"""FAST - Copyright (c) 2016 ONERA ISAE."""
# This file is part of FAST-OAD_CS23 : A framework for rapid Overall Aircraft Design
# Copyright (C) 2025 ONERA & ISAE-SUPAERO
# FAST is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import numpy as np
import importlib.util
import openmdao.api as om
import fastoad.api as oad
from fastga_he.models.performances.mission_vector.constants import SUBMODEL_CG_VARIATION
RTA_INSTALLED = importlib.util.find_spec("rta") is not None
oad.RegisterSubmodel.active_models[SUBMODEL_CG_VARIATION] = (
"fastga_he.submodel.performances.cg_variation.legacy"
)
[docs]
@oad.RegisterSubmodel(SUBMODEL_CG_VARIATION, "fastga_he.submodel.performances.cg_variation.legacy")
class InFlightCGVariation(om.ExplicitComponent):
"""
Computes the coefficient necessary to the calculation of the cg position at any point of
the DESIGN flight.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.empty_weight_variable_name = None
[docs]
def setup(self):
if RTA_INSTALLED:
self.empty_weight_variable_name = "data:weight:aircraft_empty:mass"
for submodel in oad.RegisterSubmodel.active_models.values():
if submodel is not None and ".rta" in submodel:
self.empty_weight_variable_name = "data:weight:aircraft:OWE"
break
else:
self.empty_weight_variable_name = "data:weight:aircraft_empty:mass"
# Check whether RTA is installed and if the user intends to use it
self.add_input("data:TLAR:NPAX_design", val=np.nan)
self.add_input("data:TLAR:luggage_mass_design", val=np.nan, units="kg")
self.add_input("data:weight:payload:rear_fret:CG:x", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:front_length", val=np.nan, units="m")
self.add_input("data:geometry:cabin:seats:pilot:length", val=np.nan, units="m")
self.add_input("data:geometry:cabin:seats:passenger:length", val=np.nan, units="m")
self.add_input("data:geometry:cabin:seats:passenger:count_by_row", val=np.nan)
self.add_input("data:weight:aircraft_empty:CG:x", val=np.nan, units="m")
self.add_input(self.empty_weight_variable_name, val=np.nan, units="kg")
self.add_input("data:weight:aircraft:payload", val=np.nan, units="kg")
self.add_input(
"settings:weight:aircraft:payload:design_mass_per_passenger",
val=80.0,
units="kg",
desc="Design value of mass per passenger",
)
self.add_output(
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
units="kg*m",
)
self.add_output("data:weight:aircraft:in_flight_variation:fixed_mass_comp:mass", units="kg")
self.declare_partials(
of="data:weight:aircraft:in_flight_variation:fixed_mass_comp:mass",
wrt=["data:weight:aircraft:payload", self.empty_weight_variable_name],
val=1.0,
)
self.declare_partials(
of="data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
wrt=[
self.empty_weight_variable_name,
"data:weight:aircraft_empty:CG:x",
"data:weight:aircraft:payload",
],
method="exact",
)
self.declare_partials(
of="data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
wrt=[
"data:TLAR:NPAX_design",
"data:TLAR:luggage_mass_design",
"data:weight:payload:rear_fret:CG:x",
"data:geometry:fuselage:front_length",
"data:geometry:cabin:seats:pilot:length",
"data:geometry:cabin:seats:passenger:length",
"data:geometry:cabin:seats:passenger:count_by_row",
"settings:weight:aircraft:payload:design_mass_per_passenger",
],
method="fd",
)
[docs]
def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
npax = inputs["data:TLAR:NPAX_design"]
count_by_row = inputs["data:geometry:cabin:seats:passenger:count_by_row"]
luggage_weight = inputs["data:TLAR:luggage_mass_design"]
cg_rear_fret = inputs["data:weight:payload:rear_fret:CG:x"]
l_pilot_seat = inputs["data:geometry:cabin:seats:pilot:length"]
l_pass_seat = inputs["data:geometry:cabin:seats:passenger:length"]
design_mass_p_pax = inputs["settings:weight:aircraft:payload:design_mass_per_passenger"]
x_cg_plane_aft = inputs["data:weight:aircraft_empty:CG:x"]
lav = inputs["data:geometry:fuselage:front_length"]
payload = inputs["data:weight:aircraft:payload"]
m_empty = inputs[self.empty_weight_variable_name]
l_instr = 0.7
# Seats and passengers gravity center (hypothesis of 2 pilots)
nrows = int(np.ceil(npax / count_by_row).item())
x_cg_passenger = lav + l_instr + l_pilot_seat * 2.0 / (npax + 2.0)
for idx in range(nrows):
length = l_pilot_seat + (idx + 0.5) * l_pass_seat
nb_pers = min(count_by_row, npax - idx * count_by_row)
x_cg_passenger = x_cg_passenger + length * nb_pers / (npax + 2.0)
x_cg_payload = (
x_cg_passenger * (2.0 + npax) * design_mass_p_pax + cg_rear_fret * luggage_weight
) / payload
equivalent_moment = m_empty * x_cg_plane_aft + payload * x_cg_payload
mass = m_empty + payload
outputs["data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment"] = (
equivalent_moment
)
outputs["data:weight:aircraft:in_flight_variation:fixed_mass_comp:mass"] = mass
[docs]
def compute_partials(self, inputs, partials, discrete_inputs=None):
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
self.empty_weight_variable_name,
] = inputs["data:weight:aircraft_empty:CG:x"]
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
"data:weight:aircraft_empty:CG:x",
] = inputs[self.empty_weight_variable_name]
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
"data:weight:aircraft:payload",
] = 0.0
[docs]
@oad.RegisterSubmodel(SUBMODEL_CG_VARIATION, "fastga_he.submodel.performances.cg_variation.simple")
class InFlightCGVariationSimple(om.ExplicitComponent):
"""
Computes the coefficient necessary to the calculation of the cg position at any point of
the sizing mission assuming a cg of payload as input.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.empty_weight_variable_name = None
[docs]
def setup(self):
if RTA_INSTALLED:
self.empty_weight_variable_name = "data:weight:aircraft_empty:mass"
for submodel in oad.RegisterSubmodel.active_models.values():
if submodel is not None and ".rta" in submodel:
self.empty_weight_variable_name = "data:weight:aircraft:OWE"
break
else:
self.empty_weight_variable_name = "data:weight:aircraft_empty:mass"
# Check whether RTA is installed and if the user intends to use it
self.add_input("data:weight:aircraft_empty:CG:x", val=np.nan, units="m")
self.add_input(self.empty_weight_variable_name, val=np.nan, units="kg")
self.add_input("data:weight:aircraft:payload", val=np.nan, units="kg")
self.add_input("data:mission:sizing:payload:CG:x", val=np.nan, units="m")
self.add_output(
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
units="kg*m",
)
self.add_output("data:weight:aircraft:in_flight_variation:fixed_mass_comp:mass", units="kg")
self.declare_partials(
of="data:weight:aircraft:in_flight_variation:fixed_mass_comp:mass",
wrt=["data:weight:aircraft:payload", self.empty_weight_variable_name],
val=1.0,
)
self.declare_partials(
of="data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
wrt=[
self.empty_weight_variable_name,
"data:weight:aircraft_empty:CG:x",
"data:weight:aircraft:payload",
"data:mission:sizing:payload:CG:x",
],
method="exact",
)
[docs]
def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
m_empty = inputs[self.empty_weight_variable_name]
x_cg_plane_aft = inputs["data:weight:aircraft_empty:CG:x"]
payload = inputs["data:weight:aircraft:payload"]
x_cg_payload = inputs["data:mission:sizing:payload:CG:x"]
equivalent_moment = m_empty * x_cg_plane_aft + payload * x_cg_payload
mass = m_empty + payload
outputs["data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment"] = (
equivalent_moment
)
outputs["data:weight:aircraft:in_flight_variation:fixed_mass_comp:mass"] = mass
[docs]
def compute_partials(self, inputs, partials, discrete_inputs=None):
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
self.empty_weight_variable_name,
] = inputs["data:weight:aircraft_empty:CG:x"]
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
"data:weight:aircraft_empty:CG:x",
] = inputs["data:weight:aircraft_empty:mass"]
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
"data:weight:aircraft:payload",
] = inputs["data:mission:sizing:payload:CG:x"]
partials[
"data:weight:aircraft:in_flight_variation:fixed_mass_comp:equivalent_moment",
"data:mission:sizing:payload:CG:x",
] = inputs["data:weight:aircraft:payload"]