Tech Trends - FIRST Robotic Beasts Draw Students to Engineering30 Jun, 2008 By: Kenneth Wong
Annual competition inspires young men and women to pursue interest in science and technology.
For two entire matches, ThunderChickens, Team 217 (Michigan), and its robotic mascot sat like a lame duck. Grant Cox, the team's designated robot driver, frantically pushed the steering stick in various directions, hoping to accomplish with brute force what the infrared signals had failed to do. But the bird wouldn't budge.
Just before they sent their robot Ritchie X into battle, engineers from Team 234 (Indiana) discovered that Ritchie's launching arms were unnecessary. In fact, without the dead weight, Ritchie's maneuvers would be faster. So they prepared to amputate them on the spot.
Norwell High School students from Team 348 (Massachusetts) realized that their mechanical menace, Killer Kowalski, would come crashing into the overpass when it traversed the course with the trackball in its arm. So they too decided to rearrange some of Kowalski's limbs before they let it loose.
These experiences are common for the teams battling one another at various levels of the annual FIRST Robotics Competition, which was held at the Georgia Dome in downtown Atlanta this April. The unpredictable behaviors of the machines and the need to troubleshoot on the spot are an essential part of the event. Founded in 1989 by Segway inventor Dean Kamen, For Inspiration and Recognition of Science and Technology (FIRST) has the goal of inspiring young people's interest and participation in science and technology.
ThunderChickens' robot, Ritchie X, and Killer Kowalski all share some common digital DNA. Before they were outfitted in steel, foam, and plastic, they were conceived in bits and bytes in CAD. Team 217, or "The Chicken Coop," as the students call it, relied on a group of engineers and students trained in SolidWorks to develop the initial idea into a 3D model. Among their mentors was FANUC Robotics, an industrial robotic system maker that uses SolidWorks.
According to the rules of the competition, the robot had to be built from 422 common parts, included in the kits provided. In its starting position, it had to be less than 120 lb (without battery) and measure no more than 28" x 38" x 60". The use of CAD software allows some teams to experiment with the configuration of their assemblies and maximize what they could fit within the allotted space.
"You can tell which teams designed their robots in software and which ones didn't," observed Peter Frankton from ThunderChickens. "There were teams like ours, [with robots that] packed all the minute details into the prescribed parameters, and others with gigantic arms sticking out, nowhere near the parameters."
Ben Martin, design captain of Team 234, or Cyber Blue, recalled, "CAD [Autodesk Inventor] is great for prototyping, because it lets you see how different parts of [Ritchie X] are going to fit together."
Wayne Penn, a graduate student at Boston University and a member of Team 348, observed, "CAD [SolidWorks] allowed us to double-check and verify before we built the machine that the [assembly] did not exceed the physical package constraint."
FIRST Overdrive, the main event of the competition, was played on a 54' x 27' track, split into a red zone on one side and a blue zone on the other by a center fence. The opposing teams' robots scored against each other by crossing the designated finish lines, carrying the trackballs past those lines, or knocking the balls off or over the fence. Among those possible scoring actions, tackling the trackball was rewarded the highest number of points (8).
"During the matches, the robot could not expand beyond 80" in any direction. But the trackball it needed to tackle was 40" in diameter," said Frankton. "So it was a major design challenge."
Figure 1. Team 234's Ritchie X, designed in Autodesk Inventor, used a telescope-like tower structure to raise and lower its grabbing arms.
Team 234 built an extensible, telescopic arm into Ritchie X (figure 1, p. 14). "It's a cascade-type telescope that goes up and down," explained Martin. "We used CAD to make sure that [the robot] had the correct height for the two-story telescope."
Team 348 equipped Killer Kowalski with retractable arms that could grip and toss the trackballs. "We modeled the trackball and the overpass," explained Penn. "We used the various constraints to open and close the gripper, put it through animation to see how it moved, and simulated the drive conditions."
A number of people on Team 217 were sheet metal fans. So they outfitted the ThunderChickens' robot with a shuttle-and-drive bay made of sheet metal. "Pretty much anything we could, we made out of sheet metal," said Grant. "Then we sent our design to RackSolutions [a team sponsor], where they manufactured it."
Profiles of Robotic Giants
The ThunderChickens' robot's arms, which won the General Motors Industrial Design Award (Detroit regional round), were made of inexpensive white PVC (polyvinyl chloride) material (figure 2). "We heated the PVC until we could bend it the way we wanted," said Frankton. When the arms snapped as anticipated, they could be easily replaced, and the robot went back into action without missing a beat.
Figure 2. Team 217's robot, designed in SolidWorks, used a set of arms made with inexpensive PVC materials to grab and toss the trackball in the FIRST Robotics competition.
Balance was a common problem with the FIRST contraptions. For the spectators, part of the fun was watching the mechanical beasts topple over. "When you have a 5' robot that transforms into 6.5', then tries to hurtle a 40" ball weighing 10 lb, it can be difficult to keep the robot standing still," explained ThunderChickens' Frankton. "So we had to find the center of gravity to make sure the weight is distributed evenly. SolidWorks helped us do that."
Norwell Robotics' Penn said, "We found most of the bugs [in Killer Kowalski] while building it in CAD, so we were able to fix most of the problems." The use of SolidWorks allowed Team 348 to discover that switching the material for several parts from aluminum to titanium would have resulted in a lighter assembly, but the option proved unfeasible due to cost and additional welding needs.
Cyber Blue's team learned that sometimes the ideal custom part is conceivable in Inventor but cannot be reproduced easily in a shop. "You can make [a part] as perfect as you want in CAD," he observed. "But when you make it, for some reason or other — maybe the drill bit is a bit off — the part ends up looking slightly different, and it won't fit."
The Chicken and the Egg
When not chasing after its opponents in the ring, Team 217's creature is actually a sensitive animal. To make this point, the team submitted an entry to the Autodesk Visualization Design Competition.
The whimsical animation clip, titled "The Hug Machine" and created in Autodesk 3ds Max, shows an egg hatching mechanical legs and offering a hug to a chicken. The affectionate gesture transforms the background scenery from the dreary monotone into a lush green landscape, affirming Autodesk's community-oriented theme for this year's competition.
"We had an artist on our team," said Frankton. "She [Kari Kipela] did the storyboarding, then we just used the [primitive] shapes in the software to create the chicken and the egg."
Ed Debler, a mentor to Team 217, reflected on the changing face of ThunderChickens. "When we started out [in 1999], we'd be lucky if we got one or two girls on the team," he said. "This year, we had 18."
Of the roughly 30 students on Team 234, 11 were women. One of them, Miranda Goelz, was responsible for drive subsystem wiring and stress analysis, contradicting the common perception that engineering is an unappealing field for female students.
Team 348 was a predominantly male team, Penn acknowledged. However, he pointed out, "Two of the women on our team, Chelly Nadeau and Heather Conway, were instrumental in the conception of the design, the evaluation of the different CAD models, and taking those ideas to prototyping and manufacturing."
Despite a momentary disconnect in their remote control, Team 217 (ThunderChickens) went on to become one of the three teams in an alliance that won the World Championship at FIRST; Team 234 (Cyber Blue) won the Autodesk Inventor Award; and Team 348 (Norwell Robotics) was a championship finalist.