Domestic Service Robots in the Real World: More on the Case of Intelligent Robots Following Humans

Abstract

The international initiative “Robocup”, and in particular its “@Home” league of Robocup, are excellent environments for focusing robotics research and AI as well as, more specifically, for testing the abilities of domestic service robots. Following humans has long been recognized as a basic capability in this context. It allows in our case for convenient path programming (teaching of itineraries). Although, the cognitive requirements are quite high (20 lin of knowledge, 200 lin/s of expertise), humans usually proceed in the same way. The environment is dynamic and disturbances may occur, which may cause errors. Therefore, safety measures must be devised, such as close human-robot interaction to prevent path crossing by third parties; the availability of light signals as a discrete warning; close interaction for accurate positioning in complex trajectories; coordinated, unidirectional blocking; vocally warnings and the ability to stop when people cross the path between the robot and the guide; the definition of a maximal radius of influence beyond which stopping is triggered; procedures for emergency stopping; robust vision-methods; and ultrasonic sensors and map-based obstacle avoidance. At the most abstract semantic level, about 15 bits per second of information must be acquired. For this purpose a variety of sensors are considered, each with specific advantages: a color camera, a planar laser range scanner, a 3D-ranger, ultrasonic sensors, and joint sensors. Smooth and stable real-time behavior is ensured by a 5-level hierarchical control structure and agents implemented in different technologies (computers, PLC, servo controllers, etc.), inheriting some developments resulting from research in Eurobot context.