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- 摘要
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- 实验方案
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - On Characterization of Vibration Measurement Using Microwave Doppler Radar
摘要： Doppler radar is a compact, microwave sensor for detecting vibration of the target object, from a distance. In this paper, Doppler only measurements are used to characterize the vibrational properties namely vibration amplitude and the frequency. The focus of the study is to understand the potential effect of the measurement environment on measurement quality. The investigations lead us to propose a system consisting of two single channel radars (in lieu of one quadrature radar), spatially separated both along range and azimuth directions. The proposed system introduces diversity, ensures robustness in detection while keeping the system design cost-effective in large scale deployments.
关键词： diversity,vibration,radar,Doppler,sensor
更新于2025-09-19 17:15:36
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An Easily Fabricated Linear Piezoelectric Actuator Using Sandwich Longitudinal Vibrators With Four Driving Feet
摘要： A piezoelectric actuator using three sandwich longitudinal vibrators is proposed and tested. The two horizontal vibrators are parallel to each other and orthogonal to the vertical vibrator. The ends of the two horizontal vibrators serve as the four driving feet. The actuator has a simple fabricating process, which will shorten the period of fabrication. Two modes of the actuator are used to get the elliptical trajectories on the driving feet. The frequencies of the two modes are tuned to be about 21.60 kHz with modal analysis by the finite element method (FEM). The operating principle is also examined with transient analysis by FEM. A prototype is fabricated and its vibration characteristics are verified by using a scanning laser Doppler vibrometer. The prototype shows the best mechanical performance with the optimum working frequency and phase difference of 18.50 kHz and 60°, respectively. The typical output of the prototype is a no-load speed of 439.41 mm/s, a maximum thrust of 40 N, and a maximum power of 5.01 W at the voltage of 200 VP?P. The mechanical characteristics of the prototype show that the exciting voltages can be used for the speed control due to the approximately linear relationship between them.
关键词： resonant state,vibration test.,Linear piezoelectric actuator,sandwich longitudinal vibrators
更新于2025-09-19 17:15:36
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D controller for precise nanopositioning in the presence of hardware-induced constant time delay
摘要： The fast and accurate tracking of periodic and arbitrary reference trajectories is the principal goal in many nanopositioning applications. Flexure-based piezoelectric stack driven nanopositioners are widely employed in applications where accurate mechanical displacements at these nanometer scales are required. The performance of these nanopositioners is limited by the presence of lightly damped resonances in their dynamic response and actuator nonlinearities. Closed-loop control techniques incorporating both damping and tracking are typically used to address these limitations. However, most tracking schemes employed use a first-order integrator whereas a triangular trajectory commonly used in nanopositioning applications necessitates a double integral for zero-error tracking. The phase margin of the damped system combined with the hardware-induced delay deem the implementation of a double-integrator unstable. To overcome this limitation, this paper presents the design, analysis and application of a new control scheme based on the structure of the traditional Two-Degrees-of-Freedom PID controller (2DOF-PID). The proposed controller replaces the integral action of the traditional 2DOF-PID with a double integral action (2DOF-PI2D). Despite its simplicity, the proposed controller delivers superior tracking performance compared to traditional combined damping and tracking control schemes based on well-reported designs such as positive position feedback (PPF), Integral resonant control (IRC), and Positive Velocity and Position Feedback (PVPF). The stability of the control system is analyzed in the presence of a time delay in the system. Experimental results validating the efficacy of the proposed chattering-free control of a piezo-driven nanopositioning system are included.
关键词： Vibration,Piezoelectric actuators (PEAs),Precision Motion control
更新于2025-09-19 17:15:36
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Fast Attitude Maneuver of a Flexible Spacecraft with Passive Vibration Control Using Shunted Piezoelectric Transducers
摘要： This paper is concerned with designing a bang-bang control input to perform a quick rotational maneuver of a rigid spacecraft hub connected with flexible appendages. The control design is based on only the rigid body mode making it very simple to design and at the same time achieve the quickest maneuver possible. The induced vibrations are suppressed using piezoelectric transducers bonded to the appendages and connected to an electric circuit with the objective of converting the vibrational energy to electrical energy and then dissipating it using passive electric elements, such as a resistance and an inductor. The proposed control design method is applied to a spacecraft containing a rigid hub and flexible appendages. The attitude control torque is produced using either the reaction wheels contained inside the rigid hub or jet thrusters mounted outside it. The control design process starts with deriving the nonlinear partial differential equations of motion for the spacecraft using Hamilton’s principle which accounts for the electromechanical coupling and the presence of resistive or resistive-inductive circuits. To simplify the analysis, the nonlinear ordinary differential equations of motion are then obtained using the assumed mode method. The effectiveness of the control design method is numerically tested on a spacecraft that is required to perform a quick attitude maneuver and, simultaneously, suppress the induced vibrations. The simulations show a quick and accurate maneuver has been achieved combined with very low levels of vibrations resulting from the reduced coupling between flexible and rigid motions as well as the damping added as a result of the passive shunt circuit. Furthermore, the resistance-inductance shunt circuit is shown to be more effective in damping the vibrations than the resistance shunt circuit.
关键词： vibration control,piezoelectric transducers,attitude maneuver,bang-bang control,flexible spacecraft,shunt circuits
更新于2025-09-19 17:15:36
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Vibration analysis and control of fluid containers using piezoelectrically-excited side wall
摘要： The vibration analysis and control of containers with heavy loaded fluid is undertaken in this paper. The problem of fluid–structure vibration is viewed and analyzed from several viewpoints including both analytical methods and numerical techniques. In order to effectively control the fluid–structure vibration, one of the side walls is made flexible where two piezoelectric patches are utilized to sense the distributed displacements resulting from fluid-structure movements, while the other one is used to actively control the vibration. For this, a boundary control technique is used to actively control the multi-modal vibration of fluid–structure. The simulation results for the analytical models are further validated using a comprehensive finite element method. Before applying the proposed controller, the results show that the fluid vibration is different in different heights and distances. However, the simulation results indicate that the piezoelectrically-excited beam is able to suppress the vibrations of all the positions very effectively and quickly. These results prove the feasibility of utilizing piezoelectrically-excited beams in vibration control of fluid–structure.
关键词： boundary control,piezoelectric-based vibration control,finite element method,Fluid–structure interaction
更新于2025-09-19 17:15:36
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Low-frame-rate single camera system for 3D full-field high-frequency vibration measurements
摘要： A single-camera stereo-digital image correlation (stereo-DIC) system to obtain 3D full-field vibration measurements is proposed. The optical setup is composed of two planar mirrors and a single low frame rate camera, thus resulting in a compact and low-cost equipment. The two mirrors are used to create pseudo-stereo images of a target surface on the camera sensor, which are then correlated by using stereo-DIC. The image acquisition process is carried out at low frame rates and the Nyquist-Shannon frequency limitation is overcome by adopting a down-sampling approach under the hypothesis that the vibration signal is characterized by a single known frequency component. The developed pseudo-stereo DIC system allows to obtain 3D full-field vibration measurements in a frequency range up to 4 kHz even with an available frame rate (at full resolution) of 178 fps. The effectiveness of the described approach has been verified by performing vibration measurements on a cantilever plate and a turbine blade.
关键词： Single low-speed camera,Vibration measurement,Down-sampling approach,Digital image correlation
更新于2025-09-19 17:15:36
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[IEEE 2019 24th Microoptics Conference (MOC) - Toyama, Japan (2019.11.17-2019.11.20)] 2019 24th Microoptics Conference (MOC) - Fundamental Study of Saturation Output Power on Quantum Dot Semiconductor Optical Amplifier (SOA) under High Temperature (85 ?°C)
摘要： This paper proposed a new crossbeam ultrasonic motor, which was made of a cross-shaped metal frame and eight pieces of lead zirconate titanate ceramic plates with a size of 10 mm × 3 mm × 1 mm. Two cross-cone-shaped horns were machined at two ends of the crossbeam, and the tips of the horns served as the driving feet. Ellipse trajectories of the two driving feet were generated by superimposing two orthogonal ?rst bending vibrations with the same resonance frequency but a temporal shift of 90?. A Symmetric structure of the proposed ultrasonic motor solved the problem of mode frequencies degeneracy. A new method to excite these two bending vibrations was proposed. Finite-element method simulation was developed to obtain the vibration characteristics of the crossbeam motor. The new excitation method was compared with the traditional one, and it was found that the vibration amplitudes of the driving feet under the new excitation method were about three times that of the traditional one. At last, experiments were accomplished on a fabricated prototype. The two tested ?rst bending resonance frequencies agreed well with each other at ～40.5 kHz. Mechanical output performance of the prototype was tested; the maximum speed was ～64 r/min, and the maximum output torque was ～10.4 mN · m. This paper provides a new idea for an ultrasonic motor with a miniature structure and also a new excitation method for bending vibration.
关键词： vibration characteristic,Crossbeam,bending vibration,excitation method,ultrasonic motor
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Effects of CsF Post-deposition Treatment on Cu(In, Ga)Se <sub/>2</sub> Thin Films and Solar Cells
摘要： This paper proposed a new crossbeam ultrasonic motor, which was made of a cross-shaped metal frame and eight pieces of lead zirconate titanate ceramic plates with a size of 10 mm × 3 mm × 1 mm. Two cross-cone-shaped horns were machined at two ends of the crossbeam, and the tips of the horns served as the driving feet. Ellipse trajectories of the two driving feet were generated by superimposing two orthogonal ?rst bending vibrations with the same resonance frequency but a temporal shift of 90?. A Symmetric structure of the proposed ultrasonic motor solved the problem of mode frequencies degeneracy. A new method to excite these two bending vibrations was proposed. Finite-element method simulation was developed to obtain the vibration characteristics of the crossbeam motor. The new excitation method was compared with the traditional one, and it was found that the vibration amplitudes of the driving feet under the new excitation method were about three times that of the traditional one. At last, experiments were accomplished on a fabricated prototype. The two tested ?rst bending resonance frequencies agreed well with each other at ～40.5 kHz. Mechanical output performance of the prototype was tested; the maximum speed was ～64 r/min, and the maximum output torque was ～10.4 mN · m. This paper provides a new idea for an ultrasonic motor with a miniature structure and also a new excitation method for bending vibration.
关键词： bending vibration,Crossbeam,vibration characteristic.,ultrasonic motor,excitation method
更新于2025-09-19 17:13:59
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Laser dot projection videogrammetry for vibration measurement and control of a piezoelectric flexible cantilever plate
摘要： A novel full-field non-contact vibration measurement method is investigated for a piezoelectric flexible cantilever plate, using laser dot-projection videogrammetry. Several laser dots are projected as marks for visual system. The three-dimensional coordinates of each mark are monitored by a binocular stereo vision system, composed of two cameras. After image processing, the vibration signal of the first bending mode is obtained. For the first torsional mode, two laser displacement sensors are utilized to detect the vibration. To suppress the residual vibration quickly, an adaptive nonlinear controller and a fuzzy tuning nonlinear controller are designed and adopted. To verify the investigated measurement and control methods, experiments are conducted by using a piezoelectric flexible cantilever plate experimental platform. The experimental results demonstrate that the investigated laser dot projection measurement method is effective for first bending vibration detection. Furthermore, compared with PD control, the adopted nonlinear algorithms have better damping performance, especially for small amplitude residual vibration.
关键词： Vibration measurement,Nonlinear control algorithm,Piezoelectric flexible plate,Laser dot projection,Videogrammetry
更新于2025-09-19 17:13:59
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An Indoor Photovoltaic Energy Harvester Using Time-Based MPPT and On-chip Photovoltaic Cell
摘要： Magnetostriction of grain-oriented 3% SiFe sheets was measured prior to assembly into model transformer cores. Core vibration was measured using a laser scanning vibrometer and harmonic spectra of acoustic noise were evaluated from the microphone outputs. Explanations show why no correlation exists between vibration harmonics profiles and A-weighted acoustic noise spectra. High localized vibration did not cause high noise due to phase differences in surface vibrations, and it is shown that this is the main reason why the A-weighted noise of a three-phase core can be less than that of an equivalent single-phase core. Noise from cores assembled from low magnetostriction materials was not always lowest because of the variable effect of electromagnetic forces.
关键词： electrical machine cores,magnetostriction,transformer cores,Acoustic noise,electrical steels,vibration
更新于2025-09-19 17:13:59