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Time Series-, Time-Frequency- and Spectral Analyses of Sensor Measurements in an Offshore Wave Energy Converter Based on Linear Generator Technology
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作者 Erland Stromstedt Andrej Savin +1 位作者 Olle Svensson Mats Leijon 《Energy and Power Engineering》 2013年第1期70-91,共22页
Inside the second experimental wave energy converter (WEC) launched at the Lysekil research site on the Swedish west coast in March 2009 a number of sensor systems were installed for measuring the mechanical performan... Inside the second experimental wave energy converter (WEC) launched at the Lysekil research site on the Swedish west coast in March 2009 a number of sensor systems were installed for measuring the mechanical performance of the WEC and its mechanical subsystems. One of the measurement systems was a set-up of 7 laser triangulation sensors for measuring relative displacement of the piston rod mechanical lead-through transmission in the direct drive. Two measurement periods, separated by 2.5 month, are presented in this paper. One measurement is made two weeks after launch and another 3 months after launch. Comparisons and correlations are made between different sensors measuring simultaneously. Noise levels are investigated. Filtering is discussed for further refinement of the laser triangulation sensor signals in order to separate noise from actual physical displacement and vibration. Measurements are presented from the relative displacement of the piston rod mechanical lead-through, from magnetic flux in the air gap, mechanical strain in the WEC structure, translator position and piston rod axial displacement and active AC power. Investigation into the measurements in the time domain with close-ups, in the frequency domain with Fast Fourier transform (FFT) and with time-frequency analysis with short time Fourier transform (STFT) is carried out to map the spectral content in the measurements. End stop impact is clearly visible in the time-frequency analysis. The FFT magnitude spectra are investigated for identifying the cogging bandwidth among other vibrations. Generator cogging, fluctuations in the damping force and in the Lorenz forces in the stator are distinguished and varies depending on translator speed. Vibrations from cogging seem to be present in the early measurement period while not so prominent in the late measurement period. Vibration frequencies due to wear are recognized by comparing with the noise at generator standstill and the vibration sources in the generator. It is concluded that a moving average is a sufficient filter in the time domain for further analysis of the relative displacement of the piston rod mechanical lead-through transmission. 展开更多
关键词 Wave Power Wave Energy Converter Linear Generator sensor measurements Spectral Analysis COGGING Filtering Laser Triangulation sensor Draw-Wire sensor Force Transducer Strain Gauges Search Coil Power Generation
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Experimental Measurements of the Sensitivity of Fiber-optic Bragg Grating Sensors with a Soft Polymeric Coating under Mechanical Loading,Thermal and Magnetic under Cryogenic Conditions 被引量:2
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作者 关明智 王省哲 +2 位作者 辛灿杰 周又和 马力祯 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第1期140-144,共5页
The strain and temperature sensing performance of fiber-optic Bragg gratings (FBGs) with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryo... The strain and temperature sensing performance of fiber-optic Bragg gratings (FBGs) with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable (cable- around-conduit conductors, cable-in-conduit conductors), independently or utilized together with other strain measurement methods. 展开更多
关键词 FBG net Experimental measurements of the Sensitivity of Fiber-optic Bragg Grating sensors with a Soft Polymeric Coating under Mechanical Loading Thermal and Magnetic under Cryogenic Conditions
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Design of Gas Sensors Circuits with in-System Programmable Ddevices
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作者 Duren Liu Jin Liu Zhichun Ren 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期146-147,共2页
In-system programmable devices are products that combined modern electronic techniques and semiconductor techniques.They are indispensable devices in designing modern circuits and systems.This paper presents two pract... In-system programmable devices are products that combined modern electronic techniques and semiconductor techniques.They are indispensable devices in designing modern circuits and systems.This paper presents two practical circuits designed with programmable devices and its design method.By introducing programmable devices into gas sensor circuits,we can further improve system reliability,stability,sensitivity and integration degree,and enhance flexibility of system design. 展开更多
关键词 in-system programmable device gas sensor music warning circuit gas sensor measurement circuit
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COMPACT PHASE GRATING INTERFERENCE SENSOR FOR MICRO-DISPLACEMENT 被引量:2
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作者 XIAO Gang XIE Tiebang WANG Xuanze 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第1期131-133,共3页
On the basis of existing techniques, a compact micro-displacement sensor of phase grating interference (PGI) is described, which adopts cylindrical hologram diffraction grating as the calibration standard. The optic... On the basis of existing techniques, a compact micro-displacement sensor of phase grating interference (PGI) is described, which adopts cylindrical hologram diffraction grating as the calibration standard. The optical principle of the sensor is explained, and the relation between the grating motion displacement and the phase shift of interference stripes is deduced. The improvement of the integral structure and the method of photoelectric signal processing are described in detail. With the software system based on the virtual instrument development platform Labwindows/CVI and other hardwares such as the precision displacement worktable, the surfaces of typical parts are measured and the characterization results are given. The sensor has wide measuring range and high resolution, its sensitivity and resolution being independent of the wavelength of the incident light. The vertical measuring range is 0-6 mm, and the vertical resolution is 0.005μm. The experimental results show that the sensor can be used to measure and characterize the surface topography parameters of the plane and curved surface. 展开更多
关键词 sensor Surface topography Phase grating interference(PGI)Micro-displacement measurement
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Indoor 3D Reconstruction Using Camera, IMU and Ultrasonic Sensors
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作者 Desire Burume Mulindwa 《Journal of Sensor Technology》 2020年第2期15-30,共16页
The recent advances in sensing and display technologies have been transforming our living environments drastically. In this paper, a new technique is introduced to accurately reconstruct indoor environments in three-d... The recent advances in sensing and display technologies have been transforming our living environments drastically. In this paper, a new technique is introduced to accurately reconstruct indoor environments in three-dimensions using a mobile platform. The system incorporates 4 ultrasonic sensors scanner system, an HD web camera as well as an inertial measurement unit (IMU). The whole platform is mountable on mobile facilities, such as a wheelchair. The proposed mapping approach took advantage of the precision of the 3D point clouds produced by the ultrasonic sensors system despite their scarcity to help build a more definite 3D scene. Using a robust iterative algorithm, it combined the structure from motion generated 3D point clouds with the ultrasonic sensors and IMU generated 3D point clouds to derive a much more precise point cloud using the depth measurements from the ultrasonic sensors. Because of their ability to recognize features of objects in the targeted scene, the ultrasonic generated point clouds performed feature extraction on the consecutive point cloud to ensure a perfect alignment. The range measured by ultrasonic sensors contributed to the depth correction of the generated 3D images (the 3D scenes). Experiments revealed that the system generated not only dense but precise 3D maps of the environments. The results showed that the designed 3D modeling platform is able to help in assistive living environment for self-navigation, obstacle alert, and other driving assisting tasks. 展开更多
关键词 3D Point Cloud Position Estimation Iterative Closest Point (ICP) Ultrasonic sensors Distance measurement 3D Indoor Reconstruction
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Recent Development of Dielectric Elastomer Transducers and Potential Applications
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作者 Seiki Chiba Mikio Waki 《Energy and Power Engineering》 CAS 2023年第2期105-126,共22页
Power generation using dielectric elastomer transducers is cheap, light, stackable, easy to install, and highly efficient. Also, since the dielectric elastomer transducer is an actuator developed into an artificial mu... Power generation using dielectric elastomer transducers is cheap, light, stackable, easy to install, and highly efficient. Also, since the dielectric elastomer transducer is an actuator developed into an artificial muscle, if the DE motor is further developed, it might be possibly be able to drive a vehicle. Efficient robot driving, various industrial machines and the use of dielectric elastomer sensors to optimize the driving may also help solve the above problems from the perspective of eco-driving. This paper describes the latest level of development of dielectric elastomers, their main problems and solutions to these problems, and their potential applications. The possibilities and concrete plans for building local global smart cities (including local generation power for local consumption), efficient transportation, and environmental monitoring systems utilizing dielectric elastomers are also discussed. 展开更多
关键词 High-Efficiency Power Generation Lightweight and High-Output Actuator sensor with Wide measurement Range Flexible SWCNT Spray
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Particle Measurement Sensor for in situ determination of phase structure of fluidized bed 被引量:1
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作者 Qiang Zhang Cang Huang Dong Jiang Xiaobo Wei Zhen Qian Fei Wei 《Particuology》 SCIE EI CAS CSCD 2009年第3期175-182,共8页
Based on three-dimensional (3D) acceleration sensing, an intelligent particle spy capable of detecting, transferring, and storing data, is proposed under the name of Particle Measurement Sensor (PMS). A prototype ... Based on three-dimensional (3D) acceleration sensing, an intelligent particle spy capable of detecting, transferring, and storing data, is proposed under the name of Particle Measurement Sensor (PMS). A prototype 60-mm-dia PMS was tested to track its freefall in terms of velocity and displacement, and served as a particle spy in a fluidized bed delivering the in situ acceleration information it detects. With increasing superficial gas velocity in the fluidized bed, the acceleration felt by PMS was observed to increase. The variance of the signals, which reflect the fluctuation, increased at first, reaching a maximum at the gas velocity (Uc) which marks the transition from bubbling to turbulent fluidization. Through probability density distribution (PDD) analysis, the PDD peak can be divided into the emulsion phase peak and the bubble phase peak. The average acceleration of emulsion and bubble phase increased, while the variance of both phases reached a maximum at Uc, at the same time. However, the difference between the variances of two phases reached the maximum at Uc. Findings of this study indicate that PMS can record independent in situ information. Further, it can provide other in situ measurements when equipped with additional multi-functional sensors. 展开更多
关键词 Particle measurement sensor Fluidized bed Acceleration Gas-solid two-phase flow Phase structure
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Low-cost and miniature all-silica Fabry–Perot pressure sensor for intracranial pressure measurement
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作者 李玉婷 张文涛 +3 位作者 王兆刚 许红彬 韩晶 李芳 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第11期49-52,共4页
The monitoring of increased intracranial pressure(ICP) is necessary in the diagnosis and treatment of patients with neurological disease because it can provide an insight into the mechanism of the head injury. In th... The monitoring of increased intracranial pressure(ICP) is necessary in the diagnosis and treatment of patients with neurological disease because it can provide an insight into the mechanism of the head injury. In this letter, we develop a novel miniature Fabry–Perot(F-P) sensor for ICP measurement. The proposed sensor is fabricated by using a commercially available fusion splicer and a fiber cleaver, by which many difficult art problems involved in fabrication are solved and the online monitoring of the F-P cavity is actualized. The sensor exhibits a linear response to the applied pressure over the range of 0–25 k Pa(ample for ICP measurement), with a sensitivity of 10.18 nm/k Pa, a resolution of 0.1 k Pa, and a reduced thermal sensitivity of 0.068 nm/°C, which shows it can meet the requirements of ICP measurement. 展开更多
关键词 Low-cost and miniature all-silica Fabry Perot pressure sensor for intracranial pressure measurement ICP length
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DFB fiber laser sensor for simultaneous measurement of acoustic and magnetic fields
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作者 Rui Ma Wentao Zhang +1 位作者 Wenzhu Huang Fang Li 《Chinese Optics Letters》 SCIE EI CAS CSCD 2018年第6期24-28,共5页
A novel distributed feedback(DFB) fiber laser sensor, which can measure acoustic and magnetic fields simultaneously, is proposed. The magnetic field can be measured by detecting the change of resonant frequency of t... A novel distributed feedback(DFB) fiber laser sensor, which can measure acoustic and magnetic fields simultaneously, is proposed. The magnetic field can be measured by detecting the change of resonant frequency of the fiber laser, and the acoustic pressure can be measured by detecting the phase shift of the fiber laser. Both of the signals can be simultaneously demodulated in the frequency domain without affecting each other. Experimental studies show that the acoustic pressure sensitivity of this sensor is about-130 d B(0 dB re 1 pm∕μPa) and the sensor has a good linearity with a magnetic field sensitivity of 0.57 Hz∕mT. 展开更多
关键词 LENGTH DFB fiber laser sensor for simultaneous measurement of acoustic and magnetic fields
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Optical Fiber Sensor's Applied in Vibration Measurement of Turbine Blade
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作者 Fajie Duan, Zhiqiang Fang, Yuyang Sun State Key Lab of Precision Measuring Technology & Instruments, Tianjin University, P. R. China 《光学学报》 EI CAS CSCD 北大核心 2003年第S1期823-824,共2页
A new type optical fiber sensor--Tip timing Sensor is introduced in this paper. It is mostly used in vibration measurement of turbine blade, which can realize real-time and non-contact measurement.
关键词 of AS Optical Fiber sensor’s Applied in Vibration measurement of Turbine Blade in
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Estimation on structural responses using multi scale measurements 被引量:2
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作者 LU Wei WU FengQi +1 位作者 TENG Jun ZHOU QiuShi 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第9期1707-1713,共7页
Different measurands from the different types of sensors can obtain different information regarding the structural behavior in a real structural health monitoring system.To enrich information and estimate the structur... Different measurands from the different types of sensors can obtain different information regarding the structural behavior in a real structural health monitoring system.To enrich information and estimate the structural responses based on much more known information,the estimation on structural responses using multi scale measurements from multi-type sensors is proposed in this paper.Pattern identification is constructed with the pattern library given by strain measurements and deformation measurements.Considering the uncertainty of the measurements as well as to enhance the robustness of the proposed algorithm,more than one best pattern is selected to synthesize the finally estimated stress responses.To validate the capacity of the proposed acquisition method using multi scale measurements,finite element model analysis is conducted to estimate the structural stress response in Shenzhen Bay Stadium as an example.The performance of the pattern identifications,constructed by two kinds of pattern libraries captured by sole strain measurement,and multi scale measurements which are constructed by both kinds of strain measurements and deformation measurements,respectively,are compared in this paper to observe measurements constructed from strain measurements and deformation measurements outperformed others.Errors analysis for a series of parametric studies in which noise at different levels has also included in the measurements are further carried out,and robustness of the proposed information acquisition scheme under noisy measurement is demonstrated. 展开更多
关键词 structural health monitoring multi scale sensor measurements pattern identification information fusion
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ANFIS-based Sensor Fusion System of Sit-to-stand for Elderly People Assistive Device Protocols 被引量:5
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作者 Omar Salah Ahmed A.Ramadan +3 位作者 Salvatore Sessa Ahmed Abo Ismail Makasatsu Fujie Atsuo Takanishi 《International Journal of Automation and computing》 EI CSCD 2013年第5期405-413,共9页
This paper describes the analysis and design of an assistive device for elderly people under development at the EgyptJapan University of Science and Technology(E-JUST) named E-JUST assistive device(EJAD).Several e... This paper describes the analysis and design of an assistive device for elderly people under development at the EgyptJapan University of Science and Technology(E-JUST) named E-JUST assistive device(EJAD).Several experiments were carried out using a motion capture system(VICON) and inertial sensors to identify the human posture during the sit-to-stand motion.The EJAD uses only two inertial measurement units(IMUs) fused through an adaptive neuro-fuzzy inference systems(ANFIS) algorithm to imitate the real motion of the caregiver.The EJAD consists of two main parts,a robot arm and an active walker.The robot arm is a 2-degree-of-freedom(2-DOF) planar manipulator.In addition,a back support with a passive joint is used to support the patient s back.The IMUs on the leg and trunk of the patient are used to compensate for and adapt to the EJAD system motion depending on the obtained patient posture.The ANFIS algorithm is used to train the fuzzy system that converts the IMUs signals to the right posture of the patient.A control scheme is proposed to control the system motion based on practical measurements taken from the experiments.A computer simulation showed a relatively good performance of the EJAD in assisting the patient. 展开更多
关键词 Adaptive neuro-fuzzy inference systems(ANFIS) sensor fusion assistive technologies sit-to-stand motion analysis inertial measurement units
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Experimental measurements of gas-solid flow and splitting mechanisms of a coal pipe splitter with a perpendicularly arranged upstream elbow
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作者 Hao Zhou Yan Huang +3 位作者 Yu Yang Guiyuan Mo Jianzhong Li Kefa Cen 《Particuology》 SCIE EI CAS CSCD 2016年第2期143-150,共8页
The effect of the vertical pipe length on the performance of a coal pipe splitter with a perpendicularly arranged upstream elbow was investigated experimentally employing a fiber optic measuring system. The upstream e... The effect of the vertical pipe length on the performance of a coal pipe splitter with a perpendicularly arranged upstream elbow was investigated experimentally employing a fiber optic measuring system. The upstream elbow and coal pipe splitter were installed in two perpendicular planes. Contours of dis- tributions of the particle concentration and size were obtained in different transverse sections. The experimental data show that the maximum/minimum concentration ratio in transverse sections A, B, and C decreased rapidly as the length of the vertical pipe increased. The left/right-leg average concentration ratio remained about 1, and a balanced split was thus achieved. With a perpendicularly arranged upstream elbow, the vertical pipe length had little effect on the splitter performance, which is beneficial for engineering design and convenient for industrial application. 展开更多
关键词 Gas-solid flow Concentration measurement Coal pipe splitter Fiber optic sensor
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