Interval Methods Help a Robot Succeed

Interval methods helped a robot designed by the University of Texas at El Paso (UTEP) team win a prestigious third place world-wide in the robot competition held during the American Association of Artificial Intelligence conference in Portland, Oregon, August 6-7, 1996.

Robots have to deal with two types of uncertainty:

Traditionally, statistical methods have been used to deal with these two types of uncertainty. There are, however, two major problems related to these methods: The team leaders of the UTEP team, graduate students David Morales and Tran Son and their supervisor Chitta Baral, decided to abandon statistical methods and use interval-based methods instead.

To take sensor errors d into consideration, their robot assumes that any pixel that could be (within this error) inside an obstacle has to be avoided. As a result, e.g., when going in a corridor, the robot actually follows the "virtual corridor" whose width is 2d smaller than the actual width.

To compensate for the actuator errors, with unknown probabilities, the robot does not attempt any statistical filter-type corrections; instead, it uses the sensor feedback to periodically adjusts its position and orientation.

Several other novel ideas have been used. The resulting algorithms turned out to be computationally simpler and more reliable than the previously known ones. In the robot competition, the robot Diablo implementing these algorithms won the third place in complicated office navigation competition where robots had to navigate in a realistic office environment. Diablo proved to be 100% reliable, always staying on track and never hitting any obstacle. The only points it lost were due to speed.

Due to novel algorithms, UTEP's commercially built robot outperformed more than 20 much more technologically sophisticated robots from all over the world, including teams from prestigious institutions long involved in world-class robotic research such as Carnegie-Mellon University and the Universities of Stuttgart and Bonn.

In addition to D. Morales and T. Son, the main team included Luis Floriano and Monica Nogueira. Support team members who assisted with the robot's programming were Alfredo Gabaldon, Richard Watson, Glen Hutton, and Dara Morgenstein.

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