Dynamically Reconfigurable Tactile Sensor for Robotic Manipulation

We present a tactile sensor intended for manipulation by mobile robots, e.g., in the home. The surface consists of an array of small, rounded bumps or “nibs,” for reliable traction on objects like wet dishes. When the nibs contact a surface they deflect, and capacitive sensors measure the corresponding local normal and shear stresses. A feature of the sensor is the ability to reconfigure dynamically depending on which combinations of sensing elements it samples. By interrogating different combinations of elements the sensor can detect and distinguish between linear and rotational sliding, and other dynamic events such as making contact. These dynamic events, combined with the sensed grasp and load forces, are useful for acquiring objects and performing simple in-hand manipulations. A proposed slip detection method estimates minimum required grasping force with an error less than 1.5 N and uses tactile controlled rotational slips to reorient an unknown weight/surface object with 78% success rate.