Background

I received a Bachelor of Engineering (Hons 1, University Medal) & Bachelor of Science (Advanced) from the University of Sydney in 2021. My majors were in Space Engineering, Physics, and Mathematics. I completed my honours thesis in vibration control as a visiting research student at Nearmap, and had previously interned at Saber Astronautics and ISAE-SUPAERO. Before that, I was a student researcher at the Sydney Institute for Astronomy (SIfA) where I developed a data-driven classification pipeline for asteroseismology.

Research Portfolio

Robust Machine Learning & Control

React to Surprises: Stable-by-Design Neural Feedback Control and the Youla-REN
In preparation (2025)
Nicholas H. Barbara, Ruigang Wang, Alexandre Megretski, Ian R. Manchester

R2DN: Scalable Parameterization of Contracting and Lipschitz Recurrent Deep Networks
Submitted to 64th IEEE Conference on Decision and Control (2025)
Nicholas H. Barbara, Ruigang Wang, Ian R. Manchester

On Robust Reinforcement Learning with Lipschitz-Bounded Policy Networks
Symposium on Systems Theory in Data and Optimization (SysDO 2024)
Nicholas H. Barbara, Ruigang Wang, Ian R. Manchester

Learning Over Contracting and Lipschitz Closed-Loops for Partially-Observed Nonlinear Systems
62nd IEEE Conference on Decision and Control (2023)
Nicholas H. Barbara, Ruigang Wang, Ian R. Manchester

Learning Over All Stabilizing Nonlinear Controllers for a Partially-Observed Linear System
IEEE Control Systems Letters (2023)
Ruigang Wang, Nicholas H. Barbara, Max Revay, Ian R. Manchester

Asteroseismology

Classifying Kepler light curves for 12 000 A and F stars using supervised feature-based machine learning
Monthly Notices of the Royal Astronomical Society (2022)
Nicholas H. Barbara, Timothy R. Bedding, Ben D. Fulcher, Simon J. Murphy, Timothy Van Reeth

Finding binaries from phase modulation of pulsating stars with Kepler – VI. Orbits for 10 new binaries with mischaracterized primaries
Monthly Notices of the Royal Astronomical Society (2020)
Simon J. Murphy, Nicholas H. Barbara, Daniel Hey, Timothy R. Bedding, Ben D. Fulcher

Gravity-mode period spacings and near-core rotation rates of 611 γ Doradus stars with Kepler
Monthly Notices of the Royal Astronomical Society (2019)
Gang Li, Timothy Van Reeth, Timothy R Bedding, Simon J Murphy, Victoria Antoci, Rhita-Maria Ouazzani, Nicholas H. Barbara

Space Systems Engineering

New GEO paradigm: Re-purposing satellite components from the GEO graveyard
Acta Astronautica (2020)
Nicholas H. Barbara, Stephanie Lizy-Destrez, Paolo Guardabasso, Didier Alary

The Recycler: an Innovative Approach to On-Orbit Servicing and Repurposing
71st International Astronautical Congress (2020)
Paolo Guardabasso, Michele Pio Savino, Calum Turner, Roberta Valeriani, Marie-Laure Vuyge, Nicholas Barbara, Stéphanie Lizy-Destrez

Related Software Projects

RobustNeuralNetworks: JAX implementations of robust neural networks developed @ ACFR
In preparation (2025)
Nicholas H. Barbara, Ruigang Wang, Ian R. Manchester

RobustNeuralNetworks.jl: a Package for Machine Learning and Data-Driven Control with Certified Robustness
Proceedings of the JuliaCon Conferences (2025) | Presented at JuliaCon 2023
Nicholas H. Barbara, Max Revay, Ruigang Wang, Jing Cheng, Ian R. Manchester

MuJoCo.jl: Julia Bindings and Visualiser for the MuJoCo Physics Engine
Presented at JuliaCon 2024
Jamie Mair, Nicholas H. Barbara

Miscellanious Projects

My research often leads me towards more theoretical flavours of science and engineering. However, my interest in developing fundamental theory stems from a desire to enable greater autonomy in real-world systems. I therefore try to get hands-on with hardware whenenever I have the time. Below are a few interesting projects that I've worked on over the years.
Learning-Based Control with the Qube Servo
January 2025

I recently implemented some of the robust neural network architectures developed in our lab at ACFR on the Qube Servo. The GIF on the left shows the Qube being controlled by a Youla-REN policy, which I trained using a custom deep RL pipeline based on the MJX physics simulator.


Youla-REN policies augment an existing stabilising controller with a recurrent equilibrium network (REN) to improve performance while preserving stability. I started by designing a classical swing-up controller, combining an energy-pumping controller with an LQR, and added an extended Kalman filter for state estimation. Putting it all together with RENs, deep RL, and domain randomisation results in the swing-up policy in the GIF.

Robotic Control with Cassie
Mar 2021 - Dec 2024

It's not every day that one has a bipedal robot on hand for a passion project. Luckily, we have a Cassie robot at the ACFR which a number of our PhD student and postdocs use for their research in in motion planning and control.


I joined the Cassie team at the start of my PhD to assist with designing, testing, and implementing locomotion and balancing policies. Along the way, I learned a lot about interfacing, robotic software engineering (ROS), and state estimation with discrete contact events. Most importantly, I had the opportunity to get hands-on with a range of interesting control architectures based on inverse kinematics and task-space inverse dynamics control.


I also got to embark on a very unnecessary but entirely enjoyable side-project to control Cassie directly from Julia via its native C/C++ interface. Very unnecessary... but a great deep-dive into low-level interfacing between programming languages, and it worked! (GIF on the left.)

Piezoelectric Vibration Control
Jul 2020 - Jan 2021

During my Bachelor's thesis, I had the opportunity to design and build a vibration control test-bed for Nearmap, an aerial imaging company based in Sydney. Over the course of six months, I: 1) built a piezoelectric cantilever beam system; 2) modelled the system analytically, with FEA, and via system identification; 3) designed active damping controllers with positive position feedback and LQG control; and 4) implemented the controllers in real-time on an STM32 microcontroller.

A Star Tracker for CubeSats
Mar 2018 - Jul 2019

One of my earliest research positions was as part of a team of students working to a develop a commercial off-the-shelf (COTS) star tracker for attitude determination on small satellites. At the time, there were very few commercial star trackers that were small yet accurate enough for CubeSats. Our goal was to develop our own, in-house instrument for deployment on University of Sydney satellites.


I worked on preliminary designs of the CROSS star tracker. CROSS has since been flown to space and deployed on board the CUAVA-2 satellite.

USYD Rocketry Team
Jul 2018 - Jun 2020

I was the lead Flight Analysis engineer for USYD Rocketry Team’s competition-winning rockets Silvereye and Firetail. My role was to process flight data, predict our rockets' trajectories and peak altitudes, and use that information to inform design decisions. I also helped to build the rockets, and was a mentor to a group of more junior students in the Flight Analysis team.


Silvereye placed 1st in the 10,000 ft COTS category at the 2019 Spaceport America Cup. Firetail placed 1st in the 30,000 ft COTS category at the 2020 Australian Universities Rocketry Competition.