ENH: Implementing 3-dof-simulation #745

aZira371 · 2024-12-03T23:26:18Z

Pull request type

Code changes (bugfix, features)

Checklist

Tests for the changes have been added (if needed)
Docs have been reviewed and added / updated
Lint (black rocketpy/ tests/) has passed locally
All tests (pytest tests -m slow --runslow) have passed locally
CHANGELOG.md has been updated (if relevant)

Current behavior

for issue #655

New behavior

(DRAFT)
ENH: adds 3 DOF simulation capability to rocketpy.Flight.

*ENH: added "u_dot_3dof" for "solid_propulsion"
mode

*ENH: adding "u_dot_generalized_3dof" for "standard" mode (still incomplete)

*ENH: new parameter "simulation_mode" for swtiching between 3 dof and 6 dof

*ENH: updated conditions for "__init_equations_of_motion"

*ENH: 2 new example files have been created to test 3 dof model "test_bella_lui_flight_sim" and "test_camoes_flight_sim"

Breaking change

No

Additional information

This is a draft pull request!
Equations of motion have been modified in such a way that values related to various rotational dofs is set to zero.

ENH: adds 3 DOF simulation capability to rocketpy.Flight. *ENH: added "u_dot_3dof" for "solid_propulsion" mode *ENH: adding "u_dot_generalized_3dof" for "standard" mode (still incomplete) *ENH: new parameter "simulation_mode" for swtiching between 3 dof and 6 dof *ENH: updated conditions for "__init_equations_of_motion" *ENH: 2 new example files have been created to test 3 dof model "test_bella_lui_flight_sim" and "test_camoes_flight_sim"

Lucas-Prates · 2024-12-04T12:56:48Z

Thank you for your interest in implementing 3-DOF in RocketPy, @aZira371 . I will try to take a better look into it, but I notice one thing already: use 6 DOF as the default input for simulation_mode for two reasons:

most people will use 6 DOF;
changing it to 3 DOF introduces breaking changes, and we really want to avoid that. You can see that a breaking change occurred because the tests failed.

ENH: adds 3 DOF simulation capability to rocketpy.Flight. *ENH: added "u_dot_3dof" for "solid_propulsion" mode *ENH: added "u_dot_generalized_3dof" for "standard" mode *ENH: new parameter "simulation_mode" for swtiching between 3 dof and 6 dof *ENH: updated conditions for "__init_equations_of_motion"

ENH: fixed standard 3 dof *MNT: Cleaned up the "u_dot_3dof" and "u_dot_generalized_3_dof" *MNT: Corrected Typos in "simulation_mode" description *ENH: "u_dot_generalized_3_dof" fixed and tested on examples.

Gui-FernandesBR · 2025-02-08T16:12:53Z

Git rebase develop
Revert changes in the jupyter notebook
Create PointMassMotor
Create BaseRocket
Create PointMassRocket
Modify Rocket class where it's needed (here other people can help you, including Gui)
Modify the Flight class again, if needed (delete u_dot_3dof)
Include integration tests (here you can ask for help)
Format and lint the code (see the Makefile)

…into enh/3-dof-simulation

…otor ENH: added "BaseRocket" and "PointMassRocket" to rocket class ENH: added "PointMassMotor" to motor class with various input cases of thrust values

codecov · 2025-02-25T20:06:34Z

Codecov Report

Attention: Patch coverage is 25.00000% with 159 lines in your changes missing coverage. Please review.

Project coverage is 78.73%. Comparing base (4a41f7a) to head (0673076).
Report is 12 commits behind head on develop.

Files with missing lines	Patch %	Lines
rocketpy/simulation/flight.py	10.00%	108 Missing ⚠️
rocketpy/rocket/rocket.py	24.32%	28 Missing ⚠️
rocketpy/motors/PointMassMotor.py	56.60%	23 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #745      +/-   ##
===========================================
- Coverage    79.09%   78.73%   -0.37%     
===========================================
  Files           96       98       +2     
  Lines        11583    12118     +535     
===========================================
+ Hits          9162     9541     +379     
- Misses        2421     2577     +156

☔ View full report in Codecov by Sentry.
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…e tests ENH: Added a new jupyter notebook for a simplified 3 DOF example MNT: PointMassMotor intialization error fixed MNT: PointMassRocket properties enhanced based on the example runs

MNT: Cleaned up the flight class u_dot_generalized_3dof TODO: Add info for 3 dof cases and fix some new issues when parachute is added.

…cketPy into enh/3-dof-simulation

rocketpy/motors/PointMassMotor.py

phmbressan · 2025-05-16T19:48:09Z

rocketpy/simulation/flight.py

+        mach = free_stream_speed / speed_of_sound
+
+        # Drag computation
+        if t < self.rocket.motor.burn_out_time:


Shouldn't the time be in the interval of burn start and burn out? Do you know @MateusStano ?

It should do whatever the normal udot does. I think we changed this recently and this branch is not updated though

@aZira371 I would say you should merge develop into this branch and check if this u_dot is updated with the newer standard one

rocketpy/motors/PointMassMotor.py

phmbressan · 2025-05-16T19:57:12Z

rocketpy/rocket/rocket.py

+        motor_mass_func = (
+            self.motor.total_mass if hasattr(self.motor.total_mass, "get_value_opt")
+            else Function(lambda t: self.motor.total_mass)
+        )


This check seems to be in place in order to convert to a Function the self.motor.total_mass if it is not one. However, the attribute from the motor class is annotated with funcify, so it will always be a Function.

phmbressan · 2025-05-16T20:00:35Z

rocketpy/motors/PointMassMotor.py

+    @funcify_method("Time (s)", "Acceleration (m/s^2)")
+    def total_mass(self):
+        """Returns the constant total mass of the point mass motor."""
+        return self.dry_mass


To me it makes sense to evaluate the mass_flow_rate of a point mass motor if the user inputs a thrust curve. The schema would be quite similar to what is already done in the Motor parent class (e.g. Motor.total_mass_flow_rate). Let me know what you think about it.

Yes I was confused about what to implement for mass flow rate. Like different types of motors have different ways to calculate this. When it comes to point mass motor the problem I faced was that the input can be any kind of data irrespective of propellant nature. Thus could not understand which equations to implement for mass flow rate.

rocketpy/environment/environment.py

rocketpy/motors/PointMassMotor.py

MateusStano · 2025-05-23T18:29:35Z

rocketpy/rocket/rocket.py

+class BaseRocket:
+    """Base class for a rocket model with minimal attributes and methods."""
+    def __init__(self, mass):
+        self.mass = mass
+        self.motor = None
+    def add_motor(self, motor):
+        self.motor = motor
+        self.evaluate_total_mass()
+    def evaluate_total_mass(self):
+        if self.motor:
+            return self.mass + self.motor.total_mass
+        return self.mass
+
+


This class seems useless right now. You can just remove it

MateusStano · 2025-05-23T18:43:53Z

rocketpy/rocket/rocket.py

+class PointMassRocket(BaseRocket):
+    """Rocket modeled as a point mass for 3-DOF simulations."""  


Maybe having this inherit from the Rocket class will make the implementation easier. Then all_info and plots and prints will already be defined

MateusStano · 2025-05-23T18:47:24Z

rocketpy/simulation/flight.py

+        elif self.equations_of_motion == "solid_propulsion" and self.simulation_mode == '3 DOF':
+            # NOTE: The u_dot is faster, but only works for solid propulsion
+            self.u_dot_generalized = self.u_dot_3dof
+        elif self.simulation_mode == '3 DOF':
+            # NOTE: The u_dot is faster, but only works for solid propulsion
+            self.u_dot_generalized = self.u_dot_generalized_3dof


Can the PointMassRocket run with 6dof? If not then I think we should just check if the rocket is a PointMassRocket and set the equations of motion to 3dof

rocketpy/simulation/flight.py

MateusStano · 2025-05-23T18:52:20Z

rocketpy/simulation/flight.py

+        mach = free_stream_speed / speed_of_sound
+
+        # Drag computation
+        if t < self.rocket.motor.burn_out_time:


It should do whatever the normal udot does. I think we changed this recently and this branch is not updated though

@aZira371 I would say you should merge develop into this branch and check if this u_dot is updated with the newer standard one

Develop

-MNT: removing the parameters not needed for point mass kind of motors -MNT: removing extra parameter thrust_curve -MNT: fixing problems with motor class inheritance

-ENH: removed 'BaseRocket' class now 'PointMassRocket' inherits directly from 'Rocket' class

-MNT: fixed calculations of mass flow rate and exhaust velocity -MNT: adjusted propellant initial mass setter error by allocating the input initial mass to the property

MNT: renaming pointmassmotor.py -MNT:snake case renaming

-MNT: incorporating latest structural changes made to PointMassMotor and PointMassRocket

-MNT: cleaned up PointMassRocket rocket.py for linters. -ENH: including PointMassMotor in motors and rocketpy __init__.py -MNT: adopting to structural changes in 3dof on the 3_DOF_TRIAL.ipynb -MNT: including pointmassmotor in settings.json as a spell word

Copilot

Pull Request Overview

Adds 3-DOF simulation support alongside the existing 6-DOF model, introduces a simulation_mode switch in Flight, and defines a new PointMassRocket plus corresponding PointMassMotor for simplified dynamics.

Added simulation_mode parameter to Flight and wired up u_dot_generalized_3dof
Created PointMassRocket class and PointMassMotor implementation
Updated imports to expose new point-mass classes

Reviewed Changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
rocketpy/simulation/flight.py	Introduce `simulation_mode`, route to new 3-DOF methods
rocketpy/rocket/rocket.py	Add `PointMassRocket` with zero-inertia modeling
rocketpy/rocket/init.py	Export `PointMassRocket`
rocketpy/motors/pointmassmotor.py	Implement `PointMassMotor`
rocketpy/motors/init.py	Export `PointMassMotor`
rocketpy/init.py	Expose new point-mass classes
.vscode/settings.json	Add `pointmassmotor` to tool settings

Comments suppressed due to low confidence (4)

rocketpy/simulation/flight.py:492

The new simulation_mode argument is not documented in the __init__ docstring. Add descriptions of valid modes ('6 DOF', '3 DOF') and behavior changes.

        simulation_mode="6 DOF",

rocketpy/simulation/flight.py:1627

The new u_dot_generalized_3dof method lacks unit tests to verify its correctness. Consider adding tests for basic trajectories and mass variation in 3-DOF mode.

    def u_dot_generalized_3dof(self, t, u, post_processing=False):

rocketpy/simulation/flight.py:1201

u_dot_3dof is not defined in the Flight class, leading to an AttributeError. Either implement u_dot_3dof or update this reference to the correct 3-DOF method.

            self.u_dot_generalized = self.u_dot_3dof

rocketpy/rocket/rocket.py:2010

The __init__ body contains parameter declarations (self, radius: float = 0, ...) inside the method instead of in the signature, causing a syntax error. Move all parameters into the signature and remove these misplaced lines.

    def __init__(self, mass, radius=0.05):

Copilot · 2025-07-16T13:59:23Z

rocketpy/simulation/flight.py

@@ -1191,9 +1193,15 @@ def __init_solver_monitors(self):

    def __init_equations_of_motion(self):
        """Initialize equations of motion."""
-        if self.equations_of_motion == "solid_propulsion":
+        if self.equations_of_motion == "solid_propulsion" and self.simulation_mode == '6 DOF':


When equations_of_motion is "standard" and simulation_mode is '6 DOF', u_dot_generalized is never set. Add a catch-all or explicit branch to assign self.u_dot_generalized = self.u_dot for standard 6-DOF.

Lucas-Prates added Enhancement New feature or request, including adjustments in current codes Flight Flight Class related features labels Dec 4, 2024

Lucas-Prates linked an issue Dec 4, 2024 that may be closed by this pull request

ENH: 3-DOF simulation #655

Open

Lucas-Prates changed the title ~~DRAFT: for ENH/3-dof-simulation (See #655)~~ ENH: Implementing 3-dof-simulation Dec 4, 2024

aZira371 added 2 commits December 6, 2024 01:26

MNT: cleaned up new functions and

9b00c57

ENH: fixed standard 3 dof *MNT: Cleaned up the "u_dot_3dof" and "u_dot_generalized_3_dof" *MNT: Corrected Typos in "simulation_mode" description *ENH: "u_dot_generalized_3_dof" fixed and tested on examples.

Gui-FernandesBR force-pushed the develop branch from 2931c30 to 7864590 Compare February 8, 2025 19:00

aZira371 added 2 commits February 25, 2025 17:15

Rebase: Merge branch 'develop' of https://github.com/aZira371/RocketPy …

87e9180

…into enh/3-dof-simulation

ENH: Addition of point mass classes to rocketpy.rocket and rocketpy.m…

4524219

…otor ENH: added "BaseRocket" and "PointMassRocket" to rocket class ENH: added "PointMassMotor" to motor class with various input cases of thrust values

aZira371 and others added 6 commits April 11, 2025 20:31

ENH: PointMassMotor and PointMassRocket working as intended after som…

57b4732

…e tests ENH: Added a new jupyter notebook for a simplified 3 DOF example MNT: PointMassMotor intialization error fixed MNT: PointMassRocket properties enhanced based on the example runs

MNT: Removing unnecessary files added by mistake.

81ce869

Merge branch 'RocketPy-Team:master' into enh/3-dof-simulation

0673076

MNT: Cleaned up PointMassMotor and PointMassRocket class

47c9f2f

MNT: Cleaned up the flight class u_dot_generalized_3dof TODO: Add info for 3 dof cases and fix some new issues when parachute is added.

Merge branch 'enh/3-dof-simulation' of https://github.com/aZira371/Ro…

f6ad658

…cketPy into enh/3-dof-simulation

MNT: Cleaning up flight class and PointMassMotor class

33cb63a

aZira371 marked this pull request as ready for review May 10, 2025 17:51

aZira371 requested a review from a team as a code owner May 10, 2025 17:51

phmbressan reviewed May 16, 2025

View reviewed changes

MateusStano requested a review from Gui-FernandesBR May 16, 2025 20:54

MateusStano requested changes May 23, 2025

View reviewed changes

aZira371 and others added 6 commits June 11, 2025 01:18

Merge branch 'enh/3-dof-simulation' into develop

1d2d4dc

Merge pull request #1 from aZira371/develop

fe21271

Develop

MNT: point mass motor cleanup

b18b241

-MNT: removing the parameters not needed for point mass kind of motors -MNT: removing extra parameter thrust_curve -MNT: fixing problems with motor class inheritance

ENH: restructuring rocket class

8aa1016

-ENH: removed 'BaseRocket' class now 'PointMassRocket' inherits directly from 'Rocket' class

MNT: fixing certain calculations on point mass motor

87e7dce

-MNT: fixed calculations of mass flow rate and exhaust velocity -MNT: adjusted propellant initial mass setter error by allocating the input initial mass to the property

Rename PointMassMotor.py to pointmassmotor.py

0e4d8a4

MNT: renaming pointmassmotor.py -MNT:snake case renaming

aZira371 and others added 3 commits July 12, 2025 00:02

Merge branch 'develop' into enh/3-dof-simulation

41e94f1

MNT: updates to 3dof example

e299a30

-MNT: incorporating latest structural changes made to PointMassMotor and PointMassRocket

Gui-FernandesBR requested a review from Copilot July 16, 2025 13:58

Copilot AI reviewed Jul 16, 2025

View reviewed changes

		class PointMassRocket(BaseRocket):
		"""Rocket modeled as a point mass for 3-DOF simulations."""

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ENH: Implementing 3-dof-simulation #745

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aZira371 commented Dec 3, 2024 •

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