Development of Flexible Tactile Sensing Array Using MEMS-Based Technologies
Date Issued
2009
Date
2009
Author(s)
Cheng, Ming-Yuan
Abstract
This dissertation presents the developments of various types of tactile sensor arrays which will be used as the artificial skins for robot applications. Conductive-polymer-based mechanism and the capacitive mechanism are employed as the sensing techniques. Polyimide (PI) as well as polydimethylsiloxane (PDMS) are used as the substrate materials. For the conductive-polymer-based approach, the tactile sensing elements are formed by dispensing or attaching conductive polymer bumps on the pre-defined electrodes. This novel fabrication method can effectively reduce the crosstalk between each sensing element. Discrete temperature sensor chips are employed as the temperature sensing cells. Also, the temperature and tactile sensing elements are heterogeneously integrated on a flexible substrate using micromachining techniques. Scanning circuits are implemented. Finally, measured temperature and tactile images have been successfully obtained by using the integrated 8?8 and 32?32 sensing arrays. Extendable spiral electrodes, which are highly stretchable and durable, are also designed and fabricated as the row and column interconnects for tactile sensing arrays. The fabricated sensor array can conform to complex surfaces The device can be twisted up to 70 degree without any damage in structure or functionality. For the approach using the capacitive sensing mechanism, tactile sensing arrays are realized by using MEMS fabrication techniques and flexible printed circuit board (FPCB) technologies. The sensing array consists of two micromachined PDMS structures and a flexible FPCB. Each capacitive sensing element comprises two sensing electrodes and a common floating electrode. The sensing electrodes as well as the metal interconnects for signal scanning are implemented on the FPCB, while the floating electrode is patterned on one of the PDMS structures. This special design can effectively reduce the complexity of device structure and thus makes the device highly manufacturable and robust. The characteristics of the devices with different dimensions are measured and discussed. The corresponding scanning circuit is also designed and implemented. The tactile images induced by the PMMA stamps of different shapes are also successfully captured by a fabricated 8?8 array.
Subjects
artificial skin
flexible electronics
micromachining
tactile sensing array
temperature sensing array
spiral electrode
conductive polymer
floating electrode
capacitive sensing
Type
thesis
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