FEAT: new actuator class for roll, throttle, and thrust vector control

[zuorenchen]

Pull request type

• Code changes (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

• In ENH: Add Thrust Vector Control (TVC) #154, TVC feature is requested.
• Only air_brake is implemented as a controller

New behavior

• A new Actuator base class is added.

  • This class follows the implementation of air_brake
  • The actuator range can be clamped to limit
  • The actuator will be saturated to the rate limit (if the actuator demand_rate (a.k.a. sampling_rate) is discrete)
  • The actuator dynamics is modelled as a 1st-order low pass IIR filter (if the actuator demand_rate (a.k.a. sampling_rate) is discrete)

• Inheriting the Actuator base class are

  • throttle: an actuator that applies a throttle gain value on top of motor thrust.
  • roll: an actuator that applies a magic / hand-of-god roll torque on the rocket
  • thrust vector: actuators that gimbal the motor thrust vector on x and y axis

• New files:

  • actuator classes in new /actuator folder
  • prints for actuators
  • test_actuator (generated by copilot)
  • example applied on halcyon_flight_sim

• Modified files:

  • rocket.py: implement add_actuator methods
  • flight.py: apply actuators on the ODEs

known issue

• Throttling doesn't change the propellant mass flow. It is essentially throttling the ISP of motor.

Breaking change

• Yes
• No

Additional information

co-authored-by: RickyRicato rickywang44@gmail.com @chichunwang

[zuorenchen]

TODO:

• Docs
• Support rate_limit and time_constant in continuous controller ENH: Discrete and Continuous Controllers #946
• Refactor air_brakes with Actuator class
• Interact with multiple Actuator in a single controller
• Implement in 3-DoF sim

@Gui-FernandesBR @giovaniceotto do you want this in a continuous improvement approach (leave the TODOs in future PRs), or complete all TODOs in one PR?

Feel free to send PRs to branch: /enh/actuator-merge-rocketpy in fork: ARRC-Rocket/ActiveRocketPy/ if you want to contribute more on this topic.

[codecov]

Codecov Report

❌ Patch coverage is 82.28346% with 45 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.13%. Comparing base (9cf3dd4) to head (d6787a8).
⚠️ Report is 74 commits behind head on develop.

Files with missing lines	Patch %	Lines
rocketpy/rocket/rocket.py	18.18%	27 Missing ⚠️
rocketpy/simulation/flight.py	54.83%	14 Missing ⚠️
rocketpy/prints/roll_actuator_prints.py	92.85%	1 Missing ⚠️
rocketpy/prints/throttle_actuator_prints.py	92.85%	1 Missing ⚠️
rocketpy/prints/thrust_vector_actuator_prints.py	92.85%	1 Missing ⚠️
rocketpy/rocket/actuator/actuator.py	97.87%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #965      +/-   ##
===========================================
+ Coverage    80.27%   81.13%   +0.86%     
===========================================
  Files          104      121      +17     
  Lines        12769    14806    +2037     
===========================================
+ Hits         10250    12013    +1763     
- Misses        2519     2793     +274     

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[MateusStano]

Hello @zuorenchen! These are great enhancements to the library!

We are currently working in a restructure of the Flight-Controllers code so that we can make controlled simulations more robust and the related code more scalable.

Your throttle and TVC models are in particular really good for us.

We will soon make a draft PR of the Flight-Controllers restructure in another branch, and we are looking into merging the changes you made here into this new refactor. This might take a few weeks but soon we will get there! Just letting you know