scholarly journals Control of Spring Softening and Hardening in the Squared Daisy

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 448
Author(s):  
Mathieu Gratuze ◽  
Abdul-Hafiz Alameh ◽  
Seyedfakhreddin Nabavi ◽  
Frederic Nabki
Keyword(s):  
Standardized Testing ◽  
Experimental Comparison ◽  
Maximal Velocity ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Mems Actuators ◽  
Nonlinear Mechanical ◽  
Different Types ◽  
Operating Bandwidth ◽  
Nonlinear Behaviors

Nonlinear, mechanical microelectromechanical system (MEMS) resonating structures exhibit large displacement and a relatively broad operating bandwidth. These unique features make them particularly of interest for the development of MEMS actuators and sensors. In this work, a mechanical MEMS structure allowing the designer to determine the type of nonlinearity, that is, softening or hardening, based on its anchor scheme is presented. Effects of the excitation signal on the behavior of the proposed MEMS in the frequency domain are investigated. In this regard, a comprehensive experimental comparison among the nonlinear behaviors of softening and hardening has been conducted. To reduce the hysteresis effect to a minimum, an excitation approach, which is a pulsed sweep in frequency with a discrete resolution, is presented. The maximal velocity, quality factor, bandwidth, and resonant frequency of these two types of nonlinear MEMS resonators are compared under three different types of excitation. Finally, it is shown that the performance and characteristics extracted from nonlinear mechanical MEMS resonating structures are highly dependent on the excitation method. Hence, in the present case, the apparent performances of the MEMS resonator can increase by up to 150% or decrease by up to 21%, depending on the excitation approaches. This implies the necessity of a standardized testing methodology for nonlinear MEMS resonators for given end applications.

Design of a MEMS Resonant Wind Sensor on Airplane Wing

2013 ◽  
Vol 562-565 ◽  
pp. 436-440
Author(s):  
Chao Wei Si ◽  
Guo Wei Han ◽  
Jin Ning ◽  
Wei Wei Zhong ◽  
Fu Hua Yang
Keyword(s):  
High Vacuum ◽  
Pressure Change ◽  
Wind Pressure ◽  
Damping Factor ◽  
Deep Reactive Ion Etching ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Element Simulation ◽  
Airplane Wing ◽  
Soi Substrates

A new kind of wind sensor made up of MEMS resonators is designed in the paper capable of sensing the lift, the resistance and the turbulence of airplane wings by mounting on the surface. The designed wind sensor is made up of four MEMS wind pressure gauges fixed around a square wind resistance block which used to block the wind to change the wind pressure on the surface, and the change of wind pressure is detected by MEMS wind pressure gauges to reveal the air condition on the surface of the airplane wings. As known, a MEMS resonator is a second-order resonant system whose damping factor is mainly dependent on the air pressure, and the characteristic is often used to detecting the airtightness of a sealed chamber for the damping factor is sensitive under high vacuum, while a MEMS resonator with the damping factor sensitive at atmospheric pressure is designed in this paper for sensing wind pressure change, and the MEMS resonator is manufactured on SOI substrates with deep reactive ion etching technology. Also relations between the wind pressure change and the wind speed around a block at atmosphere is revealed by finite element simulation. Compared to traditional wind sensors such as anemometers and Venturi tubes, the designed MEMS wind sensor with a very small size is suitable to mount on different zones of a wing with a large amount to monitor the air condition and have less influence on air flow.

ROM of Superharmonic Resonance of Second Order of Electrostatically Actuated MEMS Resonators

2015 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Christian Reyes
Keyword(s):  
Second Order ◽  
Voltage Response ◽  
Order Model ◽  
Reduced Order ◽  
Superharmonic Resonance ◽  
Electrostatically Actuated ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Method Effects ◽  
Ground Plate

This paper deals with the voltage-amplitude response (or voltage response) of superharmonic resonance of second order of MEMS resonator sensors under electrostatic actuation. The system consists of a MEMS flexible cantilever above a parallel ground plate. The AC frequency of actuation is near one fourth the natural frequency. The voltage response of the superharmonic resonance of second order of the structure is investigated using the Reduced Order Model (ROM) method. Effects of voltage and damping voltage response are reported.

Dynamic behaviours of the Double-end tuning fork based comb-driven microelectromechanical resonators for modulating the magnetic flux synchronously

2021 ◽  
Author(s):  
Zhenxi Liu ◽  
Jiamin Chen ◽  
Wuhao Yang ◽  
Tianyi Zheng ◽  
Qifeng Jiao ◽  
...  
Keyword(s):  
Detection Limit ◽  
Magnetic Flux ◽  
Resonance Frequency ◽  
Tuning Fork ◽  
Paper Making ◽  
Initial Space ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Mems Fabrication ◽  
First Time

Abstract MEMS resonators have been widely used in the magneto-resistive (MR) sensor for modulating the magnetic flux to enhance the detection limit. However, the manufacturing tolerances in MEMS fabrication processes make it challenging to fabricate the identical resonators with the same vibration frequency, which greatly decreases the detection limit of the MR sensor. To synchronize the MEMS resonators and improve the performance of the MR sensor, the double end tuning fork (DETF) based comb-driven MEMS resonators is proposed in this paper, making the system operate at the out-of-phase mode to complete the synchronization. The dynamic behaviour of the resonators is investigated through theoretical analysis, numerical solution based on MATLAB code and Simulink, and experimental verification. The results show that the transverse capacitances in the comb will significantly affect the resonance frequency due to the second-order electrostatic spring constant. It is the first time to observe the phenomenon that the resonant frequency increases with the increase of the bias, and it can also decrease with increasing the bias through adjusting the initial space between the fixed finger and the moving mass, they are different from the model about spring softening and spring hardening. Besides, the proposed DETF-based comb-driven resonators can suppress the in-phase and out-of-phase mode through adjusting the driving and sensing ports, and sensing method, meanwhile make the magnetic flux modulation fully synchronized, and maximize the modulation efficiency, and minimize the detection limit. These characteristics are appropriate for the MR sensor, even other devices that need to adjust the resonance frequency and vibration amplitude. Furthermore, the model and the design can also be extended to characteristic the single end tuning fork (SETF) based MEMS resonator and other MEMS-based MR sensors.

Controlling Crystallization Structures in Thin Si Film for Improving Characteristics of MEMS Resonators

2012 ◽  
Vol 1427 ◽  
Author(s):  
Shinya Kumagai ◽  
Hiromu Murase ◽  
Takashi Tomikawa ◽  
Syohei Ogawa ◽  
Ichiro Yamashita ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Domain Size ◽  
Q Factor ◽  
Random Orientation ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Small Grains ◽  
Thin Polycrystalline ◽  
Lateral Crystallization ◽  
Conventional Annealing

ABSTRACTAn approach to control the tensile stress and Q factor of thin Si film beams in MEMS resonators was investigated. Metal-induced lateral crystallization (MILC) using Ni nanoparticles that were synthesized within a cage-shaped protein, apoferritin, was applied to a thin morphous Si film for making a MEMS resonator with thin film beams. The MILC produced a thin polycrystalline Si (poly-Si) film with large crystallized domain (50-60 μm) with nearly the same crystalline orientation, whereas the poly-Si film obtained by conventional annealing (without MILC) consisted of small grains (less than 1 μm) with random orientation. The MEMS resonator with a beam made of poly-Si film by MILC was fabricated. The large domain size and the improved crystallinity increased the tensile stress, and resulted in 20% increase in Q factor in the resonant characteristics.

scholarly journals Experimental Comparison of a 70 Watt Switched Reluctance Machine with Different Types of Converter Topologies

2017 ◽  
Vol 117 ◽  
pp. 306-313 ◽  
Author(s):  
Meda Venkata Nitesh ◽  
S. Arjun ◽  
Shaik Afzal Ahammed ◽  
P. Ramesh ◽  
N.C. Lenin
Keyword(s):  
Experimental Comparison ◽  
Switched Reluctance Machine ◽  
Switched Reluctance ◽  
Reluctance Machine ◽  
Different Types ◽  
Converter Topologies

Voltage Response of MEMS Resonators Under Simultaneous Resonances

2014 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Christian Reyes
Keyword(s):  
Natural Frequency ◽  
Electrostatic Actuation ◽  
Voltage Response ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Simultaneous Resonances

This paper deals with MEMS resonator sensors under double electrostatic actuation. The system consists of a MEMS cantilever between two parallel fixed plates. The frequencies of actuation are AC near natural frequency, and AC half natural frequency. The voltage response of the structure is investigated, and parameter influences reported.

scholarly journals FORCE-VELOCITY RELATIONSHIP OF LEG EXTENSORS OBTAINED FROM THREE DIFFERENT TYPES OF LOAD

2018 ◽  
Vol 15 (3) ◽  
pp. 467
Author(s):  
Marko Ćosić ◽  
Saša Đurić ◽  
Milena Živković ◽  
Aleksandar Nedeljković
Keyword(s):  
Concurrent Validity ◽  
Isometric Force ◽  
Maximal Velocity ◽  
Muscle System ◽  
Different Types ◽  
Force Velocity ◽  
Muscle Groups ◽  
Leg Extensors ◽  
Relationship Of ◽  
The Impact

The first aim of this study was to evaluate the shape of force-velocity (F-V) relationships in case of gravitational (W), inertial (I) and combined (W+I) type of load assessed from squat jump (SJ) performed on a modified Smith machine. The second aim was to determine whether there were differences between the same parameters (maximal force, F0; maximal velocity, V0; maximal power, P0) obtained from linear F-V relationship among three different loads. The third aim was to evaluate the concurrent validity of the parameters F0 obtained from different types of load in SJ, with maximum isometric force in squat (Fiso), as well as one repetition maximum in squat (1RM). Fifteen male participants were tested in SJ with three different types of load, squat for obtaining 1RM and isometric squat for obtaining the Fiso. The observed F-V relationships were exceptionally strong and approximately linear (median r ≥ 0.98) independently of used load. The differences between same parameters of different types of load were determined in parameters F0 and V0, while there were no differences between P0. Regarding third aim, concurrent validity for F0 showed to be moderate to high and significant in all 3 types of load (r ≥ 0.56), except between F0 and Fiso in W type of load, where it was non-significant (r ≥ 0.47). The significance of the study reflects in better understanding of the mechanisms of the functioning of muscle system in case of different types of load. Future studies should investigate the impact of different types of load to kinetic and kinematic parameters in case of different motoric tasks and muscle groups.

scholarly journals Evaluation of Residual Stress of C Oriented AlN/Si (111) and Its Impact on Mushroom Shaped Piezoelectric Resonator 

2021 ◽  
Author(s):  
AKHILESH PANDEY ◽  
Shankar Dutta ◽  
Nidhi Gupta ◽  
Davinder Kaur ◽  
R. Raman
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Mode Shapes ◽  
Quality Factors ◽  
Resonator Structure ◽  
Resonator Design ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Quality Factor Q ◽  
Preferred Oriented

Abstract Aluminum nitride-based MEMS resonators are one of the interesting recent research topics for its tremendous potential in a wide variety of applications. This paper focuses on the detrimental effect of residual stress on the AlN based MEMS resonator design for acoustic applications. The residual stress in the sputtered c axis (<001>) preferred oriented AlN layers on Si (111) substrates are studied as a function of layer thickness. The films exhibited compressive residual stresses at different thickness values: -1050 MPa (700 nm), -500 MPa (900 nm), and -230 MPa (1200 nm). A mushroom-shaped AlN based piezoelectric MEMS resonator structure has been designed for the different AlN layer thicknesses. The effect of the residual stresses on the mode shapes, resonant frequencies, and quality factor (Q) of the resonator structures are studied. The resonant frequency of the structures are altered from 235 kHz, 280 kHz, and 344 kHz to 65 kHz, 75 kHz and 371 kHz due to the residual stress of -1050 MPa (thickness: 700 nm), -500 MPa (thickness: 900 nm) and -230 MPa (thickness: 1200 nm) respectively. At no residual stress, the quality factors of the resonator structures are 248, 227, 241 corresponding to the 700 nm, 900 nm, and 1200 nm thick AlN layers respectively. The presence of the residual stress reduced the Q values from 248 (thickness: 700 nm), 227 (thickness: 900 nm), 241 (thickness: 1200 nm) to 28, 53, and 261 respectively.

Nonlinear Design-for-Control: Deploying Nonlinearity for Useful Purposes

2001 ◽  
Author(s):  
Douglas E. Adams
Keyword(s):  
Mechanical Design ◽  
Good Reason ◽  
Feedback Loops ◽  
Nonlinear Characteristics ◽  
Nonlinear Design ◽  
Nonlinear Mechanical ◽  
Design For Control ◽  
Potential Benefits ◽  
Nonlinear Behaviors ◽  
Destructive Behaviors

Abstract Nonlinearity can be beneficial. It can enhance/degrade system performance, strengthen/weaken linear systems, and give rise to extraordinarily constructive/destructive behaviors. In spite of these potential benefits, engineers have historically neglected and/or removed nonlinearity when designing, analyzing, and controlling mechanical systems for good reason. This paper examines the notion of nonlinear mechanical design-for-control in the context of common applications where nonlinearity enhances performance in some way. Examples of how general nonlinear characteristics and specific nonlinear behaviors have been used in engineering applications are given. A framework for carrying out design optimization with reconfigurable nonlinear mechanical feedback loops is also discussed.

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