peddie / attsim

Attitude dynamics simulation

attsim

attsim is a super basic rigid-body attitude dynamics simulator, using C and GSL.

Installation

Install the GNU Scientific Library and the BLAS and ATLAS packages for linear algebra

sudo apt-get install libgsl0-dev libatlas3gf-base libblas3gf libatlas-dev libblas-dev libatlas-base-dev

Install GNUPlot to generate nice PDF plots

sudo apt-get install gnuplot-x11

Clone this repository

git clone git://github.com/peddie/attsim.git
cd attsim

Clone and build Greg Horn's mathlib library for spatial rotations

git clone git://github.com/ghorn/mathlib.git
pushd mathlib && make && popd

Build the simulator

make

Installation on OS X

Install standard OSX buildtools if necessary: https://github.com/kennethreitz/osx-gcc-installer/blob/master/README.rst Download and install a newer gcc from http://hpc.sourceforge.net/

export CC=/usr/local/bin/gcc

Download GSL source: ftp://ftp.gnu.org/gnu/gsl/ and

./configure && make && sudo make install

sudo port install gnuplot

Now follow the instructions above starting with "Clone this repository". When it comes time to build the simulator:

make -f Makefile.mac

Run

./sim <seconds>

Analyze

gnuplot results.plot
<pdf viewer> *.pdf

Extend

emacs dynamics.c
<hack>
make && ./sim 222 && gnuplot results.plot

Features

• Simulates attitude dynamics of a body subjected to arbitrary body-frame or inertial-frame torques.

• Currently allows for feedback control via measurement gyros and magnetometer and using magnetic torquers

• Basic aerodynamics model

• Fast (approximately 7000-10000 times realtime)

Bugs

• Not sure yet whether it does torque-free precession correctly.

• Not sure yet whether the bdot control is reasonable (just made some stuff up).

If you find anything please let us know!

Coming Soon

• OpenGL output!

• Unit tests!