返回首页
当前位置: 主页 > 直升机资料 >

Helicopter Flight Simulation Motion Platform Requirements(64)

时间:2011-11-12 12:15来源:蓝天飞行翻译 作者:admin
曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
  
The above model also predicts a degradation in closed-loopThis root is also the principal root of interest in the performance from degradations in the motion filter alone.
pilot’s control of altitude. The corresponding effects on Figure B4 illustrates how the closed-loop vertical-velocity roots migrate as the motion filter changes. However, these closed-loop poles are those that result when the model’s gains are fixed at the full-motion (V1) condition for all the remaining conditions (V2, V3, V4, V10). This situation was examined to show the effect of the motion filter alone without pilot adaptation. Only the region near the origin is depicted, since the poles and zeros far from the origin exhibit negligible change.
Two effects of the motion filter alone are noticed. First, the effective heave damping is reduced as the motion filter’s natural frequency increases. This result also occurs when the adjustment rules of the model are followed. Second, pole-zero dipoles form in which the separation between the pole and zero become more prominent as the motion filter is made more restrictive (going from V1 to V4). As the filter natural frequency increases, these dipoles encroach upon the pilot-vehicle crossover frequency. Thus, a broad range of integrator-like characteristics in the crossover region does not occur. So if the pilot wanted to
Imag axis
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
achieve a similar, but slower, closed-loop response, more than just a simple gain change on his part would be necessary. He would also have to adjust his dynamic compensation, which would likely entail an increase in workload or a reduction in his opinion of simulator fidelity. As expected, the closed-loop bandwidth without using the pilot adjustment rules becomes worse. The bandwidth of the V10 configuration is 3.60 rad/sec without the adjustment rules versus 4.27 rad/sec with them.
Since this model was applied to Vertical Experiment I (sec. 4), it is interesting to compare the phase-plane time-histories from that experiment (figs. 40–43, 49) with the phase-plane time-histories that the model predicts. The model’s predictions for the five configurations analyzed (V1, V2, V3, V4, and V10) are shown in figure B5. Although the model shows degradations as the quality of the platform motion becomes worse, the model poorly represents the experimental results in two ways. First, the model introduces a pronounced underdamped oscillatory mode for the V1-V4 configurations, which has a frequency of 8 rad/sec. This mode is not present in the experimental results, which show a reasonably smooth response during the ascent. Second, the model does not predict the oscilla-tory behavior that occurs experimentally at the terminal altitude point (85 ft), which is especially prevalent in the motionless (V10) configuration. The adjustment rules need to be modified in the model in an attempt to match the experimental results. This modification is left for future work.
 
直升机网 www.helicopter.cn
直升机翻译 www.aviation.cn
本文链接地址:Helicopter Flight Simulation Motion Platform Requirements(64)
 
------分隔线----------------------------