CIFER®-MATLAB Interfaces: Development and ... - Cal Poly

Two sets of data were used: one was a simulation of the UAV, and the second from a series of
flight tests on the vehicle. The goals of the analysis were to investigate data consistency using the
frequency response arithmetic utility, and to explore the RMS and cross-over characteristics of
the vehicle. The results of the analysis were compared to scaled bandwidth criteria for manned
aircraft. This analysis was the final, most involved, validation of the CIFER ® -MATLAB
interface.
4.4.1 Data Consistency checks:
Checking data for kinematic consistency assures that measured data obeys kinematic laws and
does not contain hidden scale factors or delays. The frequency arithmetic feature of CIFER ®
allows reconstruction of parameters not measured during flight tests from the responses of those
that were measured. Additionally, it can be used to show whether or not data is consistent with
kinematic laws. There are several relations among commonly measured rates and attitudes for
aircraft as shown in Equations 4.4 through 4.8 5 . Herein, it was assumed that V 0 and W 0 were
small.
p = φ [4.4]
q = θ [4.5]
= a − gθ
−W q V r
[4.6]
u
x 0
+
0
v −U
β = a
y
−U
r + W p + gφ
[4.7]
=
0 0 0
w = U α = a + U q −V
p
[4.8]
o z o 0
The simulation data includes measurements of phi and theta as well as the rates and accelerations
in all axes, however, alpha and beta channels were not provided. Velocity perturbations were
reconstructed from the time domain data in the FRESPID program using Equations 4.6 through
4.8. The frequency responses could then be calculated for the velocity perturbations. Using
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