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251 results on '"Zhang, Kunfeng"'

1. A Friction Disturbance Compensation Method for Electromechanical Actuator Based on Fractional Order Adaptive Neural Network

Author

Chen Yufeng, Xu Xiaolu, Zhang Jinpeng, Zhang Kunfeng, Yue Qiang, Zhang Wenjing

Subjects
electromechanical actuator, friction, lugre model, fractional order control, adaptive control, radial basis function neural network, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

Friction torque disturbance affects the tracking performance of electromechanical actuator servo system, bringing position and speed tracking errors, and even may leading to instability of the servo system. Aiming at the problem of poor tracking performance of electromechanical actuator servo system under friction torque disturbance, a FOANN friction compensation algorithm is proposed to estimate and compensate the friction torque. Firstly, base on LuGre friction model, a electromechanical actuator model is established, and the unmeasured state variable in the LuGre model is estimated by radial basis function neural network. Secondly, a FOANN controller is designed, and the stability of corresponding closed-loop system is proved by Lyapunov stability theory. Finally, through simulation and experimental platform, the dynamic performance of FOANN is compared with those of traditional PD and MRAC. The simulation and experimental results show that, with the proposed FOANN friction torque compensation algorithm, the tracking errors of both position and velocity of electromechanical actuator servo system are greatly reduced. FOANN algorithm can effectively estimate and compensate friction torque, reduce the impact of friction disturbance and enhance the dynamic performance of the servo system.

Published
2024
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6. Research progress and prospect of CO2-water-rock interaction on petrophysical properties of CO2 geological sequestration

Author

YANG Shugang, CAI Mingyu, ZHANG Kunfeng, CAO Dongdong, ZHAO Xinglei, and LIU Shuangxing

Subjects
co2 geological sequestration, co2-water-rock interaction, porosity, permeability, wettability, mechanical property, Chemical technology, TP1-1185, Petroleum refining. Petroleum products, TP690-692.5, Geology, QE1-996.5
Abstract

The CO2-water-rock interaction is the core issue of CO2 geological sequestration. The injection of CO2 disrupts the chemical balance of rock-formation water， and the changes in the chemical properties of formation water， primary mineral dissolution， and secondary mineral precipitation will lead to changes in the physical properties of reservoir and caprock， such as porosity， wettability， and mechanical properties and thus directly affect the CO2 injection capacity， sequestration efficiency， and sequestration security and stability. Based on the mechanism of CO2-water-rock interaction， this paper systematically expounds on the research progress of the effects of CO2-water-rock interaction on porosity， permeability， wettability， and mechanical properties of formation rocks. The results show that the change in rock porosity and permeability caused by CO2-water-rock interaction is closely related to its initial porosity and permeability characteristics and mineral composition， and the change of rock porosity and permeability characteristics directly affects the injection capacity and sequestration potential of the reservoir and the sealing capacity of the caprock. The change in wettability is related to the initial hydrophilic and oil-philic characteristics. The CO2-water-rock interaction usually weakens the water wettability of the hydrophilic rocks and enhances that of the oil-philic rocks， thus affecting the microscopic distribution and seepage characteristics of the multiphase fluids in the pores of the rocks. Due to the dissolution of cement and the formation of dissolution holes， the CO2-water-rock interaction will cause rock damage， and the mechanical parameters such as compressive strength， tensile strength， and elastic modulus will decrease. To a certain extent， the security of sequestration is affected. Under the setting of carbon neutrality， the CO2-water-rock interaction and rock physical property response under the scenarios of micro-nano-scale pore， deep microbial mediation， impure CO2 or industrial tail gas injection， and full sequestration cycle still need to be further studied.

Published
2023
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18. A Joint Detection and Recognition Algorithm of Non-cooperative Communication Signal Based on Improved YOLOv3

Author

Zhang, Kunfeng, Sun, Kuanyuan, Yi, Dengbiao, Duan, Yongsheng, Meng, Xianghao, Chinese Institute of Command and Control, 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, and Zhang, Junjie James, Series Editor

Published
2022
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