2018-08-10: Intern Andrew Puetz Continues his Quadcopter Research in the Ai

Along with all of the other interns who have joined us for the summer, Andrew Puetz (pronounced "pits") has also dedicated many weeks to the Autonomy Incubator; however, this was not his first year spending time with us.  Last summer, Andrew was apart of the 2017 NASA Langley Academy, and his team had several visits to the Ai to do some flight tests.  His work with UAVs introduced him to research work with aeronautic flying.

Despite the fact that Andrew has his Bachelor's degree in Mechanical Engineering from South Dakota State University, he has "always had the goal of doing things with aerospace," he explained to me.  "I've always been interested in [it].  I was a Buzz Lightyear fan and a Star Wars nerd as a kid, so I guess that's what we can blame it all on."

He essentially split his time between two main projects.  He came back to NASA in February to begin his first project with the Vehicle Analysis Branch (VAB), where he was working on an autonomous quadcopter project.  This research, though, was still taking place in the Ai building.

Andrew and Zac O'Gull are not only working on their quadcopter projects
together, but they're also in matching outfits!

The main objective was to serve as an affordable test bed for control scheme testing that could contribute to the Space Launch System (SLS) control scheme in the future.  They aim to eventually balance a completely unimpeded inverted pendulum (IP) on top of itself.

"The IP is a naturally unstable body, so it'll fall if something isn't holding it.  That's the same thing as the SLS.  If we're not controlling it, it'll just spiral out of control, which is where the thrusters at the bottom of it come in."  The quadcopter they are working with is very similar, as it has four motors around it, so it is able to balance itself like how the SLS would.  This allowed them to model the dynamic body of the SLS.

With all of this in mind, they were able to accomplish research with an unstable hanging mass below the quadcopter.  This hanging mass serves as a model for the sloshing action by the fuel tank that would present a problem to the SLS.  "Sometimes during launch, a dynamic body, like the SLS, may experience where the fuel gets to be a rhythmic slosh back and forth, and that can make the SLS's body spiral out of control because the controller isn't able to dampen it down and get it under control."


They attached a hanging mass below the quadcopter,
which they call MamaBird.

They tested their controller with an Augmented Adaptive Controller (AAC), which is an additional level of control.  Andrew explained how the AAC "is able to do things outside the normal design envelope of a controller, so it will notice 'ah, we're really getting out of balance for the stability margin, things are really going bad,' and kick in the AAC and bring it back under control."  They tested it in their control scheme with the disturbed hanging mass, so the quadcopter was able to bring it under control and "dampen it back down," so it wasn't throwing it out of balance again.

All of this work with the VAB technically is not part of the Ai; however, he was able to do just about all of the research for this project in the Ai building because of the great flight area.  Along with this, though, he also has just finished up an internship with the Ai, where he was working on his second project, but he has come back to continue working on it.

Andrew Puetz soldering.

For this Ai specific project, he is working with a small hovercraft testbed to support swarm algorithm research in the future.  His specific part of this began with heavy research on other hovercraft projects from the past.  They were all of the same size, typically the RC-sized small control vehicles, that used control schemes that somebody built on their own using either MATLAB^TM or a coding language.  Once he became more familiar with it, he then went on to built a crude controller in Simulink^TM with the idea that "maybe this summer I'd get a chance to put it onto a flight controller and try it out on a small hovercraft vehicle," and he made the first few steps.  Matt Vaughan, one of the AMA team members at the Ai, had 3D printed and built the body, and the propeller motors were scavenged off of a small quadcopter.

They call this quadcopter PapaBird.

"The idea is that there's all these people around the world with these small little quadcopters, and when the frames break, they take the thrusters off and 3D print the hovercraft body and they then have another vehicle that they can play with."

"So, basically its just reduce, reuse, recycle, right? Just in robot form!" I asked him quite proudly.

"Yes! Leave no part behind, that's a good way to put it," Andrew responded, obviously just as proud of my discovery.

He has not actually been able to try it out yet, but he did get to work with Sparky 2.0, a flight control board.  Sparky has similar characteristics and abilities to Pixhawk, its just a smaller and lighter board in comparison.  He learned how to put custom firmware onto the Sparky in order to see if it was a viable candidate for a flight controller for the hovercraft swarms of the future.

Andrew's internship technically wrapped up at the beginning of August, but after sifting through many different options for what to do next, he decided to come back.  He is still considering pursuing a Mechanical Engineering Master's degree at SDSU, but for now he has chosen to continue some research at NASA Langley through the fall.  He has many great opportunities ahead of him, and we are all thrilled to have him as a part of the Ai!