German roboticists have made a mobile robot, Autonomous City Explorer (ACE), that rolls up to any humans nearby, and asks for directions to reach its destination.
The breakthrough from the Technical University of Munich is the first time that such a robot has been designed that can be properly let loose in the real world, such as city roads.
Martin Buss, who led the team behind this advance, revealed that they dumped the robot called Autonomous City Explorer (ACE) outside the university, and instructed it to find its way to the Marienplatz in the centre of Munich, some 1.5 kilometres away.
He further revealed that the robot lacked an inbuilt map of Munich or a GPS system, and just like a lost human in a similar situation, all it could do was ask for directions.
ACE uses cameras and software to detect humans nearby, based on their motion and upright posture. A speaker working in sync with the animated mouth is used to get the person's attention, and to ask them to touch the screen if they want to help.
Willing guides are then asked to point the robot in the correct direction, with the response being analysed by posture recognition software.
Once the direction is set, the robot says "thank you" before trundling off.
Pointing, rather than telling the robot where to go, avoids confusion caused by the fact that the robot and the facing pedestrian each have a different sense of left and right.
Buss revealed that during the experiment, though ACE interacted with 38 people over a period of nearly five hours, it eventually reached its destination.
Only once was ACE given the wrong directions, and it had to finally stop due to obstacles. Afterwards, it asked someone else for help, who put it back on course.
"In theory the robot has to continue on its incorrect path until it needs new information, this is why we are currently working on a system to check the information from humans for plausibility," says team member Andrea Bauer.
Impressed with the study, Paul Newman, a roboticist at the University of Oxford in the UK, said: "It's absolutely the way to go."
He says that navigating a changing environment can be a complicated cognitive task, and "invoking humans when appropriate" could be a relatively simple way for robots to meet the challenge.
A report describing ACE has been published in the International journal of Social Robotics.