4 mode climbing hills. That's what I see on mine at least. Everyones waiting on better battery technology before they spend any money. The batteries have been made, when we'll be allowed to buy them I'm guessing nobody knows for sure.

streetdrivenquad
25th January, 2013 @ 10:15 am PST

This is hardly anything special, the Aptera weighs 1800lb, gets nearly 200 miles per charge and does 0 to 60 in less than 10 sec. (closer to 7 sec.).

Jerry Peavy
25th January, 2013 @ 11:44 am PST

Some people aren't understanding the breakthru is in having all wheel drive that's computer controlled. You can do the same with one engine/motor right now, but you waste energy braking the wheels you need to turn slower. This system just runs that wheel's motor slower. It can also use regenerative braking. The article describes how the handling and traction is greatly improved. What this means is someday Formula 1 cars will use this layout.

kuryus
25th January, 2013 @ 05:08 pm PST

@ streetdrivenquad. If the batteries have been made then its obvious that the makers want to sell a million in the first rush before the Chinese copy them and sell the at realistic prices.

pointyup
25th January, 2013 @ 09:21 pm PST

This article makes walking and horse back riding sound so much better. But hay - it's better than batteries!

donwine
26th January, 2013 @ 07:24 am PST
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