A self-balancing unicycle experimental vehicle from Honda to be shown at the Tokyo Motor Show next month might just be history in the making. Weighing less than 10kg, the 24 by 12 by 6-inch U3-X experimental vehicle runs for an hour, is small enough to be carried onto an airplane as hand luggage, has a wheel which spins in two planes and is set to challenge, perhaps even change, society’s concept of personal mobility.

Little more than a century after mass market personal transport became a reality, it seems we’re set to have a mobility renaissance thanks to the need for zero emission vehicles, better electric motors, rapidly improving battery technology and the exploding field of material science.

Mass produced personal transport currently comes in two, three and four wheeled forms but with new materials and technologies beginning to catch up with science fiction, and an army of young designers unrestrained by old thinking, the concept of personal transport seems set to evolve into forms that we have hardly before imagined.

The need for urgent action on global warming has seen large amounts of money allocated to R&D for environmentally sustainable transport and we’re beginning to see a range of new and very different form factors.

At the IBC conference a fortnight ago in Amsterdam I tried a device known as the Hands Free Transporter, a Segway derivative with the normal handlebars replaced by controls held between the knees.

I was very taken with the HFT’s capabilities and potential as a personal transport solution for the masses.

The focus of this story is a similar but much smaller experimental one-wheeled device that fits comfortably between a rider's legs, and balances on one wheel to provide free movement in all directions just as if you were walking - forward, backward, side-to-side, and diagonally, all seamlessly.

A prime example of just how far R&D has advanced personal transport in such a short time, is the Embrio, a self-balancing Unicycle concept shown by Bombardier (now BRP) in 2003. The design study anticipated what type of personal transport we might be using in the year 2025. The Embrio concept was developed by BRP using technologies it expected to achieve mass market viability in the ensuing 22 years and I remember writing the story, and thinking how much it sounded like science fiction.

Though Honda’s U3-X is still experimental, only runs for an hour, isn’t as fast as the Embrio and is not hydrogen fuel cell powered, it is already in prototype form and weighs just 10 kg, rather than the 164 kg weight BRP expected of the Embrio in 2025.

Six years later, Honda’s U3-X is one sixteenth of the weight of the Embrio envisioned for 2025 – and 2025 is still more than a decade and a half away.

And though the HFT is two-wheeled rather than one, it has a top speed of 20 kmh, weighs in at 50kg and it is available now.

Honda’s U3-X was cleverly developed by pursuing the concept of "harmony with people" and with its size and weight, it will clearly mix comfortably with pedestrian traffic, though Honda will be conducting extensive testing in a real-world environment to verify and refine the practicality of the device.

The design of the U3-X places the rider on the eye level zone of other pedestrians so that it as friendly and non-threatening to fellow footpath users as possible, while also making it easier for the rider to reach the ground from the footrest without stretching.

Like the Segway and Hands Free Transporter, the U3-X’s speed is adjusted by shifting body weight, though the U3-X adds a whole new dimension in that it doesn’t just go backwards and forwards – it goes sideways, thanks to an ingenious omni-directional wheel system which Honda has dubbed its “HOT Drive System” which is short for Honda Omni Traction Drive System.

Now standing back and trying to view the U3-X with some historical perspective, it’s quite possible that a hundred years from now when battery technology has improved its energy density several orders of magnitude, this machine might well be viewed in the same light as the first examples of the automobile produced by Karl Benz and Gottlieb Daimler 120 years ago.

Clearly personal transport must get smaller and lighter, particularly if it is to share the footpath with humans made from flesh and blood. It also makes sense to make personal transportation devices easily backpackable, so they can be carried on public transport, and at just two feet tall and 12 inches by six inches in cross section, the U3-X is so small that it would never disrupt crowd flow or obstruct a railway carriage as we often see with bicycles on public transport around the world.

Being small and light has its advantages in that it takes much less energy to move it, a lesson that seems to have taken us more than a century to learn with our cars. It's also not the first time that someone has thought of applying self-balancing technology to the unicycle format, as we've covered several concepts employing something like this in recent times, namely the Unomoto One-wheeled Self-balancing Electric Unicycle and this Focus Designs Unicycle Concept.

Redefining next-generation mobility for Honda is the role of Honda’s well-funded R&D Corporation’s Fundamental Technology Research Center in Saitama in Japan which was the birthplace of Honda’s bipedal, humanoid robot ASIMO back in 1986. Developmental work at the FTR Center has seen Asimo evolve rapidly through more than 30 iterations in the last two decades. FTR is also where the remarkable walking assist devices (here, here and here) the company has been showing over the last two years took shape and we can’t wait to see what they come up with next. My bet is that the form factor of the U3-X is probably very close to what we’ll see when it reaches market – just when that will be is anybody’s guess, and will most probably be dictated by advances in battery technology beyond the devices lithium ion batteries, cos one hour just isn’t enough just yet.

With the world’s most prolific demographic, the post-war baby boom moving into old age, Honda and the world’s number one automobile manufacturer (Toyota) both recognize that low speed, footpath bound mobility assist devices will be in great demand a decade from now. Toyota has also shown both walking- and wheeled-chair mobility assist devices in addition to its iREAL wheeled exoskeleton which I was lucky enough to try at the last full Tokyo Motor Show back in 2007.

While the Segway and BRP Embrio use sensors and electric motors to remain upright, the balance control technology of the Honda U3-X is not specified, though it was developed through the robotics research of ASIMO, Honda's bipedal humanoid robot.

As I found with the Hands Free Transporter I tried, which I simply hopped aboard and rode away, controlling a device with body weight alone is surprisingly easy and within a minute or two, it’s like you are controlling a vehicle with thought alone as I was able to be incredibly precise with the HFT and Honda’s press statement predicts similar results with the U3-X.

It works like this - sensors detect slight changes in the incline of the device based on the weight shift of the rider and determines the rider's intention in terms of the direction and speed. Based on the data, the machine delivers smooth and agile movements and simple operation by weight shift only.

Though it is a genuine engineering triumph of some magnitude in its entirety, the U3-X’s most remarkable piece of engineering is the Honda Omni Traction Drive System which enables both forward and backward movement as well as side-to-side movement.

The HOT drive is indeed one of the coolest things you have ever seen if you’re mechanically inclined and consists of many small motor-controlled wheels in-line connected to form one large wheel. Forward and backward movement is done by moving the large wheel, and side-to-side movement is done by moving the small wheels. By combining both, the U3-X moves diagonally, though to the rider, it’s more like thinking "I’ll go that way", and away it goes.

When being carried, the seat and the footrests fold away so it looks more like a ghetto blaster than a transportation device.

And at Honda’s stated weight of less than 10kg, the light-weight it’s highly portable – indeed, it’s not that long ago that computers weighed more than this.

Finally, the U3-X will also incorporate a car2car and car2driver and car2infrastructure communications system named HELLO! (Honda ELectric mobility LOop) and a LOOP portable communication tool that fits in the palm of your hand and “allows people and mobility devices to communicate with each other.”

Though the Tokyo Motor Show is still four weeks away, and promises to be the most significant car show in recent history due to the plethora of eco-centric vehicles we’ll see, I’d be very surprised if the U3-X isn’t the vehicle that we’ll read about in history books a century from now. It just might be a landmark device in transportation history.

Mike Hanlon

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