Evaluating Tactile Perception of Robot-Controlled HIFU Embossing

Embossed surfaces provide raised patterns and textures that can support access to information and act as tactile guidance on physical interfaces. Recent work has introduced a mold free embossing technique that combines High Intensity Focused Ultrasound (HIFU) with a robot arm to locally deform materials such as acrylic and MDF, enabling digitally controlled embossing. While this approach offers high design flexibility and is safe, research on how the resulting patterns are perceived through touch remains limited. In this work, we use a robot-controlled HIFU embossing system to create six textures that represent common tactile features relevant to exploratory touch, including contours, roughness, geometric shapes, and localized bumps on acrylic and MDF. Nineteen participants took part in a blindfolded tactile exploration study. Using both quantitative and qualitative data, we characterize how people perceive and differentiate textures produced through robot-controlled HIFU embossing.