Porous Dielectric Elastomer Based Flexible Multiaxial Tactile Sensor for Dexterous Robotic or Prosthetic Hands

Abstract

This article presents a lightweight, flexible, multiaxial, and multimodal capacitive tactile sensing design for robotic or prosthetic hand manipulation. The sensor conforms readily to curved surfaces, which wrap around the back and sides of a finger. With a microstructured porous dielectric material, the sensor has a desirable combination of a wide dynamic range with high resolution (0.5-500 kPa in the normal direction). Each taxel measures a combination of normal, shear, and torsional stresses. The capacitive sensor uses active shielding to reduce sensitivity to electromagnetic interference and when contacting a variety of materials with different conductivity and dielectric constants-including soft, wet materials such as tofu or gelatin. By dynamically changing the combinations of electrodes sampled, the sensor can also provide dynamic tactile information at frequencies over 100 Hz. With this combination of capabilities, the sensor is demonstrated for detecting changes in grasp force, and events such as making or breaking contact and the onset of linear or torsional sliding. This work presents the design and characterization of the sensor and demonstrates it in tasks such as handling fragile food items.