Page 350 - Concise Encyclopedia of Robotics

Virtual Reality
universe superimposed on the real one. The HMD uses small liquid-crystal
display (LCD) screens, whose images are magnified by lenses and/or
reflected by mirrors to obtain the desired effects.
Sound system: Stereo,high-fidelity sound is the norm in all VR universes.
Loudspeakers can be used for low-level, group VR experiences. In an
individual system, a set of headphones is included in the HMD. The
sound programming is synchronized with the visual programming.
Speech recognition and speech synthesis can be used so that virtual people,
virtual robots, or virtual space aliens can communicate their virtual
thoughts and feelings to the user.
Input devices: Passive and exploratory VR systems do not need input
devices, except for the media that contain the programming. Interactive
systems can make use of a variety of mechanical equipment. The nature
of the input device(s) depends on the VR universe. For example, driving a
car requires a steering wheel, gas pedal, and brake (at least). Games need
a joystick or mouse. Devices called bats and birds resemble computer
mice, but are movable in three dimensions rather than only two. Levers,
handles, treadmills, stationary bicycles, pulley weights, and other devices
allow for real physical activities on the part of the operator. For complete
hand control, special gloves can be used. These have air bladders built in,
providing a sense of touch and physical resistance, so objects seem to have
substance and heft.The computer can be equipped with speech recognition
and speech synthesis so that the user can talk to virtual creatures. This
requires at least one sound transducer at the operating location.
A complete system: Figure 4 is a block diagram showing the hardware
for a typical interactive VR system, in which the user gets the impression
of riding a bicycle down a street. This can be used for exercise as well as
for entertainment. The system provides sights, sounds, and variable
pedal resistance as the user negotiates hills and encounters wind. If a tele-
operated android is put on a real bicycle, the VR system can be used to
control that robot and bicycle remotely. This would involve the addition
of two wireless transceivers (one for the computer and the other for the
telechir), along with modems and antennas.
Applications
Virtual reality has been used as an entertainment and excitement medium.
It also has practical applications.
Instruction: Virtual reality can be used in computer-assisted instruction
(CAI). For example, a person can be trained to fly an aircraft, pilot a sub-
marine,or operate complex and dangerous machinery,without any danger
of being injured or killed during training. This form of CAI has been
used by the military for some time. It has also been used for training

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