Fingertip Three-Axis Tactile Sensor for Multifingered Grasping

A fingertip three-axis tactile sensor system with the capability of measuring both normal and shear force distribution using quantum tunneling composites is presented. The practical design and fabrication of a tactile sensor for the robot fingertip are described in detail. Also, an integrated fingertip-shaped tactile sensor with 13 tactile cells is developed. The tactile sensor is mounted on a multifingered robotic hand fingertip, and its effectiveness is validated with experimental results. The fabricated fingertip tactile sensor shows that the full-scale range of detectable force are about 10, 10, and 20N for the x-, y-, and z -directions, respectively. Each detector response was proportional to the magnitude of the applied stress. The fingertip tactile sensor showed a high repeatability, low hysteresis, and minimal three-axis force crosstalk. Experiments are conducted with dynamic grasping force control, based on fingertip three-axis sensor feedback. The grasping force of the finger is adjusted adaptively to the three-axis tactile feedback, such that the force on each fingertip is restricted inside the friction cone without any undesired slip or detaching from the object when grasping it.