Time filter

Source Type

Nan Y.-X.,Beijing Institute of Technology | Jiang J.-W.,Beijing Institute of Technology | Wang S.-Y.,Beijing Institute of Technology | Fang Y.-J.,China South Industries Research Academy
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2013

Using LS-DYNA software, impact response of submunitions drop on concrete was simulated and tested, with different drop angles and attack ones. The drop law of the maximum overload and the impact action time were obtained in the ranges of 60°~90° drop angles and less than 5° attack ones. The numerical simulation results agreed well with those of test. The study results were useful for establishing an impact response theoretical model of submunitions drop. Source

Li X.-Y.,Hunan University | Yang H.-L.O.,Hunan University | Meng C.,China South Industries Research Academy | Yang C.,Hunan University
ICMT 2012 - 16th International Conference on Mechatronics Technology | Year: 2012

In this paper, a novel on-line dead time compensation method is proposed for the permanent magnet synchronous motor drive system. Using a sliding mode observer, this method does not require any additional hardware circuit and off-line experimental measurements. The output voltage errors caused by the dead time and nonideal switching characteristics of power devices are considered disturbance voltages. Disturbance voltages are online estimated based on the sliding mode observer and fed to the reference voltages to compensate the impact of the dead time. This method can avoid taking the zero-current clamping phenomenon into account. The proposed method is applied to permanent magnet synchronous motor system and implemented by MATLAB/Simulink simulation. The simulation results indicate that the compensation method can effectively improve the motor current waveforms and the inverter output performance. Source

Li D.,Beijing Institute of Technology | Xu P.,China South Industries Research Academy | Qin G.,China Aerospace Science and Technology Corporation | Yang D.,Beijing Institute of Technology
Proceedings of 2014 International Conference on Modelling, Identification and Control, ICMIC 2014 | Year: 2015

Moving objects detection in a complicated surrounding is one of the most significant issues to be solved in the infrared target recognition because of the time-varying background. Biomimetic approach is a promising solution for tackling this problem. Visual detection and processing of motion in flies is thought to occur based on an elementary delay-and-correlate operation at an early stage in the visual pathway, which is the so-called 'Reichardt detector'. However, the original Reichardt detector is a coarse description of the visual system of the fly. In this paper, we studied moving target detection method in a complicated background using a two-dimensional 2 quadrant motion detector network consisting of a grid of modified double channel motion detectors. At first, the scheme of modified double channel motion detector is analyzed and general properties of the modified double channel motion detectors are presented in detail. Then, the modified double channel motion detectors are interconnected in a grid to form a two-dimensional detectors network that can be used to model motion in two-dimensional scenes. The infrared image sequences including moving vehicle objects in the complicated background are used to confirm the proposed method in the experiment. The experimental results illustrate that, the proposed method achieves much better detection performance in infrared frames than the original Reichardt's model. Moving object could be detected in infrared frames without the interference of background. © 2014 Swinburne University of Technology, Australia. Source

Yu J.,North China Institute of Science and Technology | Xu X.,China South Industries Research Academy
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2015

According to the characteristic of multibeam bathymetry in which measurement depth is influenced by terrain, revision algorithm was proposed based on average slope along the horizontal and vertical terrain. Five depth revision factors were obtained, and a depth smooth template was designed. The initial scan depth data were revised by the 5 revision factors, and then the revised depth data were filtered by the template. Simulation results show that, the depth of measurement error can be reduced greatly after revision, the designed template relative to the conventional Gauss template has higher smooth precision, more adapted to the water depth data filtering. Through two ways, the measurement accuracy has been improved obviously, and seabed terrain accuracy and smoothness both have been better modified. ©, 2015, Editorial Office of Journal of System Simulation. All right reserved. Source

Wang X.,CAS Institute of Electronics | Wang X.,China South Industries Research Academy | Yang H.,CAS Institute of Electronics | Li F.,CAS Institute of Electronics | And 5 more authors.
Analog Integrated Circuits and Signal Processing | Year: 2014

An analog hearing aid with the function of frequency compensation is proposed and implemented considering the human factors. Introducing the current-mode technique, a filter designed by the state space methodology is integrated in the hearing aid to offer the function which only appears in the DSP unit of digital hearing aid. Combined with the filter embedded in the driver circuit adopting the minimum current selecting technique, the enhance frequency compensation can well match to the common low-frequency hearing loss with a stopband attenuation of 80 dB/dec. Moreover, a low-noise automatic gain control (AGC) is presented to improve the programmability with discreet gains, knee points and compression ratios. To enhance the comfortable level, the attack time and release time is set 20 and 100 ms with a peak detector. The input-referred noise is below 5 μVrms. The hearing aid can drive a 16 receiver at the supply voltage of 1 V. The die area is 2.3 × 1.5 mm2 (AGC) and 0.93 × 0.86 mm2 (driver) in a 0.13 μm standard CMOS process and 1 × 1 mm2 (filter) in a 0.35 μm standard CMOS process. © 2014 Springer Science+Business Media New York. Source

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