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734 results on '"Chen, Weifang"'

1. USLC: Universal Self-Learning Control via Physical Performance Policy-Optimization Neural Network

Author

Zhang, Yanhui and Chen, Weifang

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

This study addresses the challenge of achieving real-time Universal Self-Learning Control (USLC) in nonlinear dynamic systems with uncertain models. The proposed control method incorporates a Universal Self-Learning module, which introduces a model-free online executor-evaluator framework to enable controller adaptation in the presence of unknown disturbances. By leveraging a neural network model trained on historical system performance data, the controller can autonomously learn to approximate optimal performance during each learning cycle. Consequently, the controller's structural parameters are incrementally adjusted to achieve a performance threshold comparable to human-level performance. Utilizing nonlinear system stability theory, specifically in the context of three-dimensional manifold space, we demonstrate the stability of USLC in Lipschitz continuous systems. We illustrate the USLC framework numerically with two case studies: a low-order circuit system and a high-order morphing fixed-wing attitude control system. The simulation results verify the effectiveness and universality of the proposed method., Comment: 15 Pages

Published
2024

2. Low-cost adaptive obstacle avoidance trajectory control for express delivery drone

Author

Zhang, Yanhui, Wei, Caisheng, Zhang, Yifan, Tian, Congcong, and Chen, Weifang

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

This paper studies quadcopters obstacle avoidance trajectory control (OATC) problem for express delivery. A new nonlinear adaptive learning controller that is low-cost and portable to different wheelbase sizes is proposed to adapt to large-angle maneuvers and load changes in UAV delivery missions. The controller consists of a nonlinear variable gain (NLVG) function and an extreme value search (ES) algorithm to reduce overshoot and settling time. Finally, simulations were conducted on a quadcopter to verify the effectiveness of the proposed control scheme under two typical collision-free trajectories.

Published
2024

3. On the shock wave boundary layer interaction in slightly-rarefied gas

Author

Liu, Hualin, Li, Qi, Chen, Weifang, and Wu, Lei

Subjects
Physics - Fluid Dynamics
Abstract

The shock wave and boundary layer interaction (SWBLI) plays an important role in the design of hypersonic vehicles. However, discrepancies between the numerical results of high-temperature gas dynamics and experiment data have not been fully addressed. It is believed that the rarefaction effects are important in SWBLI, but the systematic analysis of the temperature-jump boundary conditions and the role of translational/rotational/vibrational heat conductivities are lacking. In this paper, we derive the three-temperature Navier-Stokes-Fourier (NSF) equations from the gas kinetic theory, with special attention paid to the components of heat conductivity. With proper temperature-jump boundary conditions, we simulate the SWBLI in the double cone experiment. Our numerical results show that, when the three heat conductivities are properly recovered, the NSF equations can capture the position and peak value of the surface heat flux, in both low- and high-enthalpy inflow conditions. Moreover, the separation bubble induced by the separated shock and the reattachment point induced by impact between transmitted shock and boundary layer are found to agree with the experimental measurement.

Published
2023

7. Nonlinear Coupled Constitutive Relations for Multi-species Gas Flow with Translational, Rotational and Vibrational Modes

Author

Zeng, Shuhua, Yang, Junyuan, Yao, Shaobo, Zhao, Wenwen, Chen, Weifang, Ceccarelli, Marco, Series Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, Agrawal, Sunil K., Advisory Editor, and Zhou, Kun, editor

Published
2024
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8. Research on Constitutive Model of Stiffness and Damping of Nitrile Butadiene Rubber

Author

Chen, Kaijie, Chen, Weifang, Zhou, Yanfeng, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Rui, Xiaoting, editor, and Liu, Caishan, editor

Published
2024
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9. Study of Hysteresis Characteristics of Marine Dampers Under Shock Environment

Author

Zhou, Yanfeng, Wang, Dan, Qiu, Zhonghui, Chen, Kaijie, Chen, Weifang, Zhu, Rupeng, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Rui, Xiaoting, editor, and Liu, Caishan, editor

Published
2024
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10. Nonlinear Dynamic Characteristics Analysis of Diaphragm Coupling Rotor System with Crack Fault

Author

Nong, Su, Chen, Weifang, Zhang, Ning, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Rui, Xiaoting, editor, and Liu, Caishan, editor

Published
2024
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11. Simulation and Experiment of a Novel Vibration Reduction Unit Based on Piezoelectric Shunt Damping

Author

Xu, Penghang, Wang, Dan, Chen, Weifang, Zhu, Rupeng, Ding, Jiawei, Yang, Shuying, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Rui, Xiaoting, editor, and Liu, Caishan, editor

Published
2024
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15. Simulation and Experimental Analysis of Stiffness and Damping of the Waist Type Diaphragm Coupling

Author

Hong Yun, Wang Dan, Nong Su, Zhu Rupeng, and Chen Weifang

Subjects
Diaphragm coupling, Finite element, Stiffness, Damping, Mechanical engineering and machinery, TJ1-1570
Abstract

The stiffness and damping characteristics of the diaphragm coupling are the basis for analyzing the vibration characteristics of the shafting system with the diaphragm coupling. Based on Ansys finite element simulation software, considering contact nonlinearity and large deformation effects, this study simulates and analyzes the torsional, axial, angular and radial static stiffness characteristics and torsional and axial dynamic characteristics of the diaphragm coupling, and analyzes the influence of the diaphragm structure parameters such as the diameter of the bolt hole distribution circle, the diameter of the bolt hole, the minimum width of the diaphragm and the thickness of the diaphragm on the static stiffness. Finally, static, dynamic torsion and axial tension tests are carried out to verify the correctness of the simulation results. The results show that the diameter of the bolt hole distribution circle and the thickness of the diaphragm have a greater influence on the anisotropic stiffness of the diaphragm. The dynamic model of the diaphragm coupling can be better established through the quasi elliptic function. The nonlinear stiffness and the equivalent damping coefficient changes in a period of the diaphragm vibration can be obtained.

Published
2024
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25. Computation of Hypersonic Transitional Flows Over Cones Using Gas-Kinetic Scheme Coupled with the Turbulence Model

Author

Li, Chengrui, Liu, Hualin, Jiang, Zhongzheng, Chen, Weifang, 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, Oneto, Luca, 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, Lee, Sangchul, editor, Han, Cheolheui, editor, Choi, Jeong-Yeol, editor, Kim, Seungkeun, editor, and Kim, Jeong Ho, editor

Published
2023
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26. Aerothermodynamic Shape Optimization of a Hypersonic Lifting Body

Author

Li, Haoge, Li, Chengrui, Chen, Weifang, Zhao, Wenwen, 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, Oneto, Luca, 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, Lee, Sangchul, editor, Han, Cheolheui, editor, Choi, Jeong-Yeol, editor, Kim, Seungkeun, editor, and Kim, Jeong Ho, editor

Published
2023
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27. Experimental Validation of Nonlinear Coupled Constitutive Relations in Continuum Flows

Author

Zeng, Shuhua, Qiu, Yunlong, Jiang, Zhongzheng, Chen, Weifang, 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, Oneto, Luca, 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, Lee, Sangchul, editor, Han, Cheolheui, editor, Choi, Jeong-Yeol, editor, Kim, Seungkeun, editor, and Kim, Jeong Ho, editor

Published
2023
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40. Controlling reactions during heavy metal leaching from municipal solid waste incineration fly ash

Author

Chen Weifang, Wang Yegui, Hu Minzhu, Li Yonglun, and Fang Guilin

Subjects
characterization, toxicity characteristics leaching procedure, minteq, precipitation/dissolution, Chemistry, QD1-999
Abstract

This research aimed to characterize the physical and chemical properties of municipal solid waste (MSW) incineration fly ash, as well as to investigate the leaching of heavy metals during toxicity characteristics leaching procedure (TCLP) process. To understand the leaching behaviour, concentrations of heavy metals, chloride, sulphate and calcium at various leaching, time was monitored together with pH of the leaching solution. Results showed that the chemical compositions of fly ashes led to differences in leaching environment. For the two fly ashes under study, one resulted in a leaching environment with pH of 10–12 while the other had pH about 6–7. Based on pH, anions and cations concentrations, Minteq software was employed to investigate the speciation of heavy metals. Results showed that the shift in precipitation/dissolution balance of carbonate and hydroxides of heavy metals could explain the fluctuation in metal concentrations during the leaching process, which indicates that leaching was probably controlled by these reactions. On the other hand, addition of EDTA changed the controlling reactions. Chelating reactions between heavy metals and EDTA led to much higher leaching toxicity due to the presence of heavy metals, showing that the presence of chelating organics in natural environment may facilitate heavy metal leaching.

Published
2023
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