Initially, 200 students signed up on 72 teams, all of which built first-generation prototypes that were put through a month-and-a-half of informal competitions. From that field, 36 teams were invited to create complete designs for evaluation, which were subsequently narrowed down to 14 -- seven ground vehicles and seven aerial vehicles.
"All of the 14 vehicles are fully operational -- they all fly or drive -- but they all also have their own strengths and benefits," said Williams. "And its possible that one of these vehicles might finish last in our competition, but on a different course might do very well. That's the beauty of 3D printing."
The competition attempts to answer two questions, one military and one civilian. Can the military can deploy 3D printers at forward bases and print out reconnaissance vehicles on demand? And can civilian first-responders print out search-and-rescue vehicles with just the right capabilities to start searching for survivors while waiting for the rescue teams to arrive?
The finals competition is being held May 15, 2014, in a gymnasium at Virginia Tech where two courses, one for ground vehicles and one for aerial vehicles, have been set up. Each course has four waypoints, which the vehicles either drive or fly to while avoiding obstacles, and then take a picture of the waypoint.
According to Williams:
For the ground vehicle course, between each waypoint is an obstacle like a steep incline or a rubble field or a tunnel, where you must thread the needle, or, in one case, a maze that demonstrates sharp turning capability. The aerial vehicle's course [features] different obstacles, such as going under a bar like doing the limbo, or hovering down inside an open-top tower and taking a picture of the waypoint. And there's one waypoint that is inside a window that they have to fly close to and take the picture through the window.
To quantitatively judge the quality of the picture, the waypoint itself is an optometrist's eye chart, so the judges just score the lowest line they can read to determine how many points a team receives at that waypoint. Only one team made it to the finals with two vehicles -- one ground and one aerial. And all the vehicles carry a GoPro camera as a payload, but vehicles can score extra points for carrying an additional payload.
The second part of the judging is the teams' use of 3D printing.
What makes this competition special is that you get to selectively place material, which is completely different from the old rules, like injection molding and machining, which constrain your creativity. But 3D manufacturing literally lets the designer control every drop of material, so we can print more complex and lighter-weight objects.
In the prize category called "effective use of additive manufacturing" the judging incorporates into the score the time it takes to print the parts for the vehicle, the time it takes to assemble the vehicle, the amount of material used, and the number of non-3D-printed components.
Each team got an electronic components kit from Robotics Research. In addition, all the aerial teams had to use the same rotor blades, but the ground teams got their choice of using provided wheels or treads or of printing their own.
Teams each had a choice of all three types of 3D printers available today: a fused deposition modeling (FDM) printer from Stratasys; a poly-jet printer (the only one that supports a range of materials with properties from rubber to rigid and transparent to opaque) also from Stratasys; and a selective laser sintering (SLS) model, which uses a laser to harden and bond small grains of plastic, ceramic, glass, or metal, from 3D Systems.
They could use any of the three printers, but the catch was that the entire vehicle had to be made on that single printer. We wanted to give them space to design, but they had to look at the tradeoffs -- the pros and cons -- between these three different technologies, which offer completely different ways of doing 3D printing. Four chose FDM, seven chose poly-jet, and three chose SLS.
A total purse of $15,000 in cash prizes was made available by the Stiefel Family Foundation -- $3,000 for first prize in each category, ground and aerial, best performance and best design, plus $250 for each team that fields a functional vehicle.
— R. Colin Johnson, Advanced Technology Editor, EE Times