ImperialCollegeLondon / ImperialCollegeLondon/sharpy

Catapult assisted takeoff - launch profile not being simulated in latest version

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Description

Unfortunately, the original script for [catapult takeoff ](https://github.com/ImperialCollegeLondon/sharpy/blob/master/scripts/optimiser/base_case/generate.py) developed in v1.1.1 no longer works in SHARPy.

Once a trajectory is generated, the dynamic simulation in SHARPy does not recognise this input, therefore the aircraft remains static at the initial condition and does not accelerate.

The `TakeoffTrajectoryController` has seen no changes since v1.1.1. In the `DynamicCoupled` solver, new routines have been added after the `controlled_state` is written by the controller, so I'm guessing something is overwriting the controlled state.

Thanks to @tpleece for raising this and trying it out in v1.1.1
### Discussed in https://github.com/ImperialCollegeLondon/sharpy/discussions/197

Originally posted by **tpleece** May 31, 2022
Hi,

I'm working an a HALE project using SHARPy and I wish to perform some dynamic coupled modelling of launch/ catapult-assisted takeoffs. I'm using the generate_hale.py file in sharpy/cases/coupled/multibody_takeoff as a reference but I can't see how the launch process is implemented in this file, it seems to go straight to free flight. Can you direct me to any documentation on the generate_dyn_file function and how to use the dynamic_forces and forced_for_vel capabilities?

Contributor guide

Open the contributing guide

Research direction

Start with scripts/optimiser/base_case/generate.py and the TakeoffTrajectoryController, then inspect the DynamicCoupled solver where controlled_state is handled. Compare the current behavior with the v1.1.1 trajectory flow and the multibody_takeoff reference. Done means the generated launch profile is recognized by the dynamic simulation and the aircraft accelerates from its initial condition.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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