Article written by Brian Maffitt, owner of Total Training, Robolliance Expert, with credit to Ross Allen and Marco Pivone from Autonomous Systems Lab at Stanford University for their contributions
“Autonomy” is a lofty goal for a robot. It implies, simply, that our machines can take care of themselves… a concept usually illustrated by a vehicle’s ability to avoid hitting a wall or driving into a ditch. But there are also moving obstacles, such as other vehicles, people, animals… even thrown projectiles can pose unexpected dangers to a machine that is going about its business.
PhD candidate Ross Allen has been exploring accident avoidance in an amusing way, by teaching a drone to “fence”. He posted a video which purportedly shows a modified quadcopter adroitly dodging the deadly thrusts of Ross’s rapier.
While swashbuckling robots may seem like a silly idea on the surface, the avoidance technology Mr. Allen’s team is developing may allow future robots to avoid incoming dangers, such as birds, other vehicles, or even incoming missiles (Look Earl, a drone! Throw a rock at it!). Ross says, “We use machine learning, but in a different way than we've seen it implemented in robotics before. We use supervised learning (specifically a support vector machine) to teach the quadrotor about reachable sets.”
“We could solve optimal control problems to all the points on our map to see what is close, but this would take a really long time (10s or 100s or seconds) and we need to avoid an obstacle coming at us right now,” continues Ross. “We can use machine learning to estimate what points in our roadmap are close to us, only solve optimal control problems for those few points (a few milliseconds), find a global path through the roadmap while checking that path doesn't run into any of the obstacles, and voila! Real-time motion planning!”
Mr. Allen’s work has been summarized in a paper (“a bit out of date since it doesn't include replanning”, says Ross), and his team has a journal paper “in the works” with complete results.
So just how good a swordsman is this little flying robot? “I really suck at fencing,” says Ross, “so that somewhat levels the playing field.”
We can all rest easy, at least until the next evolution in robot self-defense comes along.