18th annual conference on manual control.pdf - Acgsc.org

experimental program was conducted at the University of Connecticut to evaluate
the four candidate display systems. The objective of these experiments was to
validate the overall display design procedure, including the analytic rankordering,
the workload assessment, and the flight director design synthesis
processes°
The analytical nucleus to the display design methodology is the Optimal Control
pilot Model (OCM)[3]-[5]. A detailed description of the OCM, in conjunction
with the three-level display design process, is given in [6]. In this paper
we first introduce the control task of interest, including the AI0 alrcraft
dynamics and the terrian profile characteristics. We apply then the display
design procedure, which yields the major analytical results of this study,
including the predictions of attentional allocation, workload demands, and
performance rank-ordering. Finally, the experimental program is described,
and the experimental results discussed.
A-10 LONGITUDINAL AIRCRAFT DYNAMICS
APPLICATION OF THE CONTROL TASK TO THE OCM
AS indicated, the control task of interest is high-speed terrain following for
a representative low-level attack flight condition. The basic set of longitudinal
equations being used is the short-period dynamics. These are the
perturbation equations written about straight and level flight, and they
describe the aircraft longitudinal rotations about its center of mass.
The (two-degree of freedom) transfer functions of interest are [7]
1 Z_s + (UoM_-Z_Mq) (i)
(s)= o o
(M_+Z6M_)S + (Z6Mw-M_Zw)
6
(s) =
_(s)
(2)
A(S) = S2 - (U M'+Z +M )s + (MqZw-UoMw) (3)
ow w q
where q = aircraft pitch rate, e = angle of attack, U o = nominal air speed,
= elevator angle, and Z6, M6, Mq, Mw, Zw are the pertinent Stability
del-ivatives.
In the present work the stability derivatives were derived from data currently
used On the Aerospace Systems Division A-10 nonlinear hybrid simulation, and,
the numerical values are given in [6]" The nominal air speed U O = 468 ft/sec.
In addition, the aircraft pitch angle, 8, and its altitude, h, are necessary in
the modeling process. Therefore
= q ; _ = Uo(8_q) (4)
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