Page 226 - Designing Autonomous Mobile Robots : Inside the Mindo f an Intellegent Machine

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CHAPTER

Becoming Unstuck in Time

In Kurt Vonnegut’s classic book, Slaughterhouse-Five, the hero is subject to incredible
horrors as a prisoner of war in Dresden, Germany during the infamous firestorm raids
by Allied bombers. To escape he becomes unstuck in time, and shifts between
various periods of reality and a fantasy life on a distant planet. Once unstuck, he is never
able to go back to thinking of time in a linear fashion, even when he has been
liberated. The experienced robot programmer will find the same shift in thinking
taking place, though with any luck it will be a more pleasant experience.

We should learn to think of time as just another axis in our position. Since science
fiction has dealt with this concept extensively, it should be a fairly natural jump.

Getting past sequential thinking

In the earlier days of mobile robot development, affordable sensor systems were lim-
ited to sonar rangers and simple retroreflective light beam detectors. Given the very
limited information these systems provided at any one moment, robots needed to
gather information for some interval in order to obtain enough data for analysis.

With the advent of GPS and excellent lidar systems, rich streams of data are available at
relatively short time intervals. Today’s programmer must recognize that the need to
manage time is still critical, and that only the scale of the time frame has changed.

Agent arbitration issues

In order for a mobile robot to operate robustly in real-world applications, the pro-
grammer cannot afford to think in sequential time. That is to say, a robot should not
simply read data, react to it, and read more data. When the robot is running under

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