Joost Hubbard

Joost Hubbard

Current MEng Aerospace Engineering student at Queen Mary University of London.

Visualizing CubeSat Dynamics: Progress on My MEng Project

2 minute read

Published:

As part of my ongoing MEng project, “Designing a Generic Digital Twin for a Cubesat”, I’ve developed an initial MATLAB-based simulation to visualize the dynamics of a CubeSat undergoing detumbling - representing significant progress in my role as the ADCS lead. This post outlines the current progress, simulation results, and the next steps to refine the model.

Current Simulation Features

The simulation focuses on visualizing the CubeSat’s motion in 3D space. While it doesn’t yet model actuators, sensors, or dynamic external torques, it provides simple control algorithms as a foundation to develop upon across the project. Here’s what the model achieves so far:

  • 3D Visualization: Simulates CubeSat orientation changes over time based on given angular velocity inputs.
  • Orientation Analysis: Plots of roll, pitch, and yaw angles to study CubeSat motion.
  • Foundational Model: A starting point for integrating actuators, sensors, and external torques.

The system runs in MATLAB following the logic outlined in the diagram below:

System Diagram

ADCSsysflow1
Figure 1: System Diagram - Outlines the system logic and data transfer between the matlab files.

Simulation Results

The current model outputs the following:

  1. Orientation Angles (Roll, Pitch, Yaw)
    The CubeSat’s orientation over time is captured in a 3D animation and plotted.

  2. Angular Velocities
    Plots display how the angular velocity components evolve as the CubeSat detumbles.

  3. Control Inputs
    While control inputs are placeholders for now, they will be part of the actuator integration in future iterations.

Below are output plots when running the simulation:

Orientation Angles Plot

OrientationPlot
Figure 2: Orientation Angles Plot.

Angular Velocities Plot

Angular Velocities Plot
Figure 3: Angular Velocities Plot.

Control Inputs Plot

Control Inputs Plot
Figure 4: Control Inputs Plot.

Video Demonstration

To make the simulation more accessible, I’ve created a video showcasing the 3D visualization of the CubeSat’s passive detumbling motion:

Figure 5: Video of detumbling motion.

Next Steps

  1. Integrating Actuators: Model actuators to actively control the CubeSat’s motion.
  2. Adding Sensors: Simulate sensor data for real-time orientation and angular velocity estimation.
  3. External Torques: Incorporate dynamic external torques, such as gravity gradient and aerodynamic drag.
  4. Testing Control Algorithms: Implement and validate more advanced control laws for alternate control modes.

Conclusion

This is an exciting step in my MEng project, and I’m looking forward to refining the model further. The addition of actuators, sensors, and external torques will significantly enhance the simulation’s accuracy and applicability to real-world scenarios.

If you’re interested in learning more or collaborating, feel free to contact me at j.hubbard@se21.qmul.ac.uk. Stay tuned for updates! 🚀

Simplifying Jupyter Books Creation: A Windows Users Guide

1 minute read

Published:

Over the summer in addition to personal research, I have been working as an active contributor to both a spacecraft dynamics textbook and a computational dynamics textbook created using Jupyter Books to complement modules taught at the Queen Mary University of London. As our project continues to evolve, we’ve recognized the need for a streamlined process to build and preview Jupyter Books locally on Windows machines. This capability is crucial for our team members to review their contributions before submitting pull requests on GitHub. To address this need, I’ve developed a comprehensive tutorial that walks through the process step-by-step.

Update on progress; impulse vs non-impulse simulation

1 minute read

Published:

Building upon my prior work using the Clohessy-Wiltshire equations to create a trajectory simulation for a target and chaser satellite (as discussed in blog post 2), the next step was to utilize and develop this code to compare the effects of impulsive and non-impulsive manoeuvres modelling. This somewhat spiralled into me writing a short paper to summarise my work (still in progress but attached to this post nonetheless).

What if? (Its a book not a question)

less than 1 minute read

Published:

On and off over the past few months I’ve been reading ‘What if?’ by Randall Monroe. Since the book is so popular it feels almost pointless to explain it, but I will just in case. The premise centres around providing logical, scientific solutions to absurd questions, think things like: ‘What would happen if you tried to hit a baseball pitched at 90% the speed of light?’. These topics are covered in a way to keep the reader engaged, using humour while still actually answering the question somewhat accurately.

Clohessy–Wiltshire Simulation

1 minute read

Published:

The initial goal was to create a code snippet that to simulate the collisions between two objects in LEO, making use of the hill clohessy equations for relative motion. This is to be used to simulate the collision between the robotic arms and any debris it may want to capture. In addition, it could be used to estimate the required force needed to push the debris out of orbit. A final use could be to simulate rendezvous with the target.