How does your computer feel today? No, I'm not asking about its state of cybernetic health but about whether it's giving you any tactile feedback or manipulative capability through your fingers. Touch is the latest to be added to the list of human senses a computer can address. It's called haptics, from the Greek haptesthai, meaning to grasp or touch.
One consistent thread in the development of computing is the continuing expansion of I/O capabilities. In the beginning, you input data into a computer by flipping switches, and its output was in the form of flashing lights. As the technology developed, input came from punch cards, paper tape, magnetic tape and keyboards, while output became human-readable words and numbers on paper or a display screen. Voice input and text-to-speech reading are still in the development phase, and it looks as though haptics may be the next big thing after that.
The earliest haptic devices for computers were braille readers. With them, a blind user can move his finger along a line of metal pins that form a braille representation of the current on-screen line of text. Although they're very useful, these devices are limited to rendering text.
There are now a few more devices that use haptic technology. Among the earliest, developed a few years ago, were joysticks and similar gaming controls that employed force feedback, offering varying resistance to movement, depending on what was happening on-screen.
The newest devices are haptic mice from Fremont, Calif.-based Logitech Inc. that use a vibration-generating motor to simulate different surface textures and materials. They're relatively simple and inexpensive, employing new technology from Immersion Corp. in San Jose. More than just a frill or a thrill, "the addition of tactile feedback to computer mice can significantly enhance user performance," says Jack Dennerlein, assistant professor of ergonomics at Harvard University. "Our laboratory studies show that people complete basic cursor-targeting tasks faster with tactile feedback."
But there are more sophisticated haptic tools available. Perhaps the best-known is the Phantom from SensAble Technologies Inc. in Woburn, Mass. This device employs a moving arm that ends in a stylus for the user to hold or a thimble into which the user inserts a finger. These are used in conjunction with software called the FreeForm Modeling System.
As the user moves the device's arm, a cursor moves around the screen. Using the device, if one encounters a "solid" object in the on-screen universe, the arm is stopped. Moving along a surface provides tactile information about the surface's texture, and the user can readily and intuitively sense curves and corners and, by exerting more pressure, cause deformation of the object.
Using "digital clay" as a sculpting medium, this system essentially does for clay and foam modeling what the word processor did for typing. The process may not be faster for creating the first object, but once that's captured, it can be manipulated, modified and rescaled digitally. The artist can copy and reuse model features, control the hardness and surface smoothness of the clay, and mirror and scale objects - and, of course, "undo" is just a keystroke away.
One major application for this technology is in moviemaking, particularly in the creation of models. North Watford, U.K.-based design studio Synapse Modelmaking Ltd. used SensAble's hardware and software to design characters and figures for the recent animated feature film Chicken Run. Because of the digital nature of the modeling, the studio was able to get nearly instant approval from the production company, Aardman Animations Ltd. in Bristol, U.K.
The film company representative "asked if he could make a change to the model," recalls Synapse director Roger Hulks, "and we implemented the change immediately - right before his eyes." Synapse got approval for its design on the spot, and the Aardman representative was dazzled. "He still goes on about it today," says Hulks.
There are many potential practical applications for haptic devices in training people to develop and practice specific motor skills, such as in the field of medicine. One use is for training in surgical procedures. Another is in telemedicine, where a doctor can physically examine and palpate areas on a patient's body, receiving accurate and informative tactile feedback even though the patient and doctor are in different locations.
Locating and clearing land mines is risky business, but haptic technology can help significantly in training. The system presents the trainee with a basic representation of the area to be investigated, and, using a standard-issue military probe attached to the Phantom, he has to locate possible mines by gently inserting a virtual representation of the probe into the on-screen "ground."
Once a definite contact has been made, the trainee continues probing until a recognizable pattern of penetrations has been made. The clear advantage of the system is that it lets people make beginners' mistakes without being killed.
Haptics is also being investigated as a tool for analyzing data. Just as color and graphical representations have enhanced the ability to manipulate and understand masses of data, haptics may contribute the ability to sense additional dimensions in a single view.