APPENDIX A
APPENDIX A SYSTEM PERFORMANCE DETERMINED WITH PILOT TRANSFER FUNCTIONS Because of the great interest in predicting system performance, an example of the response of a pilot-model-aircraft system to a glide-slope command is presented.
This computed time history is compared with a time history obtained from an actual flight test.
The flight-test data were taken from reference 10 and are shown in figure 17.
Figure 18 was computed by using the second-level multiloop pilot model, as described in this paper, and aircraft characteristics approximately the same as those in the flight- test data of figure 17. The pilot model used also included a remnant added to the pilot- model output. This remnant was obtained by taking a white-noise source, passing this white noise through a filter that was identical to the response characteristic of the pilot, and adding it to the output of the pilot model. The expression for the remnant is there-
f o r e Kn/(I + 0.2~)~. Theamplitude of theremnant Kn was adjusted so thatthemean-
square value of the remnant was approximately 0.5 of the mean-square value of the total pilot-model output. It has been shown in reference 2 that a pilot remnant defined in this manner is appropriate.
The time history in figure 18 can be seen to agree well with the time history obtained from the flight tests (fig. 17). The general amplitude and frequency of the angle- of-attack and pitch-angle time histories are in good agreement. One difference occurs in that the computed results show a large response at the discontinuous point in the com- manded flight path, which the human pilot was able to anticipate and smooth out.
I I I I L I I 0 I O 20 30 40 50 60 Time,', sec Figure 1 7 . - Records obtained f r m reference 10 for flight test of a landing approach. % = 2.30 rad/sec; = 0.20.
APPENDIX A - Concluded
APPENDIX A - Concluded
-2000 -2000 -500 -500 hC, hc.
0 hc,m ft f t 2000- -.I “I -2 b, aa, deg 0 Aqdeg rad rad
.I .E
.I
-.I .F
-“E
2 0 I I I I I I I - 1 0 I O 20 30 0 1 0 2 0 30 40 50 Time, 1, sec Time, t, sec .@re 1 8 . - Landing-approachtimehistory com- Figure 1 . 9 . - LanZiing-approachtime M s - Fi puted by using second-level multiloop pilot tory cmputed by using second-level model withremnant. % = 2.5 rad/sec; multiloop p i l o t model without remnant. % = 2.5 rad/sec; [ = 0.32.
[ = 0.32. (To f a c i l i t a t e comparison with (To f a c i l i t a t e comparison with f i g . 17, La and A9 are given in degrees f i g . 17, Lu and A9 a r e g i v e n i n a s we= as radians. ) degrees as w e l l as radians. ) To illustrate the effect of the remnant on the system response, figure 19 was com- puted without the remnant. The longer period, lightly damped altitude mode of motion is more apparent in figure 19 than it is i n figure 18.
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