Modeling and Analysis of a Novel Flexible Capacitive-Based Tactile Sensor


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In recent years, autonomous robots have been increasingly deployed in unstructured and unknown environments. In order to survive in theses environments, robots are equipped with sensors. One of the main sensors is tactile sensor which provides the robots with tactile information like texture, stiffness, temperature, vibration and normal and shear forces. In this paper, we propose a flexible capacitive tactile sensor which is designed for measuring both normal and shear forces. The tactile sensing unit consists of five layers, a bottom layer of Polyethylene Terephthalate (PET) with a pillar, two copper electrodes embedded into a Polydimethylsiloxane (PDMS) film, a spacer, a Polyimide (PI) film and finally a top PI bump. The bump and the pillar structure play a significant role in producing a torque for shear force measurement. Finite element modeling (FEM) is conducted to analyze the deformation of the sensing unit and simulated using COMSOL Multiphysics. The change of capacitance verse normal and shear forces are obtained, a comparison between the proposed sensor and other pervious sensor is conducted. The sensitivity of a cell is 0.22%/N within the full scale range of 10 N for normal force and 4%/N within the full scale range of 10 N for shear force.



Edited by:

Liyanage C De Silva, Sujan Debnath and Mohan Reddy. M.




B. Gh. Elkilany and E. A. Sallam, "Modeling and Analysis of a Novel Flexible Capacitive-Based Tactile Sensor", Applied Mechanics and Materials, Vols. 789-790, pp. 571-576, 2015

Online since:

September 2015




[1] M. Eltaib and J. Hewit, Tactile sensing technology for minimal access surgerya review, Mechatronics, vol. 13, no. 10, p.1163–1177, Dec. 2003. [Online]. Available.


[2] P. S. Gir˜ao, P. M. P. Ramos, O. Postolache, and J. Miguel Dias Pereira, Tactile sensors for robotic applications, Measurement, vol. 46, no. 3, p.1257–1271, Apr. (2013).


[3] C. Liu, J. Chen, J. Engel, J. Zou, X. Wang, Z. Fan, K. Ryu, K. Shaikh, and D. Bullen, Polymer micromachining and applications in sensors, microfluidics, and nanotechnology, Urbana, vol. 51, p.61801, (2003).

[4] J. Engel, J. Chen, and C. Liu, Development of polyimide flexible tactile sensor skin, Journal of Micromechanics and Microengineering, vol. 13, no. 3, p.359, (2003).


[5] M. Shimojo, A. Namiki, M. Ishikawa, R. Makino, and K. Mabuchi, A tactile sensor sheet using pressure conductive rubber with electricalwires stitched method, Sensors Journal, IEEE, vol. 4, no. 5, p.589–596, (2004).


[6] J. Engel, J. Chen, Z. Fan, and C. Liu, Polymer micromachined multimodal tactile sensors, Sensors and Actuators A: Physical, vol. 117, no. 1, p.50–61, (2005).


[7] E. -S. Hwang, J. -H. Seo, and Y. -J. Kim, A polymer-based flexible tactile sensor for normal and shear load detection, in Micro Electro Mechanical Systems, 2006. MEMS 2006 Istanbul. 19th IEEE International Conference on. IEEE, 2006, p.714–717.


[8] H. -k. Lee, J. Chung, S. -i. Chang, and E. Yoon, Normal and Shear Force Measurement Using a Flexible Polymer Tactile Sensor With Embedded Multiple Capacitors, Journal of Microelectromechanical Systems, vol. 17, no. 4, p.934–942, Aug. (2008).


[9] H. -K. Lee, S. -I. Chang, and E. Yoon, Dual-Mode Capacitive Proximity Sensor for Robot Application: Implementation of Tactile and Proximity Sensing Capability on a Single Polymer Platform Using Shared Electrodes, IEEE Sensors Journal, vol. 9, no. 12, p.1748–1755, Dec. (2009).


[10] P. Roberts, D. D. Damian, W. Shan, T. Lu, and C. Majidi, Soft-matter capacitive sensor for measuring shear and pressure deformation, 2013 IEEE International Conference on Robotics and Automation, p.3529–3534, May (2013).


[11] G. Liang, D. Mei, Y. Wang, and Z. Chen, Modeling and Analysis of a Flexible Capacitive Tactile Sensor Array for Normal Force Measurement, IEEE Sensors Journal, no. c, p.1–9, (2014).