scholarly journals New type of Piezoresistive Pressure Sensors for Environments with Rapidly Changing Temperature

2017 ◽  
Vol 24 (1) ◽  
pp. 185-192 ◽  
Author(s):  
Myroslav Tykhan ◽  
Orest Ivakhiv ◽  
Vasyl Teslyuk

Abstract The theoretical aspects of a new type of piezo-resistive pressure sensors for environments with rapidly changing temperatures are presented. The idea is that the sensor has two identical diaphragms which have different coefficients of linear thermal expansion. Therefore, when measuring pressure in environments with variable temperature, the diaphragms will have different deflection. This difference can be used to make appropriate correction of the sensor output signal and, thus, to increase accuracy of measurement. Since physical principles of sensors operation enable fast correction of the output signal, the sensor can be used in environments with rapidly changing temperature, which is its essential advantage. The paper presents practical implementation of the proposed theoretical aspects and the results of testing the developed sensor.

2018 ◽  
Vol 4 (1) ◽  
pp. 595-598
Author(s):  
Roland Fischer ◽  
Heinrich Ditler ◽  
Michael Görtz ◽  
Wilfried Mokwa

AbstractArtificial limbs, equipped with miniaturized tactile sensors, can handle objects with more dexterousness. Next to detecting forces, the sensor devices are also able to measure temperature. With this additional information, the touched objects can be better characterized. As such sensors, active CMOS-based capacitive pressure sensors are used in this work. The Sensors are thinned to 20-30 μm target thickness to make them bendable. One challenge of such thin sensors is the strong dependence of the output signal upon bending. To compensate this dependency, two sensors were mounted back to back. This allows a numerical adjustment of the two characteristic sensor output signals to mechanical stress curves. After electrically contacting of the stacks with a 15 μm thin polyimide foil substrate, the bending dependence of the stacks was characterized with a four-point bending procedure. By this characterization the dependency of the pressure sensor output signal on the height of mechanical stress was determined. Both sensor output signals show an inverted behavior under the same mechanical stress which confirmed prior simulation results with the same setup. Based on this information, a numerical method for compensating the bending dependence was successfully proven.


2021 ◽  
Author(s):  
Mikhail ◽  
Denis Prigodskiy

The article translated from Russian to English on pp. 691-693 (please, look down). The paper summarizes results of investigation of high-sensitivity MEMS pressure sensor based on a circuit containing both active and passive stress-sensitive elements: a differential amplifier utilizing two n-p-n piezotransistors and for p-type piezoresistors. A comparative analysis of a sensor utilizing this circuit with a pressure sensor based on traditional piezoresistive Wheatstone bridge and built on the same mechanical part is provided. MEMS pressure sensor with the differential amplifier (PSDA) has sensitivity of S = 0.66 mV/kPa/V, which exceeded the sensitivity of the element with piezoresistive Wheatstone bridge (PSWB) by 2.2 times. The sensitivity increase allows for the following sensor improvements: die size reduction, increase of diaphragm mechanical strength while keeping high pressure sensitivity, and simplifying requirements to external processing of the pressure sensor output signal. There are two main challenges related to the use of PSDA-based pressure sensors: strong dependence of output signal on temperature and higher than in PSWB noise reducing the dynamic range of the device to 10 3. The article describes methods of addressing these problems. The temperature dependence of sensor output signal can be minimized with help of an offset thermal compensation circuit and by eliminating metallization at the thin part of the diaphragm. The noise can be minimized by reducing the thickness of the active base region of the transistor. Circuit analysis with software NI Multisim shows that sensitivity of PSDA-based pressure sensor can be increased 2.3 times by circuit optimization.


2020 ◽  
Vol 8 (4) ◽  
pp. 296-307
Author(s):  
Konstantin Krestovnikov ◽  
Aleksei Erashov ◽  
Аleksandr Bykov

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.


2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Aditya Nugraha ◽  
Masri Bin Ardin

PVDF sensor is a sensor that is often used to measure force, strain, vibration and heat. In this study, PVDF sensors with surface polarization are used to detect cutting forces on the machine. The PVDF sensor that has been polarized on the surface is placed in the chuck part of the engine. Measuring instrumen for testing and calibrating PVDF sensors is oscilloscope with increased loading and reduced axial and tangential directions. After the calibration process, the PVDF sensor was used to measure cutting force on drilling machine, and then the results were compared with the PCB piezotronics force sensor. The PVDF sensor output signal is measured and studied for its voltage using an oscilloscope, where the output signal is compared to the weight given to the PVDF sensor. From the results of these tests indicate that the maximum deviation in axial loading is 0.32V while the tangential loading is 0.31VKeywords. PVDF sensor, Surface polarization, Drilling machine, Cutting force


Nanoscale ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 2779-2786 ◽  
Author(s):  
Jing Li ◽  
Santiago Orrego ◽  
Junjie Pan ◽  
Peisheng He ◽  
Sung Hoon Kang

We report a facile sacrificial casting–etching method to synthesize nanoporous carbon nanotube/polymer composites for ultra-sensitive and low-cost piezoresistive pressure sensors.


2000 ◽  
Vol 10 (2) ◽  
pp. 204-208 ◽  
Author(s):  
A Merlos ◽  
J Santander ◽  
M D Alvarez ◽  
F Campabadal

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