A temperature compensation method for piezoresistive pressure sensors based on multi-strategy fusion improved dung beetle optimization algorithm

Piezoresistive pressure sensors have broad applications but often face accuracy challenges due to temperature-induced drift. Traditional compensation methods based on discrete data, such as polynomial interpolation, support vector machine (SVM), and artificial neural network (ANN), overlook the thermal hysteresis, resulting in lower accuracy. Considering the sequence-dependent nature of temperature drift, we propose the RF-IWOA-GRU temperature compensation model. Random forest (RF) is used to interpolate missing values in continuous data. A combination of gated recurrent unit (GRU) networks and an improved whale optimization algorithm (IWOA) is employed for temperature compensation. This model leverages the memory capability of GRU and the optimization efficiency of the IWOA to enhance the accuracy and stability of the pressure sensors. To validate the compensation method, experiments were designed under continuous variations in temperature and actual pressure. The experimental results show that the compensation capability of the proposed RF-IWOA-GRU model significantly outperforms that of traditional methods. After compensation, the standard deviation of pressure decreased from 10.18 kPa to 1.14 kPa, and the mean absolute error and root mean squared error were reduced by 75.10% and 76.15%, respectively.

At present, the silicon piezoresistive pressure sensor is a mature technology in the industry, and its measurement accuracy is more rigorous in many advanced applications. Micro piezoresistive pressure sensor is fabricated by a MEMS process, and its main operational principle is that the external pressure loading causes the deflection, strain, and stress which occur on the silicon membrane. The environmental temperature, the humidity, and the pressure will reduce its performance. Moreover, the drifts of output voltage in the same temperature caused by the residual stress on the aluminum trace under thermal cycle loading also influence the performance of the piezoresistive pressure sensor. This is called the thermal hysteresis phenomenon, and the variation of output voltage is called the thermal hysteresis voltage. Among the critical issues of silicon piezoresistive pressure sensor, the hysteresis phenomenon should be deeply paid attention to obtain better sensor accuracy. For this reason, this research would like to investigate the effect of the external loading on the output voltage of a pressure sensor. Based on the process of pressure sensors, this research adopts the concept of pseudo temperature combined with a finite element method (FEM) to obtain the thermal hysteresis voltage. After several numerical analysis of thermal hysteresis voltage, the experiment is then performed to validate the simulation results. After being validated with the experimental results, the variation of thermal hysteresis voltage under a different trace layout is analyzed. Based on simulation results of a different trace layout, it is found that the trace line layout plays an important role in the thermal hysteresis performance of a pressure sensor, which indicates that the longer aluminum trace increases the hysteresis voltage. The uniform and symmetrical layout of aluminum trace can reduce the variation of resistance change and decrease the hysteresis voltage. Furthermore, the trace layout which is far away from the silicon membrane and piezoresistance is suggested to reduce the hysteresis voltage.

The traditional temperature modeling method is based on the full heating of the accelerometer to achieve thermal balance, which is not suitable for the cold start-up phase of the micro-accelerometer. For decreasing the complex temperature drift of the cold start-up phase, a new temperature compensation method based on a high-order Fourier transform combined model is proposed. The system structure and repeatability test of the micro digital quartz flexible accelerometer are provided at first. Additionally, we analyzed where the complex temperature drift of the cold start-up phase comes from based on the system structure and repeatability test. Secondly, a high-order temperature compensation model combined with K-means clustering and the symbiotic organisms search (SOS) algorithm is established with repeatability test data as training data. To verify the proposed temperature compensation model, a test platform was built to transmit the measured values before and after compensation with the proposed Fourier-related model and the other time-related model, which is also a model aiming at temperature compensation in the cold start-up phase. The experimental results indicate that the proposed method achieves better compensation accuracy compared with the traditional temperature compensation methods and the time-related compensation model. Furthermore, the compensation for the cold start-up phase has no effect on the original accuracy over the whole temperature range. The stability of the accelerometer can be significantly improved to about 30 μg in the start-up phase of different temperatures after compensation.

Anodic bonding between glass wafer and Si wafer are widely used for micro-electro-mechanical system (MEMS) device fabrication and packaging due to the good bonding quality. The residual stress in the bonding interface, which results from the different thermal expansion coefficients of the two wafer materials, is depended on the bonding temperature. In MEMS piezoresistive pressure sensor, the residual stress in anodic bonding, which can affect the accuracy of the device, is investigated by using the finite element method (FEM). The piezoresistive pressure sensor performance is evaluated and the residual stress effect at different temperatures is investigated in this research. The simulation results show that anodic bonding residual stress affect piezoresistive pressure sensor accuracy significantly.

this article deals with the influence of temperature on the output sensitivity of the piezo-resistive pressure sensor. In order to reduce the temperature drift of output for the piezo-resistive pressure sensor, the double Wheatstonce-bridge method is adopted to test the sensor with the ternperature controlled at the range of 300~373 K. Tlre results indicate that the temperature drift of the sensor output can be lowered by over 70% to improve surveying accuracy. Pressure senter is widely applied to many fields of the industry, so its accuracy can directly influence the quality of surveying system. Since the piezo-resistive pressure sensor is mostly made of semiconductor materials, the sensitivity and linearity of silicon sentor will be affected to some extent, among which non- linearity is connected with dopant density, temperature and pressure. In ideal condition, four resistor strips are equal in variables with temperature changing, in this way, electric bridge can keep balance to eliminate the effect of tempereature on the sentor. But it’s not the case in reality, temperature drift of output for the piezo-resistive pressure sensor is unavoidable, so some technical methods should be adopted to control the phenomenon. Temperature drift, playing an important role in affecting the quality and accuracy of sentor, has drawn public concern. Document 2 intrduces how to adjust supply voltage to control temperature drift of output for the piezo-resistive pressure sensor. Document 3 intrduces temperature compensation in the sensitivity of sentor. This article aims at making use of four resistors with negative temperature and Wheatstonce-bridge to reduce temperature drift and improve output accuracy of pressure sentor

Pressure measurement is a key part of many commercial and industrial systems. Piezoresistive pressure sensors are simpler to integrate with electronics, they are inherently shielded from RF noise and their response is more linear while compared to capacitive pressure sensors. And piezoresistive devices have always dominated the pressure sensor market. The analyticals that are typically used to model the diaphragm of the pressure sensor have been analysed by many researchers. To optimize the pressure sensor for parameters like linearity and sensitivity, the Finite Element Method (FEM) is incorporated. The selection of appropriate parameters of piezoresistors such as the shape and the position of the piezoresistor on the pressure sensor diaphragm, thickness of diaphragm are important. This study shows the scope of using analytical solutions and design techniques for a piezoresistive pressure sensor.

A nickel–chromium (Ni–Cr) piezoresistive pressure sensor is presented, which has the advantages of low-cost and easy fabrication processes. In the designed sensor, Ni–Cr alloy (80:20 wt%), which can be fabricated using simple processes, is used as the strain-detecting material with a smaller but acceptable gauge factor. Eutectic-bonding technology, based on silver–tin (Ag–Sn) alloy, which contains 3.5 wt% Ag and has 20 µm thickness, is used as an alternative and easy bonding choice to complete the vacuum package. Normally, Ag–Sn alloy is mostly obtained by the electrochemical deposition method. However, here the Ag–Sn solder film is directly used as a bonding material. It reduces the fabrication difficulty of eutectic bonding of the proposed pressure sensor. By studying the processes of annealing of Ni–Cr fabrication and eutectic bonding with Ag–Sn, the authors complete the alloy piezoresistive atmosphere pressure sensor. Bonding quality is evaluated by inspection through the deflection of a diaphragm of silicon with more than 95% of the area successfully bonded. The pressure–voltage characteristic test results suggest a precision within 0.3% in square fitting. The temperature coefficient offset is 620 ppm/(°C free space optic (FSO)).

Design of piezoresistive pressure sensor for enhancing stress of MEMS cantilever

This paper presents the design and simulation of MEMS based piezoresistive pressure sensor for microfluidic applications. Geometrical parameters are very much considerable when designing microstructure of the pressure sensor. Hence, an analysis is carried out by changing the dimensional parameters of three different diaphragm geometries namely square shaped diaphragm, circular shaped diaphragm and cross sectional beam shaped diaphragm respectively. This is performed in three dimensional mesh plots using Matlab. The Finite Element Method (FEM) analyses are performed in COMSOL and by comparing the results, the square type diaphragm is chosen as best diaphragm geometry for the microfluidic applications. In addition, modal analysis is carried out by using Ansys to identify the natural frequency of the best diaphragm geometry. Also Piezoresistive sensing elements are designed and simulated by performing coupled field analysis using COMSOL Multiphysics. Simulation results reveal that piezo resistive square type pressure sensors have high sensitivity in a wide range of pressures.

In this study, a variety of piezoelectric pressure transducer designs and mounting configurations were compared for measuring in-cylinder pressure on a heavy-duty single-cylinder diesel engine. A unique cylinder head design was used which allowed cylinder pressure to be measured simultaneously in two locations. In one location, various piezoelectric pressure transducers and mounting configurations were studied. In the other location, a Kistler water-cooled switching adapter with a piezoresistive pressure sensor was used. The switching adapter measured in-cylinder pressure during the low pressure portion of the cycle. During the high pressure portion of the cycle the sensor is protected from the high pressure and high temperature gases in the cylinder. Therefore, the piezoresistive sensor measured in-cylinder pressure highly accurately, without the impacts of short term thermal drift, otherwise known as thermal shock. Additionally, the piezoresistive sensor is an absolute pressure sensor which does not require a baseline or “pegging” on every engine cycle. With this measurement setup, the amount of thermal shock and induced measurement variability was accurately assessed for the piezoelectric sensors. Data analysis techniques for quantifying the accuracy of a piezoelectric cylinder pressure measurements are also presented and discussed. It was observed that all the piezoelectric transducers investigated yielded very similar results regarding compression pressure, start of combustion, peak cylinder pressure, and the overall heat release rate shape. Differences emerged when studying the impact of the transducer mounting (e.g., recessed vs. flush-mount). Recessed-mount transducers tended to yield a more accurate measurement of the cycle-to-cycle variability when compared to the baseline piezoresistive sensor. This is thought to be due to reduced levels of thermal shock, which can vary from cycle-to-cycle.

Flexible piezoresistive pressure sensors may exhibit excellent sensing performances to be applied in wearable electronics, medical diagnosis, and electronic skin. Herein, we report a multi-layer and phased-responsive reduced graphene oxide/MXene-based piezoresistive pressure sensor with hierarchical microspines constructed by sandpaper as the template. Thanks to the multi-level and multi-layer structure, the obtained sensor realized phased response and showed wide detection range (up to 70 kPa), fast response (response/recovery time of 40/80 ms), and excellent working stability (1000 fatigue cycles). Furthermore, the sensor was successfully applied for detecting various human motions including pulse beats, cheek bulging, nodding, finger bending, speech recognition, handwriting, and other pressure signals. Besides, a 6 × 6 sensing matrix integrated by the sensors was able to sensitively perceive the distribution of plane pressure. The findings in this work conceivably stand out as a new strategy to fabricate high-performance piezoresistive pressure sensors in the fields of intelligent healthcare and medical diagnosis, wearable electronic devices, electronic skin, and human-machine interaction.

High reliability of piezoresistive pressure sensors by wafer to wafer direct bonding at room temperature

A facile fabrication strategy constructed multilayer piezoresistive pressure sensor for intelligent recognition system towards privacy protection

Silicon-based Microelectromechanical System (MEMS) pressure sensors are extensively used and have the advantages of high accuracy and miniaturization. Despite this, due to inherent material limitations, they are not easily able to withstand high temperatures greater than 150°C. To overcome this disadvantage, Silicon Carbide (SiC) is the preferred material because it has excellent thermomechanical properties and operates above 600°C. Piezoresistive pressure sensors made of Silicon Carbide are ideally able to detect pressures beyond 600°C. Our work presents MEMS Single turn meander-shaped piezoresistive pressure sensor on a circular SiC diaphragm for high pressure applications of pressure range 0–40[Formula: see text]MPa in harsh environment. This work models and analyses the piezoresistive pressure sensor characteristics using an analytical modeling and simulation method to choose the best design. To ascertain its sensitivity, expressions are computationally simulated with MATLAB software using the thin plate and small deflection theory. To evaluate the viability of the model, COMSOL Multiphysics simulation is used. When compared to recent studies, our proposed sensor provides a sensitivity of near about 5.4[Formula: see text]mV/V/MPa across a pressure range of 0–40[Formula: see text]MPa.

This paper characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to MEMS pressure sensing. The sensor to be studied is a four-terminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. In a recent study, our team has determined the relation between the biaxial stress state and the piezoresistive response of a VDP structure by combining the VDP resistance equations with the equations governing silicon piezoresistivity and has proposed a novel piezoresistive pressure sensor. It is observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. With MEMS devices being used in applications which continually necessitate smaller size, characterizing the effect of relative size and misalignment on the sensitivity of the VDP sensor is important. It is determined that the performance of the sensor is strongly dependent only on the longitudinal position of the sensor on the diaphragm, and is relatively tolerant of other errors in the manufacturing process such as transverse position, sensor depth, and orientation angle.