A Layered Architecture for O ce Delivery Robots
O ce delivery robots have to perform many tasks. They have to determine the order in which to visit ofces, plan paths to those o ces, follow paths reliably, and avoid static and dynamic obstacles in the process. Reliability and e ciency are key issues in the design of such autonomous robot systems. They must deal reliably with noisy sensors and actuators and with incomplete knowledge of the environment. They must also act e ciently, in real time, to deal with dynamic situations. Our architecture is composed of four abstraction layers: obstacle avoidance, navigation, path planning, and task scheduling. The layers are independent, communicating processes that are always active, processing sensory data and status information to update their decisions and actions. A version of our robot architecture has been in nearly daily use in our building since December 1995. As of July 1996, the robot has traveled more than 75 kilometers in service of over 1800 navigation requests that were speci ed using our World Wide Web interface.