A developmental roadmap for learning by imitation in robots

Abstract — We present a strategy whereby a robot acquires the capability to learn by imitation following a developmental path-way consisting on three levels: (i) sensory-motor coordination, (ii) world interaction, (iii) imitation. With these stages, the system is able to learn tasks by imitating human demonstrators. We describe results of the different developmental stages, involving perceptual and motor skills, implemented in our humanoid robot, Baltazar. At each stage, the system’s attention is drawn towards different entities: its own body and later on, objects and people. Our main contributions are the general architecture and the implementation of all the necessary modules until imitation ca-pabilities are eventually acquired by the robot. Also several other contributions are made at each level: learning of sensory-motor maps for redundant robots, a novel method for learning how to grasp objects and a framework for learning task description from observation for program-level imitation. Finally, vision is used extensively as the sole sensing modality (sometimes in a simplified setting) avoiding the need for special data-acquisition hardware. Index Terms — Humanoid Robots, development, imitation I