The Future is Here

Willow Garage, a Silicon Valley research group celebrated the success of their PR2 mobile robot in June 2009. PR2 (Personal Robot 2) has wheels and can cover a distance of a mile and a quarter per hour. It navigated the company's cramped office, opened doors, entered rooms and plugged its power cord into ten electrical sockets - using its agile arm and hand. Scientists here wanted to see how they could push the limits of hardware, software and systems for robots and whether a robot could perform a certain set of tasks reliably.  

Sachin Chitta, one of the people who developed PR2, and an alumnus of IIT Bombay, says about the robot, "A bunch of people were pretty nervous, including me, about what would happen, what the robot would do. People were trying to mess with the robot as it was doing its task by jumping in front of it, blocking its path, but it's a persistent robot, it didn't fail, it keeps trying." Along with being persistent, it's clever as well. If it finds a door locked, it simply moves on to the next one instead of continually trying to open it. 

PR2 is a completely autonomous robot who demonstrated the ability to consistently navigate indoors, open doors and plug into regular outlets to recharge. In a 26.3 mile marathon over four days, it opened ten doors and plugged into ten sockets without fail. The robot has the map of the building. From the map it approximately knows the positions of doors all over the floor. It has a sensor that creates a 3D representation of the world around it as it moves forward, and the robot looks for patches that match information about doors. If the door is closed, it assesses where the door handle is and brings up its arm to grab the handle to open the door. While it does this, several checks happen inside the robot in the background to ensure that the robot is indeed opening a door. As it opens the door further, it simultaneously moves into the room.

PR2 Alpha Prototype
Photo Courtesy : Mr. Ken Conley

From there, it looks for the location of the outlet from the information provided by the map. One of the most difficult steps for the robot is to accurately assess the depth towards the outlet. For this, it uses a monocular five megapixel camera to gauge the exact location of the outlet. It uses its tilting laser scanner to determine the location of its plug (which is kept in place at its base through magnets). It then picks up the plug and tries to put it into the socket. If it fails to do so, it tries again with approximate information of the outlet until it succeeds. This proves the robot's reliability and persistence. 

Robots are already being used extensively in various industry production lines and defence weapons, but personal robots have yet to impact society. And although many robots before have been able to do what PR2 does, like open doors and navigate through cramped spaces, robots before PR2 could not do so reliably and persistently. An article in the New York Times stated, 'PR2 was the first to integrate the ability to do a number of operations in a real-world environment'. "There are other groups that have opened doors before," said Andrew Ng, a Stanford roboticist with several students who have gone to work for the company. But Mr. Ng also added that this seemed to be "the first robot able to repeatedly and reliably open doors and plug itself in."  

Though on the surface, it seems like a small step, it is a giant leap for scientists working in robotics. Since PR2 is designed as a platform to conduct research and build applications in mobile manipulation in real human environments, it will help many scientists to spin off ever faster into the future.