Page 26 - DCAP608_REAL TIME SYSTEMS

Unit 2: Introduction to Real-time Applications

2.4.2 Medical Notes

A few examples of medical applications of real-time systems are: robots, MRI scanners, radiation
therapy equipment, bedside monitors, and computerized axial tomography (CAT).

Example: Robot Used in Recovery of Displaced Radioactive Material
Robots have become very popular nowadays and are being used in a wide variety of medical
applications. An application that we discuss here is a robot used in retrieving displaced
radioactive materials. Radioactive materials such as Cobalt and Radium are used for treatment
of cancer. At times during treatment, the radioactive Cobalt (or Radium) gets dislocated and
falls down. Since human beings cannot come near a radioactive material, a robot is used to
restore the radioactive material to its proper position. The robot walks into the room containing
the radioactive material, picks it up, and restores it to its proper position. The robot has to sense
its environment frequently and based on this information, plan its path. The real-time constraint
on the path planning task of the robot is that unless it plans the path fast enough after an obstacle
is detected, it may collide with it. The time constraints involved here are of the order of a few
milliseconds.

2.4.3 Peripheral Equipment

A few examples of peripheral equipment that contain embedded real-time systems are: laser
printers, digital copiers, fax machines, digital cameras, and scanners.

Example: Laser Printer
Most laser printers have powerful microprocessors embedded in them to control different
activities associated with printing. The important activities that a microprocessor embedded in
a laser printer performs include the following: getting data from the communication port(s),
typesetting fonts, sensing paper jams, noticing when the printer runs out of paper, sensing when
the user presses a button on the control panel, and displaying various messages to the user. The
most complex activity that the microprocessor performs is driving the laser engine. The basic
command that a laser engine supports is to put a black dot on the paper. However, the laser
engine has no idea about the exact shapes of different fonts, font sizes, italic, underlining,
boldface, etc. that it may be asked to print. The embedded microprocessor receives print
commands on its input port and determines how the dots can be composed to achieve the
desired document and manages printing the exact shapes through a series of dot commands
issued to the laser engine. The time constraints involved here are of the order of a few
milliseconds.

Lab Exercise Go to URL http://www.fujitsu.com/us/services/computing/peripherals/
scanners/workgroup/ and collect more information on fi-60F A6 High-Speed Flatbed
Scanner.

2.4.4 Automotive and Transportation

A few examples of automotive and transportation applications of real-time systems are:
automotive engine control systems, road traffic signal control, air-traffic control, high-speed
train control, car navigation systems, and MPFI engine control systems.

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