Tactile Sensor Integrated Fingertip Capable of Detecting Precise Contact Force for Robotic Grippers

In this article, a tactile sensor integrated into the fingertip of a robotic gripper was proposed for delicate object manipulation. The sensor was designed to measure both the precise concentrated contact force and the distributed force, enabling in-hand manipulation of robotic grippers. The surface of the fingertip has an inverse-truncated cone-shaped structure. A sensing method was developed to detect the distributed force and precise contact force location through theoretical analysis and simulation of the kinematic relationship between the inverse-truncated cone-shaped surface and the capacitance sensor. In addition, a significant advantage of this sensor lies in its suitability for robotic integration, which is achieved by minimizing the complexity of the measurement electronics. Furthermore, it is easy to manufacture, resulting in cost-effective production. Through several experimental setups, the performance of distributed force sensing and concentrated contact force sensing was evaluated by achieving a maximum force range of 30 N, an average repeatability error of 1.28% of the FSO, and a resolution of 6 mN in that force range. Furthermore, the developed sensor was integrated into a robotic gripper, and its applicability was verified through object-grasping tests.