This paper presents the underlying consideration during later three years project of Robot group at LIFE. The theme is human-friendly robot system that lives together with human. The keyword is symbiosis among human and robots. The philosophical issue we should mention is on the suitable relation between them in the future. First, historical consideration is made, then three levels of human-machine relation are proposed. Our research is a t the rule level, where robots have heuristic knowledge to infer human's intention by observing hisher behavior. Fuzzy technology is useful to encode this level of knowledge. We have to make more consideration for upcoming new stage on artifacts where they evolve by themselves supported by Artificial Life technology.