Experimental validation of a polyvinylidene fluoride sensing element in a tactile sensor

Author(s):  
S Yahud ◽  
S Dokos ◽  
J W Morley ◽  
N H Lovell
Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 966 ◽  
Author(s):  
Marco Costanzo ◽  
Giuseppe De Maria ◽  
Ciro Natale ◽  
Salvatore Pirozzi

This paper presents the design and calibration of a new force/tactile sensor for robotic applications. The sensor is suitably designed to provide the robotic grasping device with a sensory system mimicking the human sense of touch, namely, a device sensitive to contact forces, object slip and object geometry. This type of perception information is of paramount importance not only in dexterous manipulation but even in simple grasping tasks, especially when objects are fragile, such that only a minimum amount of grasping force can be applied to hold the object without damaging it. Moreover, sensing only forces and not moments can be very limiting to securely grasp an object when it is grasped far from its center of gravity. Therefore, the perception of torsional moments is a key requirement of the designed sensor. Furthermore, the sensor is also the mechanical interface between the gripper and the manipulated object, therefore its design should consider also the requirements for a correct holding of the object. The most relevant of such requirements is the necessity to hold a torsional moment, therefore a soft distributed contact is necessary. The presence of a soft contact poses a number of challenges in the calibration of the sensor, and that is another contribution of this work. Experimental validation is provided in real grasping tasks with two sensors mounted on an industrial gripper.


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.


2011 ◽  
Vol 2-3 ◽  
pp. 489-494
Author(s):  
Zhi Yong Sun ◽  
Wen Lin Chen ◽  
Yun Quan Su ◽  
Li Na Hao

This article is intended to design a static micro-force sensor with a simple structure employing the polymer material PVDF (polyvinylidene fluoride) film as its sensing element, and will carry out some micro-force tracking tests. During the tracking tests, this paper employs a Fuzzy-PID control method and an ordinary PD control method to control the system, and will also analyze the results of them.


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.


2005 ◽  
Vol 02 (03) ◽  
pp. 181-190 ◽  
Author(s):  
SEIJI AOYAGI ◽  
TAKAAKI TANAKA ◽  
KENJI MAKIHIRA

In this paper, a force sensing element having a pillar and a diaphragm is proposed and thereafter fabricated by micromachining. Piezo resistors are fabricated on a silicon diaphragm for detecting distortions caused by a force input to a pillar on the diaphragm. Since a practical arrayed sensor consisting of many of this element is still under development, the output of an assumed arrayed type tactile sensor is simulated by FEM (finite element method). Using simulated data, the possibility of tactile pattern recognition using a neural network (NN) is investigated. The learning method of NN, the number of units of the input layer and the hidden layer, as well as the number of training data are investigated for realizing high probability of recognition. The 14 subjects having different shape and size are recognized. This recognition succeeded even if the contact position and the rotation angle of these objects are changed.


Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6024
Author(s):  
Somchai Pohtongkam ◽  
Jakkree Srinonchat

A tactile sensor array is a crucial component for applying physical sensors to a humanoid robot. This work focused on developing a palm-size tactile sensor array (56.0 mm × 56.0 mm) to apply object recognition for the humanoid robot hand. This sensor was based on a PCB technology operating with the piezoresistive principle. A conductive polymer composites sheet was used as a sensing element and the matrix array of this sensor was 16 × 16 pixels. The sensitivity of this sensor was evaluated and the sensor was installed on the robot hand. The tactile images, with resolution enhancement using bicubic interpolation obtained from 20 classes, were used to train and test 19 different DCNNs. InceptionResNetV2 provided superior performance with 91.82% accuracy. However, using the multimodal learning method that included InceptionResNetV2 and XceptionNet, the highest recognition rate of 92.73% was achieved. Moreover, this recognition rate improved when the object exploration was applied to demonstrate.


2002 ◽  
Vol 124 (3) ◽  
pp. 576-582 ◽  
Author(s):  
J. Dargahi

This paper reports on design, fabrication and testing of a prototype Polyvinylidene Fluoride (PVDF) tactile sensor for endoscopic and robotic applications. The sensor can measure both compliance and surface roughness. It consists of rigid and compliant elements. A relative deformation between adjacent parts of the contact object is used to measure the compliance, and the deformation of the compliant element of the sensor is used to measure the profile of a rough surface. The sensor in miniaturized form can be integrated with both endoscopic graspers and robotic end effectors. The theoretical analysis of the sensor is made and compared with experimental values. The advantages and limitations of the sensor are also discussed.


Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 391 ◽  
Author(s):  
Xu-Feng Lv ◽  
Xiang Fang ◽  
Zhi-Qiang Zhang ◽  
Zhi-Long Huang ◽  
Kuo-Chih Chuang

We study energy harvesting in a binary phononic crystal (PC) beam at the defect mode. Specifically, we consider the placement of a mismatched unit cell related to the excitation point. The mismatched unit cell contains a perfect segment and a geometrically mismatched one with a lower flexural rigidity which serves as a point defect. We show that the strain in the defect PC beam is much larger than those in homogeneous beams with a defect segment. We suggest that the defect segment should be arranged in the first unit cell, but not directly connected to the excitation source, to achieve efficient less-attenuated localized energy harvesting. To harvest the energy, a polyvinylidene fluoride (PVDF) film is attached on top of the mismatched segment. Our numerical and experimental results indicate that the placement of the mismatched segment, which has not been addressed for PC beams under mechanical excitation, plays an important role in efficient energy harvesting based on the defect mode.


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