Collaborative robots (cobots) are widely used in industrial applications, yet extensive research is still needed to enhance human-robot collaborations and operator experience. A potential approach to improve the collaboration experience involves adapting cobot behavior based on natural cues from the operator. Inspired by the literature on human-human interactions, we conducted a wizard-of-oz study to examine whether a gaze towards the cobot can serve as a trigger for initiating joint activities in collaborative sessions. In this study, 37 participants engaged in an assembly task while their gaze behavior was analyzed. We employ a gaze-based attention recognition model to identify when the participants look at the cobot. Our results indicate that in most cases (84.88\%), the joint activity is preceded by a gaze towards the cobot. Furthermore, during the entire assembly cycle, the participants tend to look at the cobot around the time of the joint activity. To the best of our knowledge, this is the first study to analyze the natural gaze behavior of participants working on a joint activity with a robot during a collaborative assembly task.

翻译：协作机器人（cobot）在工业应用中广泛使用，但仍需大量研究来提升人机协作效率及操作员体验。改善协作体验的潜在途径之一，是根据操作员的自然行为线索调整协作机器人行为。受人际互动文献启发，我们开展了一项"巫师之奥兹"（wizard-of-oz）研究，探究朝向协作机器人的注视能否作为协作会话中启动联合活动的触发信号。本研究对37名参与者在装配任务中的注视行为进行了分析，采用基于注意力的注视识别模型检测参与者何时看向协作机器人。结果表明，在大多数情况下（84.88%），联合活动发生前参与者会先注视协作机器人。此外，在整个装配周期中，参与者倾向于在联合活动发生前后注视协作机器人。据我们所知，这是首次在协作装配任务中分析参与者与机器人进行联合活动时的自然注视行为的研究。