Cross-axis Sensitivity Research Articles

Resonant MEMS Accelerometer with Low Cross-Axis Sensitivity-Optimized Based on BP and NSGA-II Algorithms.

This article proposes a low cross-axis sensitivity resonant MEMS(Micro-Electro-Mechanical Systems) accelerometer that is optimized based on the BP and NSGA-II algorithms. When resonant accelerometers are used in seismic monitoring, automotive safety systems, and navigation applications, high immunity and low cross-axis sensitivity are required. To improve the high immunity of the accelerometer, a coupling structure is introduced. This structure effectively separates the symmetric and antisymmetric mode frequencies of the DETF resonator and prevents mode coupling. To obtain higher detection accuracy and low cross-axis sensitivity, a decoupling structure is introduced. To find the optimal dimensional parameters of the decoupled structure, the BP and NSGA-II algorithms are used to optimize the dimensional parameters of the decoupled structure. The optimized decoupled structure has an axial stiffness of 6032.21 N/m and a transverse stiffness of 6.29 N/m. The finite element analysis results show that the sensitivity of the accelerometer is 59.1 Hz/g (Y-axis) and 59 Hz/g (X-axis). Cross-axis sensitivity is 0.508% (Y-axis) and 0.339% (X-axis), which is significantly lower than most resonant accelerometers. The coupling structure and optimization method proposed in this paper provide a new solution for designing resonant accelerometers with high interference immunity and low cross-axis sensitivity.

Designing MEMS accelerometer for enhanced sensitivity and reduced cross-sensitivity in landslide monitoring

MEMS accelerometers capable of detecting weak motions are required in measuring landslide movements. The sensor’s sensitivity and its independent readings of various acceleration modes are crucial factors in the design of these sensors. In addition, it is highly desired to fabricate these sensors with low-cost and flexible manufacturing technologies such as surface micromachining. This paper presents an advanced topology optimization approach to design the suspended structure for the maximum level of sensitivity and for a low cross-sensitivity in the reading of principal and lateral modes, while it is manufacturable with a low-cost surface micromachining process. The effect of inertial forces as a variable loading condition and mode switch prevention is applied using a meta-heuristic topology optimization method with simulated annealing. Considering the unique results of this topology optimization, PolyMUMPs surface micromachining is employed to manufacture the developed sensor. The fabricated sensor is subjected to measurement and subsequent comparison with analogous designs from the literature. The outcomes reveal a sensitivity of 0.3pF/g and cross-axis sensitivity of 0.048%, signifying a noteworthy advancement for surface micromachined accelerometers. Notably, this design, coupled with the devised topology optimization methodology, holds the potential for adoption by sensor manufacturers for diverse commercial applications.

Cantilever-based biaxial FBG inclinometer with low cross-axis sensitivity

This work proposes and demonstrates a biaxial sensing inclinometer based on two FBGs surface-mounted on two separate thin cantilevers with a diminishable cross-axis sensitivity. The measured sensitivities for the inclination angles in the x-z plane and y-z plane are 34.87 and 33.49 pm/deg, respectively. To enhance the protection of the delicate FBGs and minimize axis-to-axis cross-sensitivity, the carbon-steel cantilevers are strategically arranged in a perpendicular configuration, resulting in an impressively low cross-sensitivity value of just 0.9275%. This alignment not only offers mechanical shielding but also ensures optimal performance and accuracy for the FBGs.

Ultra-high-sensitivity micro-accelerometer achieved by pure axial deformation of piezoresistive beams

Microfabricated piezoresistive accelerometers with purely axially deformed piezoresistive beams have demonstrated high performance. However, the conventional design of such accelerometers requires complex theoretical calculations and specific dimensional conditions to achieve purely axial deformation, which inevitably increases the difficulty and cost of the design and manufacturing. We propose an innovative structure that can simply realize pure axial deformation of piezoresistive beams by eliminating the transverse displacement at both ends without tedious calculations. An accelerometer based on the structure was fabricated; both static and dynamic performances were tested. The results showed that the accelerometer had high sensitivity (2.44 mV g−1 with 5 V bias, without circuit amplification), low cross-axis sensitivity (1.56% and 0.49 %, respectively), and high natural frequency (11.4 kHz), with a measurement range of 0–100 g. This design method provides an easy approach for designing high-performance piezoresistive sensors.

Development of a High-Precision and Low Cross-Axis Sensitivity 3-D Accelerometer for Low-Frequency Vibration Measurement

A new high-precision and low-frequency 3-D accelerometer that utilizes a symmetrical parallel vibration-sensing mechanism and a low cross-axis sensitivity high-precision 3-D sensing system is proposed in this study. The parameters of the vibration-sensing mechanism were determined by theoretical modeling and simulation analysis, and the performance of the 3-D accelerometer was tested experimentally. The dynamic response characteristics of the accelerometer were first determined using kinetic modeling, which showed reasonable amplitude–frequency and phase–frequency characteristics in the frequency range below 10 Hz. The accelerometer was calibrated using the comparison method. The sensitivities of the accelerometer in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${X}$ </tex-math></inline-formula> -, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Y}$ </tex-math></inline-formula> -, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Z}$ </tex-math></inline-formula> -axes are 25.3, 25.3, and 21.1 V/g, respectively, with a cross-axis sensitivity of less than 1%. The resolutions of the accelerometer in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${X}$ </tex-math></inline-formula> -, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Y}$ </tex-math></inline-formula> -, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Z}$ </tex-math></inline-formula> -axes were 48, 45, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50 \mu \text{g}$ </tex-math></inline-formula> , respectively. The proposed accelerometer with high sensitivity and high resolution can be widely used for low-frequency microvibration measurements in engineering applications.

Design and characterization of an accelerometer with low cross axis sensitivity

An out-of-plane capacitive accelerometer with low cross axis sensitivity at high accelerations based on a CMOS MEMS process is developed. A truss frame with a high ratio of in-plane stiffness to out-of-plane stiffness is designed to suspend the proof mass of the accelerometer. The configuration of the proof mass with four auxiliary masses surrounding a main mass boosts the sensitivity of the accelerometer in the out-of-plane direction. A sensing circuit with period modulated output signals is realized by applying a relaxation oscillator to the sensing capacitors. The relaxation oscillator converts the capacitance changes to frequency variations. Analytical models are developed to assist the design of the accelerometer. The nonlinearity and sensitivity of the accelerometer are 1.1% and 754 Hz/g, respectively, for the acceleration ranging from 0 to 9 g. Measured cross-axis sensitivity is 4% at an acceleration of 9 g. The power consumption is 1.7 mW under a 1.8 V supply.

Design and simulation of dual-axis MEMS accelerometer

Micro electro Mechanical systems (MEMS) are integrated electro-mechanical systems with microscale features. These devices are effective and low power consumers, making them one of the prospective technologies for use in a variety of industries and fields, including as the automotive, consumer, industrial, optical, robotic, biotechnology, medical engineering, and military sectors. MEMS accelerometer is one of the prominent inertial sensor allied in different applications.The proposed work is intended on design, modelling and simulation of a dual axis crab-legged suspension system. By using the SOI MUMPs fabrication process flow formulated by MEMSCAP Foundry a capacitive-based MEMS accelerometer is designed. Natural frequency, cross axis sensitivity, frequency response, and static capacitance analysis are the main design characteristics.Sensor is designed for a low frequency applicatons by assuming a natural frequency of 4KHz, he actual bandwidth vs sensitiviy is about 2KHz and 0.088um/g respectively. The measured stiffness along × and y are kx = 176.089 N/m ky = 176.089 N/m respectively.The proposed design of the capacities sensing comb drive structure is capable of producing linear change of the displacement for applied accelerations between 1 and 1000 g (1 g = 9.8 m/s2), over which the stress values exceed the tensile strength of the silicon material. By using stationary,frequency domain studies and electro-mechanics physics, the simulation is carried out in the COMSOL Multiphysics tool.

Computational Study of a Motion Sensor to Simultaneously Measure Two Physical Quantities in All Three Directions for a UAV.

Cross-axis sensitivity is generally undesirable, and lower values are required for the accurate performance of a thermal accelerometer. In this study, errors in devices are utilized to simultaneously measure two physical quantities of an unmanned aerial vehicle (UAV) in the X-, Y-, and Z-directions, i.e., where three accelerations and three rotations can also be simultaneously measured using a single motion sensor. The 3D structures of thermal accelerometers were designed and simulated in a FEM simulator using commercially available FLUENT 18.2 software Obtained temperature responses were correlated with input physical quantities, and a graphical relationship was created between peak temperature values and input accelerations and rotations. Using this graphical representation, any values of acceleration from 1g to 4g and rotational speed from 200 to 1000°/s can be simultaneously measured in all three directions.

A Double Differential Torsional Accelerometer With Higher Than 10-kHz Measurement Bandwidth for Vibration Monitoring

This paper reports the design, fabrication, ASIC, package, and characterization of a z-axis accelerometer with double differential torsional configuration. Compared with typical comb structures, diagonally large depth non-penetrating quad-mass has a simple structure with a large feature size. Compared with traditional unbalanced proof mass structures, the fully differential sensitive configuration theoretically eliminates the influence of common mode errors such as interference force and temperature variations. Thus a high performance structure with high sensitivity and good stability was obtained. Meanwhile, the anchor was arranged internally to make the structure more compact and less stress sensitive. The sensitive structure has a size of 2.4mm×1.8mm. An optimization of kinetic properties was done to get large bandwidth and small mechanical thermal noise. The ASIC of the double differential torsional structure was implemented, which adopted single-cycle clock double-edge multiplexing to improve C/V conversion efficiency and reduce circuit noise. At the same time, the error compensation technology used on the ASIC makes the accelerometer sensitivity error less than 1% and zero bias error less than ±0.02V. The resonance frequency is about 16kHz, the ±5% bandwidth is larger than 10kHz, the cross-axis sensitivities of the x-axis and y-axis are less than 1.5% and 1%, respectively, the bias instability is less than 700μg, the noise spectral density is better than 30μg/√ Hz above 10Hz, the normalized drift over the full temperature range (-40 °C to 60 °C ) is less than 1.78g under uncompensated conditions.

Investigation of FBG Linear/Angular Acceleration Sensor for Novel Type Inertial Measurement

A novel inertial measurement unit (IMU) was proposed to measure the three-axis linear&#x002F;angular acceleration of a body using six fiber Bragg grating (FBG) optical fiber acceleration sensors sharing the same rotational center. The six acceleration sensors were shown to accurately distinguish between movements in different directions using a vibration generator and rotary motor&#x002F;encoder device. The results also indicated that the measurement range of the FBG linear acceleration sensor was &#x00B1;14 g, its average sensitivity was approximately 229.4 pm&#x002F;g, and its nonlinearity was under 0.05&#x0025;. Furthermore, the average sensitivity and nonlinearity of the FBG angular acceleration sensor were 21&#x00B0;&#x002F;s&#x00B2;&#x002F;pm and 0.23&#x0025;, respectively. When measuring linear and angular acceleration, the cross-axis sensitivity of the IMU was within 2.0&#x0025;. The measurement accuracy of the roll and pitch angle during 360&#x00B0; rotation as well as that of the yaw angle during 720&#x00B0; rotation were both in the range of 0.54 to 1.31&#x0025;. Most of results indicated that the FBG-based IMU sensor was within the performance specifications of an equivalent conventional IMU sensor. Thus, the concept underlying the proposed sensor can be confidently used as a basis to develop a high-precision IMU sensor that is unaffected by electromagnetic interference.

Two-Dimensional Low-Frequency Optical Accelerometer With High Accuracy and Low Cross-Axis Sensitivity

Two-dimensional (2D) accelerometer is a commonly used sensor for detecting horizontal vibrations. However, their low frequency response characteristics are limited by high cross-axis sensitivity and low resolution. To address this challenge, this study proposes a new 2D optical accelerometer based on a symmetric 2D vibration pickup unit and a high-sensitivity 2D angle sensor modified from a DVD pickup head. The parameters of the symmetrical 2D pickup unit were determined through modeling and simulation, and the performance of the accelerometer was tested experimentally. Experimental data show that the accelerometer has good low frequency response characteristics in the range from 1 to 10 Hz, sensitivity is better than 2.5 V/(m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), cross-axis sensitivity is less than 0.075 V/(m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), and the resolution is better than 0.4 mm/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Moreover, the sources of uncertainty of the accelerometer were analyzed in detail and the synthetic uncertainty of the accelerometer was analyzed based on experiments. Compared with conventional techniques in this area, the proposed 2D optical accelerometer has featured the advantages, such as high accuracy and low cross-axis sensitivity, and can be widely used for low-frequency vibration monitoring in engineering applications.

A High-Sensitivity Dual-Axis Accelerometer with Two FP Cavities Assembled on Single Optical Fiber.

In this paper, a dual-axis Fabry-Pérot (FP) accelerometer assembled on single optical fiber is proposed. The sensor is equipped with a special beam-splitting prism to split the light into two perpendicular directions (the X- and Y-axes); the prism surface coated with semi-permeable film and the reflective sheet on the corresponding Be-Cu vibration-sensitive spring form two sets of FP cavities of different sizes. When the Be-Cu spring with a proof mass (PM) is subjected to the vibration signal, the cavity length of the corresponding FP cavity is changed and the interference signal returns to the collimator through the original path of the prism. After bandpass filtering and demodulation, the two cavity lengths are obtained, and the acceleration measurement in dual-axis directions is completed. The resonant frequency of the proposed dual-axis fiber optic accelerometer is around 280 Hz. The results of the spectral measurements show 3.93 μm/g (g = 9.8 m/s2: gravity constant) and 4.19 μm/g for the applied acceleration along the X- and Y-axes, respectively, and the cross-axis sensitivity is below 5.1%. Within the angle range of 180°, the maximum error of measured acceleration is less than 3.77%. The proposed fiber optic dual-axis FP accelerometer has high sensitivity and strong immunity to electromagnetic interference. The size of the sensor mainly depends on the size of the prism, which is easy to reduce and mass produce. Moreover, this FP construction method has high flexibility and development potential.

Computational Study on Thermal Motion Sensors That Can Measure Acceleration and Rotation Simultaneously.

In this study, a new technique has been proposed by numerical simulations by which multiple physical quantities can be simultaneously measured. The sensor is a modification of existing physical sensors such as a thermal motion sensor. Simultaneous measurement of acceleration and rotation is presented herein. Cross-axis sensitivity is employed such that output sensitivities observed at two perpendicular axes, X and Y sensor data, are related to the input physical quantities. The physics involved in measurement is similar to that of a conventional thermal accelerometer, hence the governing equations predicting the sensor response are based on the conservation of mass, momentum, and energy, and are discretized by using a commercially available software FLUENT. A series of computational studies are conducted and using these studies a novel idea is proposed in which the maximum temperature values are obtained at various positions around a heating source and are correlated with the applied acceleration and rotational speed. A parametric study is also presented to find the optimum distance between the heater and sensors. The influence of changing gas medium on the temperature curves has also been examined and it has been concluded that CO2 generates the maximum performance due to its higher density and lower viscosity.

Design and fabrication of a micro-opto-mechanical-systems accelerometer based on intensity modulation of light fabricated by a modified deep-reactive-ion-etching process using silicon-on-insulator wafer

Accelerometers that work based on intensity modulation of light are more sensitive, economically feasible, and have a simpler fabrication process compared to wavelength modulation. A micro-opto-electro-mechanical-system accelerometer based on intensity modulation of light is designed and fabricated. A movable shutter that is attached to the proof mass is designed to change the intensity of light. Moreover, the mechanical part is designed to improve the overall sensitivity and linear behavior in the measurement range. The designed accelerometer is fabricated by a deep-reactive-ion-etching (DRIE) process. The DRIE process used in this report is based on a Bosch-like process, which uses SF6 and a mixture of H2, O2, and SF6 gases in etching and passivation subsequences, respectively. This method has a lower plasma density and a higher base pressure and causes higher verticality, which results in lower optical efficiency loss in comparison with the Bosch process. Furthermore, the functional characteristics of the accelerometer are derived with analytical and numerical methods, and the results are compared. The functional characteristics of the accelerometer are as follows: a resonant frequency of 0.56 kHz, a mechanical sensitivity of 0.6μm/g, an optical sensitivity of 16%/nm, an overall sensitivity of 9.6%/g, a footprint of 2000×2000μm2, a measurement range of 3g, a mechanical cross axis sensitivity of 0.058μm/g, and an overall cross axis sensitivity of 0.00029%/g. These functional characteristics make the design appropriate for a large range of applications.

Accurate mechanical-optical theoretical model of cross-axis sensitivity of an interferometric micro-optomechanical accelerometer.

An interferometric micro-optomechanical accelerometer usually has ultrahigh sensitivity and accuracy. However, cross-axis interference inevitably degrades the performance, including its detection accuracy and output signal contrast. To accurately clarify the influence of cross-axis interference, a modified mechanical-optical theoretical model is established. The rotation of the proof mass and the detected light intensity are quantitatively investigated with a load of cross-axis acceleration. A simulation and experiment are performed to verify the correctness of the theoretical model when the cross-axis acceleration is from 0 to 0.175 g. The results demonstrate that this model has a more than fivefold accuracy increase compared with conventional theoretical models when the cross-axis acceleration is from 0.06 to 0.175 g. In addition, we provide a suppression method to diminish the rotation of the proof mass based on squeeze film air damping, which significantly suppresses the contrast reduction caused by cross-axis interference.

Correlated Theory of Cross-Axis Interference of MEMS Devices Based on Parallel Plate and Squeeze Film Air Damping Induced Suppression

Owing to inevitable errors of the material and fabrication process, the cross-axis sensitivity commonly exists in a large number of MEMS devices based on parallel plate structures. Such cross-axis interference results in the non-negligible rotation of the plate that deteriorates the performance of MEMS devices. Therefore, suppressing the cross-axis sensitivity is extremely critical in the device design. This paper proposes a novel theory to identify the interplay between the cross-axis interference and squeeze film air damping, and further develops a correlated theory of the damping induced suppression. The model of tilting plate with a tiny amplitude is set up by exploiting the Reynolds equation coupled with the equations of the mass deflection, and the analytical expressions of corresponding properties are derived to elucidate the suppression mechanism and its characterization. The analytical calculation and numerical simulation analysis demonstrate that the damping induced improvement effect exists objectively and is remarkable in the condition of a large mass and a small air film thickness. The cross-axis sensitivity rendered by the tilt angle quantitatively declines 80% in terms of the air damping. The theoretical underpinning can be utilized to elaborate the ubiquitous interplay between squeeze film air damping and cross-axis interference in non-vacuum MEMS devices, which is of paramount importance for achieving high performance and stability. More importantly, it is not an exclusive method that can be combined with other methods to minimize the cross-axis interference fully.

Coarse-to-fine optical MEMS accelerometer design and simulation

A coarse-to-fine optical microelectromechanical systems (MEMS) accelerometer based on the Fabry-Pérot (FP) interferometer is proposed. The mechanical structure consists of a proof mass that is suspended by four L-shaped springs. The deflection of the proof mass due to the applied acceleration is detected using two FP cavities that comprise the system's optical system. Using coarse-to-fine measurement and the dual wavelength method simultaneously increases the sensitivity of the accelerometer as well as the linear measurement range. The optical simulation shows that the sensitivity of the proposed device is 10 times as high as that of a similar optical MEMS accelerometer with one FP cavity. In addition, the proposed optical system is insensitive to the displacements of the proof mass in the orthogonal directions, which considerably reduced the cross-axis sensitivity. The minimum feature size of the structure is 15 µm and the optical signal is conducted completely through the optical fibers, facilitating the device fabrication. Here are the results of the simulation: mechanical sensitivity of 190 nm/g, optical sensitivity of 8 nm/g, linear measurement of ±5g, and first resonance frequency of 1141 Hz.

Sensitivity Enhancement of a Semicircular Curved Hetero-Core Optical Fiber Accelerometer With Low Cross-Axis Sensitivity

In this article, the frequency, amplitude, and cross-axis sensitivity characteristics of a hetero-core fiber optic accelerometer subjected to mechanical vibrations are presented. The proposed accelerometer is based on a fixed-support structure and can be used for structural health monitoring. It consists of a semicircular curved hetero-core optical fiber with both ends fixed to a base, which operates as a vibration detector. To increase its sensitivity and reduce its cross-axis sensitivity, a hetero-core portion is placed near one of the fixed ends. By fabricating an ideal semicircular beam-shaped acceleration sensor with both ends fixed, good agreement between the experimentally obtained spectrum results and finite element analysis results when the accelerometer is subjected to mechanical vibrations is observed. The accelerometer’s sensitivity is clearly stable at frequencies less than approximately a quarter of the first natural frequencies of 1810, 850, and 350 Hz with sensitivities of 1.45 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 10^{-3}$ </tex-math></inline-formula> , 2.80 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 10^{-3}$ </tex-math></inline-formula> , and 6.16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 10^{-3}$ </tex-math></inline-formula> dB/g for fiber curvature radii of 7, 10, and 15 mm, respectively. Owing to its highly linear acceleration characteristics, it is possible to efficiently convert the acceleration to optical loss. The cross-axis sensitivity is in the range 4.27%–15.9%, which is better than that of previously reported accelerometer structures, which use a hetero-core fiber sensor located at the center between the two fixed ends without a free supporting point. Therefore, the proposed accelerometer, which consists only of a semicircular-shaped optical fiber, is capable of improving the sensitivity and reducing the cross-axis sensitivity by adjusting the placement of the hetero-core fiber sensor.

Monolithic Fully Decoupled Tri-Axis Gyroscope With Lateral-Comb and Low Cross-Coupling

Multi-axis integration is important for micro-electromechanical system(MEMS) gyroscopes in the future. In this paper, a monolithic integrated tri-axis gyroscope and interface circuit are designed and implemented. The presented tri-axis gyroscope with single drive and multi sense axes is fully decoupled in structure among the drive and sense modes. Quadrature coupling can also be further reduced by the in-plane and out-of-plane correction electrodes. The pitch(roll) structure is designed as a unilateral unequal height comb, which reduces the damping and improves the Q value of pitch and roll modes and simplifies the fabrication process. In addition, the interface circuit adopts a closed-loop drive and open-loop sense circuit, an additional decoupling module that effectively reduces the cross axis sensitivity. Finally, a gyroscope prototype was tested to evaluate its performance. The designed tri-axis gyroscope has low bias instability(1.2821°/h) and good noise performance(0.1635°/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\surd \text{h}$ </tex-math></inline-formula> ). The coupling coefficient is even below 1% after adding decoupling modules. Meanwhile, the bandwidth can meet the needs of the gyroscope working in a low-frequency environment.

Mode ordering of single-drive multi-axis MEMS gyroscope for reduced cross-axis sensitivity

In this letter, a design technique is presented to reduce the cross-axis sensitivity (CAS) in single-drive multi-axis microelectromechanical systems (MEMS) gyroscope. A design technique based on resonant mode ordering concerning drive-displacement amplitudes ratio and frequency differences ratio was proposed. A simplified single-drive multi-axis MEMS gyroscope, based on the mode-split approach, was analyzed for cross-axis sensitivity. The designed gyroscope utilizing a driving scheme based on a simple folded coupling spring has equal x and y – axes drive-displacement amplitudes of 3.892 μm respectively. The proposed resonant mode ordering technique was used, and an equal sense-frequency difference of 184 Hz was achieved with respect to drive-mode frequency. The designed gyroscope having common resonant mode order was analyzed, and CAS of x and y – axes was computed to be 0.241% and 0.387% respectively. The proposed resonant mode order technique successfully reduced the cross-axis sensitivity in the designed gyroscope. The reduced cross-axis sensitivities of x and y – axes were 0.025% and 0.076% respectively. Comparison of both designs showed a reduced rate of 89.627% and 80.362% in x and y – axes respectively. The main sensitivities of x and y – axes were computed to be 0.055 nm/dps respectively. Furthermore, the significance of the proposed technique was experimentally verified.