This paper proposes an enhanced noise filtering technique to the Hilbert-Huang transformation technology for the identification of structural systems using vibration measurements. The Hilbert-Huang transformation tech...This paper proposes an enhanced noise filtering technique to the Hilbert-Huang transformation technology for the identification of structural systems using vibration measurements. The Hilbert-Huang transformation technology is a set of superior algorithms non-stationary signals and also for analyzing non-linear and offers increased accuracy for linear and stationary signals. However, the signals are filtered by reconstruction from ＂＇selected＂ intrinsic mode functions （IMFs）, derived from the original signal through the empirical mode decomposition method. The proposed filtering technique offers the criterion for selecting the IMFs using the orthogonalization coefficient. In addition, a simple free vibration modal analysis has been resolved for the evaluation of the modal damping ratio. Through the enhanced filtering, it is possible to increase the accuracy for the estimation of the time-varying system＇s natural frequency and the damping ratio, indicative of the degree of damage, which helps an effective design of a control system.展开更多
Magnetism parameters vary with the position and the speed of electromagnetic actuator's motion parts.The measurement unit presented in the paper can be applied to get the position and the speed feedback informatio...Magnetism parameters vary with the position and the speed of electromagnetic actuator's motion parts.The measurement unit presented in the paper can be applied to get the position and the speed feedback information from the measurement of electromagnetism parameters,and can constitute the untouched feedback sensing unit in the closed-loop motion control,and it adapts to the diversified feedback control of electromagnetic actuator.The digital miniaturization meter,based on MSP430 single chip processor,which can do the multi-purpose measurement of Φ & B through the menu selection,can be used for the electromagnetic actuator's performance evaluation and improvement,and also the online quality control in production process.Both real-time data graph and data table can be displayed in the meter.The paper presents the system's structure,describes the principle,discusses the working modes,and shows the software flowchart and the measuring results.展开更多
Angular measuring system is the most important component of a servo turntable in inertial test apparatus. Its function and precision determine the turntable＇ s function and precision. It attaches importance to resear...Angular measuring system is the most important component of a servo turntable in inertial test apparatus. Its function and precision determine the turntable＇ s function and precision. It attaches importance to research on inertial test equipment. This paper introduces the principle of the angular measuring system using amplitude discrimination mode. The dynamic errors axe analyzed from the aspects of inductosyn, amplitude and function error of double-phase voltage and wavefonn distortion. Through detailed calculation, theory is provided for practical application; system errors are allocated and the angular measuring system meets the accuracy requirement. As a result, the schedule of the angular measuring system can be used in practice.展开更多
We investigate the dynamics of measurement-induced disturbance(MID) for a qubit-qutrit system in noninertial frames under various multi-local decoherence channels(i.e.,dephasing,phase-flip,bit-(trit-) flip,bit-(trit-)...We investigate the dynamics of measurement-induced disturbance(MID) for a qubit-qutrit system in noninertial frames under various multi-local decoherence channels(i.e.,dephasing,phase-flip,bit-(trit-) flip,bit-(trit-) phase-flip,and depolarizing channels).We find that,for any acceleration,the MID can decay in a monotonic way to zero or to a nonzero steady value(i.e.,residual MID exists).Consequently,no sudden death of the MID occurs,which is different from entanglement.展开更多
文摘This paper proposes an enhanced noise filtering technique to the Hilbert-Huang transformation technology for the identification of structural systems using vibration measurements. The Hilbert-Huang transformation technology is a set of superior algorithms non-stationary signals and also for analyzing non-linear and offers increased accuracy for linear and stationary signals. However, the signals are filtered by reconstruction from ＂＇selected＂ intrinsic mode functions （IMFs）, derived from the original signal through the empirical mode decomposition method. The proposed filtering technique offers the criterion for selecting the IMFs using the orthogonalization coefficient. In addition, a simple free vibration modal analysis has been resolved for the evaluation of the modal damping ratio. Through the enhanced filtering, it is possible to increase the accuracy for the estimation of the time-varying system＇s natural frequency and the damping ratio, indicative of the degree of damage, which helps an effective design of a control system.
基金Sponsored by the Multidiscipline Scientific Research Foundation of Harbin Institute of Technology(Grant No.HIT.MD2002.13).
文摘Magnetism parameters vary with the position and the speed of electromagnetic actuator's motion parts.The measurement unit presented in the paper can be applied to get the position and the speed feedback information from the measurement of electromagnetism parameters,and can constitute the untouched feedback sensing unit in the closed-loop motion control,and it adapts to the diversified feedback control of electromagnetic actuator.The digital miniaturization meter,based on MSP430 single chip processor,which can do the multi-purpose measurement of Φ & B through the menu selection,can be used for the electromagnetic actuator's performance evaluation and improvement,and also the online quality control in production process.Both real-time data graph and data table can be displayed in the meter.The paper presents the system's structure,describes the principle,discusses the working modes,and shows the software flowchart and the measuring results.
文摘Angular measuring system is the most important component of a servo turntable in inertial test apparatus. Its function and precision determine the turntable＇ s function and precision. It attaches importance to research on inertial test equipment. This paper introduces the principle of the angular measuring system using amplitude discrimination mode. The dynamic errors axe analyzed from the aspects of inductosyn, amplitude and function error of double-phase voltage and wavefonn distortion. Through detailed calculation, theory is provided for practical application; system errors are allocated and the angular measuring system meets the accuracy requirement. As a result, the schedule of the angular measuring system can be used in practice.
基金Supported by the Natural Science Foundation of China under Grant Nos. 90921010,and 11174373the Fundamental Research Program of China under Grant No. 2010CB923104the Fundamental Research Funds for the Central Universities under Grant Nos. SWJTU09CX078 and 2010XS47
文摘We investigate the dynamics of measurement-induced disturbance(MID) for a qubit-qutrit system in noninertial frames under various multi-local decoherence channels(i.e.,dephasing,phase-flip,bit-(trit-) flip,bit-(trit-) phase-flip,and depolarizing channels).We find that,for any acceleration,the MID can decay in a monotonic way to zero or to a nonzero steady value(i.e.,residual MID exists).Consequently,no sudden death of the MID occurs,which is different from entanglement.
