A flexible tactile sensor array based on pressure conductive rubber for three-axis force and slip detection

This paper presents a novel flexible tactile sensor array with the capabilities to measure three-dimensional (3D) forces and slip occurrence by using the INASTAMOR pressure conductive rubber as the sensing material. The tactile sensor array has 3 × 3(= 9) sensing units, and each unit has a three-layered structure: bottom electrode, middle conductive rubber chips, and top PDMS bump. The structural design, 3D force and slip detection principles, fabrication process of this sensor array are presented. The fabricated sensor array has a spatial resolution of 7 mm. 3D force measurement and slip detection performances of this sensor array are characterized experimentally. Results demonstrated that the sensor array can measure 3D forces. The full-scale range and sensitivities of force measurements for x-, y- and z-axes are 5 N, 5 N, 20 N and 0.65 V/N, 0.67 V/N, 0.23 V/N, respectively. Results also showed the sensor array could detect slipping by using the discrete wavelet transform (DWT) to analyze the measured force data. Thus, the proposed flexible tactile sensor array could be applied to robot hand grasping application that requires slip detection and 3D contact force measurement.