| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 739430 | Sensors and Actuators A: Physical | 2014 | 9 Pages |
•We present a flexible tactile sensor based on a piezoresistive tunneling composite.•The functional composite is based on nanostructured Ni particles in silicone matrix.•This piezoresistive behavior is based on tunneling conduction mechanism.•Huge variation of electrical conduction in response to an applied deformation.•A logarithmic trans-impedance amplifier is used in the electronic readout circuit.
We present a robust and flexible tactile sensor based on piezoresistive sensing material, constituted by a polymeric composite with nanostructured spiky particles as filler. The composite is able to exploit tunneling conduction mechanism when subjected to a compressive load. We have here integrated this quantum tunneling composite (QTC) with an ad-hoc electronic read-out circuit. In addition a software interface can monitor and visualize the applied mechanical pressure, thus leading to a complete tactile sensor device.Concerning the sensing material, the piezoresistive composite shows an enhanced tunneling conduction due to the presence of nickel particles with nanostructured sharp tips embedded in a silicone matrix. We registered an increase up to nine orders of magnitude of the composite electrical conduction in response to a mechanical strain. The sensor consisted in a continuous layer of functional composite sandwiched between a matrix of patterned top and bottom electrodes. The planar sensor can thus be modeled as a two-dimensional array of resistors whose value decreases by increasing the applied pressure. We also designed an ad-hoc electronic read-out circuit, able to read and process the resistance variations of the sensor upon a compressive load, thus providing not only the pressure intensity but also the pressure distribution data. A software interface was able to achieve the real-time tridimensional response and lead to the visualization of the compressed regions on the sensor.The present device is an efficient and low-cost prototype of tactile sensing skin, thus readily enabling its use for human robotic applications.
