scholarly journals Flexible Shear and Normal Force Sensor Using Only One Layer of Polyvinylidene Fluoride Film

2019 ◽  
Vol 9 (20) ◽  
pp. 4339 ◽  
Author(s):  
Lee ◽  
Chung ◽  
Oh ◽  
Cha
Keyword(s):  
Real Time ◽  
Polyvinylidene Fluoride ◽  
Normal Force ◽  
Force Sensor ◽  
Applied Force ◽  
Pvdf Film ◽  
Simple Process ◽  
Flexible Sensor ◽  
Normal Forces

We have proposed a flexible sensor that can sense shear and normal forces, and can be fabricated through a simple process using only one layer of polyvinylidene fluoride (PVDF) film. For the measurement of shear and normal forces, one layer of PVDF film was sealed in a three-dimensionally structured polydimethylsiloxane (PDMS). In the structure, the sensor produced voltage signals corresponding to the shear and normal forces. Using this property, we aimed to demonstrate how to sense the magnitude and direction of the force applied to the sensor from its output voltages. Furthermore, the proposed sensor with a 2 × 2 array was able to measure the applied force in real time.

Research on PVDF Micro-Force Sensor

2014 ◽  
Vol 599-601 ◽  
pp. 1135-1138
Author(s):  
Chao Zhe Ma ◽  
Jin Song Du ◽  
Yi Yang Liu
Keyword(s):  
Power Dissipation ◽  
Polyvinylidene Fluoride ◽  
High Sensitivity ◽  
Force Sensor ◽  
Calibration Method ◽  
Pvdf Film ◽  
Force Sensors ◽  
Low Power Dissipation ◽  
Micro Force Sensor ◽  
Processing Circuit

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.

A Three-Axis Piezoresistive Micromachined Force Sensor for Studying Cockroach Biomechanics

2000 ◽  
Author(s):  
Michael S. Bartsch ◽  
Aaron Partridge ◽  
Beth L. Pruitt ◽  
Robert J. Full ◽  
Thomas W. Kenny
Keyword(s):  
Normal Force ◽  
Force Sensor ◽  
Strain Gauges ◽  
Ground Reaction Forces ◽  
Large Area ◽  
Blaberus Discoidalis ◽  
Normal Forces ◽  
Orthogonal Components ◽  
Reaction Forces ◽  
Force Resolution

Abstract A millimeter-scale silicon micromachined force sensor has been designed to measure in three axes the ground reaction forces produced by the cockroach Blaberus Discoidalis during typical running locomotion. Each sensor consists of a large-area (5mm × 5mm) rigid plate supported at its corners by thin flexures instrumented with two ion-implanted piezoresistors each. Comparison of piezoresistive measurements among these eight strain gauges allows the applied force to be resolved into three orthogonal components. Un-amplified sensitivity to normal forces of 1.2V/N has been demonstrated with estimated normal force resolution of 7.3μN on an 800Hz measurement bandwidth.

scholarly journals A Hybrid Two-Axis Force Sensor for the Mesoscopic Structural Superlubricity Studies

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3431
Author(s):  
Sun ◽  
Wu ◽  
Li ◽  
Zheng ◽  
Lin
Keyword(s):  
Real Time ◽  
Frictional Force ◽  
Normal Load ◽  
Force Sensor ◽  
Solid Surfaces ◽  
Mems Sensors ◽  
Shear Forces ◽  
Electromechanical Systems ◽  
Normal Forces ◽  
Storage Technologies

Structural superlubricity (SSL) is a state of nearly zero friction and zero wear between two directly contacted solid surfaces. Recently, SSL was achieved in mesoscale and thus opened the SSL technology which promises great applications in Micro-electromechanical Systems (MEMS), sensors, storage technologies, etc. However, load issues in current mesoscale SSL studies are still not clear. The great challenge is to simultaneously measure both the ultralow shear forces and the much larger normal forces, although the widely used frictional force microscopes (FFM) and micro tribometers can satisfy the shear forces and normal forces requirements, respectively. Here we propose a hybrid two-axis force sensor that can well fill the blank between the capabilities of FFM and micro tribometers for the mesoscopic SSL studies. The proposed sensor can afford 1mN normal load with 10 nN lateral resolution. Moreover, the probe of the sensor is designed at the edge of the structure for the convenience of real-time optical observation. Calibrations and preliminary experiments are conducted to validate the performance of the design.

scholarly journals Generating Electricity from Natural Evaporation Using PVDF Thin Films Incorporating Nanocomposite Materials

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 585
Author(s):  
Ariel Ma ◽  
Jian Yu ◽  
William Uspal
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Capillary Flow ◽  
Short Circuit ◽  
Current Source ◽  
Nanocomposite Materials ◽  
The Other ◽  
Pvdf Film ◽  
Ambient Conditions

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.

A Study of Effect of Various Normal Force Loading Forms on Frictional Stick-Slip Vibration

2021 ◽  
Author(s):  
Xiaocui Wang ◽  
◽  
Runlan Wang ◽  
Bo Huang ◽  
Jiliang Mo ◽  
...  
Keyword(s):  
Dynamic Behaviour ◽  
Normal Force ◽  
Time Varying ◽  
Stick Slip ◽  
Vibration Signals ◽  
Theoretical Methods ◽  
Normal Forces ◽  
Frequency Domains ◽  
Amplitude Vibration ◽  
Fourier Spectra

In this work, a comparative study is performed to investigate the influence of time-varying normal forces on the friction properties and friction-induced stick-slip vibration by experimental and theoretical methods. In the experiments, constant and harmonic-varying normal forces are applied, respectively. The measured vibration signals under two loading forms are compared in both time and frequency domains. In addition, mathematical tools such as phase space reconstruction and Fourier spectra are used to reveal the science behind the complicated dynamic behaviour. It can be found that the friction system shows steady stick-slip vibration, and the main frequency does not vary with the magnitude of the constant normal force, but the size of limit cycle increases with the magnitude of the constant normal force. In contrast, the friction system harmonic normal force shows complicated behaviour, for example, higher-frequency larger-amplitude vibration occurs as the frequency of the normal force increases. The interesting findings offer a new way for controlling friction-induced stick-slip vibration in engineering applications.

ELECTROMECHANICAL CHARACTERISTICS OF POLYVINYLIDENE FLUORIDE FOR FLEXIBLE ELECTRONICS

2013 ◽  
Vol 37 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Wen-Yang Chang ◽  
Cheng-Hung Hsu
Keyword(s):  
Flexible Electronics ◽  
Polyvinylidene Fluoride ◽  
Input Voltage ◽  
Pvdf Film ◽  
Resistive Load ◽  
X Ray Diffraction ◽  
Leakage Currents ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Stress Cycles

The electromechanical characteristics of PVDF are investigated, including the crystallization, frequency responses, hysteresis, leakage currents, current-voltage characteristics, and fatigue characteristics using X-ray diffraction and an electrometer. Results show that the frequency band of PVDF increases with increasing resistive load and capacitance. The hysteresis area of ΔH slightly increases with increasing input voltage. The magnitude of the current values increases with decreasing delay time at a given drive voltage. PVDF film induced larger degradation when the number of stress cycles was increased to about 105 cumulative cycles.

scholarly journals Elephant trunks form joints to squeeze together small objects

2018 ◽  
Vol 15 (147) ◽  
pp. 20180377
Author(s):  
Jianing Wu ◽  
Yichao Zhao ◽  
Yunshu Zhang ◽  
David Shumate ◽  
Stephanie Braccini Slade ◽  
...  
Keyword(s):  
Granular Materials ◽  
Theoretical Study ◽  
Robotic Manipulators ◽  
Force Sensor ◽  
The Self ◽  
Applied Force ◽  
African Elephants ◽  
Food Items ◽  
Unique Method ◽  
Push Down

Wild African elephants are voracious eaters, consuming 180 g of food per minute. One of their methods for eating at this speed is to sweep food into a pile and then pick it up. In this combined experimental and theoretical study, we elucidate the elephant’s unique method of picking up a pile of food by compressing it with its trunk. To grab the smallest food items, the elephant forms a joint in its trunk, creating a pillar up to 11 cm tall that it uses to push down on food. Using a force sensor, we show the elephant applies greater force to smaller food pieces, in a manner that is required to solidify the particles into a lump solid, as calculated by Weibullian statistics. Elephants increase the height of the pillar with the force required, achieving up to 28% of the applied force using the self-weight of the pillar alone. This work shows that elephants are capable of modulating the force they apply to granular materials, taking advantage of their transition from fluid to solid. In the future, heavy robotic manipulators may also form joints to compress and lift objects together.

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