iRobot Packbot Scout
For the premier issue of Robot magazine the guys from the popular Discovery Channel show Mythbusters documented their attempt to recreate an iRobot PackBot using stock components of the Vex Robotics Design System. Even though no one had any previous experience with the Radio Shack robotics kit, co-hosts Jamie Hyneman and Adam Savage together with build team member Grant Imahara were able to build a rough, but functional, PackBot prototype in less than two days.
The iRobot PackBots are a series of self-righting unmanned ground vehicle (UGV) robots designed for use by the military for scouting and surveillance. Although the specific features vary from model to model, all share an ingenious tank tread system called QuickFlip™ that consists of two pairs of polymer tracks. The larger set of tracks are primarily responsible for locomotion while a smaller set at the front of the vehicle known as the “flipper” tracks are able to rotate a full 360 degrees allowing the robot to climb up stairs and over rocks and other debris. The flippers can also quickly self-right the robot if it gets flipped upside down during its operation.
At the other end of the robotics spectrum lies the Vex Robotics Design System. The components of the kit were originally derived from the parts issued to FIRST Robotics Competition teams. FIRST (For Inspiration & Recognition of Science and Technology) is a non-profit organization founded in 1989 by Dean Kamen to inspire young people to explore science and technology. The starter kit contains over 500 pieces including three variable-speed motors, a servo, radio control transmitter/receiver, programmable microcontroller, multiple gears, various wheels, and erector set style hardware for building chassis. The pieces can also be purchased ala carte as well as some not included in the starter kit like the tank treads needed to build the PackBot prototype.
Although they did not meet their goal of creating a robot capable of climbing stairs, the Mythbusters did manage to create an impressive PackBot knockoff nonetheless. The tread material did not offer enough traction nor were the motors quite powerful enough to climb stairs, but their robot was able to navigate over debris including Jamie’s legs and an apple box. The three ‘busters are no strangers to radio controlled vehicles and hobby robotics so while the project doesn’t reflect how well those with little to no robot experience would fare, the trio’s success does say quite a bit about the power and flexibility of the Vex system.
The outcome surprised Hyneman who said, “I must admit I was expecting to turn up my nose at a do-it yourself robotics kit from Radio Shack. But guess what? The VEX System kicks butt.”