Multimodal Haptic Device Enabling Naturalistic Surface Rendering During Active Touch

When exploring a surface in the physical world, humans perceive a rich array of tactile cues that reveal its physical properties, including roughness, friction, softness, and temperature. These sensations, however, are largely absent in digital interactions. Existing haptic devices typically render only a subset of these cues, making natural, multimodal touch with bare fingertips a persistent challenge. Here, we present SensaSurf, a haptic device capable of reproducing these four primary surface properties during active fingertip exploration. The device integrates a flexible electrovibration layer for texture and friction rendering, a pneumatically actuated one-degree-of-freedom origami joint for stiffness modulation, and a temperature-controlled origami bellow that adjusts contact area and surface temperature. The system offers independent control over over six physical parameters (amplitude, frequency, and irregularity of lateral force; effective stiffness; contact area; and temperature) across ranges relevant to natural surfaces and human perception. Perceptual experiments demonstrate that this control enables distinct and natural rendering of multimodal tactile sensations across key psychophysical dimensions of surfaces. To our knowledge, SensaSurf is the first device to integrate all primary tactile modalities within a single platform for active touch. It opens new opportunities for investigating multisensory perception and advancing surface digitization in virtual and augmented environments.