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suspected. As a practical matter, this may well be giving too much power to stop
production lines. But the fact is, unless everyone is on the ball and feels like they
can make a difference, then quality processes may not work. Empowerment puts
the emphasis on quality first and foremost.
Process documentation Good quality control systems call for the documenta-
tion of the quality process. For a small group, this may prove to be too burden-
some. If the design and manufacturing group is 5 to 20 people, then consider
adopting formal documentation. Advice and documentation can be found at
www.isoeasy.org/ and at www.praxiom.com. A web site discussing some of the
basics is located at www.optants.com/tutor/ciptqm.htm.

Testing

Testing is an important aspect of reliability. The word testing has different definitions
for every engineer. This is because many kinds of tests exist, and they are all used to
accomplish different ends. Many test engineers have been able to make a career out of
testing systems. This section outlines the different types of tests.

STRESS TESTS
As we discussed previously, it’s possible to stress portions of the robot with various
environmental factors like temperature, vibration, and humidity. Many things can be
learned from stress tests, including
The limits of operations At what point will the robot stop working and why?
As an example, it’s possible to raise and lower the robot’s temperature to find out
which components will stop working. Further, we can find out whether the com-
ponents break or just become temporarily inoperative. From such tests, the design
can be modified to make the robot more robust.
Spec verification Will the robot work during a particular stress test? If it does,
then it’s possible to say with confidence that it will do so again. This is an accepted
way to verify that the robot can meet a particular specification. The specification
is often published along with the test method.
Life testing If a significant number of robots are tested, it’s possible to develop
a statistically valid prediction for their lifetimes. Accelerated baking (at a high
temperature) can age components at a fast rate. The components to be baked are
slowly taken up to a temperature like 50° C and left to operate for days. Any fail-
ure to operate is noted. If enough components are in the oven for a long enough
time, it’s possible to then develop a predicted failure rate for the component. The