4. Playful Robots

What is a robot, how can it be designed considering sensor and actuator possibilities, materials, shape, and control? How can it operate in the unstructured world that it should face when interacting with people? The definitions of robot given by international agencies (ISO, IEEE) open a wide spectrum of possibilities for the implementation of robotic devices, that go beyond the classical mental images that we may have of robots, and get closer to what entertainment producers are proposing in the last seventy years, since electronics has reached the reliability and costs compatible with this mass market. What is important to consider in the design of a robot able to play with people with different abilities in an inclusive way? We discuss different aspects of the development of playing robots, from the ones related to physical aspects, such as shape, external appearance, dimension, material, to the ones enabling functionalities, such as sensors and actuators, and to the ones related to data elaboration and behaviour definition, including adaptation to the human player, a relevant aspect when interacting with people that may exhibit a wide range of possibly unexpected reactions. The final aim for a playing robot is to produce a feeling of animacy, which makes the robot a companion to play with. The goal of this chapter is to provide an insight about the set of tools that could be used to implement playful robots.