A Modular Architecture for Office Delivery Robots

Reid Simmons
Richard Goodwin, Karen Zita Haigh, Sven Koenig, Joseph O'Sullivan

School of Computer Science, Carnegie Mellon University

Office delivery robots have to perform many tasks. They have to determine which office to visit next, plan a path to that office, follow that path reliably, and avoid obstacles in the process. We present a complete robot architecture that addresses all of these issues in novel ways. Our architecture accounts for noisy robot sensors and actuators, a dynamic and partially unknown environment, and real-time behavior despite limited processing power. The architecture is composed of four abstraction levels: Obstacle avoidance is performed by our Curvature-Velocity Method; Navigation is done using Partially Observable Markov Decision Process Models; Path Planning uses a decision-theoretic generate, evaluate and refine strategy with sensitivity analysis; and Task scheduling is performed using a symbolic planning architecture. The levels are implemented as independent processes that use the Task Control Architecture to communicate among each other. A version of our robot architecture has been in daily use since December 1995. Since then, our robot has served over 1500 navigation requests that were specified using our World Wide Web and Zephyr interfaces, and traveled a total of more than 60 kilometers in the process.
Joseph Kieran O'Sullivan
Last modified: Sun Jan 19 13:18:13 EST 1997