Willow Garage’s PR2 Robot Operates Autonomously for 139 km!

PR2 Travels 139km
In a test of its fortitude, the PR2 has gone the distance.

What do you do when your robotic child is all grown up? I guess you make it run a marathon. Over the past few years, Willow Garage has taught its PR2 robot to be autonomous. The Silicon Valley startup showed the bot how to plug itself in. They taught it to navigate on its own. They even taught it how to call for help in case of emergency. On December 8th it was time to see how well those lessons were learned. Willow Garage told the PR2 to start rolling and not stop. It traveled over 70 km in 7 days…then it kept going for six days more! On December 21st the bot ended its marathon having gone a total of 138.9 km (~ 86 miles). The PR2’s epic journey probably doesn’t look like much from the outside, after all the robot was simply wandering around the Willow Garage office, but it represents a major accomplishment for the company and for open source robotics. In the future, robots like the PR2 will be able to perform a wide variety of jobs, and without human supervision.

PR2 Travels around the office
Willow Garage employees gave the PR2 a little flair for its epic journey.

This marathon run is important because it pushed the limits of the PR2’s autonomous operation, not because it could gauge the physical stamina of the machine’s parts. I don’t just care if a wheel breaks, I want to know how long I can leave a robot alone and not have to worry about whether it is stuck or fallen over. To that end, this in-office demonstration was a great example of how the robot could function on its own. When the PR2 encountered an obstacle, it moved around it. When its batteries were low, it found an outlet and plugged itself in. Most importantly, when it got desperately stuck it sent a text message to an engineer who could log on to a web portal and remotely get the robot rolling again. According to Willow Garage, that scenario only happened twice: “During the run, there were only two interventions: one to help the robot maneuver around a chair, and another to tell the robot where it was (“re-localization”). In both cases, the robot noticed there was an issue and sent a message for help, and the issue was resolved over the web.” Two bugs in 139 km? Not bad.

What finally did the robot in? Its plug got stuck somewhere the robot couldn’t reach. That simple. If this robot was in your house, doing chores, you could have solved that problem in 5 seconds. This 139 km marathon run shows that personal robots will not only be able to operate autonomously, but that their most common failures might be very easy to fix.

Certainly engineers have created robots that have gone farther than the PR2. NASA’s Mars Rover? That has Willow Garage beat thousands of times over. Yet the PR2 is both more practical and more accessible. The techniques used to keep the PR2 running autonomously are available to all robot developers through the open source ROS software library. There are now 16 different groups around the world developing the PR2, and many more using ROS. PR2 developers can write code for the robot that takes days, or even weeks, to finish and remain confident that the bot can finish the task. The PR2’s marathon session is just a tiny step in the grand history of robotics, but with the connectivity of the open source community it will be a step multiplied many thousands of times.

[image credit: Willow Garage]
[source: Willow Garage Blog]