Avionics Panel Button Tester by Motion Control Systems
Developed to test a wide range of switch panels requiring a
detailed certification printout and real time graphical
with this machine was capturing reliably the defection transitions. With
any dome based switching mechanism there is that "chicklet" feel when the
switch is pressed and released. What is really
happening is once the switch is depressed to a certain
point, it "pops" down, or essentially pulls away from the
finger. Therefore the force/distance graph in a time
based domain looks similar to a miniature mountain peak.
As the switch continues to be pressed to it's end of travel,
a larger "mountain peak" is displayed next to the first.
As the switch is released the same thing happens, only
in reverse: As the finger lifts, the switch "pops" up,
causing a third force spike. Consequently a third,
smaller peak is generated. Therefore the switch
actuation profile is seen as three force/deflection
peaks/valley relationships side by side.
The system requirement is to capture the differentials
between the "peaks" and "valleys" and show whether
they fall within certain parameters, flagging any failures.
This all sounds fairly simple until one takes into account
the force transitions can be 10th's of ounces and the
distance differentials can be as low as .002". Factor
in a throughput requirement of a few seconds per test and
the complexity of the motion of software relationship begins
to become apparent. To further complicate the matter,
"Off Axis" testing is also required for each switch.
This is to certify what happens when a pilot strikes the
switch with a quantified "glancing" force.
The result is that the differential between the peaks and
valleys is reduced, making reliable data capture even more
dicey. We have delivered a number of these units over
the years, and the one shown here is the most refine,
capable and powerful to date.