Pressure Sensor For Measurement Research Articles

Performance Evaluation of Micro Automatic Pressure Measurement Sensor for Enhanced Accuracy

The major objective of this research is to design sensitive components, conversion components, and various sensor circuits to achieve the miniaturization design for more accurate measurements. This article conducts performance testing on the designed miniaturized pressure sensor to determine whether it meets the qualified standards. The response time of designed sensor results increases with the increase of pressure under experimental conditions of different pressure application values (5MPa to 50MPa). The detection accuracy of the micro automatic pressure measurement sensor designed in this paper can reach 0.0452\%; the average pressure is 0.00364%, and the insulation resistance is 68.44 megohms, which meets reliability requirements. The sensitivity is 0.0582%; the nonlinearity is 0.0741%; the hysteresis is 0.0266%; the repeatability of 0.0625% meets the qualification standard for this instrument. Still, compared with traditional sensors, the sensor reduces the response time of results by about 60%. However, the author conducted the detection in an ideal environment. The actual working environment of sensors is relatively good. Therefore, the detection results obtained in this article may have some errors compared to the actual situation, and further analysis and testing are needed to optimize the performance of the designed sensor.

Blast wave pressure measurement and analysis in air and granular media inside a shock tube using a fiber Bragg grating sensor.

In this work, we have demonstrated the use of a fiber Bragg grating (FBG) sensor to measure the pressure profile of blast waves generated inside a vertical shock tube (VST). An FBG pressure sensor probe has been designed and developed that can be incorporated into the wall of the VST. The VST facility is used to generate blast waves with decay times of the order of a few milliseconds to simulate explosive events. Pressure measurement experiments have been carried out at different incident blast wave peak pressures inside the VST. The FBG pressure sensor measurements are validated against a standard piezoelectric pressure transducer at an acquisition rate of 1MHz. The pressure signals of both sensors are found to match well with similar rise times and decay profiles. The validated FBG pressure sensor is then incorporated into a sand column mounted in the test section of the VST to measure the pressure profile of blast wave-induced stress waves in granular media. The FBG and piezoelectric pressure sensor data are compared using fast Fourier transform analysis and continuous wavelet transform. The feasibility of FBG sensors for blast pressure measurement under harsh conditions imposed inside shock tube environments is established.

Experimental and numerical comparisons among various skewed blades of low speed axial fan rotors

Literature indicates that there is lack of study related to the effects of axially skewed blades on the aerodynamic performance of axial flow fans. In this study rotors of various blade skews, namely, axial, circumferential and axial-circumferential types, are studied and their aerodynamic performances are compared to those of the baseline radial rotors of two types, namely, constant chord and varying chord. The skew in a blade can be considered as combination of sweep and dihedral. The skew change from the circumferential to axial type causes reversal of dihedral induced radial blade force and hence a reversal of meridional streamline curvature which in turn reverses the modulation of the end-wall loads. The inherent forward sweep in the forward skewed blades also modulates hub and tip loads. Thus, in a forward axial skew blade the forward sweep and positive dihedral combine favorably to unload the tip and to upload the hub. In the forward circumferentially skewed blades, forward sweep and the negative dihedral have mutually countering effects on end-wall load modulation. The highlight of this study is that it has demonstrated experimentally the unloading of the tip in the forward axially skewed blades which resulted in reduced losses and better performance including increased stall margin. Reduced tip loading was also verified from the casing pressure sensor measurements which showed weakening of tip vortex. The relative influence of sweep and dihedral on performance was additionally demonstrated in the axially-circumferentially skewed rotor of the constant chord type, with improvements attributable to higher sweep.

The distribution law of shock wave pressure in typical trenches

Trenches, as important practical military facilities, have important theoretical and military value in evaluating the damage power of ammunition, operational application, and effective safety protection of personnel on the battlefield through the spatiotemporal evolution of explosive shock waves within them. At present, there is a lack of in-depth research on the distribution and impact of overpressure inside the trench. The paper constructed a typical finite element simulation model of a trench, numerically calculated the shock wave overpressure inside the trench and on the wall, analyzed the spatiotemporal distribution of shock wave pressure in various parts of the trench, conducted on-site explosion tests, and installed shock wave pressure sensor measurement points in the trench. The pressure time history curve was obtained, and verified and compared with the simulation calculation results. Research data shows that the peak overpressure of the shock wave in the trench increases sequentially from the front wall to the back wall. The peak overpressure of the shock wave at the front wall attenuates by 10 % to 20 % compared to the inside of the trench, and increases by 40 % to 60 % at the back wall; The peak overpressure in the trench exhibits a “V-shaped” distribution at different depths, decreasing first and then increasing as the depth increases. The maximum overpressure peak increases by 40 % to 50 % compared to the minimum; Based on simulation and measured data in the trench, as well as the distribution law of shock wave pressure, safety protection suggestions for on-site combat personnel in the trench are provided.

Simulation analysis of thermal shock response of piezoelectric shock wave pressure sensor

Under the influence of transient high temperatures, piezoelectric shock wave pressure sensors produce a thermal shock response that affects the accurate acquisition of the pressure signal. In order to analyse the effect of thermal shock on the measurement of piezoelectric pressure sensors, a rectangular pulse temperature of 1800 ℃ with a duration of 30 ms was applied to the surface of the sensor diaphragm by the method of thermal coupling, and the temperature distribution inside the sensor under transient thermal excitation was explored, and the thermal expansion displacement and preload change of the sensor were analysed. The results show that: the temperature rise of the piezoelectric crystal is small and does not reach the Curie point temperature, which has less influence on the material properties of the piezoelectric crystal; the thermal shock response of the piezoelectric pressure sensor is mainly caused by the thermal deformation of the pressure-sensing diaphragm, which affects the stability of the preload inside the sensor and leads to a negative signal output from the sensor. This study provides a reference for the research of thermal shock suppression methods for piezoelectric pressure sensors.

Unravelling the gait and balance: A novel approach for detecting depression in young healthy individuals

Depression is a prevalent mental health disorder that affects people of all ages and origins; therefore, early detection is essential for timely intervention and support. This investigation proposes a novel method for detecting melancholy in young, healthy individuals by analysing their gait and balance patterns. In order to accomplish this, a comprehensive system is designed that incorporates cutting-edge technologies such as a Barometric Pressure Sensor, Beck Depression Inventory (BDI), and t-Distributed Stochastic Neighbour Embedding (t-SNE) algorithm. The system intends to capitalize on the subtle motor and physiological changes associated with melancholy, which may manifest in a person’s gait and balance. The Barometric Pressure Sensor is used to estimate variations in altitude and vertical velocity, thereby adding context to the evaluation. The mood states of participants are evaluated using the BDI, a well-established psychological assessment instrument that provides insight into their emotional health. Integrated and pre-processed data from the Barometric Pressure Sensor, BDI responses, and gait and balance measurements. The t-SNE algorithm is then used to map the high-dimensional data into a lower-dimensional space while maintaining the local structure and identifying underlying patterns within the dataset. The t-SNE algorithm improves visualization and pattern recognition by reducing the dimensionality of the data, allowing for a more nuanced analysis of depression-related markers. As the proposed system combines objective physiological measurements

Four-Leg Sustained Dynamic Compression Staple and Screw Generates Superior Lapidus Construct as Compared to Plate and Screw: A Biomechanical Study

Category: Ankle; Basic Sciences/Biologics Introduction/Purpose: Lapidus procedures are frequently used to treat moderate to severe hallux valgus in the setting of first tarsometatarsal instability or arthritis. The push for early weightbearing can lead to nonunion rates reaching 12%. A growing number of surgeons are utilizing orthopedic staples manufactured from NiTiNOL in foot and ankle arthrodesis procedures. These staples are inserted in an “open expanded” state which enables application of sustained dynamic compression (SDC) between bony segments, which can persist even when challenged with joint settling / bony resorption. The biomechanical performance of these devices has not been quantified in the setting of Lapidus procedures. This study determined the optimum SDC staple construct during Lapidus procedures, and to compare their performance to traditional plate and screw construct in an established model. Methods: Lapidus procedures were performed on synthetic bone replicates (Sawbones) using three SDC staple constructs and one static device construct: (1) dorsal four-leg inline SDC staple, (2) dorsal four-leg inline SDC staple with medial two-leg SDC staple (3) dorsal four-leg inline SDC staple with plantar medial-distal to lateral-proximal cannulated screw and (4) dorsomedial plate and distal dorsal to proximal plantar cannulated screw (FigA). Samples underwent four-point bending with calibrated servo- hydraulic machine (MTS). Max load and construct stiffness was calculated. Interfragmentary contact force, area, and pressure was measured with pressure sensor (Tekscan) and joint plantar gap measurements were completed with 3D motion capture system (Motion Analysis). Testing consisted of stepwise loading to 1, 2, and 3mm of crosshead displacement. For brevity, only data from 3mm displacement test are included herein. Data were analyzed with one-way ANOVA with Dunnett’s post hoc test (N=5/group). Results: The four-leg inline staple + two-leg staple and the four-leg inline staple + screw groups exhibited a 2.5x (p=0.03) and 7.5x (p <.001) increase in joint contact force as compared to the plate + screw group, respectively (FigB). The four-leg inline staple + two-leg staple and the four-leg inline staple + screw groups demonstrated a 3.5x (p=0.002) and 6.6x (p <.001) increase in joint contact area as compared to the plate + screw group, respectively (FigC). The four-leg inline staple + screw group exhibited a 65.1% reduction in plantar gap as compared to the plate + screw group (p=.039, FigD). Conclusion: The four-leg inline staple + screw group exhibited the optimal Lapidus construct biomechanical properties (greatest joint contact force, greatest joint contact area, and least plantar gap). The biomechanical testing performed herein was undertaken to simulate loading akin to early post-operative weight bearing. These data highlight the ability of the four-leg SDC NiTiNOL staple in combination with a static screw to provide meaningfully increased joint compression, uniformity of joint compression, and decreased construct motion as compared to the standard plate + screw construct that is frequently used clinically.

A Silica Capillary-Based Sensor with Access Channels for the Simultaneous Measurement of Pressure and Temperature

A hybrid fiber sensor for the simultaneous measurement of pressure and temperature is proposed. The sensor is constituted of a section of silica capillary tube (SCT) whereat access channels are created with two different methods: instilling a bubble on the fiber by employing successive arc discharges on the SCT whilst under pressure and splicing the SCT with another section of SCT with a smaller inner diameter. The reflection-based sensor enhances Fabry–Perot interference (FPI) and antiresonant (AR) guidance, simultaneously, in a single sensing element of a few millimeters. A comparison study between the access channel methods reveals higher spectral visibility for the bubble method and similar pressure and temperature resolutions. For a 2.58 mm long sensor with a bubble, the sensitivity to pressure is 4.09 ± 0.01 nm/MPa and −3.7 ± 0.1 nm/MPa for the FPI and AR, respectively, while its sensitivity to temperature is −0.20 ± 0.02 pm/°C and 24.0 ± 0.5 pm/°C, respectively, for the FPI and AR, which are within the numerically calculated sensitivities. The sensor is robust and has a convenient reflective probe with easy and low-cost fabrication, granting high competitiveness in actual applications.

High sensitivity fiber optic esophageal pressure sensor based on OFDR

In this paper, a distributed esophageal pressure measurement sensor is proposed. Optical frequency domain reflection (OFDR) technology is adopted to measure the axial strain change of the optical fiber. By designing a sensitizing structure, the sensing performance can be well improved. The analysis based on finite element simulation of the sensor is carried out and its feasibility is verified. Compared with the solid high-resolution esophageal manometry system widely used at this stage, the proposed sensor is low cost and simple in structure. The sensitivity of the sensor can reach 65.920μɛ/kPa.

Development of proposals for formalising the process of filtering navigation information of an underwater robot at shallow depths

The purpose of the article is to increase the efficiency of solving the problems of stabilising underwater robots at shallow depths based on complex processing of navigation information and its filtering using the Kalman theory. This goal is achieved by defining a set of mathematical dependencies for formalising the process of filtering navigation information of underwater robots based on complex data processing. In this case, the filtering is carried out using a distributed set of Kalman filters of different structures, which were selected considering the characteristics of the data being evaluated. It has been established that at present, underwater robots at shallow depths are widely used around the world for various tasks, including search operations and underwater inspections. However, the operation of these robots is characterised by difficult conditions. These conditions include unknown parameters of underwater navigation, the impact of external disturbances, changes in the mass, size and hydrodynamic characteristics of robots while operating in water. Currently, the concept of control based on intelligent methods is considered a promising approach to automating the control of moving objects. However, the use of such controllers for underwater robots, together with the problems of obtaining up-to-date navigation information, has not yet achieved sufficient efficiency. In addition, the issues related to the development of a navigation information processing system using nonlinear filters and the creation of intelligent controllers for underwater robots are still insufficiently covered in the scientific and technical literature. The most significant result is a set of mathematical dependencies for formalising the process of filtering navigation information of underwater robots using a set of distributed Kalman filters of different structures. Such sets are closely correlated with the relevant characteristics of the data being evaluated. In this context, the inertial module with Kalman filtering algorithms can be used to measure angular motion parameters and solve the problems of roll, pitch and yaw stabilisation. Due to the low speeds of underwater robots at shallow depths and the absence of high-frequency interference in the pressure sensor measurements, the data from the pressure sensor can be used to determine the vertical speed

Fabrication of 4H-SiC piezoresistive pressure sensor for high temperature using an integrated femtosecond laser-assisted plasma etching method

The processing, particularly, etching of brittle, hard, and anti-corrosion materials represented by the third-generation wide bandgap semiconductor silicon carbide (SiC), is a significant challenge. Although SiC has excellent electrical, mechanical, and chemical properties, the difficulty of processing limits its application in various sensor devices. To solve this problem, in this study, an integrated processing method of femtosecond laser-assisted SiC dry etching is proposed, which realizes high surface quality and high rate etching of the SiC microstructure. Specifically, the effects of different laser processing parameters on the processing effect were first studied through orthogonal experiments. Experiments indicate that compared with laser power and laser scan times, laser processing speed has a more obvious impact on the processing effect. Subsequently, considering the elastic modulus anisotropy of SiC, a 5 MPa piezoresistive pressure sensor chip was designed. Using the proposed composite processing method, a chip sensitive diaphragm was obtained. The diaphragm thickness and diameter are 76 μm and 1700 μm respectively. The overall sensor chip dimension was 4000 μm × 4000 μm × 350 μm. Static tests demonstrated that the sensor have excellent performance with sensitivity of 6.8 mV/MPa, linearity of 0.69% FS, and repeatability of 0.078% FS. In addition, by designing high-temperature packaging, the sensor achieved a pressure test at 400 °C. This study verifies the feasibility of the composite processing method, realizes the fabrication and measurement of high-temperature pressure sensors, and provides a reference for the micro-and nanostructure processing of various SiC sensors.

Sparse sensor reconstruction of vortex-impinged airfoil wake with machine learning

Reconstruction of unsteady vortical flow fields from limited sensor measurements is challenging. We develop machine learning methods to reconstruct flow features from sparse sensor measurements during transient vortex–airfoil wake interaction using only a limited amount of training data. The present machine learning models accurately reconstruct the aerodynamic force coefficients, pressure distributions over airfoil surface, and two-dimensional vorticity field for a variety of untrained cases. Multi-layer perceptron is used for estimating aerodynamic forces and pressure profiles over the surface, establishing a nonlinear model between the pressure sensor measurements and the output variables. A combination of multi-layer perceptron with convolutional neural network is utilized to reconstruct the vortical wake. Furthermore, the use of transfer learning and long short-term memory algorithm combined in the training models greatly improves the reconstruction of transient wakes by embedding the dynamics. The present machine-learning methods are able to estimate the transient flow features while exhibiting robustness against noisy sensor measurements. Finally, appropriate sensor locations over different time periods are assessed for accurately estimating the wakes. The present study offers insights into the dynamics of vortex–airfoil interaction and the development of data-driven flow estimation.Graphic abstract

Performance of a MEMS IMU for Localizing a Seaglider AUV on an Acoustic Tracking Range

A Seaglider instrumented with an inertial attitude and heading reference system was tracked for three days on an acoustic tracking range in Dabob Bay, Washington, operated by the Naval Undersea Warfare Center, Keyport, WA, USA. Inertial measurements were integrated to yield estimates of position and compared with tracked positions. Within 3 min, the integrated positioning results deviated from tracked positions by more than a kilometer. The addition of a depth constraint from pressure sensor measurements slowed the error growth over time, but even with this constraint, measurements were too noisy to accurately determine position without aid from additional sensors. Inertial data did contribute to accurate localization when used to estimate vehicle attitude and incorporated into an existing flight model; however, results did not demonstrate marked improvement over existing flight models. Although not a decisive demonstration of vehicle positioning with a standalone low-cost, low-power sensor, the results presented here provide a benchmark for comparison as MEMS inertial sensors continue to evolve using a valuable ground-truth of subsea Seaglider position not previously available.

Wireless, multimodal sensors for continuous measurement of pressure, temperature, and hydration of patients in wheelchair

Individuals who are unable to walk independently spend most of the day in a wheelchair. This population is at high risk for developing pressure injuries caused by sitting. However, early diagnosis and prevention of these injuries still remain challenging. Herein, we introduce battery-free, wireless, multimodal sensors and a movable system for continuous measurement of pressure, temperature, and hydration at skin interfaces. The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity, a temperature sensor for measuring skin temperature, and a galvanic skin response sensor for measuring skin hydration levels. The movable system enables power harvesting, and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage. Experimental evaluations and numerical simulations of the devices, together with clinical trials for wheelchair patients, demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.

A Context-Aware Smartphone-Based 3D Indoor Positioning Using Pedestrian Dead Reckoning.

The rise in location-based service (LBS) applications has increased the need for indoor positioning. Various methods are available for indoor positioning, among which pedestrian dead reckoning (PDR) requires no infrastructure. However, with this method, cumulative error increases over time. Moreover, the robustness of the PDR positioning depends on different pedestrian activities, walking speeds and pedestrian characteristics. This paper proposes the adaptive PDR method to overcome these problems by recognizing various phone-carrying modes, including texting, calling and swinging, as well as different pedestrian activities, including ascending and descending stairs and walking. Different walking speeds are also distinguished. By detecting changes in speed during walking, PDR positioning remains accurate and robust despite speed variations. Each motion state is also studied separately based on gender. Using the proposed classification approach consisting of SVM and DTree algorithms, different motion states and walking speeds are identified with an overall accuracy of 97.03% for women and 97.67% for men. The step detection and step length estimation model parameters are also adjusted based on each walking speed, gender and motion state. The relative error values of distance estimation of the proposed method for texting, calling and swinging are 0.87%, 0.66% and 0.92% for women and 1.14%, 0.92% and 0.76% for men, respectively. Accelerometer, gyroscope and magnetometer data are integrated with a GDA filter for heading estimation. Furthermore, pressure sensor measurements are used to detect surface transmission between different floors of a building. Finally, for three phone-carrying modes, including texting, calling and swinging, the mean absolute positioning errors of the proposed method on a trajectory of 159.2 m in a multi-story building are, respectively, 1.28 m, 0.98 m and 1.29 m for women and 1.26 m, 1.17 m and 1.25 m for men.

Mars Entry, Descent, and Landing Instrumentation 2 Trajectory, Aerodynamics, and Atmosphere Reconstruction

On February 18th, 2021, the Mars 2020 entry system successfully delivered the Perseverance rover to the surface of Mars at Jezero Crater. The entry capsule carried a set of instrumentation installed on the heat shield and backshell, named the “Mars Entry, Descent, and Landing Instrumentation 2.” The instruments include pressure transducers, thermocouples, heat flux gauges, and radiometers to measure the aerodynamic and aerothermodynamic performance of the entry vehicle. This paper describes the trajectory and atmosphere reconstruction results based on the pressure sensor measurements. The process uses a Kalman filter approach to estimate the freestream atmospheric properties from the pressure measurements combined with a model of the pressure distribution of the heatshield and other sensor inputs, including an inertial measurement unit and other on-board navigation sensors, and several external atmospheric observations. The results indicate that the upper altitude density was up to 150% higher than nominal, which is consistent with the observed early entry guidance start time. The density below 40 km was within 12% of the preflight predictions. The reconstructed axial force coefficient was approximately 2% lower than the preflight prediction across the flight range.

Measuring posture change to detect emotional conditions for workers: A scoping review.

The emotional management of workers can not only increase the efficiency of work, but also contribute to the improvement of the productivity of a company. This scoping review surveyed the literature to identify the relationship between postural expression and emotion during sedentary tasks. We searched relevant literature published up to December 1, 2019 using seven electronic databases (PubMed, CINAHL, Embase, Web of Science, PsycINFO, IEEE Xplore, and MEDLINE Complete). A total of 14 publications were included in this scoping review. It was found that the application of pressure sensor and camera-based measurement equipment was effective. Additionally, it was proposed to predict the emotional state of the worker by using forward and backward movements as the main variable as opposed to left and right movements. The information-based analysis technique was able to further increase the accuracy of workers' emotion prediction. The emotion prediction of workers based on sitting posture could be confirmed for certain movements, and the information-based technical method could further increase the accuracy of prediction. Expansion of information-based technical research will further increase the possibility of predicting the emotions of workers based on posture, and this will in turn promote safer and more efficient work performance.

Inline tape width control for thermoplastic automated tape layup

Automated tape layup, is predisposed to positioning defects like gaps and overlaps which are detrimental to the structural integrity of the part. This work investigates the details of the design of inline width control concept, a technique for inline control of consolidated tape width to eliminate gaps. Continuous inline width variation is achieved by online control of the compaction force, during the layup process. Successful calibration and benchmarking tests using standard pressure measurement sensors are presented. Performance assessment tests are performed which demonstrate online variation of force from 50 N to 1000 N, having a standard deviation of 10 N. Correlation models for width control are obtained and it is shown that a width increase of 5–50 % of initial width is achievable using the prototype. An example of linearly varying force resulting in a trapezium shaped consolidated tape is also shown as a part of the feasibility study.

Realization of an ultra-high pressure dynamic calibrate system by drop hammer based on fiber Bragg grating strain sensor.

In this letter, we propose a novel technique for dynamic ultra-high pressure calibration that measured pressure by FBG based strain sensor. Generally, the traditional method of dynamic ultra-high pressure calibration by standard sensor is costly and it is difficult to improve the accuracy. Therefore, we prefer FBG strain sensor to replace the standard sensor to calibrate the ultra-high pressure. In this proposal, the calibration process is that the central wavelength of the FBG attached to the elastic element changes rapidly with the strain of the elastic element during the drop hammer impact, synchronously. This allows the calibration accuracy to be easily increased to 0.02% and the cost to be reduced by 1/100 compared to traditional calibration techniques. The experiment results show that coefficient of linear correlation between the strain waveform and the pressure signal reaches 0.999. The strain calibration based on FBG is of great significance to the measurement and calibration of dynamic ultra-high pressure sensors.

Finite Element Modeling of Planus and Rectus Foot Types for the Study of First Metatarsophalangeal and First Metatarsocuneiform Joint Contact Mechanics.

The foot is a highly complex biomechanical system for which finite element (FE) modeling has been used to evaluate its loading environment. However, there is limited knowledge of first metatarsophalangeal (MTP) and first metatarsocuneiform (MTC) joint contact mechanics. Our goal was to develop a framework for FE modeling of the medial forefoot which could accurately predict experimental measurements of first MTP and first MTC joint loading. Simulations of planus and rectus foot types were conducted for midstance of gait. A custom-built force-controlled cadaveric test-rig was used to derive intracapsular pressure sensor measurements of contact pressure, force, and area during quasi-static loading. The FE model was driven under the same boundary and loading conditions as the cadaver. Mesh sensitivity analyses and best-fit calibrations of moduli for first MTP and first MTC joint cartilage were performed. Consistent with previous experimental research, a lower compressive modulus was best-fit to the first MTP compared to first MTC joint at 10 MPa and 20 MPa, respectively. Mean errors in contact pressures, forces, and areas were 24%, 4%, and 40% at the first MTP joint and 23%, 12%, and 19% at the first MTC joint, respectively. The present developmental framework may provide a basis for future modeling of first MTP and first MTC joint contact mechanics. This study acts as a precursor to validation of realistic physiological loading across gait to investigate joint loading, foot type biomechanics, and surgical interventions of the medial forefoot.