danielkelshaw / fds

Flight Dynamics Simulator

Hello! I am currently a PhD student @ImperialCollege. My research lies at the intersection of machine learning, physics, and differential geometry. The goal of this research is to leverage reduced-order models for high-dimensional, complex physical phenomena - utilising tools from differential geometry and physics to operate directly on low-dimensional manifolds.

Previously, I worked as a machine learning research intern @NasaJPL, @ESA, @MindFoundry, @Dyson, and @BAESystems.

fds's Issues

Add time to d/state.csv

At the moment, only the time_step is outputted, it would be useful to have the corresponding time as well so that useful plots can be made in post-processing.

Add Simulation Constants

In order to run the simulation there are a number of constants which should be defined first:

• tsim
• time_step / dt
• logging_interval

Among others...

Implement UAVClass::write_state()

At the moment there is no way to write the results to a file - this can be implemented through the UAVClass::write_state() method. This should take the state information and write it to a tabulated file, with each row representing a timestep.

Update README

Update the README.md with the project requirements, namely:

• Eigen
• nlohmann/json.hpp
• boost

Give instructions on how to compile using make.

Add Basic makefile

Add a basic makefile for ease of compilation, should include:

• make
• make clean

Provide CLI

It would be nice if the code were able to parse inputs from the command line to show which inputs to use for the analysis - this could prove useful later on when many simulations are needed. It would be faster to make new config files (and keep them for later analysis) than continually overwrite it.

Alter Gust Parameter File

At the moment the parameters for the gust model are held in the parameters.json file:

https://github.com/Design4Demise/FDS/blob/f7663586dd42ab562f63b6a7fe3643e2d83a2753/fds/src/wind.cpp#L22-L40

When using a Gust model (e.g: DrydenGustModel) this should use the gust intensity. The parameter file should be changed to reflect this and then the parameters can be read into gustPtr->sigma_u etc...

Retab Files

At the moment there is a mix of tabs/spaces - retab to make sure everything is aligned

Store Derivative Information in UAVClass

At the moment the state is updated directly and the derivative vector is not stored. This could prove useful at some point so should be stored within the UAVClass.

Implement Thrust Model

At the moment the Dynamics model only represents a simple, unpowered glider. A thrust model reflective of the chosen propulsion system should be employed so that dynamics over a prolonged period can be analysed.

Implement DynamicsClass::calc_forces_moments()

Implement DynamicsClass::calc_forces_moments() method to allow for calculation of the state derivatives.

Implement Dryden Gust Model

Relies on #26

Implement the Dryden Gust Model using Transfer Functions - this is a popular gust model used by the DoD

Segregate Propulsion Parameters into PropulsionClass

At the moment UAVClass holds all of the parameters for the propulsion system as they are defined in the same parameters.json file. Really, they should be held within the PropulsionClass - reducing the dependancy of the classes on each other.

Implement Wind Model

In order to simulate the effects of wind / gusts a wind model must be implemented, this can be a standalone class; WindClass.

The DynamicsClass::calc_forces_moments() will need to incorporate this in order to update the dynamics model.

Provide Gradient-Based Trim-State Optimisation

At the moment there is no trim-state initialisation. This can be implemented through a simple gradient-based optimisation approach with a few imposed constraints to minimise a cost function.

Implement DynamicsClass::calc_derivatives()

Implement the DynamicsClass::calc_derivatives(Eigen::Matrix<double, 13, 1> in_state) method.

Waiting on: #9

Write main.cpp

Everything is now in place to run the simulation - I just need to write the code in main.cpp which brings everything together.

Resolution of this issue marks completion of a basic gliding flight dynamics simulator.

Add Control Surfaces

At the moment the Dynamics model just represents a simple glider with no control surfaces. It should be simple enough to add additional forces / moments generated from the control surfaces by accounting for the corresponding aerodynamic derivatives.

Implement Generic Transfer Function Class

Provide an implementation of a transfer function class for the canonical form - this will prove useful in #32

Although the case is set for the gust model (#32) it would be nice to have a generalisable case if/when we need further transfer functions.

Initialise Repository Structure

Setup basic structure for future development.

Acceleration Calculation Bug

There is currently an issue with the acceleration calculations - these are way too big and change direction in an odd fashion - this is having an odd effect on the simulation.

Add Rotation Utilities

Add various utilities for rotation:

• Euler2Quaternion
• Quaternion2Euler
• Euler2Rotation
• Quaternion2Rotation

Provide Dynamics Class

Provide a Dynamics class which is instantiated with a given UAV.

Set a dynamicsPtr in the UAV instance to point to the Dynamics object created - this will link the two classes.

Add boost/filesystem Utilities

In order to store the results from the simulation it would be good to create a Results folder which can hold the generated files. This can be managed by the boost library.

Provide UAV Class

Provide a UAV class for reading / holding / writing parameters concerning the simulated UAV system.

• State of the Aircraft.
• Read parameters from file.
• Write state to file.

Implement Error Handling for Crash

At the moment there is not collision detection with the ground - this means that the Results/state.csv files sometimes look odd as they don't stop when the UAV goes below the ground plane.

Fix Propulsion Issue

At the moment the aircraft doesn't seem to get much thrust from the propulsion system - need to see if there's an issue with the code here.

Add JSON Data Parsing

Provide the ability to read information from a JSON file - this should be in the UAV class.

Provide Ability to Read Initial State from File

At the moment the simulation won't run as the initial state vector is unpopulated - this can be fixed by allowing the user to provide an initial_state.json file which will load in the relevant parameters.