A reference implementation of a quaternion-based spacecraft attitude controller using Linear Quadratic Regulator (LQR) control theory. The controller is designed for precision pointing using reaction wheels, with support for both 3-wheel orthogonal and 4-wheel tetrahedral configurations. Additional accuator configurations are possible with minimal modification (ex: RCS thrusters).
- Optimal LQR control using reduced-state quaternion error formulation
- Configurable for different spacecraft inertia properties and actuator layouts
- Rigorous stability analysis and performance metrics
- Interactive simulation with detailed visualization of system response
- Comprehensive test suite validating performance across various scenarios
Install the required dependencies:
pip install -r requirements.txtRun the interactive simulation:
python simulation.pyTo run a specific test scenario directly:
python simulation.py <test_number>The visualization tool provides real-time plots of:
- Attitude quaternions and Euler angles
- Angular rates
- Control torques
- Pointing error
- Phase portraits
- System energy
The controller uses a reduced-state formulation that converts quaternion error to an Euler angle representation for linear control. The system is modeled as:
dx/dt = Ax + Bu
Where:
- x = [attitude_error (3); w_error (3)]
- A captures the linearized rigid body dynamics
- B represents the actuator influence matrix
You can find more complete documentation in attitude_controller.py