直升机信息_直升机_直升飞机_旋翼机_Helicopter

Rotation Motionless
When either translational motion or rotational motion was present for Tasks 1 and 3 (yaw rotational regulation), it was the full translational or rotational motion calculated by the vehicle math model. That is, the cockpit provided the full accelerations that the math model calculated and that the visual scene provided, along with the effective motion delays in equations (1)–(4). This statement was true, except for the longitudinal motion provided by the translational motion configuration; for yaw turns about a point, the longitudinal acceleration at the pilot’s station is always negative (centripetal acceleration in eq. (6)). These accelerations, if integrated twice to motion-system position commands, would cause continual longitudinal cab movement aft for this motion configuration. Eventually, the simulator cab would exceed its available longitudinal displacement. Thus, a second order, high-pass filter was used in the longitudinal axis so that the cab would return to its initial position in the steady state. This type filter is typically used in flight simulation, and it had the form of
˙˙xcom Ks2
()s = 2 2 (9)
axp s + 2ζωms +ωm
where ˙˙ is the commanded longitudinal acceleration of
xcomthe simulator cab, axp is the math model’s longitudinal
acceleration at the pilot’s position, K is the motion gain, ζ is the damping ratio, and ω m is the filter’s natural frequency.
As described earlier, Task 2 (180° hover turn) did not allow full motion. Thus, a high-pass filter of the same form in equation (9) was used in all axes. The values of K and ω m were empirically selected to use as much cockpit motion as available (fig. 6).
For Task 3, the vertical motion was always the full math model vertical motion, even in the Motionless condition.
That is, Motionless for Task 3 refers to the simulator cab being motionless in the horizontal plane. Table 1 lists K and ω m for each tested configuration in each axis. A configuration with K = 1 and ω m = 1.0E-5 rad/sec effectively makes the filter in equation (9) unity for the tasks, considering the task time-scale. The filter damping ratio (ζ ) was 0.7 for all configurations.
Each of these tasks could be performed on a typical hexapod motion system, except for the vertical transla-tions required in Task 3. In particular, the amount of cab translation corresponding to the ±15° rotations in Task 1 is less than ±1.2 ft. For Task 2, typical pilot aggressive-ness levels resulted in maximum cab yaw orientations of less than ±5° and lateral travels of less than ±0.5 ft. Finally, for Task 3, maximum cab yaw orientations were also less than ±5° and lateral travels were less than ±0.5 ft. However, the vertical simulator cab translation for Task 3 was near 10 ft, which could not be accomplished by today’s hexapods.