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Aerodynamic disturbances #203

Merged
merged 8 commits into from
Feb 1, 2024
Merged

Aerodynamic disturbances #203

merged 8 commits into from
Feb 1, 2024

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GabrieleMeoni
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@GabrieleMeoni GabrieleMeoni commented Jan 30, 2024 •
edited by GiordanoNesci
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Description

Summary of changes:

  • Created new function calculate_aero_torque that calculates the aerodynamical torque on the satellite under the hypotesis that the satellite is described by a cuboid mesh, as it is as of now (see geometrical model). The model only works for Earth as a central body as of now. The model is based on the aerodynamical parameters calculation presented in"Roto-Translational Spacecraft Formation Control Using Aerodynamic Forces", Ran S. et al. , JOURNAL OF GUIDANCE, CONTROL, AND DYNAMICS, 2017.
  • Implemented this function in the function calculate_disturbance_torques in attitude_model.py
  • Created pytests for this additional code

Resolved Issues

How Has This Been Tested?

Two types of tests have been created in order to verify and validate the function:

  1. Real word comparison with GOCE data. The satellites perturbations in the same orbit as GOCE shall have the same order of magnitude of reported GOCE perturbations.
  2. Corner cases: in three cases has been evaluated the torque resulting from a simple 1-axial rotation of the satellite which resulted in a predictable torque direction or in no torque at all.

Related Pull Requests

None, attitude model not used in development nor tests.

GabrieleMeoni
GabrieleMeoni commented Jan 30, 2024
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@GiordanoNesci. The model looks good, but this code shows poor integrability with PASEOS. You also did not create a PR.

Please, make also sure that you merge the last student branch

paseos/attitude/disturbance_calculations.py Show resolved Hide resolved
paseos/attitude/disturbance_calculations.py Outdated
"""

# Set data useful for aerodynamic coefficients calculation
temperature_spacecraft = 300 # [K] we could connect this with the thermal model
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There is a thermal model, this is completely disconnected.

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There is the possibility to treat the temperature as an input from the thermal model (when the latter is used). As of now the temperature of the spacecraft is treated as a constant, since the model is not sensitive to the temperatures.

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Ok, thanks.

paseos/attitude/disturbance_calculations.py Outdated

# Set data useful for aerodynamic coefficients calculation
temperature_spacecraft = 300 # [K] we could connect this with the thermal model
temperature_gas = 1000 # [K] valid for upper stratosphere, could be completely wrong higher up
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This shall be an input or a property of the central body.

paseos/attitude/disturbance_calculations.py Outdated
temperature_spacecraft = 300 # [K] we could connect this with the thermal model
temperature_gas = 1000 # [K] valid for upper stratosphere, could be completely wrong higher up
altitude = np.linalg.norm(r)-6371 # [km]
density = 10**(-(altitude+1285)/151) # from data fit from thermospheric mass density
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As above.

paseos/attitude/disturbance_calculations.py Show resolved Hide resolved
paseos/attitude/aero_disturbance_test.py Outdated Show resolved Hide resolved
paseos/attitude/aero_disturbance_test.py Outdated Show resolved Hide resolved
paseos/attitude/aero_disturbance_test.py Outdated Show resolved Hide resolved
paseos/attitude/aero_disturbance_test.py Outdated Show resolved Hide resolved
paseos/attitude/aero_disturbance_test.py Outdated Show resolved Hide resolved
@GiordanoNesci
Update aero_disturbance_test.py
f1c3037 
Reviewed tests and rewritten in pytest
@GiordanoNesci
Update disturbance_calculations.py
ed4828f 
Fixed version of the aero disturbances (there was a j instead of an i in a for loop)
@GiordanoNesci GiordanoNesci added tests Anything related to the tests feature implementing a new feature physical-model All things involving some physical models labels Jan 31, 2024
@GiordanoNesci GiordanoNesci self-assigned this Jan 31, 2024
@GiordanoNesci GiordanoNesci linked an issue Jan 31, 2024 that may be closed by this pull request
Aerodynamic disturbances in Attitude Model #197
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GiordanoNesci commented Jan 31, 2024 •
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The model is almost ready to merge, but there are some minor things to fix:

  • Gas temperature and densities shall be moved to be properties of the central body, or inputs
  • The temperature of the spacecraft could be retrieved with the thermal model when it is used in the simulation

I do not know if there are any steps missing to make it implementable in the attitude model (e.g. if there is the need to get the mesh from the geometric model, to the attitude model, to the disturbance functions).

@GabrieleMeoni GabrieleMeoni merged commit 07d215b into student Feb 1, 2024
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@GabrieleMeoni GabrieleMeoni deleted the aerodynamic-disturbances branch February 1, 2024 13:18
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Aerodynamic disturbances in Attitude Model
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