Development of a flexible and stretchable tactile sensor array with two different structures for robotic hand application

Flexible and stretchable tactile sensors can fit complex surfaces nicely, and can be applied to robotic fingers or surgery gloves for a touch/grasp feeling to distinguish objects or organs, and thus they have widespread applications. This paper reports two types of stretchable capacitive tactile sensors with vertical and parallel serpentine electrode structures and their application in grasping/distinguishing objects. Results show that the proposed tactile sensors could measure small pressures with good linearity which can withstand deformations up to 90% and 55% respectively, with a near-zero or small linear temperature coefficient. A tactile sensor array, consisting of 3 x 3 parallel plate structure sensor units, is attached at the robotic finger to distinguish objects with different morphology and stiffness, and achieve a high accuracy over 90%.