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AD: What kinds of applications are possible with haptic interfaces?

HT: A wearable vest could give you directional information. If you're skydiving or going into an altered gravity environment where you cannot sense which way is up or down, it could help you orient yourself. Vibrators inside the vest could simulate the feeling of someone drawing directional lines on your back, telling you which way is up. In fact, right after John F. Kennedy Jr.'s plane went down in July 1999, the consensus was that he was spatially disoriented. This technology could alleviate such problems by enhancing situational awareness. We can put tactors, which are tactile stimulators, inside a vest to provide information by tapping or poking the user.

AD: How sensitive is the back of the body to stimuli?

HT: The resolution of a fingertip is 1 millimeter — that's how closely spaced the sensors are in our skin. On the back, it's more like 20 millimeters. Because the back has a much bigger area, it compensates — there's much more space to work with. Also, the hands are too busy, while the back is not doing anything.

AD: How could haptic interfaces make our lives easier?

HT: Consider if a sensing chair could track its occupant's postures with surface-mounted pressure distribution sensors that function like an artificial layer of skin. The chair could process pressure distribution data in real time and use the result to drive other applications. When I sit down, the chair would feel me and identify me by my distinctive “butt print.� In a car, the seat would know whether I'm big or small or an infant. It would know how much force to use in firing up the airbag. A lot of automobile manufacturers seem interested in the idea. At home, a similar sensing chair could be taught to feel me and know how I sit. Based on that information, if the chair knows I'm in front of the computer, it could turn the computer on.

AD: What is your lab currently working on?

HT: For Ford, we are running human perception studies to learn how to create harmony in haptic interfaces in a car. How do you make all the switches and buttons feel like they belong together? How do you make a luxury car actually feel luxurious? There are many ways to make a switch. Some you have to push very hard before they yield. If the switch buzzes a little bit, it feels cheap. We're trying to correlate the human perception with the physical stimulus, so that way we can customize the feel of a car to match its brand image. What Ford wants is some parameters it can go to suppliers with. For example, when you turn on a light switch, what is the maximum force required for the switch to feel tight or right? We're running experiments and making measurements. It's all about evaluating the feel of things.

AD: How soon could haptic interfaces, such as sensing or poking seats, make it into cars?

HT: If someone in the industry is interested and starts today, I imagine that we could have a real product in about five years — with all the engineering work, testing and product development that's involved.

AD: What are the consumer applications?

HT: Imagine you're home, shopping on TV, but want to feel the fabric before buying. A little tablet would simulate surface textures. It could consist of miniature motors that push up and down or vibrate. I'm looking forward to the day somebody builds this.


Imagine if cars had a sense of touch. Sensors embedded in the exterior of a car could feel if it's veering too close to another vehicle. That message could be relayed to the driver's seat, which could alert the driver with a tap on the back.

This sensing car is part of the next generation of haptics — the science that gives human/computer interfaces a more human touch. Haptics exploits human behavior, since people are more likely to pay attention to tactile cues, such as a tap on the back, than visual cues. With haptic interfaces, a computer could receive or convey information through touch, pressure, force or vibration.

First used in remote surgical operations and mining in the 1970s, haptic interfaces began appearing in consumer applications in the late 1980s, mostly in video arcades, where a steering wheel on a game would tremble when a player drove off the road. The first force-feedback joystick was marketed in 1996. By 2000, Logitech's iFeel mouse enabled users to “feel� when they moved their cursor over a link. The auto industry is likely to be the next frontier for this technology, says Hong Tan, an expert in haptics design and director of Purdue University's haptics research lab.

Tan's inventions have received funding from car manufacturers, NASA and the National Science Foundation. Tan recently spoke with American Demographics' Sandra Yin about the market potential of haptic applications.

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