To achieve the modular design of electronic artificial skin, a fully compliant temperature and pressure tactile sensor is designed and used as artificial skin of intelligent robots, which is assembled into a modularized array structure with expandable characteristics. Taking graphene nanoplatelets (GNPs) as the temperature-sensitive material of the sensor, carbon black (CB) filled silicone rubber (SR) as the elastic dielectric, and the silver conductive silicone rubber as the flexible top plate, a capacitive pressure sensitive cell is designed, and the temperature and pressure sensor array is constructed with polyimide (PI) film as the flexible substrate. The structure design, working principle and the signal acquisition and processing system of the flexible temperature/pressure tactile sensor array are introduced. The experimental results of temperature, pressure and the compound perception indicate that the flexible temperature/pressure multifunctional tactile sensor array and the signal extraction system can realize tactile perception, and it provides a design scheme for wearable artificial skin.
[1] Hammock M L, Chortos A, Tee B C K, et al. 25th anniversary article: The evolution of electronic skin (E-skin): A brief history, design considerations, and recent progress[J]. Advanced Materials, 2013, 25(42): 5997-6037. [2] Nie B Q, Li R Y, Brandt J D, et al. Iontronic microdroplet array for flexible ultrasensitive tactile sensing[J]. Lab on a Chip, 2014, 14(6): 1107-1116. [3] Wang X W, Gu Y, Xiong Z P, et al. Silk-molded flexible, ultrasensitive, and highly stable electronic skin for monitoring human physiological signals[J]. Advanced Materials, 2014, 26(9): 1336-1342. [4] Zhang B, Xiang Z M, Zhu S W, et al. Dual functional transparent film for proximity and pressure sensing[J]. Nano Research, 2014, 7(10): 1488-1496. [5] Tien N T, Jeon S, Kim D I, et al. A flexible bimodal sensor array for simultaneous sensing of pressure and temperature[J]. Advanced Materials, 2014, 26(5): 796-804. [6] Harada S, Honda W, Arie T, et al. Fully printed, highly sensitive multifunctional artificial electronic whisker arrays integrated with strain and temperature sensors[J]. ACS Nano, 2014, 8(4): 3921-3927. [7] Harada S, Kanao K, Yamamoto Y, et al. Fully printed flexible fingerprint-like three-axis tactile and slip force and temperature sensors for artificial skin[J]. ACS Nano, 2014, 8(12): 12851-12857. [8] 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):347-353,359.Huang Y, Lu W, Zhao X W, et al. Design and experiment of flexible multi-functional tactile sensors for robot skin[J]. Robot, 2011, 33(3): 347-353,359.[9] Yang Q H, Huang Y, Wu S Y, et al. Measurement of flexible temperature-pressure distribution for robot sensing skin[C]// Proceedings of SPIE --The International Society for Optical Engineering, vol.8759. Bellingham, USA: SPIE, 2012: 87592H.[10] Zhu B W, Niu Z Q, Wang H, et al. Microstructured graphene arrays for highly sensitive flexible tactile sensors[J]. Small, 2014, 10(18): 3625-3631. [11] Tian M, Huang Y, Wang W H, et al. Temperature-dependent electrical properties of graphene nanoplatelets film dropped on flexible substrates[J]. Journal of Materials Research, 2014, 29(11): 1288-1294. [12] 黄英,郭小辉,刘家俊,等.可拼接式全柔性电容触觉阵列传感器设计与实验 [J].机器人,2015,37(2):136-141,151.Huang Y, Guo X H, Liu J J, et al. Expandable fully compliant capacitive tactile sensing array: Design and experiment[J]. Robot, 2015, 37(2): 136-141,151.[13] Nie B Q, Li R Y, Brandt J D, et al. Microfluidic tactile sensors for three-dimensional contact force measurements[J]. Lab on a Chip, 2014, 14(22): 4344-4353. [14] Peng X F, Xiong C, Wang X J, et al. Ballistic thermal transport in multi-terminal graphene junctions[J]. Computational Materials Science, 2013, 77: 440-444.[15] Basko D M, Aleiner I L. Interplay of Coulomb and electron-phonon interactions in graphene[J]. Physical Review B, 2008, 77(4): No. 041409.