Design Approach for Reducing Cross-Axis Sensitivity in a Single-Drive Multi-Axis MEMS Gyroscope

In this paper, a new design technique is presented to estimate and reduce the cross-axis sensitivity (CAS) in a single-drive multi-axis microelectromechanical systems (MEMS) gyroscope. A simplified single-drive multi-axis MEMS gyroscope, based on a mode-split approach, was analyzed for cross-axis sensitivity using COMSOL Multiphysics. A design technique named the “ratio-matching method” of drive displacement amplitudes and sense frequency differences ratios was proposed to reduce the cross-axis sensitivity. Initially, the cross-axis sensitivities in the designed gyroscope for x and y-axis were calculated to be 0.482% and 0.120%, respectively, having an average CAS of 0.301%. Using the proposed ratio-matching method and design technique, the individual cross-axis sensitivities in the designed gyroscope for x and y-axis were reduced to 0.018% and 0.073%, respectively. While the average CAS was reduced to 0.045%, showing a reduction rate of 85.1%. Moreover, the proposed ratio-matching method for cross-axis sensitivity reduction was successfully validated through simulations by varying the coupling spring position and sense frequency difference variation analyses. Furthermore, the proposed methodology was verified experimentally using fabricated single-drive multi-axis gyroscope.

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Sensitivity Analysis of Single-Drive, 3-axis MEMS Gyroscope Using COMSOL Multiphysics

Micromachines ◽

10.3390/mi11121030 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1030

Author(s):

Hussamud Din ◽

Faisal Iqbal ◽

Byeungleul Lee

Keyword(s):

Microelectromechanical Systems ◽

Angular Rate ◽

Mode Analysis ◽

Comsol Multiphysics ◽

Mechanical Sensitivity ◽

Drive Mode ◽

Element Analysis ◽

Mems Gyroscope ◽

Fea Model ◽

Mode Split

In this paper, a COMSOL Multiphysics-based methodology is presented for evaluation of the microelectromechanical systems (MEMS) gyroscope. The established finite element analysis (FEA) model was successfully validated through a comparison with analytical and Matlab/Simulink analysis results. A simplified single-drive, 3-axis MEMS gyroscope was analyzed using a mode split approach, having a drive resonant frequency of 24,918 Hz, with the x-sense, y-sense, and z-sense being 25,625, 25,886, and 25,806 Hz, respectively. Drive-mode analysis was carried out and a maximum drive-displacement of 4.0 μm was computed for a 0.378 μN harmonic drive force. Mechanical sensitivity was computed at 2000 degrees per second (dps) input angular rate while the scale factor for roll, pitch, and yaw was computed to be 0.014, 0.011, and 0.013 nm/dps, respectively.

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Insights to enhance the examination of tool marks in human cartilage

International Journal of Legal Medicine ◽

10.1007/s00414-021-02609-9 ◽

2021 ◽

Author(s):

Matthias Weber ◽

Anja Niehoff ◽

Markus A. Rothschild

Keyword(s):

Light Microscope ◽

Cross Correlation ◽

Costal Cartilage ◽

Correlation Coefficients ◽

Human Cartilage ◽

Cut Marks ◽

Tool Marks ◽

The Cross ◽

Cleaning Methods ◽

The Individual

AbstractThis work deals with the examination of tool marks in human cartilage. We compared the effectiveness of several cleaning methods on cut marks in porcine cartilage. The method cleaning by multiple casts achieved the significantly highest scores (P = 0.02). Furthermore, we examined the grain-like elevations (dots) located on casts of cut cartilage. The results of this study suggest that the casting material forms these dots when penetrating cartilage cavities, which are areas where the strong collagen fibres leave space for the chondrocytes. We performed fixation experiments to avoid this, without success. In addition, 31 casting materials were compared regarding contrast under light-microscope and 3D tool marks scanner. Under the light-microscope, brown materials achieved significantly higher values than grey (P = 0.02) or black (P = 0.00) whereas under the 3D scanner, black materials reached higher contrast values than grey (P = 0.04) or brown (P = 0.047). To compare the accuracy and reproducibility of 6 test materials for cartilage, we used 10 knives to create cut marks that were subsequently scanned. During the alignment of the individual signals of each mark, the cross-correlation coefficients (Xmax) and lags (LXmax) were calculated. The signals of the marks in agarose were aligned with significantly fewer lags and achieved significantly higher cross-correlation coefficients compared to all tested materials (both P = 0.00). Moreover, we determined the cross-correlation coefficients (XC) for known-matches (KM) per material. Agarose achieved significantly higher values than AccuTrans®, Clear Ballistics™, and gelatine (all P = 0.00). The results of this work provide valuable insights for the forensic investigation of marks in human costal cartilage.

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A high-frequency non-resonant elliptical vibration-assisted cutting device for diamond turning microstructured surfaces

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-06608-3 ◽

2021 ◽

Vol 112 (11-12) ◽

pp. 3247-3261

Author(s):

Zhengjian Wang ◽

Xichun Luo ◽

Haitao Liu ◽

Fei Ding ◽

Wenlong Chang ◽

...

Keyword(s):

Heat Generation ◽

High Frequency ◽

Diamond Turning ◽

Coupling Ratio ◽

Modal Characteristics ◽

Elliptical Vibration ◽

Microstructured Surfaces ◽

Operational Frequency ◽

The Cross ◽

Cross Axis

AbstractIn recent years, research has begun to focus on the development of non-resonant elliptical vibration-assisted cutting (EVC) devices, because this technique offers good flexibility in manufacturing a wide range of periodic microstructures with different wavelengths and heights. However, existing non-resonant EVC devices for diamond turning can only operate at relatively low frequencies, which limits their machining efficiencies and attainable microstructures. This paper concerns the design and performance analysis of a non-resonant EVC device to overcome the challenge of low operational frequency. The structural design of the non-resonant EVC device was proposed, adopting the leaf spring flexure hinge (LSFH) and notch hinge prismatic joint (NHPJ) to mitigate the cross-axis coupling of the reciprocating displacements of the diamond tool and to combine them into an elliptical trajectory. Finite element analysis (FEA) using the mapped meshing method was performed to assist the determination of the key dimensional parameters of the flexure hinges in achieving high operational frequency while considering the cross-axis coupling and modal characteristics. The impact of the thickness of the LSFH on the sequence of the vibrational mode shape for the non-resonant EVC device was also quantitatively revealed in this study. Moreover, a reduction in the thickness of the LSFH can reduce the natural frequency of the non-resonant EVC device, thereby influencing the upper limit of its operational frequency. It was also found that a decrease in the neck thickness of the NHPJ can reduce the coupling ratio. Experimental tests were conducted to systematically evaluate the heat generation, cross-axis coupling, modal characteristics and diamond tool’s elliptical trajectory of a prototype of the designed device. The test results showed that it could operate at a high frequency of up to 5 kHz. The cross-axis coupling ratio and heat generation of the prototype are both at an acceptable level. The machining flexibility and accuracy of the device in generating microstructures of different wavelengths and heights through tuning operational frequency and input voltage have also been demonstrated via manufacturing the micro-dimple arrays and two-tier microstructured surfaces. High-precision microstructures were obtained with 1.26% and 10.67% machining errors in wavelength and height, respectively.

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Towards a biomimetic gyroscope inspired by the fly's haltere using microelectromechanical systems technology

Journal of The Royal Society Interface ◽

10.1098/rsif.2014.0573 ◽

2014 ◽

Vol 11 (99) ◽

pp. 20140573 ◽

Cited By ~ 5

Author(s):

H. Droogendijk ◽

R. A. Brookhuis ◽

M. J. de Boer ◽

R. G. P. Sanders ◽

G. J. M. Krijnen

Keyword(s):

Microelectromechanical Systems ◽

Damping Ratio ◽

Fast Response ◽

Gyroscopic System ◽

Drive Mode ◽

Mems Gyroscope ◽

Coriolis Forces ◽

Mems Technology ◽

Large Measurement ◽

Theoretical Performance

Flies use so-called halteres to sense body rotation based on Coriolis forces for supporting equilibrium reflexes. Inspired by these halteres, a biomimetic gimbal-suspended gyroscope has been developed using microelectromechanical systems (MEMS) technology. Design rules for this type of gyroscope are derived, in which the haltere-inspired MEMS gyroscope is geared towards a large measurement bandwidth and a fast response, rather than towards a high responsivity. Measurements for the biomimetic gyroscope indicate a (drive mode) resonance frequency of about 550 Hz and a damping ratio of 0.9. Further, the theoretical performance of the fly's gyroscopic system and the developed MEMS haltere-based gyroscope is assessed and the potential of this MEMS gyroscope is discussed.

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A New Design of a Piezoelectric Triaxial Micro-Accelerometer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.645-646.841 ◽

2015 ◽

Vol 645-646 ◽

pp. 841-846 ◽

Cited By ~ 1

Author(s):

Jian Yan Wang ◽

Ting Ting Wang ◽

Hang Guo

Keyword(s):

Simulation Analysis ◽

Structural Parameters ◽

Sol Gel ◽

Triaxial Accelerometer ◽

Response Frequency ◽

Pzt Films ◽

New Type ◽

The Cross ◽

Cross Axis ◽

Micro Accelerometer

Accelerometer in MEMS always is made by capacitive or piezoresistive, whose dynamic response is not good, the operating frequency is narrow, and the cross-axis sensitivity is low. A new type of piezoelectric micro-accelerometer is designed, and its structure is “x” type. The sensing unit is piezoelectric PZT films, which is achieved by sol-gel method. The accelerometer is a triaxial accelerometer. The theoretical and simulation analysis is used to achieve the charge sensitivity and response frequency, and also get the optimal structural parameters. A new circuit connection is proposed to improve the sensitivity and avoid the cross-axis sensitivity. The design achieves the z-axis sensitivity with more than 40 pC/g, x, y-axis sensitivity with more than 8pC/g, and the response frequency is about 3000Hz.

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Advancements of the examination of tool marks in human cartilage

10.21203/rs.3.rs-262182/v1 ◽

2021 ◽

Author(s):

Matthias Weber ◽

Anja Niehoff ◽

Markus A. Rothschild

Keyword(s):

Light Microscope ◽

Cross Correlation ◽

Costal Cartilage ◽

Correlation Coefficients ◽

Human Cartilage ◽

Cut Marks ◽

Tool Marks ◽

The Cross ◽

Cleaning Methods ◽

The Individual

Abstract This work deals with the examination of tool marks in human cartilage. We compared the effectiveness of several cleaning methods on cut marks in porcine cartilage. The method cleaning by multiple casts achieved the significantly highest scores (P = 0.02). Furthermore, we examined the grain-like elevations (dots) located on casts of cut cartilage. The results of this study suggest that the casting material forms these dots when penetrating cartilage cavities, which are areas where the strong collagen fibers leave space for the chondrocytes. We performed fixation experiments to avoid this, without success. In addition, 31 casting materials were compared regarding contrast under light-microscope and 3D tool marks scanner. Under the light-microscope, brown materials achieved significantly higher values than grey (P = 0.02) or black (P = 0.00) whereas under the 3D scanner, black materials reached higher contrast values than grey (P = 0.04) or brown (P = 0.047). To compare the accuracy and reproducibility of 6 test materials for cartilage, we used 10 knives to create cut marks that were subsequently scanned. During the alignment of the individual signals of each mark, the cross-correlation coefficients (Xmax) and lags (LXmax) were calculated. The signals of the marks in agarose were aligned with significantly fewer lags and achieved significantly higher cross-correlation coefficients compared to all tested materials (both P = 0.00). Moreover, we determined the cross-correlation coefficients (XC) for known-matches (KM) per material. Agarose achieved significantly higher values than AccuTrans®, Clear Ballistics™, and gelatine (all P = 0.00). The results of this work provide valuable insights for the forensic investigation of marks in human costal cartilage.

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Cross-Axis Coupling Effects in Single-Axis Nuclear Magnetic Resonance Gyroscopes

Sensors ◽

10.3390/s20030734 ◽

2020 ◽

Vol 20 (3) ◽

pp. 734

Author(s):

Zhiguo Wang ◽

Yi Zhang ◽

Xiang Zhan ◽

Qiyuan Jiang ◽

Hui Luo

Keyword(s):

Magnetic Field ◽

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Vibration Frequency ◽

Coupling Effects ◽

Rotation Rates ◽

Angular Vibration ◽

The Cross ◽

Cross Axis ◽

Nuclear Magnetic

Nuclear magnetic resonance gyroscopes (NMRGs) may be operated in an environment with violent vibration that usually contains both linear components and angular components. To analyze the influence of angular vibration on an NMRG, cross-axis coupling effects are studied. The cross-axis rotation rates induce an equivalent magnetic field. Its influence can be described by the Bloch equations. The approximate frequency shift and amplitude of the spin oscillator with an equivalent magnetic field in the cross-axis were obtained, which was validated by numerical simulation. The findings show that the angular vibration component leads to a remarkable error for the NMRG. When the angular vibration frequency is near the Larmor frequency, the oscillation frequency of the spins may be locked to the angular vibration frequency, destroying the NMRG’s ability to measure rotation rates. The cross-axis coupling problem should be considered in the design of an NMRG and corresponding inertial navigation systems.

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Using a Planar Array of MEMS Microphones to Obtain Acoustic Images of a Fan Matrix

Journal of Sensors ◽

10.1155/2017/3209142 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Lara del Val ◽

Alberto Izquierdo ◽

Juan José Villacorta ◽

Luis Suárez

Keyword(s):

Microelectromechanical Systems ◽

Processing System ◽

Signal Acquisition ◽

Acoustic Images ◽

Mems Microphone ◽

The Matrix ◽

Planar Array ◽

Mems Microphones ◽

The Individual ◽

Signal Acquisition And Processing

This paper proposes the use of a signal acquisition and processing system based on an8×8planar array of MEMS (Microelectromechanical Systems) microphones to obtain acoustic images of a fan matrix. A3×3matrix of PC fans has been implemented to perform the study. Some tests to obtain the acoustic images of the individual fans and of the whole matrix have been defined and have been carried out inside an anechoic chamber. The nonstationary signals received by each MEMS microphone and their corresponding spectra have been analyzed, as well as the corresponding acoustic images. The analysis of the acoustic signals spectra reveals the resonance frequency of the individual fans. The obtained results reveal the feasibility of the proposed system to obtained acoustic images of a fan matrix and of its individual fans, in this last case, in order to estimate the real position of the fan inside the matrix.

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Full‐waveform processing and interpretation of kilohertz cross‐well seismic data

Geophysics ◽

10.1190/1.1443508 ◽

1993 ◽

Vol 58 (9) ◽

pp. 1248-1256 ◽

Cited By ~ 8

Author(s):

Ashraf A. Khalil ◽

Robert R. Stewart ◽

David C. Henley

Keyword(s):

Oil Recovery ◽

Seismic Data ◽

Shear Waves ◽

Synthetic Seismograms ◽

Oil Field ◽

S Wave ◽

Sonic Log ◽

The Cross ◽

Interval Velocities ◽

The Individual

High‐frequency, cross‐well seismic data, from the Midale oil field of southeastern Saskatchewan, are analyzed for direct and reflected energy. The goal of the analysis is to produce interpretable sections to assist in enhanced oil recovery activities ([Formula: see text] injection) in this field. Direct arrivals are used for velocity information while reflected arrivals are processed into a reflection image. Raw field data show a complex assortment of wave types that includes direct compressional and shear waves and reflected shear waves. A traveltime inversion technique (layer stripping via ray tracing) is used to obtain P‐ and S‐wave interval velocities from the respective direct arrivals. The velocities from the cross‐well inversion and the sonic log are in reasonable agreement. The subsurface coverage of the cross‐well geometry is investigated; it covers zones extending from the source well to the receiver well and includes regions above and below the source/receiver depths. Upgoing and downgoing primary reflections are processed, in a manner similar to the vertical seismic profiling/common‐depth‐point (VSP/CDP) map, to construct the cross‐well images. A final section is produced by summing the individual reflection images from each receiver‐gather map. This section provides an image with evidence of strata thicknesses down to about 1 m. Synthetic seismograms are used to interpret the final sections. Correlations can be drawn between some of the events on the synthetic seismograms and the cross‐well image.

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The Liturgical Mystery

The Oxford Handbook of Mystical Theology ◽

10.1093/oxfordhb/9780198722380.013.7 ◽

2020 ◽

pp. 128-143

Author(s):

Andrew Louth

Keyword(s):

Christian Faith ◽

Christian Understanding ◽

The Cross ◽

The Individual

This chapter argues that the heart of the ‘mystical’ in the Christian faith is inalienably liturgical. Despite the fact that modern use of the ‘mystical’, and especially ‘mysticism’, is concerned wholly with the experience of the individual, whether in the context of the sacramental life or outside it, the root meaning of the mystical in Christian understanding is bound up with the sacraments, and pre-eminently the eucharist, the divine liturgy. It is argued further that the eucharist is to be seen less as a text than an action, or movement, and an action performed by Christ: on the cross, eternally in heaven, and now in the eucharist. He is coming to draw the whole cosmos into unity with him and his offering himself to the Father. This is an act of reconciliation and love, with entailments, ascetical, ontological, metaphysical, and cosmic.

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