Micro Electronic Mechanical System Research Articles

Dynamic plastic hinge rotation measurement for RC columns under seismic loads using MEMS inclinometers

Plastic hinge rotation is an efficient and essential response parameter for post-disaster damage assessment on RC structures. In this paper, a micro-electronic mechanical system (MEMS) inclinometer-based approach is developed to dynamically measure the plastic hinge rotation of RC columns under earthquake loads. The plastic hinge rotation is regarded as the relative angle of rotation, measured by inclinometers, between cross-sections such that influence from the absolute rotation of floors can be eliminated. Meanwhile, since the inclinometers are densely installed near the bottom, translational acceleration-induced error can be compensated by subtracting the lowest sensor’s output from others’. However, issues caused by rotational and translational vibration are considered as the major challenges in real applications. The contribution of external vibration to the sensor’s overall output is revealed via analysis on a simplified inclinometer model. A numerical study utilizing typical RC column’s deformation characteristics and dimensions is conducted to analyze the influence of major factors: vibrational frequency, sensor position and damage extent. A method for static and dynamic inclinometer calibration is presented. The related calibration experiments are carried out to quantify the sensor’s sensitivity as well as the relationship between rotational frequency and error. The calibration method is validated with a set of vibration tests that use three seismic waves as input. Finally, performance of the proposed approach in full scale structures is investigated through a shake table test.

Prior Kinematic Information Fusion for Pedestrian Localization With Toe-Heel-Shank MIMUs

With the development of the micro-electronic mechanical system (MEMS) inertial measurement units (IMU), the foot-mounted pedestrian inertial navigation system (PINS) based on the zero velocity update (ZUPT) is widely used. The systematic errors of MEMS IMU cause low precision of PINS at swing phase. However, the bio-mechanical constraints, which can be used to suppress the divergence of PINS, exist in lower limbs. In this study, three magnetometer and IMUs are fixed on the toe, heel and shank, respectively. The attitude of each segment is estimated by a MAHONY filter. The gait is defined as four successive phases. For each phase, the velocity and position constraints are constructed based on dynamic geometric constraint and Coriolis theory. Based on the perfect measurement method, the kinematic constraints, which are calculated by inertial data and attitude, are added into the observed equations. The noises are considered as additive Gaussian white noise. The linear Kalman filter is set to iteratively estimate the optimal positioning result. Several experiments with different walking velocities and trajectories are performed. The results show that the algorithm which is proposed in this study, greatly suppresses the velocity and positioning error.

An improved GNSS/INS navigation method based on cubature Kalman filter for occluded environment

Global navigation satellite systems and inertial navigation systems (GNSSs/INSs) based on the cubature Kalman filter (CKF) can provide an effective land vehicle navigation and positioning solution. The accuracy of CKF depends mainly on the prior probability density function (PDF), which is inaccurate when the GNSS signal is temporarily blocked in an urban environment. Although the improved CKF (ICKF) can reduce cubature point errors by using the historical information obtained iteratively, the generation of cubature points is still related to measurement noise. To obtain a more accurate PDF, adjustment off the sensor measurement noise is necessary. In this paper, an adaptive ICKF for GNSS/INS system based on the Mahalanobis distance called MD-ICKF is proposed, which expands the usability of the micro-electronic mechanical system based integrated navigation system in an urban environment. Two lower triangular matrices obtained by Cholesky decomposition are used to adjust the cubature point errors during each iteration. Furthermore, the measurement noise will be inflated to obtain a more accurate PDF when it exceeds the threshold calculated by the MD and chi-square test. The field experiment results show that the proposed method has better positioning accuracy and performance than CKF and ICKF in an occluded environment

Future Energy Source for Remote IoT Systems using MEMS-based Piezoelectric Energy Harvesting Devices.

Piezoelectric energy harvesting (PEH) device is an energy converter that will convert mechanical vibration energy into electrical energy. The energy converter is implemented using Micro-Electronic Mechanical System (MEMS). The vibration is extracted from the surroundings, and the extracted vibration is converted into electrical energy using PEH for low power sensors used in the IoT environment. PHE device will generate the maximum power when the vibration of the surrounding is exactly matched with the resonant frequency of the device. This paper presents two different PHE MEMS devices which will convert the vibration into electrical energy. The proposed device has two design materials; T shape resonant model is designed by arranging beams in multilayer and an ultra-violet resin seismic mass. There are four-layer formed together; the substrate first layer is built using polyethylene terephthalate (PET). The third layer is formed by using piezo-electric material; the second and fourth layers are build using aluminium and platinum electrode. In the model, two different types of piezoelectric materials are used to build the PEH device. Two types of material used in the devices are ZnO and PZT-5A. Rayleigh-Ritz and Macaulay methods are used to model the system for analysing the mechanical behaviour of the model and structural analysis for the better energy extraction using FEM. The proposed PHE device using ZnO and PZT-5A is generating power at the rate of 1.8 W and 1.35 W with a voltage rating of 545 and 45 mV, respectively. The Proposed PHE device is built for remote location low power IoT devices.

Simulative and Experimental Characterization of an Adaptive Astigmatic Membrane Mirror.

Adaptive optical (AO) components play an important role in numerous optical applications, from astronomical telescopes to microscope imaging systems. For most of these AO components, the induced wavefront correction, respectively added optical power, is based on a rotationally symmetric or segmented design of the AO component. In this work, we report on the design, fabrication, and characterization of a micro-electronic-mechanical system (MEMS) adaptive membrane mirror in the shape of a parabolic cylinder. In order to interpret the experimental characterization results correctly and provide a tool for future application development, this is accompanied by the setup of an optical simulation model. The characterization results showed a parabolically deformable membrane mirror with an aperture of 8 × 2 mm2 and an adaptive range for the optical power from 0.3 to 6.1 m−1 (dpt). The optical simulation model, using the Gaussian beamlet propagation method, was successfully validated by laser beam profile measurements taken in the optical characterization setup. This MEMS-based adaptive astigmatic membrane mirror, together with the accompanying simulation model, could be a key component for the rapid development of new optical systems, e.g., adaptive laser line generators.

DNA Printing Integrated Multiplexer Driver Microelectronic Mechanical System Head (IDMH) and Microfluidic Flow Estimation.

The system designed in this study involves a three-dimensional (3D) microelectronic mechanical system chip structure using DNA printing technology. We employed diverse diameters and cavity thickness for the heater. DNA beads were placed in this rapid array, and the spray flow rate was assessed. Because DNA cannot be obtained easily, rapidly deploying DNA while estimating the total amount of DNA being sprayed is imperative. DNA printings were collected in a multiplexer driver microelectronic mechanical system head, and microflow estimation was conducted. Flow-3D was used to simulate the internal flow field and flow distribution of the 3D spray room. The simulation was used to calculate the time and pressure required to generate heat bubbles as well as the corresponding mean outlet speed of the fluid. The “outlet speed status” function in Flow-3D was used as a power source for simulating the ejection of fluid by the chip nozzle. The actual chip generation process was measured, and the starting voltage curve was analyzed. Finally, experiments on flow rate were conducted, and the results were discussed. The density of the injection nozzle was 50, the size of the heater was 105 μm × 105 μm, and the size of the injection nozzle hole was 80 μm. The maximum flow rate was limited to approximately 3.5 cc. The maximum flow rate per minute required a power between 3.5 W and 4.5 W. The number of injection nozzles was multiplied by 100. On chips with enlarged injection nozzle density, experiments were conducted under a fixed driving voltage of 25 V. The flow curve obtained from various pulse widths and operating frequencies was observed. The operating frequency was 2 KHz, and the pulse width was 4 μs. At a pulse width of 5 μs and within the power range of 4.3–5.7 W, the monomer was injected at a flow rate of 5.5 cc/min. The results of this study may be applied to estimate the flow rate and the total amount of the ejection liquid of a DNA liquid.

Implementation of a MEMS-Based GNSS/INS Integrated Scheme Using Supported Vector Machine for Land Vehicle Navigation

The performance of the integrated global navigation satellite system (GNSS) and inertial navigation system (INS) has been proven to be more accurate, reliable, and continuous than stand-alone systems. The development of micro-electronic mechanical system (MEMS) enables inertial measurement unit (IMU) to meet the low-cost and small-size requirements of vehicular navigation. However, the stochastic error characteristics of the inertial sensors and the instability caused by the GNSS signal outages pose a threat to the MEMS-based GNSS/INS land vehicle navigation system. Within this context, we propose the following two-step GNSS/INS integrated architecture at two levels: 1) enhancing the signal-to-noise ratio (SNR) of MEMS-INS raw measurements utilizing a hybrid denoising algorithm with wavelet transform and support vector machine (SVM) and 2) improving the positioning accuracy by a SVM-based data fusion approach which could predict the accumulated error of the MEMS inertial sensors during the GNSS outages. A rotation platform experiment and a field test were carried out, which suggests that the proposed method can effectively eliminate the stochastic errors of MEMS-IMU, and significantly improve the overall positioning accuracy in land vehicle navigation.

Optical Grating Techniques for MEMS-Based Spectrometer—A Review

This paper examined the innovations of the spectrometers for the measurement of consistency based parameters of the handheld Micro Electronic Mechanical System (MEMS) Spectrometer. Fast, highly sensitive, miniature spectroscopy techniques empowered quick, savvy and effective measures for various applications. In the light spectroscopy-based identification and quantification, advances in the field of wavelength discrimination are significant and essential. The identification of grid parameters and limiting conditions are necessary for the design and fabrication of diffraction gratings, for the spectrometer. This work evaluates the emerging trends in Micro-Spectrometer's Grating Techniques, focusing on the aspects of grating parameters and the recent developments of grating. The main parameters for evaluating the performance of a grating have been reviewed and found that grating efficiency, groove density, free spectral range and resolving power play a significant part in the grating performance. The fabrication technique employed as well as the materials used in the fabrication process, play a significant role in the efficiency of the grating. Silicon, Silicon dioxide (SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), Glass (Silica glass), Poly methyl methacrylate (PMMA), Chromium and Silicon nitride(Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) are the most used materials. The integration of new materials that are ideal for the state-of-the-art semiconductor industry techniques for MEMS fabrication along with a new blazing structure would increase the efficiency of the grating.

Development of V-Shaped Beam on the Shock Resistance and Driving Frequency of Micro Quartz Tuning Forks Resonant Gyroscope.

The application of gyroscopes in harsh environments has always been a hot topic. As a high-quality material for manufacturing gyroscopes, quartz crystals need to be designed and optimized to meet the normal operation of gyroscopes in harsh environments. The Micro Electronics Mechanical System(MEMS) quartz tuning forks resonant gyroscope is one of the quartz gyroscopes. The elastic structure (V-shaped beam) between the anchor support point and tuning forks plays a vital role in the MEMS quartz tuning forks resonant gyroscope. This structure determines the natural frequency of the gyroscope, and more importantly, determines the shock resistance of the gyroscope structure. In this article, the MEMS quartz tuning forks gyroscope with different V-shaped beam thicknesses are simulated and analyzed by finite element analysis simulation software. After the modal analysis and shock simulation (the half-cycle sine shock pulse with amplitude of 1500 g (g is the acceleration of gravity) and duration of 2 ms in the six shock directions), the results show that when the beam thickness is 80 μm, the maximum stress is 94.721 MPa, which is less than the failure stress of quartz crystal. The gyroscope’s shock resistance is verified through shock testing.

A New In-Flight Alignment Method with an Application to the Low-Cost SINS/GPS Integrated Navigation System.

The optimization-based alignment (OBA) methods, which are implemented by the optimal attitude estimation using vector observations—also called double-vectors—have proven to be effective at solving the in-flight alignment (IFA) problem. However, the traditional OBA methods are not applicable for the low-cost strap-down inertial navigation system (SINS) since the error of double-vectors will be accumulated over time due to the substantial drift of micro-electronic- mechanical system (MEMS) gyroscope. Moreover, the existing optimal estimation method is subject to a large computation burden, which results in a low alignment speed. To address these issues, in this article we propose a new fast IFA method based on modified double-vectors construction and the gradient descent method. To be specific, the modified construction method is implemented by reducing the integration interval and identifying the gyroscope bias during the construction procedure, which improves the accuracy of double-vectors and IFA; the gradient descent scheme is adopted to estimate the optimal attitude of alignment without complex matrix operation, which results in the improvement of alignment speed. The effect of different sizes of mini-batch on the performance of the gradient descent method is also discussed. Extensive simulations and vehicle experiments demonstrate that the proposed method has better accuracy and faster alignment speed than the related traditional methods for the low-cost SINS/global positioning system (GPS) integrated navigation system

A decision-tree based multiple-model UKF for attitude estimation using low-cost MEMS MARG sensor arrays

Micro-electronic-mechanical system (MEMS) is widely used in various applications, especially as a low-cost and small size system for attitude estimation which requires high accuracy and fast response. This work proposes a novel decision-tree based multiple-model unscented Kalman filter (DTMM-UKF) for attitude estimation. It is a quaternion-based attitude estimator that fuses related strap-down magnetic, angular rate, and gravity (MARG) sensor arrays. A set of novel criteria for testing whether the magnetometer and accelerometer are reliable is developed. To improve the anti-interference performance, we define four different filter models for the UKF. Particularly, a decision tree is established to automatically switch filter model based on these reliability test criteria. The priori attitude estimation is obtained from the process model using gyroscope data. Fusing the accelerometer and magnetometer data together, the observation attitude could be solved based on corresponding objective function and Jacobian matrix determined by the filter model. Under the UKF frame, the final optimal attitude could be determined by fusing priori estimation and observed attitude. Experimental tests show that the DTMM-UKF algorithm has better robustness and higher real-time estimation accuracy.

Application of Modified Ellipsoidal Filter in Integrated Strapdown Inertial Navigation System

Consideration is given to solving the correction problems of slowly varying shifts of microelectronic mechanical system of gyroscopes readings using object position measurements via global navigation satellite system. For measurement noises only their maximum values are known, the presence of stochastic properties is not assumed. The moving object attitude is described by quaternions. The task of strapdown inertial navigation systems readings correction is considered in a simplified formulation, an inertial coordinate system is used, the Coriolis force and inhomogeneity of the Earth gravitational field are not taken into account. The application of the proposed approach is demonstrated on the test example.

A Large-Size MEMS Scanning Mirror for Speckle Reduction Application

Based on microelectronic mechanical system (MEMS) processing, a large-size 2-D scanning mirror (6.5 mm in diameter) driven by electromagnetic force was designed and implemented in this paper. We fabricated the micromirror with a silicon wafer and selectively electroplated Ni film on the back of the mirror. The nickel film was magnetized in the magnetic field produced by external current coils, and created the force to drive the mirror’s angular deflection. This electromagnetically actuated micromirror effectively eliminates the ohmic heat and power loss on the mirror plate, which always occurs in the other types of electromagnetic micromirrors with the coil on the mirror plate. The resonant frequency for the scanning mirror is 674 Hz along the slow axis, and 1870 Hz along the fast axis. Furthermore, the scanning angles could achieve ±4.5° for the slow axis with 13.2 mW power consumption, and ±7.6° for the fast axis with 43.3 mW power consumption. The application of the MEMS mirror to a laser display system effectively reduces the laser speckle. With 2-D scanning of the MEMS mirror, the speckle contrast can be reduced from 18.19% to 4.58%. We demonstrated that the image quality of a laser display system could be greatly improved by the MEMS mirror.

Controlled synthesis of anisotropic hexagonal boron nitride nano-web

The assembly of one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) nanomaterial show entirely different properties than their individual counterparts. Since the shape of nanomaterials plays a crucial role in designing devices with desired applications, relentless efforts are on-going to obtain the parameters for controlling the shape of the final product. Present study concerns the synthesis and growth of a combined 2D and 3D structure of Hexagonal Boron Nitride Nanofibers Web (BNNFs-Web) from 1D structure of BNNFs. Magnesium catalytic layer deposited on Silicon substrate produces Web-like nucleation sites when etches with NH3 flow at 300°C. The precursor's mixture of B, γ-Fe2O3 and MgO annealed at 500°C uses these nucleation sites as a pattern, and grow BNNFs-Web in a unique 2D and 3D configuration at 1000°C. XRD, Raman and FTIR spectroscopies confirmed the h-BN phase of the as-synthesized BNNFs-Web. This unique 2D and 3D material can offer distinguish features with improved properties as compared to other nanostructures of h-BN. Such a material can be a much better choice for its potential applications in different fields of bio-medical, microelectronic mechanical system and solid state neutron detectors.

Mid‐Infrared Spectroscopy for Monitoring of Anaerobic Digestion Processes – Prospects and Challenges

AbstractTo develop an online probe that is not only sufficiently robust, but also able to measure crucial process variables in biogas plants is a tough challenge. Therefore, a mid‐infrared (MIR) spectroscopic attenuated total reflection (ATR) probe and robust probe fitting were established. A fully automated probe control, calibration after probe cleaning, and analysis of the absorption spectra using machine learning were implemented in order to reduce maintenance of the probe to a minimum. The relevant wavelengths in the MIR spectrum for organic acids, total alkalinity, and ammonium nitrogen concentration were identified. Finally, intensive lab testing was carried out, followed by operation of the complete online measurement system at an industrial biogas plant. In order to improve signal strength and sensitivity, microelectronic mechanical system (MEMS)‐based Fabry‐Pérot interferometers were also investigated.

Experimental Study of a Fourier Transform Spectrometer Based on Scanning Micro-Electromechanical Mirrors

ABSTRACT This paper presents a non-scanning Fourier transform spectrometer based on a micro-electronic mechanical system micro-mirrors and a single detector. The fundamental principle and key parameters of this Fourier transform spectrometer were analyzed in detail. Theoretical analysis showed that, when the dip angle of the slantwise mirror is 0.38713°, the resolution of the system is 9.7 nm (at 1350 nm). Experiments demonstrated that, the spectra resolution is less than 10 nm, the wavelength deviation is ∼1.5 nm, the signal-to-noise ratio is higher than 30 dB and the intensity deviation at peak wavelength is less than 0.4%.

MICRO-AIR-VEHICLE-BORNE NEAR-RANGE SAR WITH MOTION COMPENSATION

The major di-culty of realizing a micro-air-vehicle-borne (MAV-borne) synthetic aperture radar (SAR) is the motion errors that need to be precisely measured and compensated. This paper presents two novel motion measuring algorithms speciflcally for near-range applications. These algorithms use only low-cost micro-electronic-mechanical system (MEMS) inertial measurement units (IMU). A MAV-borne SAR system was built equipped with a commercial ofi-the-shelf (COTS) motion sensing board. Several MAV-borne SAR measurements were performed for the flrst time in a hall with a realistic scene. SAR images were generated with proposed motion measuring algorithms in ofi-line mode. Obvious improvements in SAR image quality in terms of focusing have been observed after motion compensation with the proposed motion measuring algorithms. These results show that MAV-borne SAR together with low-cost IMU can yield very useful images.

Wafer-level SLID bonding for MEMS encapsulation

Hermetic packaging is often an essential requirement to enable proper functionality throughout the device’s lifetime and ensure the optimal performance of a micro electronic mechanical system (MEMS) device. Solid-liquid interdiffusion (SLID) bonding is a novel and attractive way to encapsulate MEMS devices at a wafer level. SLID bonding utilizes a low-melting-point metal to reduce the bonding process temperature; and metallic seal rings take out less of the valuable surface area and have a lower gas permeability compared to polymer or glass-based sealing materials. In addition, ductile metals can adopt mechanical and thermo-mechanical stresses during their service lifetime, which improves their reliability. In this study, the principles of Au-Sn and Cu-Sn SLID bonding are presented, which are meant to be used for wafer-level hermetic sealing of MEMS resonators. Seal rings in 15.24 cm silicon wafers were bonded at a width of 60 μm, electroplated, and used with Au-Sn and Cu-Sn layer structures. The wafer bonding temperature varied between 300 °C and 350 °C, and the bonding force was 3.5 kN under the ambient pressure, that is, it was less than 0.1 Pa. A shear test was used to compare the mechanical properties of the interconnections between both material systems. In addition, important factors pertaining to bond ring design are discussed according to their effects on the failure mechanisms. The results show that the design of metal structures can significantly affect the reliability of bond rings.

Small Digital Angle Sensor Based on MEMS

One design method of small digital angle sensor based on microelectronic mechanical system (MEMS) is introduced. The angle sensor is build with the embedded microprocessor STM32F103 as the core. The acceleration value of MEMS accelerometer in X, Y, and Z-axis directions was used to calculate the angle of measured target on the horizontal direction and vertical direction, and the digital and miniaturization of digital angle sensor are realized.

Design and Optimization of New Compact Tunable 2.4‐GHz Band Pass Filter Using Coupled λ/2 Microstrip Open‐Loop Resonators and Mems‐Switch Technique

ABSTRACTA new compact WLAN‐band pass filters are proposed using a half wavelength microstrip open‐loop and λ/2 microstrip resonators based on direct‐cross coupling method and micro electronic mechanical system (MEMS) technology. The filter is not only compact in size due to the slow‐wave effect, but also has multitransmission zeros at both low and high rejection bands, as well as low insertion loss in the pass band. A demonstration filter has been designed and tested. Simulation results almost agree with the measured results. Some discrepancy between them can still be observed, which can be attributed to the unexpected tolerance of fabrication. Due to the simplicity of the design and its fabrication, it shows that this type of band pass filter has great potential for actual applications in communication and other systems. By applying the MEMS technology, a switchable band pass filter based on the quadruplet filter is able to be designed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2444–2450, 2013