A capacitive angular sensor with flexible digitated electrodes

Sensor Review ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 382-388 ◽  
Author(s):  
Damir Krklješ ◽  
Dragana Vasiljević ◽  
Goran Stojanović
Keyword(s):  
Printed Electronics ◽  
Angular Displacement ◽  
Angular Position ◽  
Capacitive Sensor ◽  
Measurement Range ◽  
Content Type ◽  
Full Turn ◽  
Sensor Structure ◽  
Capacitor Structure ◽  
Incremental Encoder

Purpose – This paper aims to present a prototype of a capacitive angular-position sensor which exploits advantages of flexible/printed electronics. The novelty of the sensor is that the capacitor structure is placed at the circumference of the rotor and stator, that it posses two channels (capacitor structures) electrically shifted for p/4 and that the rotor is common for both channels. The electrodes of the sensing capacitor are digitated, providing a triangular transfer function. Design/methodology/approach – This sensor prototype consists of two flexible inkjet-printed silver electrodes forming a cylindrical capacitor structure. One of them is wrapped around the stator and another is wrapped around the rotor part of a simple mechanical platform used to precisely adjust the angular displacement. Findings – The capacitance as a function of angular position was measured using an inductance capacitance impedance (LCZ) Meter, and results are presented for a full-turn measurement range. The experimental results are compared with analytical ones and very good agreement has been achieved. Originality/value – The proposed capacitive sensor structure can be used as an absolute or an incremental encoder with different resolutions, and it can be applied in automotive industry or robotics.

A Planar Capacitive Sensor Parameter Design for Security Detection

2015 ◽  
Vol 713-715 ◽  
pp. 642-646
Author(s):  
Xiang Dong Yang ◽  
Yu Gong ◽  
Nan Li ◽  
Pai Wang
Keyword(s):  
Potential Distribution ◽  
Signal Strength ◽  
Capacitive Sensor ◽  
Measurement Range ◽  
Experimental Results ◽  
Parameter Design ◽  
Structure Parameters ◽  
Sensor Parameter ◽  
Sensor Structure

A planar capacitive sensor is designed for security detection. The different length of the sensor electrodes are design and the experiments are presented. For the relations between sensor structure parameters and the sensor potential distribution, detailed analyses are presented and the qualitative conclusions are discussed. The signal strength and measurement range of the sensor can be improved by enlarge the length of the sensor electrodes. The experimental results indicate that the sensor is more portable, easy to minimize, and applicable to the detection of a variety of sizes of containers. It is feasible to be applied to security detection.

In-situ capacitive sensor for monitoring debris of lubricant oil

2018 ◽  
Vol 70 (7) ◽  
pp. 1310-1319 ◽  
Author(s):  
Yishou Wang ◽  
Zhibin Han ◽  
Tian Gao ◽  
Xinlin Qing
Keyword(s):  
Capacitive Sensor ◽  
Oil Well ◽  
Capacitive Sensors ◽  
Parallel Plates ◽  
Content Type ◽  
Lubricant Oil ◽  
Sensor Structure ◽  
Simulation And Experiment ◽  
Oil Debris ◽  
Future Work

Purpose The purpose of this study is to develop a cylindrical capacitive sensor that has the advantages of high resolution, small size and designability and can be easily installed on lubricant pipeline to monitor lubricant oil debris. Design/methodology/approach A theoretical model of the cylindrical capacitive sensor is presented to analyze several parameters’ effectiveness on the performance of sensor. Numerical simulations are then conducted to determine the optimal parameters for preliminary experiments. Experiments are finally carried out to demonstrate the detectability of developed capacitive sensors. Findings It is clear from experimental results that the developed capacitive sensor can monitor the debris in lubricant oil well, and the capacitance values increase almost linearly when the number and size of debris increase. Research limitations/implications There is lot of further work to do to apply the presented method into the application. Especially, it is necessary to consider several factors’ influence on monitoring results. These factors include the flow rate of the lubricant oil, the temperature, the debris distribution and the vibration. Moreover, future work should consider the influence of the oil degradation to the capacitance change and other contaminations (e.g. water and dust). Practical implications This work conducts a feasibility study on application of capacitive sensing principle for detecting debris in aero engine lubricant oil. Originality/value The novelty of the presented capacitance sensor can be summarized into two aspects. One is that the sensor structure is simple and characterized by two coaxial cylinders as electrodes, while conventional capacitive sensors are composed of two parallel plates as electrodes. The other is that sensing mechanism and physical model of the presented sensor is verified and validated by the simulation and experiment.

Measurement and analysis of winding thickness variations in sectional warping process

2018 ◽  
Vol 30 (6) ◽  
pp. 772-783
Author(s):  
Recep Eren ◽  
Ozge Celik ◽  
Fatih Suvari ◽  
Seyit Ali Koksal
Keyword(s):  
Angular Position ◽  
Sheet Thickness ◽  
Woven Fabrics ◽  
Point Of View ◽  
Thickness Variation ◽  
Laser Sensor ◽  
Content Type ◽  
Key Factor ◽  
Thickness Variations ◽  
Incremental Encoder

Purpose Sectional warping is the most widely used warp preparation process in weaving. Winding all warp sections with the same length and same tension is a key factor for a good quality warp preparation. It is required that winding thickness (increase in radius due to warp winding) remains the same within and between warp sections. The purpose of this paper is to investigate winding thickness variations within and between warp sections, which can lead to quality problems in woven fabrics. Design/methodology/approach A measurement system is developed and then an experimental investigation into winding thickness variations is carried out. Winding thickness is measured with respect to number of drum revolutions using a laser sensor with 20 microns resolution. The number of drum revolutions and drum angular position are measured by an incremental encoder. Both sensors are mounted on an industrial sectional warping machine. A real-time software written in C programming language collects and records the data for all sections of warp with respect to drum number of revolutions and then results are evaluated to determine winding thickness variations. Findings Results show that warp sheet thickness starts with a higher value and it decreases up to around 30 drum revolutions and then it remains constant or decreases very slightly which can be considered as insignificant from practical point of view. Warp sheet thickness (i.e. thickness of one warp layer) fluctuates within each section up to 10 percent CV with five drum revolutions average warp sheet thickness. There are also warp sheet thickness variations between warp sections up to 3 mm. Originality/value Considering the short of practical research results on winding thickness variations in the literature, results of this study will be an original contribution to understanding winding thickness variation level. Also, results presented in this paper can be used to develop control algorithms for thickness control in sectional warping machines.

Development and operation of a fiber Bragg grating based online monitoring strategy for slope deformation

Sensor Review ◽  
2015 ◽  
Vol 35 (4) ◽  
pp. 348-356 ◽  
Author(s):  
Yongxing Guo ◽  
Dongsheng Zhang ◽  
Jianjun Fu ◽  
Shaobo Liu ◽  
Shengzhuo Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Online Monitoring ◽  
Deformation Monitoring ◽  
Slope Deformation ◽  
Remote Access ◽  
Monitoring Strategy ◽  
Content Type ◽  
Flexible Pipes ◽  
Sensor Structure ◽  
Distributed Strain

Purpose – The purpose of this paper is to investigate an online monitoring strategy that incorporates fiber Bragg gratings (FBGs) for deformation displacement detection, with the background that slope deformation monitoring is crucial to engineering safety supervision and disaster prevention. Design/methodology/approach – A “beam element” method has been proposed, introduced and experimentally verified in detail. The deformation displacement along a flexible bar can be obtained based on this method, using the distributed strain detected by the FBGs embedded in the bar. A novel sensor structure containing inclinometer casings and a series of connected flexible pipes with FBGs embedded has been proposed. Based on the features of this structure, two FBG deformation sensors have been manufactured and installed into a slope. A matched monitoring station which permits real-time supervision, warning and remote access across the Internet was established and operated. Findings – Displacement data from September 2013 to August 2014 are obtained, which is basically consistent with the practical situation. Originality/value – The FBG deformation sensors demonstrated a robust and reliable measurement performance, which is promising for real-time disaster warning in slope engineering.

scholarly journals A Simple Method for the Detection of Biofilms Using a Heatable Capacitive Sensor Structure (CSS): Description, Proof of Concept, and Some Technical Improvements

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 445
Author(s):  
Kai-Uwe Zirk ◽  
Manuel Olze ◽  
Harald Pötzschke
Keyword(s):  
Printed Circuit Boards ◽  
Free Water ◽  
Spray Coating ◽  
Internal Surface ◽  
Capacitive Sensor ◽  
Simple Method ◽  
Realistic Condition ◽  
Main Challenge ◽  
Sensor Structure ◽  
The Difference

This article presents a novel method for the detection of biofilms based on a heatable, capacitive sensor structure (CSS). Biofilms are capable of strongly binding large amounts of water to their extracellular biopolymer matrix, which is detectable via its dielectric properties. A main challenge is to determine the difference between the inherent occurring presence of moisture in the ecosystem, which is necessary to form a biofilm and an actual formed biofilm. Therefore, the CSS is carefully heated to evaporate unbound surface moisture and determine whether there is a remaining residual alternation of the capacitance in comparison to the dry state. As a reproduceable substitute for complex, real biofilms, a hygroscopic, medical hydrogel-based on polysaccharides was used and applied by spray coating. Printed circuit boards (PCB) in different geometries and materials were used as CSS and compared in terms of their performance. A layer-thickness of 20 µm for the hydrogel coating to be sufficiently detected was defined as a realistic condition based on known values for real biofilms cited in literature. For this thickness a double-meander structure proves to be preferable over interdigitating and spiral geometries. It does offer a 30% lower, yet sufficient sensitivity, but shows advantages in manufacturing (one layer instead of two) and conductive heating capability. In the experiments, free water showed virtually no residual change, while the hydrogel-coated CSS still shows an approx. 300% higher value compared to a dry capacity. Yet, the overall small capacities of about 6–30 pF in dry state are difficult to measure and therefore sensitive to interferences and noise, which results in a high deviation. The principle of measurement can be evaluated as proofed by the carried out experiments, though offering room for improvement in the design of the study. The new method might be especially useful for pipes (e.g., hydrodynamically ineffective sensors installed in a pipe wall) if they at least are not permanently flooded with an aqueous medium, but can occasionally dry. If the internal surface is still only moist, it can be dried by initial heating.

scholarly journals Optimization of a Handwriting Method by an Automated Ink Pen for Cost-Effective and Sustainable Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 264
Author(s):  
Florin C. Loghin ◽  
José F. Salmerón ◽  
Paolo Lugli ◽  
Markus Becherer ◽  
Aniello Falco ◽  
...  
Keyword(s):  
Printed Electronics ◽  
Low Cost ◽  
Electronic Devices ◽  
Cost Effective ◽  
Capacitive Sensor ◽  
Fabrication Technique ◽  
Rfid Tag ◽  
Environmental Friendly ◽  
Fast Prototyping ◽  
Do It Yourself

In this work, we present a do-it-yourself (DIY) approach for the environmental-friendly fabrication of printed electronic devices and sensors. The setup consists only of an automated handwriting robot and pens filled with silver conductive inks. Here, we thoroughly studied the fabrication technique and different optimized parameters. The best-achieved results were 300 mΩ/sq as sheet resistance with a printing resolution of 200 µm. The optimized parameters were used to manufacture fully functional electronics devices: a capacitive sensor and a RFID tag, essential for the remote reading of the measurements. This technique for printed electronics represents an alternative for fast-prototyping and ultra-low-cost fabrication because of both the cheap equipment required and the minimal waste of materials, which is especially interesting for the development of cost-effective sensors.

Fabrication and characterization of a flexible capacitive sensor on PET fabric

2018 ◽  
Vol 30 (5) ◽  
pp. 687-697 ◽  
Author(s):  
Sabereh Golabzaei ◽  
Ramin Khajavi ◽  
Heydar Ali Shayanfar ◽  
Mohammad Esmail Yazdanshenas ◽  
Nemat Talebi
Keyword(s):  
Detection Threshold ◽  
Capacitive Sensor ◽  
Aluminum Electrode ◽  
Dielectric Thickness ◽  
Content Type ◽  
Flexible Sensors ◽  
Pet Fabric ◽  
Aluminum Plates ◽  
Dielectric Insulation

Purpose There is a developing interest in flexible sensors, especially in the new and intelligent generation of textiles. The purpose of this paper is to fabricate a flexible capacitive sensor on a PET fabric and to investigate some affecting factor on its performance. Design/methodology/approach PET fabric, coated with graphite or with graphite/PEDOT:PSS, was applied as electrodes. Two types of electrospun nanoweb layers from polyamide and polyvinyl alcohol polymers were used as dielectrics. Some factors including electrode area, fabric conductivity, fabric roughness, dielectric thickness, dielectric insulation type and vertical pressure were considered as independent variables. The capacity of the sensor and its detection threshold considered as the outcome (response) variables. Control samples were fabricated by using aluminum plates and cellulosic layer as electrodes and dielectric, respectively. Findings Results showed that post-coating with PEDOT:PSS would improve the conductivity of electrodes up to 300 Ω in comparison with just graphite-coated samples. It was also found that either by improving the conductivity or increasing the area of electrode plates the sensitivity of sample would be increased in pressure stimulating tests. Originality/value The fabric sensor showed remarkable response toward pressure with a lower detection threshold of 30mN/cm2 (obtained capacity ~ 4×104 pF) in comparison with aluminum electrode sensors.

scholarly journals Detection of Single Steel Strand Distribution in Grouting Duct Based on Capacitive Sensing Technique

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2564 ◽  
Author(s):  
Nan Li ◽  
Mingchen Cao ◽  
Hangben Du ◽  
Cunfu He ◽  
Bin Wu
Keyword(s):  
Capacitive Sensor ◽  
Experimental Results ◽  
Capacitive Sensing ◽  
Capacitance Measurements ◽  
Position Detection ◽  
Steel Bar ◽  
Sensor Structure ◽  
Steel Strand ◽  
Center Distance ◽  
Post Tensioned

Grouting ducts (containing steel strands) are widely used to increase the structural strengths of infrastructures. The determination of the steel strand’s integrity inside of ducts and the grouting quality are important for a strength evaluation of the structure. In this study, a capacitive sensing technique was applied to identify the cross-sectional distribution of the steel strands. The distribution was expressed in polar coordinates in an external post-tensioned pre-stressed duct model. An improved capacitive sensor structure was designed, which consisted of four electrodes, and different electrode-pairs were used to determine various locations’ information of the steel strands. Two rounds of measurements were conducted using the designed sensor to detect the angle (θ) and center distance (r) of the steel strand in the duct. The simulated and experimental results are presented and analyzed. In general, it is difficult to locate the angle of a steel strand directly from first-round capacitance measurements by analyzing the experimental results. Our method based on Q-factor analysis was presented for the position detection of a steel bar in an external post-tensioned pre-stressed duct. The center distance of the steel bar could be identified by second-round capacitance measurements. The processed results verified the effectiveness of the proposed capacitive sensor structure. Thus, the capacitive sensing technique exhibited potential for steel strand cross-section distribution detection in external post-tensioned pre-stressed ducts.

Real-Time System for Liquid Level Measurement

2013 ◽  
Vol 441 ◽  
pp. 356-359
Author(s):  
Wei Wei ◽  
Hai Ying Jiang ◽  
Qin Jian Sun ◽  
Qiang Huang ◽  
Zhi Wei Wang
Keyword(s):  
Harmonic Oscillation ◽  
High Sensitivity ◽  
Capacitive Sensor ◽  
Liquid Level ◽  
Capacitance Measurement ◽  
Measurement Circuit ◽  
Real Time System ◽  
Level Measurement ◽  
Sensor Structure ◽  
Level Height

A small level measurement system is designed by installing a compact capacitive level sensor in the small container. By analyzing the capacitive sensor structure, a sensor measurement circuit is designed with high sensitivity, measuring stability and good repeatability. Capacitance measurement circuit makes use of multiple harmonic oscillation principle. The microcomputer measures the oscillation frequency of the multivibrator, and calculates the liquid level height based on the monotonic function about the liquid level height and frequency.

scholarly journals A new joint friction model for parameter identification and sensor-less hand guiding in industrial robots

2020 ◽  
Vol 47 (6) ◽  
pp. 847-857
Author(s):  
Guanghui Liu ◽  
Qiang Li ◽  
Lijin Fang ◽  
Bing Han ◽  
Hualiang Zhang
Keyword(s):  
Industrial Robot ◽  
Angular Displacement ◽  
Weighted Least Squares ◽  
Friction Model ◽  
Industrial Robots ◽  
Model Parameters ◽  
Dynamic Parameters ◽  
Content Type ◽  
Joint Friction ◽  
Six Dof

Purpose The purpose of this paper is to propose a new joint friction model, which can accurately model the real friction, especially in cases with sudden changes in the motion direction. The identification and sensor-less control algorithm are investigated to verify the validity of this model. Design/methodology/approach The proposed friction model is nonlinear and it considers the angular displacement and angular velocity of the joint as a secondary compensation for identification. In the present study, the authors design a pipeline – including a manually designed excitation trajectory, a weighted least squares algorithm for identifying the dynamic parameters and a hand guiding controller for the arm’s direct teaching. Findings Compared with the conventional joint friction model, the proposed method can effectively predict friction factors during the dynamic motion of the arm. Then friction parameters are quantitatively obtained and compared with the proposed friction model and the conventional friction model indirectly. It is found that the average root mean square error of predicted six joints in the proposed method decreases by more than 54%. The arm’s force control with the full torque using the estimated dynamic parameters is qualitatively studied. It is concluded that a light-weight industrial robot can be dragged smoothly by the hand guiding. Practical implications In the present study, a systematic pipeline is proposed for identifying and controlling an industrial arm. The whole procedure has been verified in a commercial six DOF industrial arm. Based on the conducted experiment, it is found that the proposed approach is more accurate in comparison with conventional methods. A hand-guiding demo also illustrates that the proposed approach can provide the industrial arm with the full torque compensation. This essential functionality is widely required in many industrial arms such as kinaesthetic teaching. Originality/value First, a new friction model is proposed. Based on this model, identifying the dynamic parameter is carried out to obtain a set of model parameters of an industrial arm. Finally, a smooth hand guiding control is demonstrated based on the proposed dynamic model.

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