Haptic interfaces

Most interfaces between users and computer systems involve the equivalent of switches—keyboard keys or mouse but-tons. These interfaces cannot respond to degrees of pres-sure (for an exception, see graphics tablet). Further, there is no feedback returned to the user through the interface device—the key or mouse does not “push back.”

Haptic (from the Greek word for “touch”) interfaces are different in that they do register the pressure and motion of touch, and they often provide touch feedback as well.

Force-feedback systems use movement of the control as a way to provide feedback to the operator. A common example is the control stick in an aircraft that begins to vibrate as the aircraft approaches a stall (where it would lose control). This provides immediate feedback to the pilot using the device by which he or she is already controlling the plane.

More sophisticated forms of force feedback are used in remote-controlled devices for manipulation or exploration. The first application was developed in the 1950s for han-dling radioactive materials. Today a combination of posi-tion and movement sensing and force feedback can be used with special gloves to enable users to grasp and heft 3D virtual objects while getting a sense of their weight, shape, and even texture.

In games, haptic joysticks and other controls such as steering wheels can provide sensations such as resistance to a car’s turn or the sensation of a bat hitting a ball. The Nin-tendo Wii game console comes with a controller that tracks the direction and speed of its movement along with a set of simple but engrossing sports games to show its capabilities.

Some emerging or near-future uses of haptic technology include:

•  remote surgery, where the surgeon can feel the resis-tance of tissues and the location of anatomical features

•  use of haptic technology to provide robots with more humanlike gripping capabilities

•  3D sculpture in a virtual 3D world modeling the char-acteristics of different materials and tools

Like virtual reality itself, haptics is currently found in niche applications such as entertainment, control, and training systems. Besides the expense of the technology itself, there is the need for specialized programming. How-ever, the time may come when haptic support, like mouse and pen support, is included in operating systems and widely available programming libraries.