Mathematical models for an RCS system
C Matlab C++ Makefile Python
Switch branches/tags
Nothing to show
Clone or download
Latest commit c152eb6 May 6, 2018



We want active stabilization for LV3, but wish to escape the vexxing dynamic pressure limitations of the present aerodyamic canard based roll-control system used on LV2.3.

The concept:

  • Cold-gas rocket propulsion
  • 8 N thrust (roll), 11 N (pitch x, y)
  • Nitrogen tank at 4500 psi
  • 8x 3D-printed bell nozzles
  • PWM throttling
  • "Robust control"

Rao bells (e.g. nearly ideal nozzles) are hard to machine c.f. conical nozzles, but easy to 3D print. This also enables “plug & play” optimal expansion ratios for any trajectory. Here is the basic workflow:

  • Determine flight envelope from simulation (for instance, using OpenRocket)
  • Run nozzle_sizing.m script to determine nozzle design parameters
  • Plug expansion ratio into parametric solid model and export .stl
  • Print nozzles, install in carrier ring
  • ???
  • Fly!

This repo includes mathematical models, matlab and python controller scripts, eagle files for a custom MOSFET relay board, solenoid PWD test data for transfer functions, system test data and bode analysis, and the Solidworks CAD assembly for the LV3 Reaction Control System.

Suplimentary Links

Link to AIAA SPACE 2015 presentation slides

Link to AIAA SPACE 2015 conference proceedings paper