These robots will also have to be able to discover if their work is not proceeding according to plan. In other words, the robots will need to have the ability to notice that something is wrong and even to find out what went wrong.

The most common way of finding mistakes in robots today is to use models that predict the robot’s position after a certain action. If the robot winds up in the predicted position, it is acting correctly and if it finds itself in another position, then something is wrong. But with fully automated robots, it is often difficult, not to say impossible, to set up precise models.

In his doctoral dissertation, Ola Pettersson at Örebro University has studied how mistakes can be discovered without models. Instead Ola has investigated the behavioral patterns of robots to see if they have acted incorrectly.

“Studying behavioral patterns in order to detect mistakes in mobile robots is a new method,” says Ola Pettersson. “Research is therefore needed to find out whether the method really works. In our research we suggest that the robot should learn what is right or wrong behavior.”

The method the Örebro scientist is using will make it easier for humans to use robots. “We will simply be able to tell the robot that it’s doing something right or wrong, instead of describing it in mathematical models,” says Ola Pettersson.

The dissertation shows that it is possible to detect a mistake and even to determine what type of mistake it was, by studying the robot’s patterns of behavior. Several different techniques have been tested, and their usefulness has been shown in a large number of experiments, using both simulated and real robots. Statistical methods have been used to compare the various results.

Ola Pettersson will defend his thesis in computer science on Friday, October 1, 2004, at 1:00 p.m. in Auditorium T, Örebro University. The dissertation is titled Model-Free Execution Monitoring in Behavior-Based Mobile Robotics.

For more information, please contact Ola Pettersson at phone: +46 21-34 26 34, cell phone: +46 739-67 89 07, e-mail: A picture of Ola Pettersson is available in the press room on the Örebro University Website: