An Ultrathin and Lightweight Soft Inflatable Actuator for Natural Tactile Sensory Feedback

The human sense of touch converts skin deformations into electrical impulses, enabling functional tasks such as object recognition and manipulation. Providing haptic information is crucial for improving usability in applications like prosthetics. Soft actuators have the potential to deliver modality‐matched feedback and high compression forces in a compact form. However, their full potential has been partially demonstrated. This study presents a soft inflatable actuator utilizing thermoplastic polyurethane to provide rich multimodal sensory feedback, including pressure and vibration. The actuator weighs less than 2 g and is 0.4 mm thick, significantly improving upon previous designs. Mechanical characterization reveals that the actuator can produce high‐bandwidth vibrations (200 Hz) and high forces (28 Newtons at 60 kPa). Psychometric tests, conducted with 14 able‐bodied individuals and three transradial amputees, show performance comparable to state‐of‐the‐art invasive and noninvasive solutions (Weber constants within 0.19–0.22). Additionally, the actuator successfully provides different artificial roughness sensations in able‐bodied individuals. Finally, amputees achieve an overall accuracy of 73.3% in a classification task, with dominant sensations of touch and pressure (45% of the stimuli). These results demonstrate that the proposed soft feedback actuator is effective, versatile, and lightweight, with potential for integration into robotic systems for feedback restoration and augmentation.