Performance Improvement of Fault-Tolerant Flight Control System and Development of Diagnostic System

Computer systems are widely used in
variety of tasks. For critical missions such
as the medical system in the operation
room, the aviation control system, or the
nuclear reactor control system,
malfunction of the computer system may
cause great casualty.
In the past three decades, one can see the
significant growth in this issue: how to
make the computer system more
dependable ?
One way to achieve higher dependability
is to make the computer system fault-free;
that is, to build a near perfect physical
system, and execute a near perfect
procedure. However, it is a dependabilityand-
resources trade-off. As the computer systems are getting more and more
complex, it is more and more difficult to
design, build, and verify the system that
can per-form perfect operation at any
circumstance throughout the system's life
time; and the cost to develop and build a
near perfect system is increasing
exponentially as the system scale and
complexity increase.
Another way to achieve higher dependability
is to make the system fault-tolerant.
A fault-tolerant system is a system that
will keep operating normally and give the
correct responses and answers when one or
more of the components fail to perform it's
normal task. A more general concept of
fault-tolerance also includes man made
fault, such as the human mistakes
committed during hardware or software
design and implementation, or bugs in
short term. Another possible human
mistake is the operating error due to the
improper design of human computer
interface, or the lack of training for
operators.
To achieve fault-tolerance, redundant
hardware is required. It is a big problem in
the early era of computer development
while the computers are in the size of a
refrigerator, and they are costly. With the
advent of microprocessors, the volume,
weight, power and cost associated with
redundant component decreases
dramatically. With microprocessors, faulttolerant
systems can be built highly
dependable and affordable.