This last summer (2010) I was lucky enough to be part of the 2010 NASA Robotics Academy at Marshall Space Flight Center in Huntsville, Alabama. There I was partnered with other college students from around the nation who also had a passion for robotics. Some of them were already experts in their field, and had extensive robotics experience. I was placed on a team with three other students, and was assigned to work on a distributed swarming robotic system under Dr. Robert Ray. Our goals were to develop a swarming system based on the iRobot Create platform, and have the robots autonomously interact and cooperate with each other. The iRobot Create is made for robotic research and experimentation, and is simply the Roomba without the vacuum cleaner, but with a cargo bay to add your own stuff and a 21 pin connector to interface with the Create. This makes it a great way to get started on a robotics project like the one we did. They are inexpensive and easy to work with. We were trying to create a swarm of 6 robots which would be location aware, and would make coordinated movements together. This was to be a centralized psuedo-swarm that did not use "swarm / hive intelligence." Bcause in a flight environment we would never want a robot to have the ability to make it's own decisions and possibly act on its own, we had a centralized desktop computer which ran the AI and directly controlled the different robots. With this important decision made, we had a number of goals to accomplish, which included: Wireless communication between the robots and the computer AI for all 6 robots to move independently and simultaneously Location determination for all of the robots My responsibilities as the mechanical engineer for the project was to design and create the integration of the electronics which allowed wireless communication between the central computer and each robot. Mechanically, I had to get the electronics mounted onto the robot. This included the Freescale "Tower" which contained the real-time processor and a board with a network adapter. Also there was the wireless router / adapter, and the voltage regulator. Early models needed a laser level as well. Electronically, I had to design and make cable adapters to transfer power and data between the robot and the added electronics. I also had to design and make the cables that connected all of the various components. The space available inside the robot was tight, and I attempted to make the profile as low as possible, which made routing the cables more challenging as well, and required creativity so they could fit. Being able to build each robot allowed me to work hands-on with the hardware rather than on the computer. Actually putting it together also provides the feeling that you are making a lot of progress and is a great thing to do whenever something else is frustrating. The biggest challenge was doing location determination for the robots, many techniques were tried, but in the end none of them worked. The first approach was to use lasers, which fanned into a line on each robot, and light detectors in different spots of the room to trilateralate the position of the robots, but we could not find lasers who matched frequencies with the detectors or vice-versa. Additionally the laser on each robot was not very powerful, so within a few inches it would no longer pick up the signal, even in the dark. About the same time I was pursuing this technique I encountered a lot of problems with signal processing on the computer side as well, and the difficulties of trying to use Labview in real time to detect pulses. Labview is great for a lot of things, but I could not be great at identifying signals and processing them in real-time. The next approach was to use the diode "walls" which came with the iRobot Create. The thought was that we could detect the walls ourselves with the IR sensor on the Create and determine the location of the Creates as the direction of the IR beam spun around the room. In theory it would work great, but there were more difficulties. The difficulties which this ran into was the ability for the Create to send data back to the computer, which had a lot of problems with interference chopping the packets into pieces. The second problem was the range of the walls, which could not be made good enough to determine their location within a decent range, although it was better than before. Precision had always been a problem with this approach before as well. I tried to collimate the IR LED as best as I could, but it would never be good enough for what we actually wanted, which was plus or minus a few centimeters at a range of about 10 meters. Location detection was never something that could be implemented in the robots, and by the end of our 5-week project we were unable to make them location-aware, although the other goals of coordinated movement and wireless communication were met. As I waited in the airport for my flight out of Huntsville, I was talking to a member of the all-graduate student team which was also part of the NASA Robotics Academy about my frustrations with the hardware available to us as interns and the difficulties of my project. I told him that I thought the best way to press forward in the future was to use sonar to track the distances and trilateralate the positions of the robots. He told me about an amazing system which is called CRICKET, developed by MIT to ultrasonically locate the positions of robots with centimeter accuracy in an indoor environment. As it turns out, they developed exactly what I was dreaming about. I think the biggest lesson I learned this summer is that even if it seems like time is very limited and you must charge ahead down one path that looks easy, it is good to ask yourself if it is the best way to do it, and approach it with a somewhat cynical mind so I can identify problems earlier. It is also good to seek help whenever encountering a problem, especially from those more experienced than you, even if you think you have it figured out, because you just might not. Despite the setbacks in location determination, using dead reckoning we were still able to get the robots to move together, both independently and simultaneously. This project succeeded in all other areas of development, and was a sucess. It may be continued by robotics academy students next year.
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After finishing Afternoon Delite , Ellen Farber and I soon decided to move on to another summer project. I don't know exactly how this idea was created, but it was decided that we should make a rocket out of old coors light cans. Yay recycling! It was originally proposed that we create the Coors V, in commemoration of the Saturn V. This project also required a lot of running around to hardware stores at home depot, trying to find the best place to buy the epoxy that we wanted, and buying the necessary supplies. We used an E-9 motor because that was the largest we could find in nearby hobby stores, and managed to adapt the motor mounting kit to the inside of a can with the top and bottom removed. When the motor was selected we realized that we had to scale back the rocket so Instead of a 5 of 7-can configuration we went with a single can stack. The project became a test bed for what will eventually by the Coors V rocket. Engine : E9 Body: Coors light cans x3 Parachute: estes rocket kit plastic chute Nosecone: Coors light bottle Altitude : 426 ft The nose-cone and entire forward section were separated during the ejection charge because we had not been able to securely fasten the shock cord to the can. Video coming soon. The Coors V will require about 56 cans. I'm working on it. While at the NASA Robotics Academy this summer, one of the activities we did was attend the Alabama Space Grant Consortium's High-powered Rocketry Workshop. There we learned about the University Student Launch Initiative (USLI) competition and all of the various facets for starting a team and competing. That all sounded like a lot of paperwork, and as everyone there was primarily a robot nerd, were just excited about getting to build big rockets and get National Association of Rocketry (NAR) High-powered Level 1 certifications. We got these really great starter kits by MadCow Rocketry called the Patriot, and had a few days to build and paint them. No one on our team seemed particularly excited about the prospect of painting the rocket, which we believed added little intrinsic value to the rocket other than reduce drag. We felt that we could do better than just build some dumb rocket that went up and came back down. We wanted to do something cool. We wanted to do something different. It was no coincidence that we came to this unanimous conclusion just minutes after the conclusion of a talk by the legendary Tim Pickens. Tim Pickens Has been active in amateur rocketry for about as long as anyone can remember and made himself well known for his daring endeavors, brilliance and quality rocket design. He became the lead propulsion engineer for Space Ship One, developing the hybrid motor that won scaled composites and Virgin Galatic to win the Anasari X-prize. He then went on to start orion propulsion and made a ton of money doing rocket engine design and support for military, NASA, and commercial sectors. Recently (since we have last seen him) He has been leading the Rocket City Space Pioneers in their quest to win the Google Lunar X-prize. He is also well known for his fun and zany home projects, many of which include rocket propulsion. We came to the conclusion that we could put a video camera inside of the rocket and film the ascent and descent . After much shopping and deliberating, we decided to use an Olympus point in shoot that was owned by me (YIKES!). We had our work cut out for us in making this relatively simple project happen. It took many trips to home depot and other stores in Huntsville to find parts that would work well, fit well, and be light enough for our rocket. The most challenging part of this project was planning the assembly as we had to construct the payload bay after we had already assembled the rocket. This required adding another bulk head, camera mounting, keeping the nose-cone securely attached, payload interconnect, another shock cord mount, and hole for the lens. We also needed to create a much more complicated checklist and pre-flight procedures. Luckily our project was a success and we had a safe launch with an H motor. The camera is not really made for shooting video and actually kind of sucks at it. I need to get a better video camera for the next time that I launch this. It also had a difficult time focusing due to the edge of the hole being visible by the camera, and the rapidly spinning terrain. When the parachute charge went off. The camera went black but continued to record sound. We believe this may be from the mechanical shutter closing due to the sudden jerk, but all theories are really just speculation.
Afternoon Delite is in my room right now and is awaiting the spring, when it will fly again. It was a crazy weekend. So much stuff happened at SpaceVision and I met so many really cool and influential people in NewSpace it is kind of mind-boggling. I met a lot of people there who are giants in the industry, whose names can be mentioned in a lot of settings and almost everyone knows who they are. I did not meet enough students from other parts of the country, but there is simply a fundamental limit to the number of people I can remember from any given weekend.
Anyway, all of the speakers were pretty amazing and I had such a good time seeing all of my NASA academy pals there. I have come away with so much enthusiasm and energy that I just want to graduate right away and start making spaceships. Or go to the moon. One of the things I realized I had to do there was get my name out there, and start documenting all of the projects I have done and will be doing. Another thing that got me really excited about while I was there was learning about SEDS. Before I arrived I was not even aware that it stood for the Students for the Exploration and Development of Space. It may be a testament to how cool SpaceVision was that before the weekend was over, I had dedicated myself to creating the Montana State University SEDS chapter. We have a large student base who is interested in Space and a number of faculty who has had a lot of experience in the space industry, so I think we can have some very interesting presentations. I am also not the only one who decided to start / restart a SEDS chapter after being at SpaceVision. Ellen Farber will be leading the charge at Harvard to re-start SEDS there. I know that SpaceVision 2011 will be amazing and I plan on being there in Boulder. I got to meet a lot of people from CUSEDS and it is going to rock my socks. |
Lars OsborneBS Mechanical Eng Categories
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