Bodily Mood Expression: Recognize Moods from Functional Behaviors of Humanoid Robots

Our goal is to develop bodily mood expression that can be used during the execution of functional behaviors for humanoid social robots. Our model generates such expression by stylizing behaviors through modulating behavior parameters within functional bounds. We have applied this approach to two behaviors, waving and pointing, and obtained parameter settings corresponding to different moods and interrelations between parameters from a design experiment. This paper reports an evaluation of the parameter settings in a recognition experiment under three conditions: modulating all parameters, only important parameters, and only unimportant parameters. The results show that valence and arousal can be well recognized when the important parameters were modulated. Modulating only the unimportant parameters is promising to express weak moods. Speed parameters, repetition, and head-up-down were found to correlate with arousal, while speed parameters may correlate more with valence than arousal when they are slow.