Case 13.1: Altitude change of a subsonic aircraft

Verifies	Multidimensional table look-up
Gravitation	J2
Geodesy	WGS-84 rotating
Atmosphere	US 1976 STD
Winds	still air
Vehicle	F-16 with simple auto-pilot
Notes	Initially straight & level. t=5s, command altitude 100-ft increase

For the manuevering examples, the BlockDiagram from case 11 is modified to replace the controller with the auto-pilot configuration and generate the appropriate command signals.

from simupy import systems
from scipy import interpolate

from nesc_testcase_helper import plot_nesc_comparisons, plot_F16_controls, benchmark
from nesc_testcase_helper import ft_per_m
from nesc_case11 import (
    int_opts,
    F16ControllerBlock,
    BD,
    spec_ic_args,
    opt_ctrl,
    dim_feedback,
)

altCmdBlock = systems.SystemFromCallable(
    interpolate.make_interp_spline(
        [0, 5],
        [spec_ic_args["h"] * ft_per_m, spec_ic_args["h"] * ft_per_m + 100.0],
        k=0,
    ),
    0,
    1,
)

BD.systems[-3] = altCmdBlock
BD.systems[2] = F16ControllerBlock(*opt_ctrl, sasOn=True, apOn=True, event_t=5.)

with benchmark() as b:
    res = BD.simulate(20, integrator_options=int_opts)

Out:

Optimization terminated successfully.
         Current function value: 0.006500
         Iterations: 299
         Function evaluations: 562
pitch: 2.6351e+00  roll: 0.0000e+00  longStk: 12.9236  throttle: 13.7561
accelerations:
 [[-4.59610112e-03  4.59610020e-03  1.01317177e-10]
 [-2.98437663e-09  4.11189587e-09  2.12618714e-09]]
time to simulate: 26.182 s

plot_nesc_comparisons(res, "13p1")
plot_F16_controls(res, "13p1")

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