Design Of Accelerometer Research Articles

Suggestion for a new design of the piezoresistive accelerometer

ABSTRACTThe piezoresistive accelerometer is an electronic device used to measure the vibration level of rotating machines; we can say that an accelerometer more precise and more sensitive is a more reliable sensor. In our paper, based on the improvement of some parameters of piezoresistive accelerometer for develop their accuracy and their sensitivity. This improvement comes from extracting a suitable mathematical model of the accelerometer; this model allows proposing a new design of piezoresistive accelerometer.

A Novel Piezoresistive Accelerometer with SPBs to Improve the Tradeoff between the Sensitivity and the Resonant Frequency.

For improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers, the dependency between the stress of the piezoresistor and the displacement of the structure is taken into consideration in this paper. In order to weaken the dependency, a novel structure with suspended piezoresistive beams (SPBs) is designed, and a theoretical model is established for calculating the location of SPBs, the stress of SPBs and the resonant frequency of the whole structure. Finite element method (FEM) simulations, comparative simulations and experiments are carried out to verify the good agreement with the theoretical model. It is demonstrated that increasing the sensitivity greatly without sacrificing the resonant frequency is possible in the piezoresistive accelerometer design. Therefore, the proposed structure with SPBs is potentially a novel option for improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers.

Design and Fabrication of a Symmetrical Cantilever-Beam Capacitive MEMS Accelerometer for Geophone

Design and Fabrication of a Symmetrical Cantilever-Beam Capacitive MEMS Accelerometer for Geophone

伸縮梁構造を用いたMEMS加速度センサの特性安定化

A high-reliability design method for a MEMS accelerometer using a stretchable beam structure was proposed to prevent sensor property variations due to stresses from device fabrication and packaging. To achieve a compact piezoresistive three-axis accelerometer using a low-cost resin-mold packaging, beam buckling due to compression forces originating from residual stresses of thin films and shrinkage of mold resin must be overcome. The proposed stretchable beam structure, which gives axial flexibility by adding a ring-shape part at the center of the beam, has advantages in which it is effective against not only packaging stress but also inner stress such as thin film stress, and it does not sacrifice compactness. Formulations with a simple accelerometer model revealed that large and nonlinear variations in sensitivity occur due to beam compression. Such large variations have to be avoided to stabilize sensor performances. Besides, it is expected to enhance sensitivity up to about 1.5 times while maintaining linearity by arranging an appropriate compression force using the stretchable beam. The effects of the stretchable beam were verified using simulations and experiments on test samples. The designed stretchable beam, which has two rings connected serially, has five times the axial flexibility compared with a conventional straight beam without significant change in bending stiffness. A preferable increase of about 1.4 times and small deviations in measured sensitivity were achieved with the developed stretchable beam, compared with the straight beam with an unstable increase of about seven times and extremely large deviations. These large deviations seem to come from shape variation due to non-uniformity of dry etching technologies commonly used for MEMS devices. Thus, the effects of the proposed stretchable beam to the MEMS accelerometer design were confirmed to prevent large variations and deviations in sensor properties and to enhance sensitivity.

Measurement and Analysis of Drilling Vibration Using Tracer DAQ and LABVIEW

This study presents a vibration measurement system using Micro-Electro-Mechanical Systems (MEMS) accelerometer design to measure the vibration of a vibration source. The LABVIEW program is developed to monitor and analyze measured data. The program first acquires the analogue input signal from the three different channels, and reads the data to be analyzed. The obtained measurement data during the measurement is illustrated graphically by means of Tracer DAQ and LABVIEW. Therefore, as a result of the analysis, vibration data obtained by means of two different programs are compared. Some preliminary results of this endeavor are presented. The error evaluation of these accelerometers has been performed according to the Mean Absolute Percentage Error (MAPE) method. In the conducted evaluation, Accelerometer (Acc) 1 is 0.033%, Acc 2 is 0.019% and Acc 3 is 0.055%. We have reached that findings of proposed study are similar.

Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity.

This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved.

Design and Simulation of MEMS-based Z-Axis Capacitive Accelerometer

In this paper, a MEMS-based Z-axis capacitive accelerometer is designed and simulated. An out-of-plane Z-axis accelerometer designed for 8 µm UV-LIGA technology for an acceleration range of ±10g. The operating voltage is 5 V DC. Simulation results show good linear characteristics in the operating range of DC-400 Hz, which is the bandwidth of the accelerometer. The simulations of the device were carried out using CoventorWare ® . By using modal analysis in CoventorWare ® the resonating frequency of 3.1 kHz is obtained.

Design and Analysis of a High Sensitivity FBG Accelerometer Based on Local Strain Amplification

A fiber Bragg grating (FBG) accelerometer based on a push–pull elastic cylinder structure is demonstrated. First, the model based on the uniform cylinder structure is analyzed and the optimized accelerometer parameters are given. Then, by designing a radius-varying cylinder structure, the FBG strain becomes larger than the cylinder strain, which leads to enhanced sensitivity amplification for a small accelerometer size and relatively high resonant frequency. Meanwhile, the influence of the transverse force on the accelerometer is theoretically analyzed. These results indicate that the transverse-induced FBG deformation is very big so that a strict transverse constrain is needed. The formula of the strain magnification is derived and the design rules of the strain magnification are given. After structure optimization according to the rules, the FBG strain increases to 1.5 times, the sensitivity increases to 1.82 times, whereas the resonant frequency reduces to 0.9 times compared with the parameters of accelerometer based on uniform cylinder structure. Finally, the accelerometer size reduces to $\Phi {20~{\rm mm}\times 34~{\rm mm}}$ , the sensitivity increases to 623 pm/g, and the resonant frequency reduces to 449 Hz.

Design and Analysis of Micro Accelerometer for Tool Condition Monitoring

Tool condition monitoring plays a huge role in the CNC machines in which it is used to avoid the breakage of the tools.In this paper area changed capacitive micro accelerometer is designed to measure the vibration exposure of the tool on various applications in the CNC machines. The design process and simulation of the Micro accelerometer are done using INTELLISUITE 8.6. The rectangular folded beamis designed to reduce the residual stress and to obtain a better sensitivity. Static and dynamic analysis shows that sensitivity of the designed capacitive accelerometer is good enough to detect the vibration of the tool.

Design, Simulation and Fabrication of Triaxial MEMS High Shock Accelerometer.

On the basis of analyzing the disadvantage of other structural accelerometer, three-axis high g MEMS piezoresistive accelerometer was put forward in order to apply to the high-shock test field. The accelerometer's structure and working principle were discussed in details. The simulation results show that three-axis high shock MEMS accelerometer can bear high shock. After bearing high shock impact in high-shock shooting test, three-axis high shock MEMS accelerometer can obtain the intact metrical information of the penetration process and still guarantee the accurate precision of measurement in high shock load range, so we can not only analyze the law of stress wave spreading and the penetration rule of the penetration process of the body of the missile, but also furnish the testing technology of the burst point controlling. The accelerometer has far-ranging application in recording the typical data that projectile penetrating hard target and furnish both technology guarantees for penetration rule and defend engineering.

A wafer level vacuum encapsulated capacitive accelerometer fabricated in an unmodified commercial MEMS process.

We present the design and fabrication of a single axis low noise accelerometer in an unmodified commercial MicroElectroMechanical Systems (MEMS) process. The new microfabrication process, MEMS Integrated Design for Inertial Sensors (MIDIS), introduced by Teledyne DALSA Inc. allows wafer level vacuum encapsulation at 10 milliTorr which provides a high Quality factor and reduces noise interference on the MEMS sensor devices. The MIDIS process is based on high aspect ratio bulk micromachining of single-crystal silicon layer that is vacuum encapsulated between two other silicon handle wafers. The process includes sealed Through Silicon Vias (TSVs) for compact design and flip-chip integration with signal processing circuits. The proposed accelerometer design is sensitive to single-axis in-plane acceleration and uses a differential capacitance measurement. Over ±1 g measurement range, the measured sensitivity was 1fF/g. The accelerometer system was designed to provide a detection resolution of 33 milli-g over the operational range of ±100 g.

Design and fabrication of a MEMS capacitive accelerometer with fully symmetrical double-sided H-shaped beam structure

This paper presents a MEMS capacitive accelerometer with fully symmetrical double-sided H-shaped beam structure. The fully symmetrical structure is fabricated from a single double-device-layer SOI wafer, which has identical buried oxide layer and device layer on both sides of a thick handle layer. A large proof mass with through wafer thickness (560μm) is fabricated in this process. Two layers of single crystal silicon H-shaped beams with highly controllable dimension suspend the proof mass from both sides. The resonance frequency of the accelerometer is measured in open loop system by a network analyzer. The quality factor and the resonant frequency are 106 and 2.24kHz, respectively. The accelerometer with open loop interface circuit is calibrated on B&K Vibration Transducer Calibration System (Type 3629). The sensitivity of the device is 0.24V/g, and the nonlinearity is 0.29% over the range of 0–1g.

Large Frequency Range and High Sensitivity Fiber Bragg Grating Accelerometer Based on Double Diaphragms

A fiber Bragg grating (FBG) accelerometer based on double diaphragms is presented and experimentally demonstrated. Design, fabrication, and optimization of the FBG accelerometer are analyzed. Experimental results indicate that the FBG accelerometer provides broad flat frequency range from 50 to 800 Hz, corresponding sensitivity range from 23.8 to 45.9 pm/G, while the flatness is <;3 dB. Cross-axis sensitivity is <;2.1% of the main-axis sensitivity, dynamic resolution can reach 0.385 mG/√(Hz), and dynamic range is 80 dB. Random error of the FBG accelerometer is analyzed by using Allan variance analysis method, which is promising in cross well seismic exploration.

Monolithic z-axis CMOS MEMS accelerometer

This paper describes the design, fabrication, and characterization of a monolithic z-axis capacitive torsional accelerometer fabricated in a 0.18-μm one-polysilicon six-metal layer complementary metal–oxide–semiconductor (CMOS) micro-electro-mechanical-system (MEMS) multi-project wafer process. After completion of the CMOS process, an additional aluminum layer and a thick photoresist masking layer are employed to achieve etching and microstructural release. The sensing electrodes are composed of stacked metal layers isolated by silicon dioxide layers in the CMOS process, with the metal-5 to metal-6 layers as the top electrodes and the metal-1 to metal-3 layers as the bottom electrodes. The simulated capacitance sensitivity of the sensor device is 0.8fF/g within the range of 0–6g. A three-phase switched-capacitor sensing circuit is used to read the sensing capacitances of the accelerometer. The measured sensitivity is 205mV/g, and the nonlinearity is 0.9% over 0–6g. The cross-axis sensitivities with respect to the x-axis and y-axis are 1.36% and 1.55%, respectively. The measured output noise floor is 630μg/Hz1/2.

A design of order-adjustable Σ∆ modulator for high performance micro-machined accelerometers

Sigma-delta modulation has been widely used in micro-machined accelerometers. Previous researches are mainly focused on increasing the order of the sigma-delta modulator for the mechanical sensor to improving the performance of the micro-machined accelerometers. These designs performed well in high resolution acceleration measurement, but they are insufficient in balancing the proof mass quickly while the micro-machined accelerometer is working. In this paper, the design of order-adjustable micro-machined accelerometer is proposed. It employs a mechanical sensor to balance the proof mass, and a fifth order MEMS accelerator to measure the acceleration with high resolution. Furthermore, this work shows an optimized design with a SQNR of 156.5 and 73.6 dB which can accurately measure the acceleration input and quickly balance the proof mass, respectively.

Design and Optimization of Sigma-Delta Accelerometer

Mathematical model of sensitive structures and detection principle of Sigma-Delta accelerometer are analyzed in this paper, and then an accelerometer with SNR 107dB is designed using MATLAB, the stability of which is analyzed based on root locus plot. When input is small than-3dBFS, the system is unsaturated. The poles and zeros of accelerometer noise transfer function are then analyzed and the feed-forward coefficient and local feedback coefficient are optimized, achieving a higher SNR of 112.1dB. At last, the circuit-level simulation is conducted and in-band noise level is about-140dB.

Design, Fabrication and Test of In-Plane MEMS Piezoresistive High-g Accelerometer

The new structure of in-plane high-g MEMS sensor for 10,000-150,000g has been designed in our paper, and it was packaged in dimensions of 17.5mm×12mm×4.5mm. In our experiments, the sensitivity reach to 0.335uv/g by the Hopkinson bar system and it also is in quick respose to the frequence. Meanwhile, the results show that all acceleration-time pulses are in very close agreement for acceleration amplitudes to about 150000g. It is a new way to monolithically integral triaxial piezoresistive high-g accelerometer in the future.

(Invited) Design and Simulation of a Novel Shock Accelerometer Based on Giant Piezoresistance Effect

The design of a novel eight-beam uniaxial shock accelerometer is presented. This new multi-beam structure has a advantage of high anti-disturbance capability. The designed measurement rang of the sensor is 150,000g and the sensitivity is 23.4μV/g, which is about 20 times higher than conventional sensors of same measurement rang due to the exploiting of the giant piezoresistance effect in silicon nanowires. This achievement opens up new developments in the area of shock experiments where the high overload capability and high sensitivity are both needed.

Digital Offset Trimming Techniques for CMOS MEMS Accelerometers

This paper presents a digital trimming technique for canceling the output offsets caused by sensor mismatches in an accelerometer design. The offset cancellation techniques provide fine trimming steps with higher chip area efficiency compared with that of conventional capacitor array compensation approaches. The accelerometer, fabricated in a 0.18- μm complementary metal-oxide-semiconductor micro-electro-mechanical-system process, containing the micro-mechanical structure and readout circuits, occupies only a 0.64 × 0.9 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area. The chip draws 0.4 mA from a 1.8-V supply. The measured sensitivity is 195 mV/g and the nonlinearity is 0.78% within the ±12 g sensing range. The output noise floor is 150 μg/√{Hz}, corresponding to a 1-g 100-Hz sinusoidal acceleration. The output offset voltage can be trimmed from several tens to several hundreds of millivolts down to several millivolts.

Manufacturing yield and cost estimation of a MEMS accelerometer based on statistical uncertainty analysis

Manufacturing yield maximization to minimize the production cost is one of the most important objectives of manufacturing. The manufacturing yield is the probability to manufacture products that satisfy multiple performance requirements. For a given set of product performance requirements, its manufacturing yield can be estimated based on the system parameter uncertainties including manufacturing tolerances, which are related to the production cost. We employ three performance indices for the design of a MEMS accelerometer, and the manufacturing yield and cost are estimated using statistical uncertainty analysis methods. The effects of the MEMS accelerometer parameter uncertainties on the manufacturing yield and cost are investigated.