scenarioAttitudePointingPy

Overview

This script showcases how to create a Python Xmera module.

Demonstrates how to stabilize the attitude tumble without translational motion. This script sets up a 6-DOF spacecraft, but without specifying any orbital motion. Thus, this scenario simulates the spacecraft translating in deep space. The scenario is a version of scenarioAttitudePointing where the mrpPD feedback control module is replaced with an equivalent python based BSK MRP PD control module.

The script is found in the folder xmera/examples and executed by using:

python3 scenarioAttitudePointingPy.py

As with scenarioAttitudePointing, when the simulation completes 3 plots are shown for the MRP attitude history, the rate tracking errors, as well as the control torque vector.

The MRP PD control module in this script is a class called PythonMRPPD. Note that it has the same setup and update routines as are found with a C/C++ Xmera module. These Python modules behave exactly as other C++/C modules: they respect their given priority and can run before C++/C modules.

Similarly to C++ modules, creating an instance of the Python module is done with the code:

pyMRPPD = PythonMRPPD()
pyMRPPD.modelTag = "pyMRP_PD"
pyMRPPD.K = 3.5
pyMRPPD.P = 30.0
scSim.AddModelToTask(simTaskName, pyMRPPD)

Illustration of Simulation Results

show_plots = True

Here a small initial tumble is simulated. The resulting attitude and control torque histories are shown below. The spacecraft quickly regains a stable orientation without tumbling past 180 degrees.