Finger-Mounted Tactile Sensor for Evaluating Surfaces

2012 ◽  
Vol 24 (3) ◽  
pp. 430-440 ◽  
Author(s):  
Ryo Kikuuwe ◽  
◽  
Kenta Nakamura ◽  
Motoji Yamamoto

This paper presents a finger-mounted tactile sensor for extracting information on fine surface properties of objects such as textile fabrics. The prototype sensor has a thin structure composed of a sheet of PVDF (polyvinylidene fluoride) film sensor and some metal parts for converting compressive forces into area expansion of the PVDF film. By using a signal processing program based on the FFT (fast Fourier transform), voltage signal sequences from nine different fabrics were distinguished, even in the presence of variations in the pressing force and the speed of rubbing motion induced by the fluctuations in the user’s hand motion. In addition, the signal sequences from abraded fabrics were sorted by their levels of abrasion by extracting a signal component correlated with the abrasion level.11. This paper is the full translation from the transactions of JSME, Series C, Vol.77, No.784, 2011.

2007 ◽  
Vol 124-126 ◽  
pp. 299-302 ◽  
Author(s):  
You Min Chang ◽  
Jong Soon Lee ◽  
Kap Jin Kim

Flexible piezoelectric polymer materials for smart apparel and wearable computer applications are of great interest. Among known ferroelectric and piezoelectric polymers, polyvinylidene fluoride (PVDF) exhibit β-phase under poling and is known to give highest piezo-, pyro-, and ferroelectric properties. Previous reports suggests that, during corona poling of the PVDF film, a high surface electric potential is generated resulting in a high internal electric field within the polymer film causing the polarization of the dipoles along the direction of the applied electric field. The resultant phase change from α- to β-phase and the dipole switching generates displacement of charges or piezoelectricity. And also mechanical variation would change dipole density of PVDF film. In this report, we measured human heartbeat signal from an DAQ interfaced with a custommade voltage-amplifier with specific frequency filtering function using the corona-poled PVDF film of various sizes and thickness as a piezoelectric sensor and analyzed it. We employed elastic textile band to sensor system for comfortable fit on wrist or ankle. And then, we found the feasibility of applying flexible PVDF film sensor to smart apparel application which can sense heartbeat rate, blood pressure, respiration rate, accidental external impact on human body, etc.


2011 ◽  
Vol 675-677 ◽  
pp. 465-468 ◽  
Author(s):  
Yong Rong Wang ◽  
Pei Hua Zhang ◽  
Chun Ye Xu

Piezoelectric polymer, polyvinylidene fluoride (PVDF) film, has been widely investigated as sensor and transducer material due to its high piezo-, pyro-, and ferroelectric properties. However, there are many limitations for PVDF film as human-related tactile sensor, such as non-breathability, stretching, requirement of additional process like poling, etc. In this paper, PVDF nano-fibrous membrane which is light, flexible, and wearable was prepared by electrospinning technique. The electrospinning parameters such as the voltage, feeding rate, tip-tocollector distance, etc, were well controlled. More than 4 hours electrospinning time was needed for a certain thickness of PVDF nano-fibrous membrane. The morphology of PVDF nanofiber was determined by scanning electron microscopy (SEM), the diameter distribution was calculated and crystal structure was evaluated by FTIR spectroscopy. We found the feasibility of developing piezoelectric PVDF fibrous membranes through electrospinning technology, which is a good candidate for flexible human-related tactile sensors to sense garment pressure, blood pressure, heartbeat rate, accidental external impact on human body, etc.


2018 ◽  
Vol 180 ◽  
pp. 02036
Author(s):  
Jan Hujer ◽  
Miloš Müller

This paper describes investigation of the influence of the protective layer thickness on the calibration sensitivity of PVDF films sensors for the cavitation impacts measurements. The PVDF film sensor is casted into an aluminium block. The drop ball method is used for the measurement of the relation between impact force and the voltage detected on the PVDF film sensor. The calibration constants are measured for three different protective layers thicknesses. Five different ball weights for 400 mm drop height are used to reach the required impact force range. The ball positions for the evaluation of the impact force are measured with a high speed camera. The voltage signal detected on the PVDF film clamps was measured with a high speed digitizer. The measured signals are analysed in LabVIEW Signal Express.


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Kazuto Takashima ◽  
Keisuke Ota ◽  
Masaki Yamamoto ◽  
Makoto Takenaka ◽  
Satoshi Horie ◽  
...  

AbstractTo achieve quantitative palpation in vivo, we developed a catheter-type tactile sensor composed of a polyvinylidene fluoride film for minimally invasive surgery. We evaluated the fundamental performance of the prototype sensor by a weight-drop test. We also measured the output of the prototype sensor as it was inserted into a blood vessel model with shapes mimicking lesions. The ø2-mm sensor passed easily into the blood vessel model with lesion-like shapes. Sensor outputs corresponded to the shape of the inner wall of the blood vessel model, making it possible to determine the position of a protrusion and the convexity interval of a rough surface by filtering and frequency analysis of the output.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 585
Author(s):  
Ariel Ma ◽  
Jian Yu ◽  
William Uspal

Natural evaporation has recently come under consideration as a viable source of renewable energy. Demonstrations of the validity of the concept have been reported for devices incorporating carbon-based nanocomposite materials. In this study, we investigated the possibility of using polymer thin films to generate electricity from natural evaporation. We considered a polymeric system based on polyvinylidene fluoride (PVDF). Porous PVDF films were created by incorporating a variety of nanocomposite materials into the polymer structure through a simple mixing procedure. Three nanocomposite materials were considered: carbon nanotubes, graphene oxide, and silica. The evaporation-induced electricity generation was confirmed experimentally under various ambient conditions. Among the nanocomposite materials considered, mesoporous silica (SBA-15) was found to outperform the other two materials in terms of open-circuit voltage, and graphene oxide generated the highest short-circuit current. It was found that the nanocomposite material content in the PVDF film plays an important role: on the one hand, if particles are too few in number, the number of channels will be insufficient to support a strong capillary flow; on the other hand, an excessive number of particles will suppress the flow due to excessive water absorption underneath the surface. We show that the device can be modeled as a simple circuit powered by a current source with excellent agreement between the theoretical predictions and experimental data.


1999 ◽  
Author(s):  
Debashis Satpathi ◽  
J. P. Victor ◽  
Ming L. Wang ◽  
H.Y. Yang ◽  
C. C. Shih

2016 ◽  
Vol 12 ◽  
pp. 42-50 ◽  
Author(s):  
N. Manikandan ◽  
S. Muruganand ◽  
K. Sriram ◽  
P. Balakrishnan ◽  
A. Suresh Kumar

The polyvinylidene fluoride (PVDF) nanofiber has widely investigated as a sensor and transducer material, because of its high piezo and Ferro electric properties. The novel nano structure of PVDF has attracted considerable interest in the bio sensing and biomedical application. This paper deals with PVDF Tactile sensor. Basically The PVDF acts as piezoelectric effect which convert load into electrical signals. The tactile sensor has a main role for visual handicap and robotics. Any physical activities of robotic in all industrial the tactile sensor is a crucible role, whether it can left the object or handling glass parts pressure of object is main. The Sandwich type PVDF base tactile sensor has been fabricated using nanofiber. Using electro spinning method, the PVDF based nanofiber coated over coper the electrodes. In normal, the PVDF has α-phase and while applying electric pulse the PVDF polymer would be changed from α-phase into β-phase. Only in β-phase, the PVDF act as piezo electrics sensor and measure the piezoelectricity simultaneously measure pressure and temperature in real time. The pressure was monitored from the change in the electrical resistance via the piezo resistance of the material. The enhancement of PVDF properties has been carried by using SEM. The SEM image result showed that the size of nanofiber, the size of nanofiber is varied in the range of (180 nm-400 nm) with smooth surface. The X-Ray diffraction has shown that the PVDF was aggregated with the β-phase crystalline nature. Due to β-phase it was act as a piezo electric prosperity’s and its results are very high sensitivity.


2014 ◽  
Vol 599-601 ◽  
pp. 1135-1138
Author(s):  
Chao Zhe Ma ◽  
Jin Song Du ◽  
Yi Yang Liu

At present, sub-micro-Newton (sub-μN) micro-force in micro-assembly and micro-manipulation is not able to be measured reliably. The piezoelectric micro-force sensors offer a lot of advantages for MEMS applications such as low power dissipation, high sensitivity, and easily integrated with piezoelectric micro-actuators. In spite of many advantages above, the research efforts are relatively limited compared to piezoresistive micro-force sensors. In this paper, Sensitive component is polyvinylidene fluoride (PVDF) and the research object is micro-force sensor based on PVDF film. Moreover, the model of micro-force and sensor’s output voltage is built up, signal processing circuit is designed, and a novel calibration method of micro-force sensor is designed to reliably measure force in the range of sub-μN. The experimental results show the PVDF sensor is designed in this paper with sub-μN resolution.


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