scholarly journals Comparative Study of Traveling and Standing Wave-Based Locomotion of Legged Bidirectional Miniature Piezoelectric Robots

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 171
Author(s):  
Jorge Hernando-García ◽  
Jose Luis García-Caraballo ◽  
Víctor Ruiz-Díez ◽  
Jose Luis Sánchez-Rojas
Keyword(s):  
Traveling Waves ◽  
Vibration Mode ◽  
Glass Plate ◽  
Excitation Frequency ◽  
Standing Waves ◽  
Flexural Vibration ◽  
Precise Location ◽  
Modes Of Vibration ◽  
3D Printed ◽  
Locomotion Speed

The use of wave-based locomotion mechanisms is already well established in the field of robotics, using either standing waves (SW) or traveling waves (TW). The motivation of this work was to compare both the SW- and the TW-based motion of a 20-mm long sub-gram glass plate, with attached 3D printed legs, and piezoelectric patches for the actuation. The fabrication of the robot did not require sophisticated techniques and the speed of motion was measured under different loading conditions. In the case of the TW mechanism, the influence of using different pairs of modes to generate the TW on the locomotion speed has been studied, as well as the effect of the coupling of the TW motion and the first flexural vibration mode of the legs. This analysis resulted in a maximum unloaded speed of 6 bodylengths/s (BL/s) at 65 V peak-to-peak (Vpp). The SW approach also examined different modes of vibration and a speed of locomotion as high as 14 BL/s was achieved, requiring, unlike the TW case, a highly precise location of the legs on the glass supporting platform and a precise tuning of the excitation frequency.

The Dynamics of a Cyclic Ring of Coupled Duffing Oscillators

2005 ◽  
Author(s):  
Christopher Folley ◽  
Anil K. Bajaj
Keyword(s):  
Traveling Waves ◽  
Excitation Frequency ◽  
Standing Waves ◽  
Primary Resonance ◽  
External Forcing ◽  
External Excitation ◽  
Weakly Nonlinear ◽  
Averaged Equations ◽  
Frequency Excitation ◽  
Coupled Duffing Oscillators

The dynamics of a planar ring of N coupled identical, damped Duffing oscillators with external excitation is considered. Each oscillator is in 1:1 resonance with all other oscillators. The external forcing is a mono-frequency excitation near primary resonance with each oscillator and the analysis is considered in the context of weakly nonlinear systems. The symmetry of the system is exploited to determine, for an arbitrary number of oscillators, all possible classes of periodic solutions at the excitation frequency. These are fixed-point solutions for the system and are determined by the averaged equations. These solutions are classified into standing waves, traveling waves, and motions in-phase with the external forcing. Linear stability analysis is described for each solution class containing the highest degree of symmetry. To continue the study to motions with smaller degrees of symmetry, numerical simulations using the bifurcation analysis and branch continuation software AUTO 97 are utilized. The study presents the specific example of the dynamics of three Duffing oscillators.

Noise Propagation Through Helicopter Gearbox Support Struts—An Experimental Study

1998 ◽  
Vol 120 (3) ◽  
pp. 695-704 ◽  
Author(s):  
M. J. Brennan ◽  
S. J. Elliott ◽  
K. H. Heron
Keyword(s):  
Experimental Study ◽  
Kinetic Energy ◽  
Flexural Vibration ◽  
Dominant Mode ◽  
Analytical Models ◽  
Longitudinal Motion ◽  
Transmission Path ◽  
Modes Of Vibration ◽  
The Subject ◽  
Lateral Behavior

A dominant source of noise in a helicopter cabin is the meshing of the gears in the main rotor gearbox. The main structural noise transmission path from this gearbox to the cabin is through the gearbox support struts, and this is the transmission path which is the subject of this paper. An experimental study is described which quantifies the way in which vibration propagates through one of these struts and the experimental results are interpreted with the aid of some simple analytical models. The contribution of the various modes of vibration to the transmission of the structure-borne noise is quantified by calculating the kinetic energy of the receiving structure from measured data. The results show that although the dominant mode of vibration is longitudinal, flexural resonances occur at some frequencies, and the contribution of the flexural vibration to the kinetic energy of the receiving structure at these frequencies can be comparable with that due to the longitudinal motion. It is demonstrated that the lateral behavior of the strut is dependent upon the static loading but the longitudinal behavior is relatively insensitive to this loading.

scholarly journals Traveling and standing waves mediate pattern formation in cellular protrusions

2020 ◽  
Vol 6 (32) ◽  
pp. eaay7682
Author(s):  
Sayak Bhattacharya ◽  
Tatsat Banerjee ◽  
Yuchuan Miao ◽  
Huiwang Zhan ◽  
Peter N. Devreotes ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Traveling Waves ◽  
Standing Waves ◽  
Cell Cortex ◽  
Theoretical Studies ◽  
Direct Transformation ◽  
Diffusion Parameters ◽  
Excitable Systems ◽  
Mutant Strains ◽  
The Stability

The mechanisms regulating protrusions during amoeboid migration exhibit excitability. Theoretical studies have suggested the possible coexistence of traveling and standing waves in excitable systems. Here, we demonstrate the direct transformation of a traveling into a standing wave and establish conditions for the stability of this conversion. This theory combines excitable wave stopping and the emergence of a family of standing waves at zero velocity, without altering diffusion parameters. Experimentally, we show the existence of this phenomenon on the cell cortex of some Dictyostelium and mammalian mutant strains. We further predict a template that encompasses a spectrum of protrusive phenotypes, including pseudopodia and filopodia, through transitions between traveling and standing waves, allowing the cell to switch between excitability and bistability. Overall, this suggests that a previously-unidentified method of pattern formation, in which traveling waves spread, stop, and turn into standing waves that rearrange to form stable patterns, governs cell motility.

Investigation of Mass Sensitivity for the Piezoelectric Diaphragm Biosensor

2011 ◽  
Vol 411 ◽  
pp. 245-249
Author(s):  
Shao Kang Li ◽  
Wei Ren ◽  
Xiao Feng Chen ◽  
Xi Yao
Keyword(s):  
Software Package ◽  
Material Parameter ◽  
Analytic Solution ◽  
Vibration Mode ◽  
Structural Parameters ◽  
Flexural Vibration ◽  
Mass Sensitivity ◽  
Rayleigh Method ◽  
Acoustic Wave Device ◽  
Wave Device

The mass sensitivity of a piezoelectric diaphragm biosensor has been investigated. The piezoelectric diaphragm utilizing a flexural vibration mode is an acoustic wave device which can be immobilized with a bio-molecular recognition layer on its surface. The mass sensitivity of the sensor was analyzed by the approximately theoretical and FEM methods, respectively. The sensitivity formula expressed by the structural parameters and the material parameter was educed for easy computing. The procedure utilizing Rayleigh method for the analytic solution of the sensitivity was introduced. The expression was verified by using a commercial FEM software package, ANSYS. The simulations are well consistent with the theory.

Nonlinear Periodic Systems: Bands and Localization

2009 ◽  
Author(s):  
Alexander Vakakis
Keyword(s):  
Traveling Waves ◽  
Multiple Scales ◽  
Initial Conditions ◽  
Near Field ◽  
Standing Waves ◽  
Nonlinear Resonance ◽  
Nonlinear Effects ◽  
Periodic Media ◽  
Spatially Extended ◽  
Nonlinear Standing Waves

We consider the dynamics of nonlinear mono-coupled periodic media. When coupling dominates over nonlinearity near-field standing waves and spatially extended traveling waves exist, inside stop and pass bands, respectively, of the nonlinear system. Nonlinear standing waves are analytically studied using a nonlinear normal mode formulation, whereas nonlinear traveling waves are analyzed by the method of multiple scales. When the nonlinear effects are of the same order with the coupling ones a completely different picture emerges, since nonlinear resonance interactions are unavoidable. As a result, infinite families of strongly and weakly localized nonlinear standing waves appear with frequencies lying in pass or stop bands of the corresponding linear periodic medium. Moreover, in the limit of weak coupling these solutions develop sensitive dependence on initial conditions, and the possibility of spatial chaos in the system exists. Some additional results on chaotic dynamics in linear periodic media with strongly nonlinear disorders are reviewed.

Experimental Study on Dynamic Behavior of a Rolling Agricultural Tire

2012 ◽  
Author(s):  
Katsuhide Fujita ◽  
Takashi Saito ◽  
Toru Yamazaki
Keyword(s):  
Natural Frequency ◽  
Dynamic Behavior ◽  
Sound Pressure ◽  
Vibration Mode ◽  
Excitation Frequency ◽  
Resonance State ◽  
Natural Mode ◽  
Pressure Measurements ◽  
The Road ◽  
Agricultural Machines

When agricultural machines are operated on pavements, the vibration and noise caused by the interaction between the tire lugs and the road surface are inevitable. In conventional studies, it is considered that the dynamic behavior of a rolling agricultural tire is influenced by the vibration characteristics of the tire. Resonance occurs when the lug excitation frequency of the tire, which is defined as the lug number multiplied by the number of revolutions of the tire, becomes equal to the natural frequency of the tire. In other words, the rolling tire shows large vibrations in the direction of the natural mode corresponding to the natural frequency of the tire. However, the vibration mode of the rolling tire in resonance state has not yet been clarified. In this study, it is confirmed that the dynamic behavior of the rolling tire can be evaluated by performing sound pressure measurements using closely located microphones to the tire. Further, the vibration mode in the resonance state is identified by performing simultaneous measurements of the sound pressure, and the vibration mode corresponds to the natural mode of the tire is confirmed as well.

scholarly journals MEMS Ultrasound Transducers for Endoscopic Photoacoustic Imaging Applications

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 928 ◽  
Author(s):  
Haoran Wang ◽  
Yifei Ma ◽  
Hao Yang ◽  
Huabei Jiang ◽  
Yingtao Ding ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Vibration Mode ◽  
Photoacoustic Imaging ◽  
Rapid Development ◽  
Flexural Vibration ◽  
Ultrasound Transducers ◽  
Optical Contrast ◽  
Future Directions ◽  
Potential Applications ◽  
Mems Technology

Photoacoustic imaging (PAI) is drawing extensive attention and gaining rapid development as an emerging biomedical imaging technology because of its high spatial resolution, large imaging depth, and rich optical contrast. PAI has great potential applications in endoscopy, but the progress of endoscopic PAI was hindered by the challenges of manufacturing and assembling miniature imaging components. Over the last decade, microelectromechanical systems (MEMS) technology has greatly facilitated the development of photoacoustic endoscopes and extended the realm of applicability of the PAI. As the key component of photoacoustic endoscopes, micromachined ultrasound transducers (MUTs), including piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs), have been developed and explored for endoscopic PAI applications. In this article, the recent progress of pMUTs (thickness extension mode and flexural vibration mode) and cMUTs are reviewed and discussed with their applications in endoscopic PAI. Current PAI endoscopes based on pMUTs and cMUTs are also introduced and compared. Finally, the remaining challenges and future directions of MEMS ultrasound transducers for endoscopic PAI applications are given.

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