Our slide presentation and systems engineering paper can be downloaded here:
After enrolling in the Electrical Computer Engineering program at The University of Alabama in January 2011, I became a member of the 2010-2011 Alabama Lunabotics team. We competed in the NASA Lunabotics Mining Competition in May 2011 and placed 4th overall, and won the team spirit award. A brief summary about lunabotics can be found below (taken straight from their pamphlet):
Mining in space for resources such as water ice, and regolith, which contains many elements in the form of metals, minerals, volatiles and other compounds, is a necessary step in space resource utilization. One of the primary goals is to extract propellants from the regolith such as oxygen and hydrogen which could then be used for in-space transportation. In addition, the space mining system can be used for various construction tasks that can benefit human and robotic exploration as well as scientific investigations based on the exposed topography. An example would be digging a long trench to allow for lunar stratigraphy observations and measurements. The same trench can then be used as a radiation shelter for equipment and human crew, with the addition of regolith shielding through appropriate regolith operations.
At the competition teams from around the world compete with their remote-controlled Lunabots (robotic excavators) in a super sized 24'x25' sandbox (filled with actual BP-1 regolith simulant) called the Lunarena to see who can collect the most "moon dirt."
Teams compete in five categories including:
- On-site mining
- Systems engineering paper
- Outreach paper
- Slide presentation
- Team spirit
Teams accumulate points toward the grand prize, the Joe Kosmo Award for Excellence. Extra points are awarded for collaboration between a majority and minority serving institutions and multidisciplinary teams.
Awards include scholarships, school plaques, individual certificates, and KSC launch invitations for the winning teams. The overall winning team of the Joe Kosmo Award for Excellence will receive a trophy and travel expenses for each team member and one faculty advisor to participate with NASA's Research and Technology Studies (RATS) next fall.
NASA's Desert RATS project is a NASA led team of research partners working together to prepare for human-robotic exploration.
The competition is sponsored by NASA's Exploration Systems Mission Directorate (ESMD) Education.
To put the task into simpler words: build a robot that could be controlled remotely and pick up, transport, and dump moon dirt.
By the time I joined the team in January most of the design phases of the robot were already completed. I mainly participated in learning more about the competition and assisting with my electrical and mechanical experience.
Our team took a modular design approach and split the robot into two main components: locomotion and regolith delivery. Here is a SolidWorks model of our base and two different regolith modules.
We named our robot the MOLE (Modular Omnidirectional Lunar Excavator). The picture above shows the locomotive 'base' with its wheels positioned for zero-turn navigation (more on that later). Our primary module is shown on the left -- a simple yet effective front end loader design. On the right is the experimental percussive digger. By actuating the shovel-like digger linearly into the regolith, deeper digging depths can be achieved.
Team members from left to right: Timo Stradinger, Justin Headley, Andrew Price, Matt Westberry, David Sandel, Stephanie Troy, Adam Melton and Faculty Advisor Dr. Ricks
We started our design, and assembly, with the locomotion platform (the base). We needed the base to be able to effectively transport any module we put on top of it around the LunArena. The arena is full of BP-1 lunar regolith simulant and is the equivalent of the finest powder you can imagine mixed with a small amount of nickel-sized gravel. The LunArena is a rectangle that is broken up into roughly three equal sections: One end, where we place our lunabot to begin the match, also hosts the collection bin that we must deposit the regolith into. The middle section contains obstacles in the form of two craters and two large rocks. The third section, or other end, is where we must dig our regolith from. Once the regolith is collected, we must transport it back across the obstacles and deposit it into the collection bin. We are allowed to do that as many times as we can within the competition time limits.
All of this navigation is very hard to complete, not only because of the time constraint, but also due to the BP-1 regolith that we are having to navigate in. One concept that we implemented to address this issue was the ability to sweep all four of the lunabot's' wheels. The easiest turning method to build would be skid-steering (like a military tank), however it also digs into the soil (or in our case regolith) every time you turn. We also opted not to use car-like steering since it has a larger turning radius and our arena is not very big. With our wheels swept into '45 mode,' or 45 degree angles, from their original position, we can spin in place while maintaining positive ground displacement. Our wheels can also be positioned 90 degrees from their starting position, essentially making the front/back the left/right sides, allowing us to drive from side to side. Here is what the wheels look like when in '45 mode.'
The sweeping of the wheels is handled by two actuators connected to the wheels by aluminum linkages. Each side has its own actuator (side = when the wheels are in their home position). Once we had the base mechanically assembled we were able to mock-up the electronics and take it for a spin. Below is an example of the motors in their home positions (zero mode).
Constructing a small testing area showed us how our base would cope in the soft soil conditions. Our regolith simulant consisted of dry quik-crete mix and fine sand. It was not quite as soft or fine as the BP-1, but it acted as a great stand-in on our budget. Since our testing mainly consisted of driving around on the solid concrete floor, we did not attach our cleates to the wheels yet.
With more of the base assembled, it was time to house all of the electronics inside of their own enclosure. The enclosure contained all of the components for the base and the modules. Each module was connected to the base with eight screws and one connector, which allows module switching to occur quickly. The base does not need a module to operate -- it can be manipulated with only its components.
A glimpse inside the electronics box shows each of the six motor controllers (making twelve motor channels in all). Our wireless connectivity was handled by a WRT-54g router running DD-WRT. The router was networked to a Phidgets 1 SBC that handled all of our onboard processing and interfaced to the motor controllers, webcams, etc.
The modularity of our robot helped with several factors. First, we could build one 'base' for locomotion and many 'digging modules' to collect, store, and deposit regolith (which would allow us to pick the best one for the competition). Secondly, this assist monetarily since we provide most of our own funding through grants and fundraisers. For example, we could build one base then build a new module each year. This cuts our costs practically in half after the first year. Thirdly, even if our main module breaks or malfunctions, we could use our other module as a backup. Fourthly, this fits the overall concept of this competition perfect. We treated the lunabotics competition as if it were a real contract from NASA. Considering that it costs about $80,000 USD per pound to send something to the moon, every bit helps. Our modular design would allow you to have modules for different applications. You could have our digging module for regolith collection, another module for sintering or other assembly functions, a transport module to transport tools or parts, or even a communications module to act as a communication node for other systems. The possibilities are endless.
Once the base was fully assembled, we focused on our primary module -- the front-end loader. Designing our robot in SolidWorks made this a breeze. We choose 80/20 extruded aluminum as our main material. 80/20 is not the lightest option, but it is by far the easiest to assemble. Once our design was complete for each component we ordered our material based off of those designs.
The bucket for the front-end loader was welded together by our ME, Matt.
Here is an early video showing a full system test of both the module and base mounted together. The cleates have been mounted to the wheels and all systems are go. The remote backend software was not completed yet, so the operator was within view of the robot.
We quickly outgrew the small 8'x8' indoor enclosure. A nearby volleyball court worked great as a large-scale test site. This gave us a much larger area to reach top speeds (3 mph) with the robot and see how it handled the sand.
We were more than willing to participate in the outreach category of the competition. Once we had enough of the lunabot to show off, we took it all around Tuscaloosa, showing it off to local schools, The Boys and Girls Club, YMCA, and on campus at The University of Alabama.
After the 11 hour drive from Tuscaloosa, Al. to the Kennedy Space Center, we setup our equipment in our 10'x10' area. We were one of the first teams to arrive for the week long competition.
Here is a nice panorama of the "LunaPits" where all of the teams keep their robots and can work on them 24x7.
Here we are weighing our Lunabot to make sure that it does not break the maximum limit of 80kgs.
Once we passed all of the system checks it was time to compete! Full body suits, respirators, and goggles were required inside of the LunArena. The small particulate size of the BP-1 simulant poses a health risk. Wearing full body suits in the Florida heat was no fun!
Here I am fully suited on the left. Everything but the goggles were one time use. NASA was very prepared and on top of all P.P.E.
One of the judges was nice enough to take this photo of us loading our lunabot into the competition arena. The placement of where and what direction our lunabot faces was determined by a spinning arrow and dice.
Here is a video of our competition run from inside the LunArena. It was very hard to navigate the lunabot from the remote location. There was about a 4-5 second delay between the lunabot and the operator.
This is the view from within the operators station. NASA did provide one non-movable situational camera shown in the top left screen.
There are dozens of judges involved with the competition. These two judges make sure that we stay in bounds and do not break any of the rules during our competition run.
Here is the control operator's view from the laptop. Using the Xbox 360 controller allows an easy interface for the operator to manipulate the lunabot.
Meeting real astronauts never gets old, no matter your age.
Each year there is a dinner at the awards ceremony. We got to set underneath a real Saturn V rocket while we ate and awaited the award distribution.
NASA's Second Annual Lunabotics Mining Competition
May 23-28, 2011 Kennedy Space Center, Florida
The competition was an excellent event. This year, our team came in 8th place for the digging competition, collecting a total of 63.2kg. The team also came in 4th place overall and won the award for Team Spirit! Over 60 teams registered, 37 teams competed, and 14 qualified in the digging competition.
Here is an excerpt from the awards ceremony introducing the Alabama Lunabotics team as the Team Spirit award winners:
"In the wake of recent tornados that ravished this state, directly affecting this team's members, ruining homes, turning families' lives upside down, and severely impacting their school and community, it is impressive that this team even showed up. In the final stretch of prepping for the competition this team stepped away from their robot and volunteered to provide support and care for those around them. Not only have they shown up, but they did it with a working robot, smiles on their faces and school pride written all over them. From the time they got here they haven't stopped encouraging, cheering, volunteering, and supporting:
• They volunteered on a day they were not competing to assist the NASA Lunabotics staff and worked a full day;
• They already made efforts to begin a partnership with NASA in establishing a long term outreach program for schools in their area;
• They honored a number of other teams with home-made award;
• and these are just the tip of the iceberg.
We believe this team embodies everything that "spirit" truly means. It is with great honor that we present this year's team spirit award to the University of Alabama team, Alabama Lunabotics. ROLL TIDE!"
With 8th in the digging category, 4th overall, and 1st Team Spirit, we were very proud of our accomplishments.
NASA Edge Live @ Lunabotics Mining Competition 2011: http://www.nasa.gov/mp4/562347main_NE00062411_L10_Lunabotics2011.mp4 We are interviewed at 9:10
Competition run on NASA Edge Ustream: http://www.ustream.tv/recorded/14988604 Our run is at around 25 mins into the stream and we are interviewed at around 59 mins.
Percussive Digger demo on NASA Edge Ustream: http://www.ustream.tv/recorded/15018327 Our demo is at 25 mins.
University of Alabama