Case 13.4: Lateral offset manuever 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=20s, 2000-ft lateral course offset.

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
import numpy as np
from scipy import interpolate

from nesc_testcase_helper import plot_nesc_comparisons, plot_F16_controls, benchmark
from nesc_case11 import (
    int_opts,
    F16ControllerBlock,
    BD,
    spec_ic_args,
    opt_ctrl,
    dim_feedback,
    earth,
    baseChiCmdBlock,
    latOffsetStateEquation,
    latOffsetOutputEquation,
)


def latOffsetOutputEquationShift(t, x):
    latOffset = latOffsetOutputEquation(t, x)
    if t < 20:
        return latOffset
    else:
        return latOffset - 2000


latOffsetBlock = systems.DynamicalSystem(
    state_equation_function=latOffsetStateEquation,
    output_equation_function=latOffsetOutputEquationShift,
    dim_state=1,
    dim_input=3,
    dim_output=1,
)

BD.systems[-2] = latOffsetBlock
BD.systems[2] = F16ControllerBlock(*opt_ctrl, sasOn=True, apOn=True, event_t=20.)
BD.connect(baseChiCmdBlock, latOffsetBlock, inputs=[0])
BD.connect(
    earth, latOffsetBlock, outputs=[earth.V_N_idx, earth.V_E_idx], inputs=[1, 2]
)

with benchmark() as b:
    res = BD.simulate(60, integrator_options=int_opts)

time to simulate: 65.614 s

plot_nesc_comparisons(res, "13p4")
plot_F16_controls(res, "13p4")

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