Chapter 5 Robust Performance Tailoring with Tuning - SSL - MIT

Performing an AO tuning optimization about the uncertainty space of the first iso-
segment results in the tuning configuration listed in the table under Test 2. These
parameters are set on the hardware and a new performance measure of 346.47µm is
obtained. This tuned configuration does not meet requirements, and in fact, is worse
than the nominal hardware performance indicating that the hardware parameters are
most likely on the second iso-segment. Performing an AO tuning optimization on the
other iso-segment results in a tuning configuration that is symmetric to that found
in Test 2. This tuning configuration successfully tunes the hardware performance to
below the requirement ending the process after only three hardware tests. Comparing
these results to the baseline tuning results in Table 4.3 it is interesting to note that
the isoperformance tuning methodology results in a similar tuning configuration and
leads to a hardware performance that is very close to the baseline tuned performance.
Table 4.4: Uncertainty parameters for SCI development model.
Name Description p0
E1 Young’s Modulus of truss 1 & 2 72 [GPa]
ρ1 material density of truss 1 & 2 2900 [kg\m 3 ]
m1 00 11 000 111
00 11 d1 d2 000 111 d2 00 11
000 111
00 11
000 111
00 11
000 111
m 2
E1 ρ1 E1 ρ1 E2 ρ2 E2 ρ2 Y
d1
000 111
000 111
000 111
000 111
000 111
The development model tunes easily with isoperformance tuning due to the sym-
metry in the model. The iso-contours are distinct mirror images of each other allowing
a dramatic reduction of the uncertainty space from only one hardware measurement.
In order to demonstrate the latter half of the algorithm, the search for intersecting
subsets of the isoperformance space, a slight variation of the development model is
considered. In this example the uncertainty parameters are Young’s Modulus, E1,
and density, ρ1, of the beams in truss segments 1 and 2, as listed in Table 4.4 and
shown in the accompanying figure. In addition, the uncertainty range is increased to
±50% about the nominal parameter values. Since the uncertainty model has changed
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