Abstract
This paper presents a high-precision intelligent flexible robot grasping front-end with an integrated capacitive tactile sensor array and a conditioning chip. The capacitive tactile sensor is the primary part of the front-end, it determines the overall performance. The micro-needle array sandwich structure in the tactile sensor increases the repeatability and stability, and ensures the sensitivity. The assembled sensor exhibits a saturation at 10.53 N (421 kPa) with a sensitivity of 1.9%/kPa. Furthermore, a conditioning chip is utilized in a custom readout interface to achieve better performance by reducing signal attenuation, and to increase the compatibility of the front-end. The chip is optimized for the parasitic shunt capacitance in the capacitor array. A dual bidirectional charge-discharge conversion method and a two-port detection method are matched to achieve the goal of reducing the shunting influence, and attenuating the offset voltage or the noise input effects. A prototype of the interface has been fabricated using 180-nm CMOS technology. Sensor with the value of 0.5 pF shunted by capacitors of 47 pF has been detected with an error of 1% within 100 μs.
摘要
创新点
本文提出了一种应用于高精机器人应用的高灵敏度的柔性抓握前端。 该前端集成了电容传感器和调理芯片。 其中, 电容传感器是柔性抓握前端的主体, 它决定了整体的性能。 夹杂在两电容极板间的微针阵列结构提升了器件的可重复性、稳定性和灵敏度。 键合后的器件在10.53N(421kPa)压力输入时呈现饱和, 灵敏度为1.9%/kPa。 同时, 前端中搭配了专用的调理芯片以达到更好的性能和更高的集成度。 芯片针对电容阵列中不可消除的寄生电容效应做了专门处理。 本文中将双模双向充-放电方法和两端检测方式匹配, 来实现寄生电容的消减。 该方案对输入失调电压和输入噪声电压的消减也十分有效。 芯片在180 nm CMOS工艺条件下流片验证。测试结果显示, 0.5pF的电容在47pF寄生电容的影响下误差仅为1%。
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References
Khasnobish A, Singh G, Jati A. Object-shape recognition and 3D reconstruction from tactile sensor images. Med Biol Eng Comput, 2014, 52: 353–362
Decherchi S, Gastaldo P. Tactile-data classification of contact materials using computational intelligence. IEEE Trans Robotics, 2011, 27: 635–639
Teshigawara S, Tadakuma K. High sensitivity initial slip sensor for dexterous grasp. In: Proceedings of IEEE International Conference on Robotics and Automation, Anchorage, 2010. 4867–4872
Haris M, Qu H. A CMOS-MEMS nano-newton force sensor for biomedical applications. In: Proceedings of Nano/Micro Engineered and Molecular Systems, Xiamen, 2010. 177–181
Noda K, Shimoyama I. A shear stress sensing for robot hands-orthogonal arrayed piezoresistive cantilevers standing in elastic material. In: Proceedings of Haptic Interfaces for Virtual Environment and Teleoperator Systems, Alexandria, 2006. 63–66
Kim K, Lee K R, Kim Y K. 3-axes flexible tactile sensor fabricated by Si micromachining and packaging technology. In: Proceedings of Micro Electro Mechanical Systems, Istanbul, 2006. 678–681
Yang Y J, Cheng M Y, Chang W Y. An integrated flexible temperature and tactile sensing array using PI-copper films. Sensors Actuat A: Phys, 2008, 143: 143–153
Hu X H, Zhang X, Liu M, et al. A flexible capacitive tactile sensor array with micro structure for robotic application. Sci China Inf Sci, 2014, 57: 120204
Li P, Liu M, Zhang X, et al. A low-complexity ECG processing algorithm based on the Haar wavelet transform for portable health-care devices. Sci China Inf Sci, 2014, 57: 122303
Han J Q, Zhang X, Pei W H, et al. A compact neural recording interface based on silicon microelectrode. Sci China Tech Sci, 2013, 56: 2808–2813
da-Rocha J G V, da-Rocha P F A, Lanceros-Mendez S. Capacitive sensor for three-axis force measurements and its readout electronics. IEEE Trans Instrum Meas, 2009, 58: 2830–2836
Cheng M Y, Lin C L, Yang Y J. Tactile and shear stress sensing array using capacitive mechanisms with floating electrodes. In: Proceedings of IEEE 23rd International Conference on Micro Electro Mechanical Systems, Wanchai, 2010. 228–231
Peng P, Rajamani R, Erdman A G. Flexible tactile sensor for tissue elasticity measurements. J Microelectromech Syst, 2009, 18: 1226–1233
Hoshi T, Shinoda H. Robot skin based on touch-area-sensitive tactile element. In: Proceedings of the 2006 IEEE International Conference on Robotics and Automation, Florida, 2006. 3463–3468
Xu Z, Ming L, Bo W, et al. A wide measurement range and fast update rate integrated interface for capacitive sensors array. IEEE Trans Circuits Syst I: Regular Papers, 2014, 61: 2–11
Lei K F, Lee K, Lee M. Development of a flexible PDMS capacitive pressure sensor for plantar pressure measurement. Microelectron Eng, 2012, 99: 1–5
Pritchard E, Mahfouz M, Evans Iii B, et al. Flexible capacitive sensors for high resolution pressure measurement. In: Proceedings of IEEE Sensors, Lecce, 2008. 1484–1487
Lee H K, Jaehoon C, Chang S I, et al. Normal and shear force measurement using a flexible polymer tactile sensor with embedded multiple capacitors. Microelectromech Syst, 2008, 17: 934–942
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Hu, X., Zhang, X., Liu, M. et al. High precision intelligent flexible grasping front-end with CMOS interface for robots application. Sci. China Inf. Sci. 59, 32203 (2016). https://doi.org/10.1007/s11432-015-5358-y
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DOI: https://doi.org/10.1007/s11432-015-5358-y