Current robot tactile sensors have shortcomings such as poor wearability and portability, as well as being unpleasant to be maintained and expanded. An expandable, fully compliant capacitive tactile sensor is presented to counteract these shortcomings, which can be used as bio-inspired skin. The structure is designed with two kinds of expandable arrays, the 12×12 square tactile sensing array and the hexagon tactile model. The pressure-sensitive unit is constituted of carbon black filled silicone rubber uniformly as the elastic dielectric of the capacitive sensor, polyimide film as the flexible substrate, as well as silver conductive adhesive and metal film as the flexible parallel-plates of capacitor. In addition, the working principle and the structure design of the capacitive flexible tactile sensor are introduced, and also the wireless signal acquisition and processing systems of two corresponding capacitive arrays are proposed. The experiment results indicate that the fully compliant capacitive sensing array and capacitive signal extraction system has good stability and sensitivity to be used as artificial skin to achieve tactile perception.
 Wang X, Gu Y, Xiong Z, et al. Silk-molded flexible, ultrasensitive, and highly stable electronic skin for monitoring human physiological signals[J]. Advanced Materials, 2014, 26(9): 1336-1342.  Robins B, Dautenhahn K, Ferrari E, et al. Scenarios of robotassisted play for children with cognitive and physical disabilities[J]. Interaction Studies, 2012, 13(2): 189-234.  黄英,陆伟,赵小文,等.用于机器人皮肤的柔性多功能触觉传感器设计与实验[J].机器人,2011,33(3):347- 353. Huang Y, Lu W, Zhao X W, et al. Design and experiment of flexible multi-functional tactile sensors for robot skin[J]. Robot, 2011, 35(3): 347-353. 石金进,吴海彬,马志举.一种新型机器人仿生皮肤的设计[J].机器人,2013,35(1):32-38 Shi J J, Wu H B, Ma Z J. Design of a new robot skin[J]. Robot, 2013, 35(1): 32-38. Takei K, Yu Z, Zheng M, et al. Highly sensitive electronic whiskers based on patterned carbon nanotube and silver nanoparticle composite films[J]. Proceedings of the National Academy of Sciences, 2014, 111(5): 103-107. Nacy S M, Tawfik M A, Baqer I A. A novel fingertip design for slip detection under dynamic load conditions[J]. Journal of Mechanisms and Robotics, 2014, 6(3): 1-7. Lu N, Kim D H. Flexible and stretchable electronics paving the way for soft robotics[J]. Soft Robotics, 2014, 1(1): 53-62.  Ramuz M, Tee B C K, Tok J B H, et al. Transparent, optical, pressure-sensitive artificial skin for large-area stretchable electronics[ J]. Advanced Materials, 2012, 24(24): 3223-3227. Cirillo A, Cirillo P, De M G, et al. An artifial skin based on optoelectronic technology[J]. Sensors and Actuators A: Physical, 2014, 212(1): 110-122. Mittendorfer P, Cheng G. Humanoid multimodal tactile sensing modules[J]. IEEE Transactions on Robotics, 2011, 27(3): 401- 410.  Shirafuji S, Hosoda K. Detection and prevention of slip using sensors with different properties embedded in elastic artificial skin on the basis of previous experience[J]. Robotics and Autonomous Systems, 2014, 62(1): 46-52.  Choong C L, ShimMB, Lee B S, et al. Highly stretchable resistive pressure sensors using a conductive elastomeric composite on a micropyramid array[J]. Advanced Materials, 2014, 26(21): 3451-3458.  Sagisaka T, Ohmura Y, Nagakubo A, et al. Development and applications of high-density tactile sensing glove[M]//Lecture Notes in Computer Science, Vol.7282. Berlin, Germany: Springer-Verlag, 2012: 445-456. Dobrzynska J A, Gijs M A M. Polymer-based flexible capacitive sensor for three-axial force measurements[J]. Journal of Micromechanics and Microengineering, 2013, 23(1): 1-11. 倘余昌,刘星,孔兰芳,等.炭黑填充聚合物体系渗流转变过程中的介电性能[J].高分子材料科学与工程,2012, 28(7):72-75. Tang Y C, Liu X, Kong L F, et al. Dielectric property of carbon black filled polymer composites in percolation transition[J]. Polymer Materials Science & Engineering, 2012, 28(7): 72-75. Hayashida K, Matsuoka Y. Highly enhanced dielectric constants of barium titanate-filled polymer composites using polymergrafted carbon nanotube matrix[J]. Carbon, 2013, 60: 506-513.