In order to improve the bias stability of the micro-electro mechanical system（MEMS） gyroscope and reduce the impact on the bias from environmental temperature,a digital signal processing method is described for impr...In order to improve the bias stability of the micro-electro mechanical system（MEMS） gyroscope and reduce the impact on the bias from environmental temperature,a digital signal processing method is described for improving the accuracy of the drive phase in the gyroscope drive mode.Through the principle of bias signal generation,it can be concluded that the deviation of the drive phase is the main factor affecting the bias stability.To fulfill the purpose of precise drive phase control,a digital signal processing circuit based on the field-programmable gate array（FPGA） with the phase-lock closed-loop control method is described and a demodulation method for phase error suppression is given.Compared with the analog circuit,the bias drift is largely reduced in the new digital circuit and the bias stability is improved from 60 to 19 °/h.The new digital control method can greatly increase the drive phase accuracy,and thus improve the bias stability.展开更多
Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast trac...Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast track and simply-supported beam are combined with each other,was established.The laws of the track stress,the pier longitudinal stress and the beam-track relative displacement were analyzed.The results show that reducing the longitudinal resistance can effectively reduce the track stress and the pier stress of the continuous beam,and increase the beam-track relative displacement.Increasing the rigid pier stiffness of continuous beam can reduce the track braking stress,increase the pier longitudinal stress and reduce the beam-track relative displacement,Increasing the rigid pier stiffness of simply-supported beam can reduce the track braking stress,the rigid pier longitudinal stress and the beam-track relative displacement.展开更多
The threshold control of safety blasting vibration velocity is a significant process for the underground mining of complicated ore deposit under construction,road,and water.According to the equivalent principle of dis...The threshold control of safety blasting vibration velocity is a significant process for the underground mining of complicated ore deposit under construction,road,and water.According to the equivalent principle of displacement and velocity of mass point,differential evolution is put forward based on 3DEC dynamic analysis,making the calculation more efficient and accurate.The 3DEC model of the complicated orebody under railway is established according to the topographic maps and geological data of the eastern Pyrite Mine.The stimulus-response distribution of internal stress and displacement fields are demonstrated by analyzing the on-site monitoring vibration displacement and velocity data of the mass point.The reliability of parameter selection,such as blasting simulation waveforms,rock damping,is identified.The safety vibration velocity of railway is set to 4.5 cm/s in line with the requirement of safety blasting rules.Thus,the maximum amount of single-stage explosive in this region is 44.978 kg.The simulation result is in good agreement with the on-site monitoring datum.No displacement and settlement of the 701 railway special line was achieved by choosing the critical amount of the single-stage explosive.展开更多
In this paper, a dynamic optical arbitrary waveform generator(OAWG) based on cross phase modulation(XPM) is proposed. According to the characteristics of XPM, the nonlinear phase shift of signal can be changed along w...In this paper, a dynamic optical arbitrary waveform generator(OAWG) based on cross phase modulation(XPM) is proposed. According to the characteristics of XPM, the nonlinear phase shift of signal can be changed along with the pump power. The amplitude of signal can be changed by controlling the phase shift at one arm of a Mach-Zehnder interferometer(MZI) using XPM effect between signal and pump. Therefore, the phase and amplitude of the optical frequency comb(OFC) can be controlled by two pump arrays. As a result, different kinds of waveforms can be synthesized. Due to the ultrafast response of XPM, the generated waveform could be dynamically updated with an ultrafast frequency. The waveform fidelity is affected by the updating frequency.展开更多
This paper presents a new control strategy based on current differential feedback to accelerate the dynamic response of electromagnetic actuators, instead of traditional closed-loop control based on displacement feedb...This paper presents a new control strategy based on current differential feedback to accelerate the dynamic response of electromagnetic actuators, instead of traditional closed-loop control based on displacement feedback. The method mainly includes a differentiator, proportioner and signal synthesizer. Analysis and simulation on the step characteristics of an electromagnetic actuator were discussed, and all the results show that the approach can improve the actuator's step response greatly. Finally, the control method is applied to a real gravure system which verifies the control performance.展开更多
基金The National Natural Science Foundation of China (No.60974116)the Research Fund of Aeronautics Science (No. 20090869007)Specialized Research Fund for the Doctoral Program of Higher Education(No. 200802861063)
文摘In order to improve the bias stability of the micro-electro mechanical system（MEMS） gyroscope and reduce the impact on the bias from environmental temperature,a digital signal processing method is described for improving the accuracy of the drive phase in the gyroscope drive mode.Through the principle of bias signal generation,it can be concluded that the deviation of the drive phase is the main factor affecting the bias stability.To fulfill the purpose of precise drive phase control,a digital signal processing circuit based on the field-programmable gate array（FPGA） with the phase-lock closed-loop control method is described and a demodulation method for phase error suppression is given.Compared with the analog circuit,the bias drift is largely reduced in the new digital circuit and the bias stability is improved from 60 to 19 °/h.The new digital control method can greatly increase the drive phase accuracy,and thus improve the bias stability.
基金Project(50678176) supported by the National Natural Science Foundation of China
文摘Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast track and simply-supported beam are combined with each other,was established.The laws of the track stress,the pier longitudinal stress and the beam-track relative displacement were analyzed.The results show that reducing the longitudinal resistance can effectively reduce the track stress and the pier stress of the continuous beam,and increase the beam-track relative displacement.Increasing the rigid pier stiffness of continuous beam can reduce the track braking stress,increase the pier longitudinal stress and reduce the beam-track relative displacement,Increasing the rigid pier stiffness of simply-supported beam can reduce the track braking stress,the rigid pier longitudinal stress and the beam-track relative displacement.
基金Fund for New Teacher of the Doctoral Program of Higher Education(No. 200805611092)the Fundamental Research Funds for the Central Universities(No.2009zm0064)the Key Program of the National Natural Science Foundation of China(No.50934002) for its financial support
文摘The threshold control of safety blasting vibration velocity is a significant process for the underground mining of complicated ore deposit under construction,road,and water.According to the equivalent principle of displacement and velocity of mass point,differential evolution is put forward based on 3DEC dynamic analysis,making the calculation more efficient and accurate.The 3DEC model of the complicated orebody under railway is established according to the topographic maps and geological data of the eastern Pyrite Mine.The stimulus-response distribution of internal stress and displacement fields are demonstrated by analyzing the on-site monitoring vibration displacement and velocity data of the mass point.The reliability of parameter selection,such as blasting simulation waveforms,rock damping,is identified.The safety vibration velocity of railway is set to 4.5 cm/s in line with the requirement of safety blasting rules.Thus,the maximum amount of single-stage explosive in this region is 44.978 kg.The simulation result is in good agreement with the on-site monitoring datum.No displacement and settlement of the 701 railway special line was achieved by choosing the critical amount of the single-stage explosive.
基金supported by the National Natural Science Foundation of China(No.61377075)Program for New Century Excellent Talents in University(No.NCET-07-0611)
文摘In this paper, a dynamic optical arbitrary waveform generator(OAWG) based on cross phase modulation(XPM) is proposed. According to the characteristics of XPM, the nonlinear phase shift of signal can be changed along with the pump power. The amplitude of signal can be changed by controlling the phase shift at one arm of a Mach-Zehnder interferometer(MZI) using XPM effect between signal and pump. Therefore, the phase and amplitude of the optical frequency comb(OFC) can be controlled by two pump arrays. As a result, different kinds of waveforms can be synthesized. Due to the ultrafast response of XPM, the generated waveform could be dynamically updated with an ultrafast frequency. The waveform fidelity is affected by the updating frequency.
基金Project supported by the Science and Technology Plan of Zhejiang Province (No. 2008C11028), China
文摘This paper presents a new control strategy based on current differential feedback to accelerate the dynamic response of electromagnetic actuators, instead of traditional closed-loop control based on displacement feedback. The method mainly includes a differentiator, proportioner and signal synthesizer. Analysis and simulation on the step characteristics of an electromagnetic actuator were discussed, and all the results show that the approach can improve the actuator's step response greatly. Finally, the control method is applied to a real gravure system which verifies the control performance.
