scholarly journals Development of a Fish-Like Robot with a Continuous and High Frequency Snap-Through Buckling Mechanism Using a Triangular Cam

2021 ◽  
Vol 33 (2) ◽  
pp. 400-409
Author(s):  
Daisuke Nakanishi ◽  
Shoya Kobayashi ◽  
Kiichi Obara ◽  
Shotaro Matsumura ◽  
Yuichiro Sueoka ◽  
...  

This study focuses on the high maneuverability of fish in water to design a fish-like robot via snap-through buckling. The aim of this study is to improve swimming speed by increasing the frequency at which snap-through buckling occurs. Here, we propose a novel drive mechanism using a triangular cam that can continuously generate snap-through buckling at a high frequency. In addition, we developed a fish-like robot via the proposed mechanism and analyzed the influence of the frequency of snap-through buckling on swimming speed. The results obtained indicate that swimming speed is improved and that the relationship between frequency and swimming speed exhibits a single peak. In other words, the swimming speed is reduced when the frequency is significantly increased. We also determined that swimming speed was improved using a wide elastic thin plate as the driving mechanism.

1988 ◽  
Vol 110 (1) ◽  
pp. 86-91
Author(s):  
T. Morimitsu ◽  
H. Sakata ◽  
T. Tsujimura

A novel vibrating bristled vehicle for small pipes is proposed. Its drive mechanism with rotating eccentric weight is simulated and analyzed. The investigation shows that the vibrating bristled vehicle can move smoothly through the pipe. The motion experiments and simulations are conducted using a vehicle with 16 bristles in order to clarify the relationship between the vehicle velocity and the angular velocity of the rotating eccentric weight. The calculated vehicle velocity agrees with the experiments.


2016 ◽  
Vol 88 (3) ◽  
pp. 312-321
Author(s):  
Sun Zhihong ◽  
Tang Tianxin ◽  
Zhao Bocheng ◽  
Chen Yanting

In textile factories, the sliver can is used to deposit and transport sliver in the process of carding, combing and drawing. Increasing the capacity of the sliver can will reduce the frequency of changing the sliver can; hence, the working efficiency can be improved. A belt drive mechanism with the driven pulley eccentrically installed was developed in this study. This mechanism was used as the driving mechanism of the coiler, which has the effect of increasing the capacity of the sliver can. In this study, several commonly used methods of increasing the capacity of the sliver can were introduced first. Then, the equation of motion of the eccentric belt drive mechanism was established, and the law of motion of the driven eccentric pulley was calculated. Finally, the relationship between the eccentricity ( e) of the driven eccentric pulley and the capacity increment ( δ) of a sliver can was analyzed by utilizing the evaluation indicators of density of per sliver lap. The result indicates that with the increase in the value of eccentricity ( e), the capacity increment ( δ) of a sliver can also increases.


2021 ◽  
Vol 11 (10) ◽  
pp. 4462
Author(s):  
Alexander B. Movchan ◽  
Ross C. McPhedran ◽  
Giorgio Carta

In this paper, we discuss two problems concerning scattering and localisation of flexural waves in structured elastic plates. Firstly, we compare the scattering amplitudes of waves in a thin plate, generated by a point source, due to a single mass and to a large number of smaller masses, having the same equivalent mass and located around a circle. We show that in the second case, the scattering can be reduced, in particular in the medium- and high-frequency regimes. Secondly, we develop a homogenised model for a double-ring cluster of spring-mass resonators, connected to an elastic thin plate. We determine the conditions for which the plate exhibits vibration modes trapped between the two rings. Further, we show that the frequencies of the localised modes can be tuned by varying the geometry of the two rings and the characteristics of the resonators. The analytical results are corroborated by numerical simulations performed with independent finite element models.


2020 ◽  
Vol 29 (3) ◽  
pp. 429-435
Author(s):  
Patricia C. Mancini ◽  
Richard S. Tyler ◽  
Hyung Jin Jun ◽  
Tang-Chuan Wang ◽  
Helena Ji ◽  
...  

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2–3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation ( r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.


1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.


2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jianneng Chen ◽  
Xincheng Sun ◽  
Chuanyu Wu ◽  
Dadu Xiao ◽  
Jun Ye

AbstractThe noncircular synchronous belt drive mechanism has demonstrated certain achievements and has been used in special fields. Research regarding noncircular synchronous belt drive mechanisms has focused on optimization design and kinematic analysis in China, whereas two pulley noncircular synchronous belt transmissions have been developed overseas. However, owing to the noncircular characteristics of the belt pulley, the real-time variation in the belt length slack during the transmission of the noncircular synchronous belt is significant, resulting in high probabilities of skipping and vibration. In this study, a noncircular tensioning pulley is added to create a stable three-pulley noncircular synchronous belt driving mechanism and a good synchronous belt tensioning, with no skipping; hence, the non-uniform output characteristic of the driven pulley is consistent with the theoretical value. In the circular noncircular noncircular three-pulley noncircular synchronous belt mechanism, the pitch curve of the driving synchronous belt pulley is circular, whereas those of the driven synchronous belt and tensioning pulleys are noncircular. To minimize the slack of the belt length of the synchronous belt and the constraint of the concavity and circumference of the tensioning pulley, an automatic optimization model of the tensioning pulley pitch curve is established. The motion simulation, analysis, and optimization code for a three-belt-pulley noncircular synchronous belt drive mechanism is written, and the variation in belt length slack under different speed ratios is analyzed based on several examples. The testbed for a circular–noncircular–noncircular three-pulley noncircular synchronous belt transmission mechanism is developed. The test shows that the three-pulley noncircular synchronous belt drives well. This study proposes an automatic optimization algorithm for the tensioning pulley pitch curve of a noncircular synchronous belt transmission mechanism; it yields a stable transmission of the noncircular synchronous belt transmission mechanism as well as non-uniform output characteristics.


SAGE Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215824402110071
Author(s):  
Ying Teng ◽  
Eli Gimmon ◽  
Wentong Lu

We examine how interlocking directorates influence innovation performance differentials between firms. Our study offers a new perspective of the effect of interlocking directorate ties upon innovation performance, focusing on network effects on interfirm performance. Using a sample of China’s listed companies for the period 2012–2016, we empirically examined the relationship between board interlocks and interfirm innovation performance differentials. The results demonstrate that the presence of board interlocks reduces interfirm innovation performance differentials and leads to a convergence of innovation performance between the connected companies. Furthermore, cross-level analysis found that the relationship between board interlocks and interfirm innovation performance differentials is moderated by the interfirm industry attributes and demographic characteristics of the board. This study expands the existing research in explaining the driving mechanism of enterprise innovation performance as affected by interlocking directorate ties.


2007 ◽  
Vol 98 (6) ◽  
pp. 3197-3205 ◽  
Author(s):  
Aizhen Yang ◽  
Timothy E. Hullar

The relationship between semicircular canal radius of curvature and afferent sensitivity has not been experimentally determined. We characterized mouse semicircular canal afferent responses to sinusoidal head rotations to facilitate interspecies and intraspecies comparisons of canal size to sensitivity. The interspecies experiment compared the horizontal canal afferent responses among animals ranging in size from mouse to rhesus monkey. The intraspecies experiment compared afferent responses from the larger anterior canal to those from the smaller horizontal canal of mice. The responses of mouse vestibular-nerve afferents showed a low- and high-frequency phase lead and high-frequency gain enhancement. Regular horizontal-canal afferents showed a sensitivity to 0.5-Hz sinusoidal rotations of 0.10 ± 0.03 (SD) spike · s−1/deg · s−1 and high-gain irregular afferents showed a sensitivity of 0.25 ± 0.11 spike · s−1/deg · s−1. The interspecies comparison showed that the sensitivity of regular afferents was related to the radius of curvature R according to the formula Gr = 0.23R − 0.09 ( r2 = 0.86) and the sensitivity of irregular afferents was related to radius according to the formula Gi = 0.32R + 0.01 ( r2 = 0.67). The intraspecies comparison showed that regularly firing anterior canal afferents were significantly more sensitive than those from the relatively smaller horizontal canal, with Gr = 0.25R. This suggests that canal radius of curvature is closely related to afferent sensitivity both among and within species. If the relationship in humans is similar to that demonstrated here, the sensitivity of their regular vestibular-nerve afferents to 0.5-Hz rotations is likely to be about 0.67 spike · s−1/deg · s−1 and of their high-gain irregular afferents about 1.06 spikes · s−1/deg · s−1.


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