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Set aircraft-derived upper bounds on mass and distance states #1055

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Set aircraft-derived upper bounds on mass and distance states #1055

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19 changes: 18 additions & 1 deletion aviary/mission/flight_phase_builder.py
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@
from aviary.utils.aviary_values import AviaryValues
from aviary.variable_info.enums import EquationsOfMotion, ThrottleAllocation, Transcription
from aviary.variable_info.variable_meta_data import _MetaData
from aviary.variable_info.variables import Aircraft, Dynamic
from aviary.variable_info.variables import Aircraft, Dynamic, Mission

# Height Energy and Solved2DOF use this builder

Expand Down Expand Up @@ -220,6 +220,23 @@ def build_phase(
##############
# Add States #
##############

# Replace None upper bounds with aircraft-derived values so that
# Dymos doesn't set them to ~1e21, which creates scaled upper bounds
# of ~1e17 (mass) and ~1e15 (distance) and wrecks SNOPT conditioning.
# See https://github.com/OpenMDAO/Aviary/issues/607
if aviary_options is not None:
gross_mass = aviary_options.get_val(Mission.Design.GROSS_MASS, units='kg')
design_range = aviary_options.get_val(Mission.Design.RANGE, units='m')

mass_bounds, mass_units = user_options['mass_bounds']
if mass_bounds[1] is None:
user_options['mass_bounds'] = ((mass_bounds[0], 2.0 * gross_mass), mass_units)

dist_bounds, dist_units = user_options['distance_bounds']
if dist_bounds[1] is None:
user_options['distance_bounds'] = ((dist_bounds[0], 2.5 * design_range), dist_units)

if phase_type is EquationsOfMotion.HEIGHT_ENERGY:
rate_source = Dynamic.Vehicle.Propulsion.FUEL_FLOW_RATE_NEGATIVE_TOTAL
else:
Expand Down
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