This paper presents a novel MEMS tactile sensor that can provide elasticity measurement of a variety of target objects. This sensor can be integrated on a handheld probe or on minimally invasive surgical tools for in-vivo tissue elasticity measurement. The tactile sensor consists of a pair of contact bumps that have different values of stiffness. Two capacitive force gauges are integrated underneath the bumps. The sensor readout is composed of two channels of capacitance values and the ratio of these capacitance values can be used to calculate the elasticity of target objects. To obtain reliable measurement of capacitance ratios, an estimation algorithm is developed by using a recursive least squares method with adaptive forgetting factors. Experimental characterization of the sensor shows that this tactile sensor provides reliable elasticity measurement of polymer specimens and quickly detects changes in elasticity.
Bibliographical noteFunding Information:
The authors would like to thank L. Alexander for his help in fabricating acrylic molds for the sensor bumps. Sensor fabrication was performed at the Nano Fabrication Center at the University of Minnesota which is supported by the NSF’s National Nanotechnology Infrastructure Network (NNIN).
Manuscript received September 22nd, 2010; revised December 05, 2010; accepted January 01, 2011. Date of publication January 17, 2011; date of current version July 29, 2011. This work was supported in part by the Minimally Invasive Medical Technologies Center (MIMTeC, www.mimtec.org), a National Science Foundation Industry–University Cooperative Research Center. The associate editor coordinating the review of this paper and approving it for publication was Prof. Kiseon Kim.
- Elasticity measurement
- microelectromechanical systems (MEMS)
- tactile sensor