scholarly journals A New Flexible Tactile Sensor for Contact Position Detection Based on Refraction of Electric Field Lines

2018 ◽  
Vol 30 (9) ◽  
pp. 1953 ◽  
Author(s):  
Jinhua Ye ◽  
Jianfeng Huang ◽  
Jianpeng Chen ◽  
Haomiao Wang ◽  
Haibin Wu
Keyword(s):  
Electric Field ◽  
Tactile Sensor ◽  
Position Detection ◽  
Field Lines ◽  
Contact Position

scholarly journals A Flexible Tactile Sensor with Irregular Planar Shape Based on Uniform Electric Field

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4445 ◽  
Author(s):  
Youzhi Zhang ◽  
Jinhua Ye ◽  
Haomiao Wang ◽  
Shuheng Huang ◽  
Haibin Wu
Keyword(s):  
Electric Field ◽  
Tactile Sensor ◽  
Uniform Electric Field ◽  
Conductive Layer ◽  
Conducting Plane ◽  
Ito Film ◽  
Position Detection ◽  
Conductive Line ◽  
Plane Shape ◽  
Contact Position

Tactility is an essential perception for intelligent equipment to acquire external information. It can improve safety and performance during human-machine interactions. Based on the uniqueness theorem of the electrostatic field, a novel flexible film tactile sensor that can detect contact position and be made into any plane shape is proposed in this paper. The tactile sensor included an indium tin oxide (ITO) film, which was uniformly coated on the polyethylene terephthalate (PET) substrate. A specially designed strong conductive line was arranged along the edge of the flexible ITO film, which has weak conductivity. A bias excitation was applied to both ends of the strong conductive line. Through the control of the shape of the strong conductive line, a uniform electric field can be constructed in the whole weak conductive plane. According to the linear relationship between position and potential in the uniform electric field, the coordinate of the contact position can be determined by obtaining the potential of the contact point in the weak conducting plane. The sensor uses a three-layer structure, including an upper conductive layer, an intermediate isolation layer, and a lower conductive layer. A tactile sensor sample was fabricated. The experiment results showed that the principle of the tactile sensor used for the contact position detection is feasible and has certain precision of position detection. The sensor has good flexibility, and can be made into any plane shape, and has only four wires. It is capable of covering large areas of robot arms, and provides safety solutions for most robots.

New tactile sensor for position detection based on distributed planar electric field

2016 ◽  
Vol 242 ◽  
pp. 146-161 ◽  
Author(s):  
Haibin Wu ◽  
Jianpeng Chen ◽  
Yixian Su ◽  
Zhijing Li ◽  
Jinhua Ye
Keyword(s):  
Electric Field ◽  
Tactile Sensor ◽  
Position Detection

scholarly journals RF-Carpets that Compress Ions to High Density Beams

2015 ◽  
Vol 21 (S4) ◽  
pp. 84-89
Author(s):  
H. Wollnik ◽  
F. Arai ◽  
Y. Ito ◽  
P. Schury ◽  
M. Wada
Keyword(s):  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Ion Beams ◽  
High Density ◽  
Ion Density ◽  
Field Lines

AbstractIons that are moved by electric fields in gases follow quite exactly the electric field lines since these ions have substantially lost their kinetic energies in collisions with gas atoms or molecules and so carry no momenta. Shaping the electric fields appropriately the phase space such ion beams occupy can be reduced and correspondingly the ion density of beams be increased.

scholarly journals Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 1: Elementary models

2016 ◽  
Vol 34 (1) ◽  
pp. 55-65 ◽  
Author(s):  
A. D. M. Walker ◽  
G. J. Sofko
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Electric Field ◽  
Electric Fields ◽  
Magnetic Field Line ◽  
Geomagnetic Field ◽  
Geomagnetic Field Models ◽  
Spatial Derivatives ◽  
Field Lines ◽  
The Magnetic Field

Abstract. When studying magnetospheric convection, it is often necessary to map the steady-state electric field, measured at some point on a magnetic field line, to a magnetically conjugate point in the other hemisphere, or the equatorial plane, or at the position of a satellite. Such mapping is relatively easy in a dipole field although the appropriate formulae are not easily accessible. They are derived and reviewed here with some examples. It is not possible to derive such formulae in more realistic geomagnetic field models. A new method is described in this paper for accurate mapping of electric fields along field lines, which can be used for any field model in which the magnetic field and its spatial derivatives can be computed. From the spatial derivatives of the magnetic field three first order differential equations are derived for the components of the normalized element of separation of two closely spaced field lines. These can be integrated along with the magnetic field tracing equations and Faraday's law used to obtain the electric field as a function of distance measured along the magnetic field line. The method is tested in a simple model consisting of a dipole field plus a magnetotail model. The method is shown to be accurate, convenient, and suitable for use with more realistic geomagnetic field models.

scholarly journals A Look into Students' Interpretation of Electric Field Lines

2017 ◽  
pp. 342-364
Author(s):  
Esmeralda Campos ◽  
Genaro Zavala
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Random Sample ◽  
Qualitative Approach ◽  
Undergraduate Level ◽  
Field Lines

On Electricity & Magnetism (EM) courses at undergraduate level, the concept of electric field poses one of the most relevant and basic topics, along with the concept of magnetic field. Professors and students may use different diagrams as a tool to visualize the electric field, such as vectors or electric field lines. The present study aims to identify how students interpret and use electric field lines as a tool or resource to describe the electric field. Two versions of a test with open-ended questions were administered in Spanish in a private Mexican university to a random sample of students taking the EM course, and were analyzed with a qualitative approach. It was found that students do not interpret electric field lines diagrams correctly, which may lead to misconceptions. Many students based their answers on the concepts of superposition, force and repulsion.

scholarly journals A Triboelectric-Based Artificial Whisker for Reactive Obstacle Avoidance and Local Mapping

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Peng Xu ◽  
Xingyu Wang ◽  
Siyuan Wang ◽  
Tianyu Chen ◽  
Jianhua Liu ◽  
...  
Keyword(s):  
Obstacle Avoidance ◽  
Autonomous Robots ◽  
Tactile Sensor ◽  
Triboelectric Nanogenerator ◽  
Tactile Sensors ◽  
Biologically Inspired ◽  
External Stimulation ◽  
Autonomous Surface Vehicles ◽  
Electrostatic Induction ◽  
Contact Position

Since designing efficient tactile sensors for autonomous robots is still a challenge, this paper proposes a perceptual system based on a bioinspired triboelectric whisker sensor (TWS) that is aimed at reactive obstacle avoidance and local mapping in unknown environments. The proposed TWS is based on a triboelectric nanogenerator (TENG) and mimics the structure of rat whisker follicles. It operates to generate an output voltage via triboelectrification and electrostatic induction between the PTFE pellet and copper films (0.3 mm thickness), where a forced whisker shaft displaces a PTFE pellet (10 mm diameter). With the help of a biologically inspired structural design, the artificial whisker sensor can sense the contact position and approximate the external stimulation area, particularly in a dark environment. To highlight this sensor’s applicability and scalability, we demonstrate different functions, such as controlling LED lights, reactive obstacle avoidance, and local mapping of autonomous surface vehicles. The results show that the proposed TWS can be used as a tactile sensor for reactive obstacle avoidance and local mapping in robotics.

General Relations between Fields and Sources

2019 ◽  
pp. 63-84
Author(s):  
Richard Freeman ◽  
James King ◽  
Gregory Lafyatis
Keyword(s):  
Electric Field ◽  
Spatial Variations ◽  
Rate Of Change ◽  
Retarded Time ◽  
Finite Speed ◽  
Radiation Fields ◽  
Source Current ◽  
Field Lines ◽  
General Relations ◽  
Relationship Of

The general relationship of changes in source current, charge and/or position and the fields that they produce are examined in the context of the development of equations that are known as “Jefimenko’s Equations.” These expressions give the fields at a point removed from the source in terms of the charge and current distributions evaluated at the “retarded time.” In this development, the finite speed of light is shown to connect the time rate of change in source conditions to the spatial variations of the potential at the field point. Using a graphical argument, the transverse nature of radiation fields is demonstrated based on electric field lines as envisioned by Faraday.

scholarly journals The occurrence frequency of auroral potential structures and electric fields as a function of altitude using Polar/EFI data

2004 ◽  
Vol 22 (4) ◽  
pp. 1233-1250 ◽  
Author(s):  
P. Janhunen ◽  
A. Olsson ◽  
H. Laakso
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Radial Distance ◽  
Plasma Potential ◽  
Potential Structure ◽  
New Finding ◽  
Low Altitude ◽  
Field Lines ◽  
Auroral Arcs

Abstract. The aim of the paper is to study how auroral potential structures close at high altitude. We analyse all electric field data collected by Polar on auroral field lines in 1996–2001 by integrating the electric field along the spacecraft orbit to obtain the plasma potential, from which we identify potential minima by an automatic method. From these we estimate the associated effective mapped-down electric field Ei, defined as the depth of the potential minimum divided by its half-width in the ionosphere. Notice that although we use the ionosphere as a reference altitude, the field Ei does not actually exist in the ionosphere but is just a convenient computational quantity. We obtain the statistical distribution of Ei as a function of altitude, magnetic local time (MLT), Kp index and the footpoint solar illumination condition. Surprisingly, we find two classes of electric field structures. The first class consists of the low-altitude potential structures that are presumably associated with inverted-V regions and discrete auroral arcs and their set of associated phenomena. We show that the first class exists only below ~3RE radial distance, and it occurs in all nightside MLT sectors (RE=Earth radius). The second class exists only above radial distance R=4RE and almost only in the midnight MLT sector, with a preference for high Kp values. Interestingly, in the middle altitudes (R=3–4RE) the number of potential minima is small, suggesting that the low and high altitude classes are not simple field-aligned extensions of each other. This is also underlined by the fact that statistically the high altitude structures seem to be substorm-related, while the low altitude structures seem to correspond to stable auroral arcs. The new finding of the existence of the two classes is important for theories of auroral acceleration, since it supports a closed potential structure model for stable arcs, while during substorms, different superposed processes take place that are associated with the disconnected high-altitude electric field structures. Key words. Magnetospheric physics (electric fields; auroral phenomena) – Space plasma physics (electrostatic structures)

scholarly journals Very High-Energy Emission from the Direct Vicinity of Rapidly Rotating Black Holes

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 122 ◽  
Author(s):  
Kouichi Hirotani
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Black Hole ◽  
Electric Field ◽  
Gamma Rays ◽  
Accretion Rate ◽  
High Energy ◽  
Relativistic Electrons ◽  
Field Lines ◽  
The Magnetic Field

When a black hole accretes plasmas at very low accretion rate, an advection-dominated accretion flow (ADAF) is formed. In an ADAF, relativistic electrons emit soft gamma-rays via Bremsstrahlung. Some MeV photons collide with each other to materialize as electron-positron pairs in the magnetosphere. Such pairs efficiently screen the electric field along the magnetic field lines, when the accretion rate is typically greater than 0.03–0.3% of the Eddington rate. However, when the accretion rate becomes smaller than this value, the number density of the created pairs becomes less than the rotationally induced Goldreich–Julian density. In such a charge-starved magnetosphere, an electric field arises along the magnetic field lines to accelerate charged leptons into ultra-relativistic energies, leading to an efficient TeV emission via an inverse-Compton (IC) process, spending a portion of the extracted hole’s rotational energy. In this review, we summarize the stationary lepton accelerator models in black hole magnetospheres. We apply the model to super-massive black holes and demonstrate that nearby low-luminosity active galactic nuclei are capable of emitting detectable gamma-rays between 0.1 and 30 TeV with the Cherenkov Telescope Array.

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