scholarly journals Design and Simulation of Flexible Underwater Acoustic Sensor Based on 3D Buckling Structure

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1536
Author(s):  
Guochang Liu ◽  
Wenping Cao ◽  
Guojun Zhang ◽  
Zhihao Wang ◽  
Haoyu Tan ◽  
...  
Keyword(s):  
Flexible Substrate ◽  
Structured Data ◽  
Comsol Multiphysics ◽  
Marine Resources ◽  
Acoustic Sensor ◽  
Frequency Bandwidth ◽  
Underwater Robots ◽  
Vector Hydrophone ◽  
New Type ◽  
Marine Exploration

The exploration of marine resources has become an essential part of the development of marine strategies of various countries. MEMS vector hydrophone has great application value in the exploration of marine resources. However, existing MEMS vector hydrophones have a narrow frequency bandwidth and are based on rigid substrates, which are not easy to be bent in the array of underwater robots. This paper introduces a new type of flexible buckling crossbeam–cilium flexible MEMS vector hydrophone, arranged on a curved surface by a flexible substrate. A hydrophone model in the fluid domain was established by COMSOL Multiphysics software. A flexible hydrophone with a bandwidth of 20~4992 Hz, a sensitivity of −193.7 dB, excellent “8” character directivity, and a depth of concave point of 41.5 dB was obtained through structured data optimization. This study plays a guiding role in the manufacture and application of flexible hydrophones and sheds light on a new way of marine exploration.

Acoustic Sensor With PVDF Micro-Pillars and Patterned Electrodes

2008 ◽  
Author(s):  
Jian Xu ◽  
Marcelo J. Dapino ◽  
Daniel Gallego Perez ◽  
Derek Hansford
Keyword(s):  
Theoretical Analysis ◽  
Optimization Algorithm ◽  
Polyvinylidene Fluoride ◽  
Dynamic Range ◽  
Acoustic Sensor ◽  
Frequency Bandwidth ◽  
Electrical Parameters ◽  
New Type ◽  
Patterned Electrodes ◽  
Micro Pillars

This paper addresses the design and theoretical analysis of a new type of millimeter-size acoustic sensor that uses Polyvinylidene Fluoride (PVDF) micro-pillars and patterned electrodes. The sensor has the potential to achieve 100x the sensitivity of existing commercial sensors in combination with a dynamic range of 181dB and a frequency bandwidth of at least 100 kHz. A constrained optimization algorithm has been developed as a function of geometric parameters (sensor footprint, diameter and height of the micro-pillars, gap between pillar edges, number of pillars) and electrical parameters of the sensor and conditioning amplifier.

scholarly journals A new type of mass structured data duplicate data check

2016 ◽  
Vol 44 ◽  
pp. 01067
Author(s):  
Wen Qi Huang ◽  
Hua Jun Chen ◽  
Xiao Bin Guo ◽  
Li Peng
Keyword(s):  
Structured Data ◽  
New Type

scholarly journals Turning control of a 3- Joint carangiform fish robot using sliding mode based controllers

2015 ◽  
Vol 18 (1) ◽  
pp. 14-26
Author(s):  
Tuong Quan Vo
Keyword(s):  
Dynamic Model ◽  
Sliding Mode ◽  
Autonomous Underwater Vehicles ◽  
Sliding Mode Controller ◽  
Underwater Robots ◽  
Fish Robot ◽  
Turning Motion ◽  
New Type ◽  
Fuzzy Sliding Mode ◽  
Turning Control

The fish robot is a new type of biomimetic underwater robot which is developing very fast in recent years by many researchers. Because it moves silently, saves energy, and is flexible in its operation in comparison to other kinds of underwater robots, such as Remotely Operated Vehicles (ROVs) or Autonomous Underwater Vehicles (AUVs). In this paper, we propose an efficient advanced controller that runs well in controlling the motion for our fish robot. First, we derive a new dynamic model of a 3-joint (4 links) Carangiform fish robot. The dynamic model also addresses the heading angle of a fish robot, which is not often covered in other research. Second, we present a Sliding Mode Controller (SMC) and a Fuzzy Sliding Mode Controller (FSMC) to the straight motion and turning motion of a fish robot. Then, in order to prove the effectiveness of the SMC and FSMC, we conduct some numerical simulations to show the feasibility or the advantage of these proposed controllers.

Broadband and Enhanced Energy Harvesting Using Inerter Pendulum Vibration Absorber

2020 ◽  
Author(s):  
Aakash Gupta ◽  
Wei-Che Tai
Keyword(s):  
Large Scale ◽  
Multiple Scales ◽  
Equations Of Motion ◽  
Primary Resonance ◽  
Vibration Absorber ◽  
Frequency Bandwidth ◽  
Energy Harvesters ◽  
New Type ◽  
Electrical Damping ◽  
Relationship Of

Abstract Inerter-based vibration energy harvesters (VEHs) have been widely studied to harvest energy from large-scale structural vibrations. Recently, there have been efforts to increase the operation frequency bandwidth of VEHs by introducing a variety of stiffness and inertia nonlinearity. This paper proposes a new inerter-based VEH comprising an epicyclic-gearing inerter and a pendulum vibration absorber. The centrifugal force of the pendulum introduces a new type of inertia nonlinearity that broadens the frequency bandwidth. This inerter-pendulum VEH (IPVEH) is incorporated in a single-degree-of-freedom structure to demonstrate its performance and the equations of motion of the system are derived. The method of multiple scales is applied to derive the amplitude–frequency response relationship of the harvested power in the primary resonance. The harvested power is optimized through tuning the harvester’s electrical damping and the optimum power is benchmarked with that of conventional linear inerter-based VEHs. The results show that the IPVEH has larger bandwidth and harvested power and the improvement is correlated with the strength of its inertia nonlinearity.

Building an Active Content Warehouse

2011 ◽  
pp. 63-95 ◽  
Author(s):  
Serge Abiteboul ◽  
Benjamin Nguyen ◽  
Gabriela Ruberg
Keyword(s):  
Web Service ◽  
Structured Data ◽  
Point Of View ◽  
Web Pages ◽  
Xml Documents ◽  
Runtime Environment ◽  
Embedded Web ◽  
New Type ◽  
Active Content ◽  
Active Xml

Non-quantitative content represents a large part of the information available nowadays, such as Web pages, e-mails, metadata about photos, etc. In order to manage this new type of information, we introduce the concept of content warehousing, the management of loosely structured data. The construction and maintenance of a content warehouse is an intricate task, involving many aspects such as feeding, cleaning and enriching semi-structured data. In this chapter, we introduce the Acware (for active content warehouse) specification language, whose goal is to help all sorts of users to organize content in a simple manner. The problem we are faced with is the following: The data are semi-structured, and the operations to be executed on this data may be of any sort. Therefore, we base our approach on XML to represent the data, and Web Services, as genericcomponents that can be tailored to specific applicative needs. In particular, we discuss the specification of mappings between the warehouse data and the parameters/results of services that are used to acquire and enrich the content. From the implementation point of view, an Acware specification of a content warehouse is compiled into a set of Active XML documents, i.e., XML documents with embedded Web service calls. These Active XML documents are then used to build and maintain the warehouse using the Active XML runtime environment. We illustrate the approach with a particular application drawn from microbiology and developed in the context of the French RNTL e.dot project.

Experiment Research on Array Grouped by MEMS Vector Hydrophone

2014 ◽  
Vol 609-610 ◽  
pp. 927-931
Author(s):  
Meng Ran Liu ◽  
Ze Ming Jian ◽  
Hong Liu ◽  
Xiao Peng Song ◽  
Guo Jun Zhang
Keyword(s):  
Doa Estimation ◽  
Acoustic Sensors ◽  
Experiment Research ◽  
A Algorithm ◽  
Underwater Acoustic ◽  
Estimation Performance ◽  
Vector Hydrophone ◽  
New Type

As a new type of underwater acoustic sensors,the principle of the MEMS hydrophone is introduced in this paper.MUSIC is a algorithm for estimating the parameter of the signal and it has a high resolution.In order to verify DOA estimation performance of MEMS vector array,experiment has been done.the experiments results showed that the MEMS vector array can achieve DOA estimation and track the underwater moving target.thus,it is concluded the feasibility of the MEMS vector array.

New devices for unidirectional acoustic cloaking for large objects in infinite frequency bandwidth

2018 ◽  
Vol 32 (24) ◽  
pp. 1850264
Author(s):  
Xiaopeng Wang ◽  
Yu Han ◽  
Lele Wan ◽  
Tianning Chen ◽  
Ailing Song
Keyword(s):  
Plane Waves ◽  
Propagation Direction ◽  
Infinite Length ◽  
Frequency Bandwidth ◽  
Frequency Range ◽  
Incident Plane ◽  
Theoretical Predictions ◽  
New Type ◽  
Pass Through ◽  
Invisibility Cloaks

For years, researchers struggled to realize the acoustic invisibility cloaks with simple for large objects in broadband. In this paper, a new-type unidirectional acoustic cloak is proposed and designed by using eight especial triangles region filled with a certain refractive index inert gas. The acoustic wave can be manipulated to pass through the model but “by-pass” the cloaked region according to the traditional Snell’s law. The incident plane waves will remain without any change. Therefore, the cloaked region cannot be detected. Our designed cloak can realize the infinite length of the invisibility region along the propagation direction and offer good cloaking effect in any frequency range. The simulation results agree well with the theoretical predictions and verify the nondetectability effect of the unidirectional acoustic cloak. Our mechanism may be useful for further actual applications in hiding large objects acoustically.

scholarly journals Array MEMS Vector Hydrophone Oriented at Different Direction Angles

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4282 ◽  
Author(s):  
Mengran Liu ◽  
Lei Nie ◽  
Shanqiang Li ◽  
Wen Jia ◽  
Lansheng Zhang ◽  
...  
Keyword(s):  
Sound Source ◽  
High Performance ◽  
Practical Significance ◽  
Wave Tube ◽  
Vector Hydrophone ◽  
Good Consistency ◽  
Mems Technology ◽  
New Type ◽  
Working Principle ◽  
Standing Wave Tube

A new type of array MEMS (Microelectro Mechanical Systems) vector hydrophone has been proposed to solve the left-right ambiguity problem that is commonly found in current ones. Meanwhile, the advantages of good sensitivity and low fabrication cost are maintained. The array MEMS vector hydrophone is integrated by four units oriented at different direction angles. By the aid of this kind of vector hydrophone, not only the exact direction of the sound source can be measured, but also the position obtained. The working principle of the array microstructure has been analyzed and simulated. The result shows that the position of the sound source can be well determined. The prototype of the hydrophone is fabricated based on standard MEMS technology, and its performance is tested in a standing wave tube and an anechoic tank. The testing results show that the array hydrophone exhibits a good consistency of all the four units and satisfactory performance. More importantly, this array hydrophone exhibits excellent ability of positioning with the relatively small angle error. Thus, a MEMS hydrophone with multiple functions and relatively high performance is realized, which has important theoretical and practical significance in relevant applications such as the small-size underwater vehicles.

scholarly journals Simulation Analysis of Bionic Robot Fish Based on MFC Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Chengguang Zhang
Keyword(s):  
Smart Materials ◽  
Electromechanical Coupling ◽  
Mechanical Load ◽  
Fiber Composite ◽  
Smart Material ◽  
Robotic Fish ◽  
Electromechanical Coupling Coefficient ◽  
Control Analysis ◽  
Underwater Robots ◽  
New Type

With the development of marine resources, research on underwater robots has received unprecedented attention. The discovery and application of new smart materials provide new ideas for the research of underwater robots, which can overcome the issues of traditional underwater robots and optimize their design. A macro fiber composite (MFC) is a new type of piezoelectric fiber composite that combines actuators and sensors. The material has excellent deflection, good flexibility, and a high electromechanical coupling coefficient. Bionic mechatronics design is an effective way to innovate mechatronics in the future and can significantly improve mechatronics system performance. As an important issue for the design of bionic mechatronics, it is necessary to make robots as soft as natural organisms to achieve similar biological movement with both higher efficiency and performance. Compared with traditional rigid robots, the design and control of a soft robotic fish are difficult because the coupling between the flexible structure and the surrounding environment should be considered, which is difficult to solve due to the large deformation and coupling dynamics. In this paper, an MFC smart material is applied as an actuator in the design of bionic robotic fish. Combined with the piezoelectric constitutive and elastic constitutive equations of the MFC material, the voltage-drive signal is converted to a mechanical load applied to the MFC actuator, which makes the MFC material deform and drives the movement of the robotic fish. The characteristics of caudal fin motion during the swimming process of the bionic robotic fish were analyzed by an acoustic-solid coupling analysis method. The motion control analysis of the bionic robotic fish was carried out by changing the applied driving signal. Through numerical analysis, a new type of soft robotic fish was designed, and the feasibility of using an MFC smart material for underwater bionic robotic fish actuators was verified. The new soft robotic fish was successfully developed to achieve high performance.

Test and Validation of a Nonlinear Electromagnetic Energy Harvester

2014 ◽  
Author(s):  
Mohamed Bendame ◽  
Eihab Abdel-Rahman ◽  
Mostafa Soliman
Keyword(s):  
Energy Harvester ◽  
Vibration Energy ◽  
Frequency Bandwidth ◽  
Impact Oscillator ◽  
Vibration Energy Harvester ◽  
Optimal Power ◽  
Optimal Load ◽  
New Type ◽  
Input Acceleration ◽  
Double Impact

We investigate a new type of nonlinear vibration energy harvester that uses a double impact oscillator as its harvesting element. A prototype of the harvester is analyzed numerically and experimentally when aligned vertically. Results show that the new architecture enhanced the output power as well as the frequency bandwidth in comparison with linear harvesters. The new harvester is capable of generating up to 250 mV and has a harvesting bandwidth of about 6 Hz. The optimal load for 0.7 g input acceleration is found to be 5.5 Ω and the corresponding optimal power is determined to be 8 mWatts.

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