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Task 2: 180° hover turn
The second task required a 180° pedal turn over a runway, which was to be performed in 10 sec. The pilot again controlled the aircraft with the pedals only, and the position of the c.m. remained fixed with respect to Earth. This maneuver was taken from the current U.S. Army rotary-wing design standard (ref. 50) and, with one proviso, is representative of a handling qualities maneuver performed for the acceptance of military helicopters. However, in the military acceptance maneuver, the pilot controls all six degrees of freedom rather than one.
This maneuver did not allow for full math-model motion, since the simulator cab cannot rotate 180°. As a result, attenuated motion was used, as described later. Desired performance was to stabilize at the end of the turn to within ±3° and within 10 sec. Pilots performed six 180° turns, always turning over the same side of the runway to keep the visual scene consistent for the set of turns. Figure 9 shows the visual scene from the starting position.
Task 3: Yaw rotational regulation
The third task required the pilot to perform a rapid 9-ft climb while attempting to maintain a constant heading. This disturbance-rejection task was challeng-ing, because collective lever movement in the unaugmented AH-64 model results in a substantial yawing moment disturbance (because of engine torque) that must be countered (rejected) by the pilot with pedal inputs. This task allowed full vertical, yaw-rotational, and lateral-translational motion at the pilot’s station. Desired performance was for the pilot to acquire the new height as quickly as possible while keeping the heading within ±1° of north. The same visual scene was presented as in Task 1 (fig. 8), but with the scene also indicating height variations as the vehicle model changed altitude.
Simulated Vehicle Math Model
The math model represented an unaugmented AH-64 Apache helicopter in hover, which had been identified from flight-test data and subsequently validated by several AH-64 pilots (ref. 51). Equation (5) describes the vehicle dynamics for the rotational ψ and vertical h degrees of freedom:
Figure 9. Pilot’s visual scene in Task 2.
.
˙˙ ˙˙
h
ψ
.
=
.
0 270. 0 000. 0 000
.
.
.
0 000
.
.
0 122
118
.
.
.
˙ ˙
h
ψ
.
presented to the pilot did not vary and were always those
....
axp
....
....
....
....
....
.
.. .
0 000. .
0 000
12 9.
z˙
z
1
1
.
.
(5)
0 494. .
0 266
.
δ
.
.
.
....
....
r
..
.
...
0 000. 14 6.
+
δ
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本文链接地址：Helicopter Flight Simulation Motion Platform Requirements(19)
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