中国科学院机构知识库网格系统: 检索

A Flux Reconstruction Stochastic Galerkin Scheme for Hyperbolic Conservation Laws 期刊论文 OAI收割
JOURNAL OF SCIENTIFIC COMPUTING, 2023, 卷号: 95, 期号: 1, 页码: 18
作者: Xiao TB(肖天白); Kusch, Jonas; Koellermeier, Julian; Frank, Martin

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收藏 | 浏览/下载：64/0 | 提交时间：2023/04/20

Computational fluid dynamics High order methods Flux reconstruction Uncertainty quantification Stochastic Galerkin

Further Results on Adaptive Practical Tracking for High-Order Nonlinear Systems With Full-State Constraints 期刊论文 OAI收割
IEEE TRANSACTIONS ON CYBERNETICS, 2021, 页码: 8
作者: Xie, Xue-Jun; Wu, You; Hou, Zeng-Guang

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收藏 | 浏览/下载：22/0 | 提交时间：2022/01/27

Nonlinear systems Adaptive systems Trajectory Safety Robots Lyapunov methods Fuzzy systems Adaptive practical tracking control feasibility conditions full-state constraints high-order nonlinear systems

Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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收藏 | 浏览/下载：48/0 | 提交时间：2022/02/08

Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

Design and experimental research of a new type focus mechanism used in space-based telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Wang D.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

The position of focal plane will be changed because of temperature fluctuation and vacuum environment. In order to make the telescope work well positioning accuracy of the mechanism is 0.008mm. The performance satisfies the need of precision a focusing mechanism is needed. To majority of large space-based telescopes and the scheme design is reasonable and practicable. 2012 IEEE. the general way to do this would be to use a reflector which was located in the backfocal distance. One of typical schemes of this mechanism was introduced however because of the big axial size the mechanism can't be used when the size of the enclosure was limited. A new type of focusing mechanism was introduced which has such advantages of small size high accuracy and low mass. The design and test methods had been discussed. According to the results the repeatability positioning accuracy is 0.0025mm

A new approach to realize UART (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2011, August 12, 2011 - August 14, 2011, Harbin, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

In order to connect DSP which has synchronous serial ports to the devices implementing asynchronous communications protocol a method to implement UART communications based on programmable logic device is proposed in the paper. In the proposed method the core function of UART is integrated in CPLD with VHDL. Firstly UART data frame format and operational principle of UART were introduced after reviewing some methods to realize UART. The methods to implement UART transmitter UART receiver and baudrate generator using VHDL were illustrated in detail. Then pre-simulation and synthesize of VHDL program were executed. Finally the test with bit error rate was carried out on physical system. Experimental results indicate that 75 percent of the GLB are used by UART and the bit error rate is less than 109. The experiment was implemented utilizing the RS-422 protocol and the baudrate is 62.5kb/s. The proposed method can satisfy the system requirements of high integration stabilization low bit error rate strong anti-jamming and low cost. 2011 IEEE.

Analyse the angular velocity estimation errors of -- filter based on high sampling rate (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者: Zhang Y.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

In order to get angular velocity of stabilization servo mechanism from angular position sensors -- filter based on high sampling rate was established model and error characteristics were analyzed. With the hypothesis of constant acceleration -- filter and its angular velocity transfer function were deduced. Combing with optimum parameters the effects of and sample rate on the error characteristics were evaluated. According to the requirements of stabilization servo mechanism the frequency characteristics of angular velocity transfer function are analyzed and the filter parameters are designed. The experimental which filter tracked and smoothed sinusoidal signal the results show that when the cutoff frequency of angular velocity loop is 44.9rad/s sampling period and parameters are 0.08ms and 0.01279 respectively the phase leading of angular position is 70. -- filter tracked sinusoidal signals with maximum angular velocity(30/s) and maximum angular acceleration(30/s2) the error of angular velocity estimation was 0.053/s. In the engineering of electro-optical stabilization servo mechanism -- filter can reduce noise effectively and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors. 2011 IEEE.

The angular velocity estimation principal of -- filter based on high sampling rate (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者: Zhang Y.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

In order to get angular velocity of stabilization servo mechanism from angular position sensors -- filter and its angular velocity transfer function were predigested. Combing with optimum parameters -- filter based on high sampling rate was established the effect of and sample rate on filter nature frequency were evaluated. According to the requirements of stabilization platform the principle of steady and transient tracking filter differential were proved. With the hypothesis of constant acceleration the frequency characteristics of angular velocity transfer function were analyzed three-dimensional Kalman filter was simplified and the filter parameters were designed. The results show that when the spectrum of input signal was lower than 6rad/s parameters was 0.02 and sampling period were 0.08ms and 0.1ms respectively the filter can realize differential exactly when the spectrum was 9rad/s the precision was no less than 1.1% the phase leading of angular position was no less than 70 the natural frequency should be higher than the cut-off frequency of stabilization platform was two or three times. In the engineering of electro-optical stabilization servo mechanism -- filter has properties of tracking differential and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors. 2011 IEEE.

Three-sample rotation vector algorithm with angular rate input (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者: Zhang Y.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

In order to research the attitude algorithm with angular rate input under the conical motion a optimal threesample rotation vector algorithm based on single-step Newton backward interpolation is proposed. Using the principle of limited rigid body rotation and the characteristic of angular rate input three-sample rotation vector algorithm is derivated. To minimum attitude errors three-sample rotation vector algorithm is optimized. Three angular rate extraction methods of singlestep entire sample recursion multi-step entire sample and singlestep Newton backward interpolation are proposed. Under the condition of conical motion with semi-cone angle 3 and angular frequency 2rad/s simulation is done. The simulation results show that single-step Newton backward interpolation is superior to the other two methods and its maximum error peak is 0.01 error drift rate is 0.036/h. Experiments in three-axis flying turntable with the same parameters are carried out and the results show that error drift rates of three-channels are less than those of traditional quaternion which are 13.53% 12.08% and 23.68% lower respectively. It also verified that the new algorithm can perform a high accuracy under the conical motion. 2011 IEEE.

Study of experimental design and Response Surface method for surrogate model of computational simulation (EI CONFERENCE) 会议论文 OAI收割
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
Xi R.; Jia H.; Xiao Q.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

While the high-precision simulation is widely used in science and technology Design of Experiment (DOE) based on Response Surface (RS) method can be employed in surrogate model to reduce the cost and error. In order to illustrate the relationship between parameters and response features several DOE methods and Response Surface (RS) method are studied. The author used polynomial regression and RBF neural network based on orthogonal array to build a rocket aerodynamic discipline surrogate model respectively which proved their feasibility. From the results of the test case conclusion is drawn that characteristic as well as acclimatization of DOE methods and different approximation should be considered for different issues so the factors of cost and accuracy could reach a balance synthetically. 2011 IEEE.

Fifth-order iterative method for finding multiple roots of nonlinear equations 期刊论文 OAI收割
NUMERICAL ALGORITHMS, 2011, 卷号: 57, 期号: 3, 页码: 389-398
Li, XW; Mu, CL; Ma, JW; Hou, Linke(侯麟科)

收藏 | 浏览/下载：25/0 | 提交时间：2012/05/09

Nonlinear equation Multiple roots Newton-like method High-order convergence Iterative methods