A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

Research on the Piezoelectric Ultrasonic Actuator Applied to SFSS

2015 ◽  
Author(s):  
Y. J. Tang ◽  
Z. Yang ◽  
X. J. Wang ◽  
J. Wang
Keyword(s):  
Natural Vibration ◽  
Structural Parameters ◽  
Laser Vibrometer ◽  
Vibration Modes ◽  
Element Analysis ◽  
Linear Type ◽  
Frequency Sweep ◽  
The Finite Element Analysis ◽  
Frequency Sweep Test ◽  
Overall Performance

This paper presents an investigation of a novel linear-type piezoelectric ultrasonic actuator for application in a Smart Fuze Safety System (SFSS). Based on the requirements of SFSS, the structural parameters of the proposed piezoelectric ultrasonic actuator are determined by fuze arming mode. Moreover, sensitivity analysis of the structural parameters to the frequency consistency is conducted using FEM software, after which the optimal dimensions are obtained with two close natural vibration frequencies. To validate the results of FEM, the frequency sweep tests of the piezoelectric ultrasonic actuator are performed to determine the motor’s actual working mode frequencies with PSV-300-B Doppler laser vibrometer system. Furthermore, the results of frequency sweep test are compared with that of the finite element analysis, and further verified by impedance analyzer. To investigate the overall performance of the piezoelectric ultrasonic actuator, vibration modes of actuator’s stator, output speed and force of the piezoelectric ultrasonic actuator are tested. The experimental results show that the output speed and force of the actuator can reach 88.2 mm/s and 2.3N respectively, which means that piezoelectric ultrasonic actuator designed in this paper can meet the demands of the SFSS.

An XYZ Parallel Kinematic Flexure Mechanism With Geometrically Decoupled Degrees of Freedom

2011 ◽  
Author(s):  
Shorya Awtar ◽  
John Ustick ◽  
Shiladitya Sen
Keyword(s):  
Degrees Of Freedom ◽  
Element Analysis ◽  
Motion Direction ◽  
Form Analysis ◽  
Flexure Mechanism ◽  
Non Linear ◽  
Decoupled Motion ◽  
Motion Range ◽  
Parallel Kinematic ◽  
Cross Axis

We present the constraint-based design of a novel parallel kinematic flexure mechanism that provides highly decoupled motions along the three translational directions (X, Y, and Z) and high stiffness along the three rotational directions (θx, θy, and θz). The geometric decoupling ensures large motion range along each translational direction and enables integration with large-stroke ground-mounted linear actuators or generators, depending on the application. The proposed design, which is based on a systematic arrangement of multiple rigid stages and parallelogram flexure modules, is analyzed via non-linear finite element analysis. A proof-of-concept prototype of the flexure mechanism is fabricated to validate its large range and decoupled motion capability. The analyses as well as the hardware demonstrate an XYZ motion range of 10 mm × 10 mm × 10 mm. Over this motion range, the non-linear FEA predicts a cross-axis error of less than 3%, parasitic rotations less than 2 mrad, less than 4% lost motion, actuator isolation less than 1.5%, and no perceptible motion direction stiffness variation. Ongoing work includes non-linear closed-form analysis and experimental measurement of these error motion and stiffness characteristics.

Finite Element Quarter Vehicle Suspension Model under Periodic Bump and Sinusoidal Road Excitation

2018 ◽  
Vol 880 ◽  
pp. 163-170
Author(s):  
Ștefan Cristian Castravete ◽  
Gabriel Cătălin Marinescu ◽  
Nicolae Dumitru ◽  
Oana Victoria Oţăt
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Finite Model ◽  
Vehicle Speed ◽  
Element Analysis ◽  
Car Suspension ◽  
The Finite Element Analysis ◽  
Road Excitation ◽  
Suspension Model

The paper studies the behavior of a quarter-car suspension model under periodic road excitation: sinusoidal and bump (trapezoidal shape) for a constant vehicle speed. A theoretical and a finite element model were developed. The theoretical model has two degrees of freedom and a modal and sinusoidal excitation was performed to compare with finite model analysis. The finite element analysis consists of three parts: preload, modal analysis and deterministic external excitation. The study consists of the analysis of forces, displacements and accelerations that are transmitted to the vehicle regarding their variation in time and frequency.

Workspace Comparison Between 3-PRR and 3-RPR Micro-Manipulator

2012 ◽  
Author(s):  
Yi Dong ◽  
Feng Gao ◽  
Yi Yue ◽  
Jin Feng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
The Other ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Structural Differences ◽  
Micro Manipulator

This paper presents two compliant micro-manipulators with different structures. One uses 3-PRR mechanism while the other one adopts 3-RPR mechanism. Both of the two micro-manipulators have two translational degrees of freedom (DOF) and one rotational DOF. But the properties, such as workspace, of the two micro-manipulators are not the same. In this paper, the workspaces are studied and compared. First, the structural differences are presented. Then, the stiffness derivations of the two micro-manipulators are given and the workspaces are calculated considering the properties of piezoelectric (PZT) actuators. Finally the finite element analysis and prototype experiments are performed to validate the obtained results.

Design and Analysis of a Planar Piezo-Actuated Nanopositioner with Millimeter Scale Stroke

2016 ◽  
Vol 679 ◽  
pp. 143-148
Author(s):  
Hui Tang ◽  
Jian Gao ◽  
Xin Chen ◽  
Lan Yu Zhang ◽  
Zhao He Zeng
Keyword(s):  
Degrees Of Freedom ◽  
Cross Coupling ◽  
Optimal Designs ◽  
Fast Tool Servo ◽  
Precision Manufacturing ◽  
Element Analysis ◽  
Satisfactory Performance ◽  
The Finite Element Analysis ◽  
High Bandwidth ◽  
Promising Application

In recent years, Fast Tool Servo (FTS) mechanism in precision manufacturing equipment emerges as a promising application for the piezo-actuated flexible nanopositioner. A flexible nanopositioner with large stroke, high bandwidth, high precision and multi-Degrees-of-Freedom (multi-DOFs) is really desired for this application. In order to meet this requirement, a novel 2-DOF flexible nanopositioner consists of two pairs of differential lever displacement amplifiers (DLDA) is proposed in this paper first, also, kinetostatics modeling is conducted by using the Pseudo-Rigid Body (PRB) method. After a series of mechanism optimal designs, the performance of the designed nanopositioner is verified by using the Finite Element Analysis (FEA) method. A piezoelectric (PZT) actuator with 90 µm is selected in this simulation, the experimental results indicate that the mechanism workspace can achieve around 2.1×2.1 mm2, the bandwidth can reach up to around 136 Hz, while the cross-coupling is also kept with 1%. All the results consistently prove the proposed device possesses satisfactory performance for fulfilling the practical precision manufacturing tasks.

A Novel Z-Axis Capacitance Accelerometer with Highly Symmetrical 16-Beam Structure

2013 ◽  
Vol 562-565 ◽  
pp. 412-416
Author(s):  
Wei Li ◽  
Lu Feng Che ◽  
Xiao Lin Li ◽  
Jian Wu ◽  
Yue Lin Wang
Keyword(s):  
Proof Mass ◽  
Differential Capacitance ◽  
Wet Etching ◽  
Beam Structure ◽  
Element Analysis ◽  
Bias Stability ◽  
Maximum Range ◽  
Cross Axis ◽  
Highly Uniform ◽  
Micro Accelerometer

A novel highly symmetrical 16-beam sandwich structure Z-axis differential capacitance accelerometer is presented. In this design, the proof mass is suspended symmetrically by double-side of 16 straight beams with highly uniform dimension which can reduce the cross-axis sensitivity and rotational influences dramatically. Parameters of the beam-mass structure were analyzed and optimized by finite element analysis (FEA) software. The micro accelerometer is based on bulk-micromachining by DRIE and KOH anisotropic wet etching technologies. The beam-mass structure was released by anisotropic wet etching on both device layer sides simultaneously. The fabricated accelerometer was measured over the maximum range of 30g gravity field, results of measurement show that the close-loop sensitivity is 80mV/g, the nonlinearity is 0.27%, and the bias stability is 0.63mg for an hour.

Stability of mirror chambers and mechanics: an example of the improvement of vibrational behaviour

2010 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
C. Ruget ◽  
L. Nikitina ◽  
J. Nicolas ◽  
J.C. Martinez ◽  
J. Juanhuix
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
High Stability ◽  
Element Analysis ◽  
Detailed Design ◽  
The Finite Element Analysis ◽  
Synchrotron Light ◽  
High Level ◽  
Low Emittance

ALBA synchrotron light facility includes a 3 GeV low-emittance storage ring capable of running in the top-up mode which will feed a number of beamlines. Xaloc and CIRCE are among these beamlines. These beamlines are equipped with mirrors which need high stability. There are a lot of mirror chambers in the market and we decided to improve one of them rather than developing a new one. For this purpose, the ALBA team organized a collaboration with a supplier of beamline components. ALBA did the conceptual design of the improvements, the Finite Element Analysis (FEA) optimization and the metrology tests. The supplier provided a detailed design and the production. The improvement was implemented on several mirror chambers including actuators from two to five degrees of freedom. At the beginning of the project, the hypothesis was an excitation coming from the ground lower than 1 µm for frequencies below 45 Hz and negligible above it. The strategy[0] in terms of dynamical stability was not to amplify the ground excitation below 45 Hz or around 50 Hz. That is, to increase the frequency of the system resonances above 45 Hz (excluding the range of about 50 Hz). As a result, we obtained a high level of stability for such mirror systems and we almost met the target value for the first mode of vibration.

Finite Element Modal Analysis of Frame of Vertical Type High-Pressure Grouting Machine Based on ANSYS

2012 ◽  
Vol 184-185 ◽  
pp. 235-238
Author(s):  
Zhi Cheng Huang ◽  
Ze Lun Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Structural Design ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Element Analysis ◽  
Design And Optimization ◽  
The Finite Element Analysis ◽  
Pressure Grouting

The frame of 4MPa vertical type high-pressure grouting machine is used as the research object. The finite element analysis software ANSYS is applied to the modal finite element analysis of the frame. The first five order natural frequencies and the corresponding vibration modes of the frame are obtained, and then the influence of every mode shape on the performances of the frame was discussed. It provides a reference for the dynamic structural design and optimization of the frame of vertical type high-pressure grouting machine.

scholarly journals Finite elements with continuous stress fields in calculation of folded prismatic thin-walled rods and shells

2018 ◽  
Vol 196 ◽  
pp. 01018
Author(s):  
Sergey Nazarenko ◽  
Nina Blokhina
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Stress Fields ◽  
Displacement Fields ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Shell Finite Element ◽  
Rectangular Shell

The article deals with methods of creating a rectangular wall-beam finite element with eight degrees of freedom per node and continuous stress fields along the boundaries. This effect is achieved by specifying displacement fields in the plane of the element in forms similar to those in finite elements of Bogner, Fox, and Schmitt plate. The article provides algebraic expressions for displacement forms; methods of forming reaction and stress matrices are also considered. Test calculations carried out with the help of “Computational mechanics” FEM complex have proved high efficiency of the finite element analysis performed. A rectangular shell finite element with twelve degrees of freedom per node was developed as a combination of membrane finite element and Bogner, Fox and Schmitt plate element.

Theoretical Research for Determining the Static and Dynamic Rigidity of the Machines before Drafting the Remanufacturing Project

2015 ◽  
Vol 809-810 ◽  
pp. 1010-1015
Author(s):  
Dinu Darabă ◽  
Vasile Nasui ◽  
Nicolae Ungureanu
Keyword(s):  
Finite Element Analysis ◽  
Theoretical Research ◽  
Vibration Modes ◽  
Technological Equipment ◽  
Quality And Safety ◽  
Analysis Method ◽  
Element Analysis ◽  
Critical Rotation ◽  
The Finite Element Analysis ◽  
Dynamic Rigidity

By the developed applicative research we look for setting up a procedure for dynamically diagnosing the technological equipment proposed for remanufacturing. Actually, this paper presents some of the results of the research carried out for the establishment an analysis method of the non-functioning technological equipment structure, using the Finite Element Analysis, for stating the own vibration modes, thus based on the structure own frequencies to be stated the maximum critical rotation up to the new equipment would function in the imposed quality and safety conditions. With the proposed procedure we could exactly state the structure own frequencies that yet appear within the working frequencies band of the analyzed technological equipment, and thus we could find the revolutions at which the mechanic system could enter into resonance.

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