Expressing Emotions through Color, Sound, and Vibration with an Appearance-Constrained Social Robot

Abstract

Many researchers are now dedicating their efforts to studying interactive modalities such as facial expressions, natural language, and gestures. This phenomenon makes communication between robots and individuals become more natural. However, many robots currently in use are appearance constrained and not able to perform facial expressions and gestures. In addition, although humanoid-oriented techniques are promising, they are time and cost consuming, which leads to many technical difficulties in most research studies. To increase interactive efficiency and decrease costs, we alternatively focus on three interaction modalities and their combinations, namely color, sound, and vibration. We conduct a structured study to evaluate the effects of the three modalities on a human's emotional perception towards our simple-shaped robot "Maru." Our findings offer insights into human-robot affective interactions, which can be particularly useful for appearance-constrained social robots. The contribution of this work is not so much the explicit parameter settings but rather deepening the understanding of how to express emotions through the simple modalities of color, sound, and vibration while providing a set of recommended expressions that HRI researchers and practitioners could readily employ.

Mimebot—Investigating the Expressibility of Non-Verbal Communication Across Agent Embodiments

“…|Oh yes from relaxed to frustrated, see Figure 1. e same categories have previously been used by robot researchers in [26]. In total, our scripts contain ve to seven interactions for each of the inner states.…”

“…Emotional body laguage for the Nao robot was studied by [5] and [12]. For a non-humanoid sphere-shaped robot (Maru), sound, colors, and vibrations were used to express emotional behaviors [26].…”

Expressing Personalities of Conversational Agents through Visual and Verbal Feedback

“…Visual feedback 5 was designed with a combination of black and white. Black is related to melancholy and unhappy properties [42], while white is relaxing [15].…”

“…In particular, the gaze of the conversational agents were used to deliver back-channel feedback in turn-taking situations [13]. Diverse colors and lights were also used to express the social robots' emotions [14][15][16], and a simple blinking light was used as a subtle expression to smooth human-robot speech interactions [17].A large number of studies have focused on emotion [18]. This study argues that, for long-term HCI, the interface's personality plays a more crucial role than simple emotional reactions.…”

“…This study argues that, for long-term HCI, the interface's personality plays a more crucial role than simple emotional reactions. The current approach for personality expression was adapted from previous affective computing [19] and expressive output modality studies [15,16]. For instance, similar to prior studies, this study adopted cues to express conversational agents' internal states, such as personality.…”