A Situated Vacuuming Robot

Abstract

We undertook this project as an opportunity to ex-plore design ideals of the embodied approach. At our disposal was a Pioneer robot and its Saphira soft-ware (ActivMedia 1996). Similar to subsumption ar-chitecture (Brooks 1986), the Saphira software tackles the dilemma of how to implement layered control de-sign within a system which is inherently centralized. Brooks saw each layer as a simple and almost inde-pendent computational entity and, likewise, Saphira allows us to create a hierarchy of behaviors that each have the capacity to function simultaneously and yet asynchronously. Just as Brooks proposed a means by which one level can subsume a lower level by inhibiting its output, so behaviors can each be assigned a priority. The main strength of Saphira’s behavioral approach is not its ability to subsume or inhibit, but rather its capacity to blend behaviors. Non-conflicting behaviors run simultaneously and independently. If behaviors do conflict, their output can be combined in a number of ways. For example, if TurnSUDegrees has highest prior-ity and gives commands on the turn channel and Con-stant_VeZocity is of lower priority and gives commands on the speed channel, then both behaviors will run completely independently. However, if TurnSODegrees gives commands on the speed channel, those com-mands override the activity of Constant _ Velocity. If in-stead, both Constant-Velocity and TurnSODegrees have equal priorities then their activities will be blended, al-lowing smooth transitions between them. Vacuuming Strategies We are considering three different approaches to achieving full coverage for a given room.. One approach utilizes genetic programming to generate an algorithm that effectively vacuums the room, while the other two focus on designing behaviors for the robot to traverse the floor in a pre-specified pattern (the North/South and Concentric Squares methods). We plan on com-paring all three approaches in a variety of room envi-ronments to measure their relative utilities.