A theoretical model of flexible capacitive pressure sensor with microstructured electrode for highly sensitive electronic skin

2021 ◽  
Author(s):  
Weidong Yang ◽  
Wenxuan Ding ◽  
Menglong Liu ◽  
Jun Yang ◽  
Mao Li
Keyword(s):  
Pressure Sensor ◽  
Electromechanical Coupling ◽  
Present Model ◽  
Pressure Sensors ◽  
Compressive Force ◽  
Contact Radius ◽  
Capacitive Pressure Sensor ◽  
Electronic Skin ◽  
Highly Sensitive ◽  
Theory Framework

Abstract Electronic skin (E-skin) has attracted much attention in smart wearables, prosthetics, and robotics. The capacitive-type pressure sensor is generally regarded as one good option to design tactile sensing devices owing to its superior sensitivity in low-pressure region, fast response time and convenient manufacturing. Introducing microstructures on electrode surface is an effective approach to achieve highly sensitive capacitive pressure sensors. In this work, an electromechanical model is proposed to build the relationship between capacitance change and compressive force. The present model can predict the sensitivity of capacitive pressure sensor with microstructured electrodes, where each cellular microstructure is modeled using the contact mechanics theory. It is the first time in the literature that based on Hertz theory framework, one rigorous electromechanical theory framework is established to model flexible capacitive pressure sensor, and the model can be extended to other microstructures, such as micro-pyramid, micro-pillar, and micro-dome array. The validation indicates that the analytical results well agree with the experimental data from our previous work and other literatures. Moreover, the present model can well capture the sensitivity of pressure sensor on the beginning range of small pressure. The sensitivity on this range is the most significant for the E-skin due to its robust linearity for one pressure sensor. Besides, we analyzed the compressive force-displacement relationship, the compressive force-contact radius relationship and the influences of the geometrical and material parameters on the electromechanical coupling effect. The results show that the height and the Young’s modulus of the soft dielectric layer are regarded as the dominant influencing factors in the sensitivity of capacitive pressure sensors.

scholarly journals A Highly Sensitive and Flexible Capacitive Pressure Sensor Based on a Porous Three-Dimensional PDMS/Microsphere Composite

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1412 ◽  
Author(s):  
Young Jung ◽  
Wookjin Lee ◽  
Kyungkuk Jung ◽  
Byunggeon Park ◽  
Jinhyoung Park ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Sacrificial Layer ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
Capacitive Pressure Sensor ◽  
Mechanical Stimuli ◽  
Highly Sensitive ◽  
Flexible Pressure Sensors ◽  
Fast Rise ◽  
Better Than

In recent times, polymer-based flexible pressure sensors have been attracting a lot of attention because of their various applications. A highly sensitive and flexible sensor is suggested, capable of being attached to the human body, based on a three-dimensional dielectric elastomeric structure of polydimethylsiloxane (PDMS) and microsphere composite. This sensor has maximal porosity due to macropores created by sacrificial layer grains and micropores generated by microspheres pre-mixed with PDMS, allowing it to operate at a wider pressure range (~150 kPa) while maintaining a sensitivity (of 0.124 kPa−1 in a range of 0~15 kPa) better than in previous studies. The maximized pores can cause deformation in the structure, allowing for the detection of small changes in pressure. In addition to exhibiting a fast rise time (~167 ms) and fall time (~117 ms), as well as excellent reproducibility, the fabricated pressure sensor exhibits reliability in its response to repeated mechanical stimuli (2.5 kPa, 1000 cycles). As an application, we develop a wearable device for monitoring repeated tiny motions, such as the pulse on the human neck and swallowing at the Adam’s apple. This sensory device is also used to detect movements in the index finger and to monitor an insole system in real-time.

scholarly journals A new strategy for the fabrication of a flexible and highly sensitive capacitive pressure sensor

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ruzhan Qin ◽  
Mingjun Hu ◽  
Xin Li ◽  
Te Liang ◽  
Haoyi Tan ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Capacitive Sensor ◽  
Capacitive Pressure Sensor ◽  
Interdigital Electrode ◽  
Interdigital Electrodes ◽  
Highly Sensitive ◽  
New Strategy ◽  
Application Prospects

AbstractThe development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices, but it is still a great challenge to fabricate capacitive sensors with high sensitivity. Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors. In this work, a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone (PVP) by an interdigital electrode is reported. By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer, the sensitivity of the capacitive sensor can be improved. The capacitive sensor based on MXene/PVP here has a high sensitivity (~1.25 kPa−1), low detection limit (~0.6 Pa), wide sensing range (up to 294 kPa), fast response and recovery times (~30/15 ms) and mechanical stability of 10000 cycles. The presented sensor here can be used for various pressure detection applications, such as finger pressing, wrist pulse measuring, breathing, swallowing and speech recognition. This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics.

scholarly journals Flexible and Transparent Pressure Sensor Based on CNTs Film Microstructure

2021 ◽  
Author(s):  
Liangliang Liu ◽  
Xin Yan
Keyword(s):  
Pressure Sensor ◽  
Production Cost ◽  
Composite Electrode ◽  
Pressure Sensors ◽  
Wearable Devices ◽  
Capacitive Pressure Sensor ◽  
Detection Range ◽  
Electronic Skin ◽  
Film Microstructure ◽  
Flexible Pressure Sensors

Abstract In recent years, capacitive flexible pressure sensors have been widely studied in electronic skin and wearable devices. The traditional capacitive pressure sensor has a higher production cost due to micro-nano machining technology such as lithography. This paper presents a flexible transparent capacitive pressure sensor based on a PDMS/CNT composite electrode, simple, transparent, flexible, and arrays without lithography. The sensitivity of the device has been tested to 0.0018 kpa -1 with a detection range of 0-30 kPa. The sensor is capable of rapidly detecting different pressures and remains stable after 100 load-unload tests.

Development of circuit solution and design of capacitive pressure sensor array for applied robotics

2020 ◽  
Vol 8 (4) ◽  
pp. 296-307
Author(s):  
Konstantin Krestovnikov ◽  
Aleksei Erashov ◽  
Аleksandr Bykov
Keyword(s):  
Pressure Sensor ◽  
Output Signal ◽  
Sensor Array ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Fine Tuning ◽  
Capacitive Pressure Sensor ◽  
Cell Parameters ◽  
Linear Pattern ◽  
Sensor Structure

This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.

scholarly journals A flexible, ultra-highly sensitive and stable capacitive pressure sensor with convex microarrays for motion and health monitoring

Nano Energy ◽  
2020 ◽  
Vol 70 ◽  
pp. 104436 ◽  
Author(s):  
Yaoxu Xiong ◽  
Youkang Shen ◽  
Lan Tian ◽  
Yougen Hu ◽  
Pengli Zhu ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Pressure Sensor ◽  
Capacitive Pressure Sensor ◽  
Highly Sensitive

scholarly journals Flexible and Highly Sensitive Pressure Sensors Based on Microstructured Carbon Nanowalls Electrodes

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 496 ◽  
Author(s):  
Xi Zhou ◽  
Yongna Zhang ◽  
Jun Yang ◽  
Jialu Li ◽  
Shi Luo ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Limit Of Detection ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Physiological Signals ◽  
Healthcare Applications ◽  
Highly Sensitive ◽  
Carbon Nanowalls ◽  
Pressure Regime

Wearable pressure sensors have attracted widespread attention in recent years because of their great potential in human healthcare applications such as physiological signals monitoring. A desirable pressure sensor should possess the advantages of high sensitivity, a simple manufacturing process, and good stability. Here, we present a highly sensitive, simply fabricated wearable resistive pressure sensor based on three-dimensional microstructured carbon nanowalls (CNWs) embedded in a polydimethylsiloxane (PDMS) substrate. The method of using unpolished silicon wafers as templates provides an easy approach to fabricate the irregular microstructure of CNWs/PDMS electrodes, which plays a significant role in increasing the sensitivity and stability of resistive pressure sensors. The sensitivity of the CNWs/PDMS pressure sensor with irregular microstructures is as high as 6.64 kPa−1 in the low-pressure regime, and remains fairly high (0.15 kPa−1) in the high-pressure regime (~10 kPa). Both the relatively short response time of ~30 ms and good reproducibility over 1000 cycles of pressure loading and unloading tests illustrate the high performance of the proposed device. Our pressure sensor exhibits a superior minimal limit of detection of 0.6 Pa, which shows promising potential in detecting human physiological signals such as heart rate. Moreover, it can be turned into an 8 × 8 pixels array to map spatial pressure distribution and realize array sensing imaging.

scholarly journals Flexible and highly sensitive pressure sensors based on microcrack arrays inspired by scorpions

RSC Advances ◽  
2019 ◽  
Vol 9 (39) ◽  
pp. 22740-22748
Author(s):  
Junqiu Zhang ◽  
Tao Sun ◽  
Linpeng Liu ◽  
Shichao Niu ◽  
Kejun Wang ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Highly Sensitive ◽  
Sensitive Pressure

The pressure sensor based on microcrack arrays inspired by the scorpion.

scholarly journals Efficient in-depth analysis and optimum design parameter estimation of MEMS capacitive pressure sensor utilizing analytical approach for square diaphragm

2021 ◽  
Author(s):  
SUMIT KUMAR JINDAL ◽  
ISHAN PATEL ◽  
KRISH SETHI ◽  
SIMRIT KAUL ◽  
SREEKANTH P K ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Optimal Operation ◽  
Design Parameters ◽  
Capacitive Pressure Sensor ◽  
Computationally Efficient ◽  
Analytical Technique ◽  
Operating Modes ◽  
Depth Analysis ◽  
Piezoresistive Pressure Sensors

Abstract Capacitive pressure sensors have become more popular as compared to piezoresistive pressure sensors as they yield superior sensitivity and lesser non-linearity. Efficient analysis for modelling capacitive pressure sensors is thus increasingly becoming more important due to their innumerable use cases. The higher sensitivity of square diaphragm for the same side length in comparison to circular diaphragm makes it ideal for sensor design. In this work, a complete formulation for analysis of capacitive pressure sensor with the square diaphragm in normal and touch mode operation has been presented as these two modes are established operating modes for these sensors. A comprehensive study of sensor parameters like capacitance, diaphragm deflection, capacitive and mechanical sensitivity has been formulated to aid the choice of sensor characteristics. This work also focuses on the method to determine core design parameters for optimal operation. Computationally complex methods have been used in the past for analysis of square diaphragms. In contrast to the finite element system, the analytical technique proposed in this study is less complex and computationally efficient (FEM). The results were computed and simulated using MATLAB.

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