demo_motion_dynamics

Dynamic model for space station motion

This repo contains motion dynamics of the space station, specifically attitude and orbital dynamics. This will be a part of physics model for the Space Station.

For reference, these will be the external forces and torque considered while designing the complete motion dynamics of the space station:

Torque considered:

• Gravity Gradient
• Magnetic Torque
• Aerodynamic Torque
• Solar Radiation Pressure Torque
• Added gaussian noise

Force considered:

• Atmospheric Drag
• Solar radiation pressure
• Micro-Gravity
• Thrusts*
• Added gaussian noise

Objectives

Develop mathematical models of the space station's translational dynamics, accounting for external forces and environmental factors.

Build and Run

colcon build
cd build/demo_motion_dynamics
./main

# To vusulaise the dynamics
python scripts/vis_data.py

Without tangential velocity

Here it can be seen as soon as ISS loses it's tangential orbital velocity, it fell down to the Earth surface

With tangential velocity

More details regarding equations:

Resources and Equations

Consideration

• Considered a static inertial earth frame
• Considered a constant atmospheric model that don't change dynamically and have constant pressure and density
• All the forces and dynamics are modelled wrt to inertial frame and output is in cartesian coordinate system

TODO:

• Add more perturbation like solar radiation pressure, gaussian-noise, etc
• Shift to ROS2 and visualise the output live as the solver solves the equations
• Consider a rotational earth frame
• Add polar coordinate system for more observability
• Add a controller to adjust the orbital altitude once thrusters and enginers have been implemented
• Merge attitude dynamics