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Efficient optimization method for variable-specific-impulse low-thrust trajectories with shutdown constraint

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Science China(Technological Sciences) 2022年第3期65卷 581-594页

作者： JIA FeiDa QIAO Dong HAN HongWei LI XiangYu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China

This paper develops a sequential convex programming(SCP)-based method to solve the minimum-fuel variable-specific-impulse low-thrust transfer problem considering shutdown constraint,with emphasize on improving the computational efficiency.The variable parameter engine is more applicable for many low-thrust scenarios,therefore,both a continuously variable model and a ladder variable model are adopted.First,the original problem is convexified by processing the constraint feasible domain,which is composed of the nonlinear dynamic equations and second-order equality constraint,into convex sets.Then,the approximation is generated to close the optimal solution of the low-thrust problem by iteratively solving the convexified subproblem.Moreover,the switching self-detection and adaptive node refinement methods are presented,which can improve the accuracy of the solution and accelerate the convergence during the approximation process and is especially necessary and effective in the scenarios with shutdown constraint.In numerical simulations,the comparison with the homotopic approach shows that the proposed method only needs 4%computational time as that of the homotopic approach,and two variable-specificimpulse examples further demonstrate the effectiveness and efficiency of the proposed method.

关键词： low-thrust trajectory variable-specific-impulse shutdown constraint sequential convex programming switching self-detection and adaptive node refinement

Analysis on Impact of Rumors on Electricity Market Operations with Volatile Renewables

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Journal of Modern Power Systems and Clean Energy 2022年第3期10卷 755-765页

作者： xiangyu Ma Zhiyi li Huanhai Xin College of Electrical Engineering Zhejiang UniversityHangzhou 310063China Polytechnic Institute Zhejiang UniversityHangzhou 310063China IEEE NGICS Platform Zhejiang UniversityHangzhou 310027China

In recent years,rumors have been shown to have a significant impact on individual and societal activities.As renewables play an increasingly significant role in electricity markets,certain rumors may deviate the bidding behavior of market entities and eventually affect the performance of market operations.In this study,we attempt to reveal the general threats caused by rumors in the context of day-ahead electricity markets considering the integration of volatile renewables.First,we model the propagation of rumors in the societal system considering the weight of propagation resistance,which principally reflects the communication accessibility of market entities.Second,we develop an integrated two-layer network model to uncover the inherent coupling mechanism between market operations and rumor propagation.In particular,the role of electricity market operations on rumor propagation is characterized by changes in the truthfulness of rumors associated with electricity prices.The rumors,in turn,affect the bidding quantities of market entities in electricity market operations.Finally,numerical experiments are conducted on modified IEEE 6-bus and 118-bus systems.The results demonstrate the potential threats of rumors to electricity market operations with different penetration levels of renewables.

关键词： Electricity market integrated network modeling renewables rumor propagation

Analytical configuration uncertainty propagation of geocentric interferometric detection constellation

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Astrodynamics 2023年第3期7卷 271-284页

作者： Dong Qiao Xingyu Zhou xiangyu li School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China

Long-term configuration stability is essential for an interferometric detection constellation(IDC),which is closely related to initial uncertainty.Therefore,it is vital to evaluate the uncertainty and characterize the configuration stability.In this study,an analytical method was developed for the configuration uncertainty propagation of a geocentric triangular IDC.The angular momentum and the argument latitude were found to be significantly affected by the initial uncertainty and were selected as the core variables.By averaging the perturbation in one revolution,an analytical solution was proposed for propagating the core orbital elements in one revolution.Subsequently,the analytical solution of the orbit elements during the mission period is obtained by multiplying the solutions in iterative revolutions.The relationship between the selected orbital elements and the configuration stability parameters was established using an analytical solution.The effects of the initial uncertainty in different directions on the configuration and stable domains were studied.Simulations show that the developed method is highly efficient and accurate in predicting the configuration stability.The relative error with respect to the Monte Carlo simulations was less than 3%with a time consumption of 0.1%.The proposed method can potentially be useful for constellation design and stability analysis.

关键词： geocentric interferometric detection constellation(IDC) configuration stability configuration uncertainty propagation stable parameters

Novel Intranasal Mask Provides Potent Protection against Viral Aerosols

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Bulletin of the Chinese Academy of Sciences 2023年第4期37卷 245-246页

作者： LI XiangYu Public Information Officer Institute of Process Engineering Chinese Academy of Sciences

Researchers from the Institute of Process Engineering(IPE)of the Chinese Academy of Sciences have developed a novel intranasal mask to protect the respiratory tract from viral aerosols.It showed satisfactory protectio... 详细信息

关键词： nasal respiratory satisfactory

Stability of Multiplier Ideal Sheaves

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Chinese Annals of Mathematics,Series B 2022年第5期43卷 819-832页

作者： Qi'an GUAN Zhenqian li xiangyu ZHOU School of Mathematical Sciences Peking UniversityBeijing 100871China Siwuge Technology Co.Ltd. Tianfu Life Science ParkChengdu 610093China Institute of Mathematics AMSSand Hua Loo-Keng Key Laboratory of MathematicsChinese Academy of SciencesBeijing100190China

In the present article, the authors find and establish stability of multiplier ideal sheaves, which is more general than strong openness.

关键词： Plurisubharmonic function Multiplier ideal sheaf Strong openness and stability Coherent analytic sheaf L^(2)estimate

Researchers Develop a Novel Drypowder Inhaled Vaccine Platform

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Bulletin of the Chinese Academy of Sciences 2023年第4期37卷 243-244页

作者： LI XiangYu Public Information Officer Institute of Process Engineering Chinese Academy of Sciences

Researchers from the Institute of Process Engineering(IPE)of the Chinese Academy of Sciences have proposed a new“nano-micro composite”concept for vaccine delivery.Based on this idea,they have developed a single-dose,dry-powder,inhalable vaccine platform using nano-micro composite multilevel structures,which has been successfully prepared in the laboratory.

关键词： composite powder Researcher

Reliability-based robust geotechnical design of braced excavations considering multiple failure modes

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Underground Space 2023年第2期9卷 43-52页

作者： li Hong xiangyu Wang Wengang Zhang School of Civil Engineering Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing 400045China School of Design and the Built Environment Curtin UniversityBentley 6102Western AustraliaAustralia

Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced reliability-based robust geotechnical design method,which can consider multiple failures and uncertainty of statistical information.A universal design sample was conducted to verify the necessity of considering the uncertainty of statistical information.Ultimate limit state and serviceability limit state of braced excavations were defined,and point estimating method was used to evaluate the standard deviation of failure probabilities.Two-objective and three-objective optimization models were developed to illustrate the application of proposed methods in detail.In addition,the performance of optimization algorithms and further application of multiple-objective models were discussed.The results from this study indicate that the proposed method has a good performance in determining the optimal design with reasonable robustness and cost.New algorithms have higher efficiency in solving nonlinear and multiple-objective optimization problems than the 2nd Non-dominated sorting genetic algo-rithm.This study can guide the design of retaining systems of braced excavations in clay.

关键词： Robust geotechnical design Multi-objective optimization Multiple failure modes Genetic algorithm Statistical uncertainty

Research on Energy Efficiency Characteristics of Mining Shovel Hoisting and Slewing System Driven by Hydraulic-Electric Hybrid System

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Chinese Journal of Mechanical Engineering 2023年第6期36卷 197-211页

作者： xiangyu Wang Lei Ge Yunhua li Long Quan College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Mining shovel is a crucial piece of equipment for high-efficiency production in open-pit mining and stands as one of the largest energy consumption sources in mining.However,substantial energy waste occurs during the descent of the hoisting system or the deceleration of the slewing platform.To reduce the energy loss,an innovative hydrau-lic-electric hybrid drive system is proposed,in which a hydraulic pump/motor connected with an accumulator is added to assist the electric motor to drive the hoisting system or slewing platform,recycling kinetic and potential energy.The utilization of the kinetic and potential energy reduces the energy loss and installed power of the min-ing shovel.Meanwhile,the reliability of the mining shovel pure electric drive system also can be increased.In this paper,the hydraulic-electric hybrid driving principle is introduced,a small-scale testbed is set up to verify the feasibil-ity of the system,and a co-simulation model of the proposed system is established to clarify the system operation and energy characteristics.The test and simulation results show that,by adopting the proposed system,compared with the traditional purely electric driving system,the peak power and energy consumption of the hoisting electric motor are reduced by 36.7%and 29.7%,respectively.Similarly,the slewing electric motor experiences a significant decrease in peak power by 86.9%and a reduction in energy consumption by 59.4%.The proposed system expands the application area of the hydraulic electric hybrid drive system and provides a reference for its application in over-sized and super heavy equipment.

关键词： Mining shovel Hoisting and slewing system Hydraulic-electric hybrid drive Energy saving

GenAI4Sustainability:GPT and Its Potentials For Achieving UN’s Sustainable Development Goals

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IEEE/CAA Journal of Automatica Sinica 2023年第12期10卷 2179-2182页

作者： Rui Wang Chaojie li xiangyu li Rong Deng Zhaoyang Dong IEEE the School of Electrical Engineering and Telecommunications UNSWNSW 2052AU the School of Photovoltaic and Renewable Energy Engineering UNSWNSW 2052AU the School of Electrical and Electronic Engineering Nanyang Technological University50 Nanyang AveSingapore

SINCE 2015,17 Sustainable Development Goals(SDGs)have been understood as more promising blueprints for a peaceful,prosperous,and sustainable future[1]which are formulated to seek a framework to address global challeng... 详细信息

关键词： inequality pollution formulated