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Qin Y.,Beijing Institute of Technology | Zhao F.,Beijing Institute of Aerospace Control Devices | Wang Z.,Beijing Institute of Technology | Gu L.,Beijing Institute of Technology | Dong M.,Beijing Institute of Technology
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2017

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+., to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results. © 2017 by ASME.

Xia D.,Nanjing Southeast University | Hu Y.,Nanjing Southeast University | Wang Y.,Beijing Institute of Aerospace Control Devices
Sensors and Actuators, A: Physical | Year: 2016

To optimize conventional phase locked loop (PLL) performance through enhancement of drive mode stability of frequency and amplitude, enhanced phase locked loop (EPLL) and quadrature phase locked loop (QPLL) algorithms were investigated. First, stable point averaging analysis was applied to verify the stability of the closed-loop and determine the range of the critical parameters. When simulations were conducted to compare PLL, EPLL and QPLL, it was found the use of QPLL resulted in superior control precision and noise suppression. Next, different nonlinear dynamic closed-loops in PLL modules allowed for stable amplitude and constant frequency in the drive mode, and parameter estimates were needed for both EPLL and QPLL algorithms without amplitude demodulation. Then, after the control parameters were optimized, the EPLL and QPLL algorithms were compared at the module level by Field Programmable Gate Array (FPGA) chip, and specified amplitude and frequency startup characteristics were analyzed. Finally, under the same test conditions, system level experiments were implemented to compare some major specifications of the digital gyroscope system. During experiments, the phase noise of the drive mode detection signal was utilized to estimate the frequency control stability. The QPLL based gyroscope yielded better bias instability with 4.34°/h and a noise floor of 0.0229 °·s−1/Hz, while the EPLL system was only 9.33°/h with a noise floor of 0.0711°·s−1/Hz. © 2016 Elsevier B.V.

Han B.,Beihang University | Xu Q.,Beihang University | Yuan Q.,Beijing Institute of Aerospace Control Devices
IEEE Transactions on Industrial Electronics | Year: 2016

The combined radial-axial magnetic bearing (CRAMB) with permanent magnet (PM) providing bias magnetic flux is designed for magnetically suspended high-speed electromotor in the compressor for its compact construction. In this paper, the design principle and the initial model of CRAMB are introduced. To improve the performances of CRAMB and better meet the engineering requirements, the optimization is conducted on the bearing. Considering the incompatible objectives of the optimization model, the method of multiobjective optimization (MOO) on the bearing is proposed, which can balance these objectives compared with single-objective optimization (SOO). The objectives and constraints are provided in the form of analytical expressions by means of equivalent magnetic circuit whose rationality is demonstrated by finite-element method (FEM). To optimize the bearing efficiently, the integrated optimum methodology is adopted. After MOO process, the synthetical performances are improved, which are verified by FEM and experiment. © 1982-2012 IEEE.

Jin H.,Nanjing University | Liu F.M.,Beijing Institute of Aerospace Control Devices | Xu P.,Nanjing University | Xia J.L.,Beijing Institute of Aerospace Control Devices | And 6 more authors.
Physical Review Letters | Year: 2014

A consequent tendency toward high-performance quantum information processing is to develop the fully integrated photonic chip. Here, we report the on-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits. By introducing a periodically poled structure into the waveguide circuits, two individual photon-pair sources with a controllable electro-optic phase shift are produced within a Hong-Ou-Mandel interferometer, resulting in a deterministically separated identical photon pair. The state is characterized by 92.9±0.9% visibility Hong-Ou-Mandel interference. The photon flux reaches ∼1.4×107pairsnm-1mW-1. The whole chip is designed to contain nine similar units to produce identical photon pairs spanning the telecom C and L band by the flexible engineering of nonlinearity. Our work presents a scenario for on-chip engineering of different photon sources and paves the way to fully integrated quantum technologies. © 2014 American Physical Society.

Yang W.,University of Science and Technology Beijing | Zhu R.,Tsinghua University | Ma B.,Beijing Institute of Aerospace Control Devices
IEEE Transactions on Plasma Science | Year: 2016

There has been considerable interest in nonthermal atmospheric pressure discharges due to their widely used industrial applications. A repetitively pulsed (RP) discharge ignited in microchannels between two nonequally broad planar electrodes is studied in this paper. The discharge current attains several 10-5 A orders of magnitude, and the ion concentration produced in interelectrode space by RP discharge is estimated to be about 1017/m3. The duration of each time of RP discharge is several 10-8 s and the repetition frequency exceeds a few tenths of kilohertz. The repetition frequency of RP discharge depends on the RC product, applied voltage, and the environmental humidity. The experiments of charging aerosol particles by RP discharges have shown that for particles with diameters of 34.8 and 103 nm, the charging efficiency can attain 14.8% and 35%, respectively. © 2015 IEEE.

Li Z.,CAS Institute of Electronics | Li Z.,University of Chinese Academy of Sciences | Tan R.,CAS Institute of Electronics | Huang W.,CAS Institute of Electronics | And 3 more authors.
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams | Year: 2014

Pumped by a laser diode array with an external cavity of Littrow, whose linewidth is 0.26 nm, a cesium vapor laser is obtained using the cesium cell filled with methane of 80 kPa. At 120°C of the cesium vapor cell, laser with output power of 394 mW and wavelength of 894.6 nm is realized. The laser's optical efficiency is 7.4% while the slope efficiency is 11.2% and the threshold is 1.72 W.

Liu S.-B.,Beijing Institute of Aerospace Control Devices | Wei Z.-K.,Beijing Institute of Aerospace Control Devices | Chen D.-S.,Beijing Institute of Aerospace Control Devices | Xia G.,Beijing Institute of Aerospace Control Devices
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2013

The 3D laser imaging system is a complex system which contains a variety of advanced technologies, including laser scanner, SINS and GPS. The 3D laser imaging system can obtain the distance and angle between the scanner and the target through the scanner. Through the SINS, the 3D laser imaging system can obtain the attitude transform matrix between carrier frame and navigation frame. The 3D laser imaging system can obtain the transform matrix between navigation frame and earth frame. It is easy to calculate the coordinate of target in earth frame through using all the information. The test results show that this method can calculate the coordinate of target. It has a lot of strong-points, e. g. the theory is easy, the precision is very high and it is very easy for engineer make program.

Li C.,Beijing Institute of Aerospace Control Devices | Han J.-H.,Beijing Institute of Aerospace Control Devices
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2013

Mechanically dithered ring laser gyroscope is an inertial instrument based on Sagnac effect, whose output signal has high frequency disturbance. In practical system, a FIR filter based on DSP is usually used to filter laser gyroscope signals. However the DSP-based filter takes too much filtering time. Aiming at this problem, a FIR filter based on FPGA is designed. First, the filter coefficients are obtained according to the technical index with the aid of MATLAB window function toolbox. Then the filter design is completed based on FIR Megacore serial architecture. Thus the FIR hardware filter function is achieved in FPGA. The static initial alignment experiment is made, which shows that the filter based on FPGA has the same effectiveness in precision with the filter based on DSP, while the original filtering time of 160 μs can be shortened to 0.6 μs.

Yang T.,Beijing Institute of Aerospace Control Devices | Zhou L.-B.,Huazhong University of Science and Technology
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2014

To investigate the influence of the longitudinal dynamic end effect(LDEE) on the magnetic field and performance of the long primary double-sided linear induction motor(LP-DSLIM), the airgap magnetic field for LP-DSLIM was analyzed, in part 1, by using the analytical method. According to the derived analytical expressions of the airgap magnetic flux density, the analytical calculations, when taking into account LDEE, were extended to the prediction of the motor performances, which include electromagnetic thrust, active and reactive power, power factor and efficiency, etc in this part. The analytical results were compared and validated by the predictions from two-dimensioanl finite element analysis. The fact that thrust due to the entry-end effect comes into being as the braking force at high speed, and its influence on the resultant thrust-speed characteristics were investigated by the phasor diagram of the airgap magnetic flux density. The effects of the motor design parameters, including the goodness factor and the pole numbers, on the improving the high speed thrust-speed characteristics for LP-DSLIM were also analyzed. The analysis result show that LDEE makes the rated operating speed in the thrust-speed characteristics be far away from the synchronous speed, thereby resulting in the higher secondary copper losses and lower efficiency. Adjusting the goodness factor has little influence on the thrust improvement, while increasing the pole numbers could effectively alleviate LDEE.

Yang T.,Beijing Institute of Aerospace Control Devices | Zhou L.-B.,Huazhong University of Science and Technology
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2014

To investigate the influence of the longitudinal dynamic end effect (LDEE) on the magnetic field and performance of the long primary double-sided linear induction motor (LP-DSLIM), the one-dimensional time-harmonic magnetic field equations in the airgap region of LP-DSLIM, accounting for LDEE, were developed and solved. The analytical solutions of the fundamental airgap fields and the component fields due to entry-and exit-end are derived. The characteristics of the amplitude, phase and waveform of each three components of the traveling wave, as well as the LDEE wave's influence on the airgap magnetic field distribution were both analyzed. The analytical results were compared and validated by the predictions from corresponding two-dimensional finite element analyses. The variations of LDEE-related characteristic parameters, such as attenuating constant, half-wave length and wave velocity, with the goodness factor were given. The analysis results show that LP-DSLIM and its short primary counterpart exhibit are quite different on the airgap magnetic field distribution, especially operating at high-speed conditions. By adjusting the motor design parameters, the measures to reduce the goodness factor may effectively alleviate LDEE, whilst these effects also degrade the LP-DSLIM fundamental performance. Therefore, the compromised measures should be taken during the design procedures for LP-DSLIM.

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