UltraTac: Integrated Ultrasound-Augmented Visuotactile Sensor for Enhanced Robotic Perception

Visuotactile sensors provide high-resolution tactile information but are incapable of perceiving the material features of objects. We present UltraTac, an integrated sensor that combines visuotactile imaging with ultrasound sensing through a coaxial optoacoustic architecture. The design shares structural components and achieves consistent sensing regions for both modalities. Additionally, we incorporate acoustic matching into the traditional visuotactile sensor structure, enabling the integration of the ultrasound sensing modality without compromising visuotactile performance. Through tactile feedback, we can dynamically adjust the operating state of the ultrasound module to achieve more flexible functional coordination. Systematic experiments demonstrate three key capabilities: proximity sensing in the 3–8 cm range (R2 = 0.99), material classification (average accuracy: 99.20%), and texture-material dual-mode object recognition achieves 92.11% accuracy on a 15-class task. Finally, we integrate the sensor into a robotic manipulation system to concurrently detect container surface patterns and internal content, which verifies its promising potential for advanced human-machine interaction and precise robotic manipulation.