hpr-sim

NOTE: This project is still in development and not yet in a release state

• Overview
• Usage
• Benchmarking
• External Libraries
• Directory Index
• FAQ

Overview

The goal of this project is to build a robust, extensible flight simulation package for high power rocketry, with open-source dependencies.

Key features:

• 6-DOF kinematic model
• Monte Carlo functionality
• Parallel processing (multicore) to support large test cases
• High fidelity environment modeling: atmospheric, geodetic, wind turbulence, etc.
• Comptability w/ RASP (*.eng) engine files (http://www.thrustcurve.org/raspformat.shtml)
• Flight data visualization & plain-text export
• Simple input API for additional scripting & extensions

Current efforts are focused on builds for these platforms:

Platform	Runner OS	Test(s)
Linux (x86_64)	ubuntu-22.04
Windows 10 (x86_64)	windows-2022
Mac (arm64)	n/a	To be supported in the future

Usage

To build the simulation:

$ cd build
$ cmake --preset ubuntu ../ # Configs available for "ubuntu" or "windows"
$ cmake --build . -j # Use all available cores

To run the simulation in CLI mode (headless):

$ ./hpr-sim.py -i input/unit_test.yml -o output

To launch the GUI, simply call the program with no arguments:

$ ./hpy-sim.py

CLI help:

$ ./hpr-sim.py -h # Trigger help message

usage: hpr-sim.py [-h] [-i INPUT] [-o OUTPUT]

options:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        Input file; if none given, user interface will launch
  -o OUTPUT, --output OUTPUT
                        Output directory; if none given, assumed to be output/

Benchmarking

The unit test used for benchmarking simulates the flight of a 4 in Patriot replica kit (example: ) with a XXX motor:

Platform	Build Type	Processors	Number of Sims	Run Time	Unit Run Time
Ubuntu 22.04	Debug	8	1,000	XXX s	XXX s
	Release	8	1,000	XXX s	XXX s
Windows 10	Debug	8	1,000	XXX s	XXX s
	Release	8	1,000	XXX s	XXX s

External Libraries

Managed through git submodule; included with repository by default:

	Version	Purpose	Link
eigen	3.4.0	Linear algebra utilities	https://gitlab.com/libeigen/eigen
fmt	11.0.2	String formatting & output	https://github.com/fmtlib/fmt
gsl	2.7.0	Scientific/numerical utilties	https://github.com/ampl/gsl
pybind11	2.12.0	Python/C++ bindings	https://github.com/pybind/pybind11

Directory Index

• build - CMake build directory
  • pyinstaller - PyInstaller build output
• doc - Manual & supporting documentation
• input - Simulation & model input
• lib - External C/C++ libraries (submodules)
• output - Simulation data output
• src - Python & C++ source
  • exec - Simulation control & execution
  • gui - Graphical user interface via PyQt
  • model - Rocket & environment models
  • postproc - Simulation post-processing: data reduction, plots, etc.
  • preproc - Simulation pre-processing: input validation & model setup
  • test - Model unit test scripts
  • util - General utilities
• tools - Developer tools & scripts

FAQ

Why is there a mix of Python & C++ in this project?

• The intent is to lean on the respective strengths of python and C++:
  • Python is used for pre-processing, post-processing, and data visualization
  • C++ constitutes the bulk of the numerical routines
• pybind11 is used as a binding library to wrap the C++ routines and build them as (importable) python modules

Why not use OpenRocket ?

• Use both! They are distinct tools with different features & use-cases:
  • OpenRocket can be a used as a first-step in designing or simulating a model rocket
    • CAD-like user interface with part picker and motor database
  • hpr-sim provides advanced simulation capabilities to dig deeper into a rocket's performance and gather analysis for launch safety & recovery
    • Monte Carlo capability, dispersion analysis, parameter optimization