The presentation of a moving tactile stimulus to a person's forearm evokes a pleasant sensation. The speed, intensity, and contact area of the strokes should be systematically changed to evaluate the relationship between pleasantness and tactile stimuli in more detail. Studies have examined the relationship between stroking stimulation and pleasant sensations using airborne ultrasound tactile displays. The ultrasound-based method has the advantage of reproducible control of the speed, intensity, and contact area of the stimulus. In this study, we prepared new stimuli focusing on the modulation methods and the contact area and aimed to clarify their relationship with pleasantness in more detail. Evaluating subjective sensations, such as pleasantness, numerically and consistently is challenging, warranting evaluation based on comparison. We propose a stimulus evaluation method that combines rough evaluation using Likert scales, detailed evaluation using pairwise comparisons, and quantification of comparison data using the Bradley--Terry model. As a result, we confirmed that the stimulus using lateral modulation and that with a large contact area used in this study were more pleasant than the conventional stimulus for six out of ten participants.

翻译：向人体前臂施加移动触觉刺激会诱发愉悦感。为更详细地评估愉悦感与触觉刺激之间的关系，需系统改变抚摸刺激的速度、强度和接触面积。已有研究利用空中超声波触觉显示器探讨了抚摸刺激与愉悦感之间的关系。基于超声波的方法具有可重复调控刺激速度、强度及接触面积的优点。本研究聚焦调制方式与接触面积，制备了新型刺激，旨在更深入地阐明其与愉悦感之间的关联。愉悦感等主观感受的数值化、一致性评估具有挑战性，需要基于比较进行评价。我们提出了一种结合李克特量表粗略评估、配对比较精细评估以及利用Bradley-Terry模型对比较数据进行量化的刺激评价方法。结果表明，对于10位参与者中的6位，本研究中采用的横向调制刺激及大接触面积刺激比传统刺激更令人愉悦。