Introduction of the need model for humanoid robots to generate active behavior

The authors have been developing human-like head robots in order to develop new head mechanisms and functions for a humanoid robot that has the ability to communicate naturally with a human by expressing human-like emotion. We believe that in the future, it will be necessary for personal robots to generate active behavior to interact bilaterally between human and robot. Therefore, we developed an emotion expression humanoid robot WE-4R (Waseda eye no.4 refined) in 2003. The need model consisting of the "appetite," the "need for security" and the "need for exploration" was introduced to the mental model for humanoid robots. We also defined the "need matrix" and introduced the "equations of need" to describe the robot needs. Robots with the need model can generate and express active behavior according to their need. This paper describes the need model that is implemented in the emotion expression humanoid robot WE-4R.