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Your search keyword '"Cai, Yingkai"' showing total 19 results
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19 results on '"Cai, Yingkai"'

1. Atmospheric Density Model Optimization and Spacecraft Orbit Prediction Improvements Based on Q-Sat Orbit Data

Author

Wang, Zhaokui, Zhang, Yulin, Wen, Guangwei, Bai, Shunchenqiao, Cai, Yingkai, Huang, Pu, Han, Dapeng, and He, Yunhan

Subjects
Physics - Geophysics
Abstract

Atmospheric drag calculation error greatly reduce the low-earth orbit spacecraft trajectory prediction fidelity. To solve the issue, the "correction - prediction" strategy is usually employed. In the method, one parameter is fixed and other parameters are revised by inverting spacecraft orbit data. However, based on a single spacecraft data, the strategy usually performs poorly as parameters in drag force calculation are coupled with each other, which result in convoluted errors. A gravity field recovery and atmospheric density detection satellite, Q-Sat, developed by xxxxx Lab at xxx University, is launched on August 6th, 2020. The satellite is designed to be spherical for a constant drag coefficient regardless of its attitude. An orbit prediction method for low-earth orbit spacecraft with employment of Q-Sat data is proposed in present paper for decoupling atmospheric density and drag coefficient identification. For the first step, by using a dynamic approach-based inversion, several empirical atmospheric density models are revised based on Q-Sat orbit data. Depending on the performs, one of the revised atmospheric density model would be selected for the next step in which the same inversion is employed for drag coefficient identification for a low-earth orbit operating spacecraft whose orbit needs to be predicted. Finally, orbit prediction is conducted by extrapolation with the dynamic parameters in the previous steps. Tests are carried out with the proposed method by using a GOCE satellite 15-day continuous orbit data. Compared with legacy "correction - prediction" method in which only GOCE data is employed, the accuracy of the 24-hour orbit prediction is improved by about 171m the highest for the proposed method. 14-day averaged 24-hour prediction precision is elevated by approximately 70m., Comment: 12 pages, 7 figures, submitted to nature communication

Published
2021

4. Power Marketing Risk Prevention and Control Management of Power Supply Enterprises Based on Big Data Analysis Technology

Author

Zhang, Ye, Cai, Yingkai, Cao, Shilong, Gao, Shengyu, Wang, Yizhe, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Hung, Jason C., editor, Chang, Jia-Wei, editor, Pei, Yan, editor, and Wu, Wei-Chen, editor

Published
2022
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6. Reduction of Space Debris Collision Prediction Uncertainty Based on Q-Sat Precise Orbit

Author

Huang Pu, Wen Guangwei, Cai Yingkai, and Wang Zhaokui

Subjects
Motor vehicles. Aeronautics. Astronautics, TL1-4050, Astronomy, QB1-991
Abstract

Collision probability is employed for evaluating whether there will be a dangerous encounter between 2 space objects. The fidelity of the collision probability mainly depends on the accuracies of orbit prediction and covariance prediction for the space objects. In this paper, the collision probability between the Tsinghua Gravitation and Atmosphere Science Satellite, Q-Sat, and the space debris with a North American Aerospace Defense Command ID of 49863 on 2022 January 18 was calculated. The 2 objects approached each other dangerously close and the event was reported. First, the atmospheric density model is modified by a dynamic approach-based inversion to improve the accuracy of orbit prediction for the Q-Sat. Next, predictions of position error covariance are carried out. Orbits of the next 24 hours are predicted, and the predicted orbits are compared with the actual orbits of the Q-Sat. Backpropagation neural network was trained for predicting the position error covariance. For the space debris, the 2-line element data are employed. Orbit predictions for the space debris are also conducted and compared with the actual orbit. Another backpropagation neural network for predicting the position error covariance for the space debris is trained. Using the covariances from the backpropagation neural network, the error ellipsoids of the 2 objects are established. The error ellipsoids are later projected to the encounter plane to calculate the collision probability. Different from the reports from other institutes, the closest distance between the Q-Sat and the space debris calculated by the current method was 2.71 km. The collision probability was 1.16 × 10−11. It was not a dangerous encounter event. The onboard precise orbit determination device enabled improved orbit determination precision and orbit prediction accuracy, which is important for space safety management.

Published
2023
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13. Control Strategy of Active Load Participating in Distributed Photovoltaic Generation in Microgrid Operation

Author

Yao Zheng, Cai Yingkai, Xu Longbiao, Hui Qian, Zhang Tieyan, and He Huan

Subjects
Photovoltaics, business.industry, Computer science, Photovoltaic system, Distributed power, Topology (electrical circuits), Electricity, Microgrid, business, Grid, Active load, Reliability engineering
Abstract

The rapid growth of distributed power in microgrid operation will have a greater impact on the security and economic operation of the grid. In this paper, the overall topology of the user-side microgrid and its mathematical modeling are studied. The probability model of residential electricity consumption with active load is established. The active load interactive response control strategy is proposed to maximize the distributed PV consumption in the microgrid operation. The simulation model is built on the PSCAD simulation platform with specific examples to verify that the proposed scheme can effectively promote the local consumption of distributed photovoltaics.

Published
2019

14. Application of Data Encryption Technology in Electric Power Informationization

Author

Zhang Ye, Cao Shilong, Cai Yingkai, and Mu Rong

Subjects
lcsh:GE1-350, power informationization, Computer science, business.industry, Launched, Data security, Information security, Computer security, computer.software_genre, Encryption, Power (physics), Electric power system, Information security management, Electric power, data encryption, business, application, computer, lcsh:Environmental sciences
Abstract

A large amount of data information will be generated during the construction and operation of the power system, and once these data are leaked, it will undoubtedly threaten the information security of power users, which will bring avoidable economic losses to power companies and users. Therefore, many electric power companies are paying more and more attention to data security, and data encryption technology solves this problem well. And this article has launched a detailed analysis on the application of data encryption technology in the construction of electric power information. At the same time, it has carried out an in-depth discussion with the practical application of the two-layer encryption method in the informationization of electric power enterprises. I hope the research results of this article It can provide a certain reference for the information security management of the power system.

Published
2020

15. A Method to Inspect the Implementation of Electricity Price Based on Deep Learning Variational Autoencoder

Author

Zhang Ye, Ye Ning, Gao Xiying, Hui Qian, Zhang Wenshu, Wang Haomiao, Guan Yan, Li Dan, Song Xiaowen, Cai Yingkai, and Jinchun Song

Subjects
Measure (data warehouse), Electricity price, business.industry, Computer science, 020209 energy, Deep learning, Probabilistic logic, 02 engineering and technology, computer.software_genre, Autoencoder, Power (physics), Feature (computer vision), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Anomaly detection, Data mining, Artificial intelligence, business, computer
Abstract

In this paper, we propose a method for performing electricity price execution inspection by using a variational autoencoder technology in deep learning. The variational auto encoder based anomaly detection algorithm(VABAD) can be used both as a discriminant model and as a feature of the generation model, which effectively solves the calculation problem of multiple heterogeneous parameters of current electricity price inspection implementation. The reconstruction probability is a probabilistic measure that takes into account the variability of the distribution of variables. It is used by autoencoder based anomaly detection methods. Experimental results show that the proposed method has been validated and compared to the existing approaches. The databases used in this paper come from Power Marketing System that occurred in Liaoning, China in 2015.

Published
2018

16. Self-reconstruction Space Cellular Robot for Deep Space Exploration

Author

An Dexiao, Xie Xudong, Cai Yingkai, and Hao Tian

Subjects
Surface (mathematics), Scheme (programming language), business.industry, Computer science, Connection (vector bundle), Motion (geometry), Robotics, Extensibility, Quantitative Biology::Cell Behavior, Computer Science::Robotics, Deep space exploration, Robot, Computer vision, Artificial intelligence, business, computer, computer.programming_language
Abstract

In view of the changeful topography of the surface of the extraterrestrial planet, this paper presents a detection robot (Cell-robot) based on space cellular robotics system, which is in a complex unstructured environment. Cell-M cells can be restructured to form a more powerful assembly robot by connecting to other cell modules independently. The overall design scheme and mode of work of Cell-robot are introduced. The typical (linear configuration and multi legged configuration) configuration of Cell-robot constructed by self-reconstruction is analyzed. Experiments on autonomous connection and joint motion are carried out using a prototype to verify the extensibility of the connection and the diversity of the reconstructed motion.

Published
2018

19. A research on time delay feedback control performance in chaotic system of DC-DC inverter

Author

Cai Yingkai, Lu GuoNing, Peng Xuanzhe, and Wang Nan

Subjects
Nonlinear Sciences::Chaotic Dynamics, Period-doubling bifurcation, Nonlinear system, Control theory, Mode (statistics), Chaotic, Process (computing), Inverter, State (computer science), Bifurcation, Mathematics
Abstract

DC-DC inverter is a strong nonlinear systems, in the course of the parameter changing, the inverter would process period doubling bifurcation, torus bifurcation and saddle-node bifurcation, at last getting in chaotic state embedded with many unstable periodic orbits which will make the inverter turn into the chaotic state from the original stable operation mode. In this paper, in order to overcome the chaotic motion or the random motion in the inverter to eliminate the unstable factors achieving stable mode, we use the delayed feedback control method to realize a useful control of the inverter.

Published
2013

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