The following comes from a three-part series on the development of Honda's U3-X mobility device that appeared in a recent edition of Pole Position, a magazine for all Honda associates, describing Honda's philosophy and corporate culture.
To achieve a near perfect fusion of rider and vehicle: that is the promise of the U3-X, an entirely new form of mobility unveiled by Honda in autumn 2009. Forward, backward, side-to-side, or diagonally, the U3-X electric-powered, one-wheel-drive personal mobility device permits free movement in all directions just as in human walking, merely by shifting one's weight in the direction you want to go. But just what kind of vehicle does it take to accomplish this?
Development all started with a sketch of a 'wand'
How did development of the amazing U3-X get started? Shinichiro Kobashi (LPL, Research Division 2, Fundamental Technology Research Center), the person responsible for the device's development, makes an extraordinary statement: "It all started with a single sketch. It was a picture I drew during a Y-gaya (brainstorming) session on vehicles of the future. I wondered if it would be possible to create a vehicle with a form like this that could move freely in all directions--sort of like a witch's broom or a magic wand. I thought it would make an interesting project," he laughs.
It was in 2006 that Kobashi, who was in charge of motor control technology on the ASIMO development team at Research Division 2, had a Y-gaya session over the sketch with his supervisor Toru Takenaka (Research Division 2, Fundamental Technology Research Center). Just three short years since the project's inauguration, the U3-X had progressed to the point where it was ready to be unveiled at a press conference and test-ride event.
"Rapid development was one of our objectives right from the start," says Kobashi. "Honda lets us do interesting research. But the technical evaluations are extremely rigorous. No matter how unique the research is, if it doesn't produce results, it runs the risk of being canceled before completion. In order to prevent that from happening, we took a strategic approach from the beginning, creating a novel project structure with involvement from four departments: Research Division 2, Fabrication Technology Department, Intellectual Property Department, and Styling Design Development Division. We didn't have many members to start, but we worked in close cooperation."
Also, at the project's outset, Kobashi made the following two decisions:
1. Whenever they ran out of ideas, they would return to the basics and favor simple procedures; and
2. They would learn from past research and proactively incorporate whatever existing technologies they could.
This is how the free-moving 'magic wand' got its start.
The link between the 'Uni-ball vehicle' and the U3-X was ASIMO
Kobashi's decision to 'use whatever existing technologies they could' was based on his knowledge of ASIMO, Walking Assist, and other Honda robotics technologies, along with a wealth of other unique mobility research from the past.
It was over 20 years ago at the Idea Contest1 that a vehicle designed to move as if its rider was balancing on a ball was demonstrated, creating quite a stir. Two members of the team that presented this vehicle, dubbed the moving Uni-ball, which won both the Golden Idea Contest Award and the mechanical prize at the 1989 competition, were none other than Hiroshi Gomi (Research Division 2, Fundamental Technology Research Center) and Toru Takenaka (previously mentioned), who have watched over and supported the U3-X project.
"Takenaka was in charge of controls and I was in charge of mechanical design," remembers Gomi. "In addition to the Uni-ball, at the same time we also experimented with the 'Aqua Horse', which used foot fins to allow a person to run on water, and the 'Fantasy Bike', which had two coaxially mounted wheels, one on each side. Their common characteristic was that they were each entirely different from any vehicle that had come before, offering a freedom of mobility unobtainable anywhere else."
"It's easy to imagine how the Uni-ball moves if you think of the ball hidden beneath a computer mouse. But we just couldn't get it to move nimbly, and we really struggled to get it ready for the Idea Contest," recalls Takenaka with a smile. "Compared to the Uni-ball, the U3-X moves much more smoothly."
The reason Takenaka and Gomi are in a position to discuss the entire development process from the Uni-ball to the U3-X is because they are both involved in ASIMO research and development and Honda robotics development. They have both spent long years in research, with Takenaka working principally on ASIMO walking control mechanisms and Gomi supervising mechanical design.
"The primary factor in our ability to develop the U3-X in such a short time was the balance control and electrical component technologies developed for ASIMO," says Kobashi. "It's precisely because we had this accumulated technology base to work with that we were able to quickly pinpoint our objectives and get to work on the U3-X challenge right away." But just what was the 'U3-X challenge' of which Kobashi spoke?
A revolutionary drive system inspired by the motion of two pencils
"The ultimate achievement would be to create a personal mobility device that works just like walking. As humans, we are capable of moving freely in any direction--forward, backward, side-to-side, or diagonally," remarks Kobashi. We accomplish this quite effortlessly, but it's a real challenge to make a machine do the same thing."
It would be relatively easy to create a machine that moves forward and back, then changes gears to move side-to-side. However, to accomplish this smoothly and seamlessly without pause, just like a human, presents a far greater challenge.
Despite numerous Y-gaya sessions, development was at a standstill. The breakthrough came at an unexpected moment. It just so happened that all the conference rooms were booked, so Takenaka and Kobashi were discussing development direction in the R&D Center's anechoic [echoless] room.
"There was a pencil on the table. Takenaka used another pencil he was holding in his hand to roll it back and forth, muttering, 'Maybe we could do something like this,'" recalls Kobashi. "At the time, it didn't go any further than that, but at the same time I remember thinking, 'Hey, maybe we can!'"
If one pencil revolving side-to-side is used to roll another pencil forward and backward, this allows motion forward, backward, and side-to-side, each at 90° angles. Starting with this initial idea, after numerous Y-gaya sessions the project team successfully completed the world's first omni-directional driving wheel system (Honda Omni Traction Drive System), which uses finely controlled motors and drive gears to enable movement in all directions.
Human-friendly mobility born of a quest for simplicity
Along with the new drive system, another feature that set the U3-X apart was its principle of motion.
Unlike conventional 4-wheel and 2-wheel vehicles, the U3-X moves without the use of handles or levers. It is as if the machine reads the intent of its rider, who simply leans their body slightly in the direction they want to go, shifting their weight to go wherever they want throughout a 360° range of motion.
"Let's say the rider shifts his weight forward. If nothing happened, he would certainly fall forward. But before he can fall, the U3-X quickly moves forward, maintaining balance. Forward, backward, side-to-side, or diagonally--whatever the direction the same principle is applied to facilitate smooth motion," says Kobashi. "However, there are times when people make unpredictable moves. It's not the same as ASIMO, which only moves as it's been preprogrammed to do. In that sense, it was quite a challenge."
At first, the team tried making a prototype with two wheels, but they were unable to obtain a level of mobility that went beyond conventional devices. After much trial and error, they arrived at a one-wheel design. Although the original images were of a magic wand and of riding standing up in a position similar to walking, in the end the team settled on a seated riding position.
"With a stand-up riding position, you need to get on one foot at a time. The sensors react when you still only have one foot in position and the device moves in an attempt to maintain balance. As a result of our efforts to achieve a design that would allow the rider to get on in one easy motion, we concluded that the action of sitting on a chair represented the most reasonable approach. The R&D Center's director told us he wanted us to come up with a design where even a person using it for the first time could get on right away. With the seated riding position, anyone can get on naturally with no feeling of unease."
The U3-X created a sensation when it was featured as one of the devices in Honda's HELLO2 display at the 41st Tokyo Motor Show in 2009, which featured proposals for the next generation in mobility.
"Appearing at the motor show was a valuable experience," recalls Kobashi. "Working in fundamental research, we have very few opportunities to come in contact with customers. Everyone who set eyes on the U3-X gazed at it like it was a cute little animal--I was impressed by the tender expressions it elicited. Also significant for us was that we were able to become acquainted with associates from other divisions. In research, networking with other people can help lead to breakthroughs. I'm keen to make use of some of the contacts I made in my future research."
A human-friendly size that is less than a shoulder-width wide and allows the rider to pass naturally among pedestrians at eye level. The U3-X, designed primarily to function in harmony with people, is different in form than any other vehicle that came before it. For Shin Joon Heon, designer at the Automobile R&D Center's Styling Design Development Division, the most important design theme was to express an 'active and compact' image.
"For the U3-X, existing in harmony with people is a basic premise, so it can't be allowed to attract attention to itself as a mechanical device. We sought to create a beautiful design with gentle curves like a human body, arriving at a simple gourd shape." With the seat folded, the design is simple, with two similar-looking circles arranged vertically. The area of contact with the floor is very small.
"Since it's an entirely new form of mobility, I wanted to express a level of advancement never seen before. However, no matter how good it looked, I didn't want a design that was cold and remote. I was looking to create a design that would inspire emotional attachment like to a living creature--one that had never been seen before. At first glance, it doesn't look like it can stand on its own, and yet there it is, standing erect all by itself. Isn't it cute?" he laughs. "Designing it was a real challenge, but a lot of fun as well."
Sawa Takahashi also from the Automobile R&D Center's Styling Design Development Division, was in charge of coloring and seat materials selection. She recalls the U3-X design from a different point of view.
"Because I'm usually in charge of coloring for production automobiles, the whole development process was different from beginning to end--it was an excellent experience for me," she says. "The U3-X has a more intimate, personal feel than most other forms of transportation. So when I designed the coloring, perhaps I approached it more as a lifestyle accessory, like a handbag or a home interior. For the quality of materials and finishes, I focused on how it would feel to the touch."
One thing the two agreed on was the need to make the design 'distinctively Honda'. Shin, who also has design experience with companies in his native Korea, observes that Honda is passionate in its approach to making things. It is interesting, he says, to "find cool ways to express that hot passion." Takahashi adds, "I try to find the optimum expression of quality for the project I'm working on." The U3-X's design gives ample expression to their sentiments.