在国家全面推进实现乡村振兴和“双碳”目标的背景下,提升乡村建设品质与风貌特色成为核心任务。文章研究聚焦乡村参数化木结构装配式建筑设计展开研究,对国家政策和地方政策进行考察,并通过中国学术期刊全文数据库和Web of Science搜...在国家全面推进实现乡村振兴和“双碳”目标的背景下,提升乡村建设品质与风貌特色成为核心任务。文章研究聚焦乡村参数化木结构装配式建筑设计展开研究,对国家政策和地方政策进行考察,并通过中国学术期刊全文数据库和Web of Science搜集整理了国内外相关论文文献,借助CiteSpace文献工具对乡村装配式木结构参数化设计研究数据进行可视化分析。研究针对2000—2025年乡村建设研究趋势,提出在乡村振兴背景下利用Grasshopper和Revit等BIM技术探索乡村参数化建设新途径的设计策略,为乡村参数化木结构装配式建设发展提供参考依据。展开更多
Unmanned aircraft are highly vulnerable to crosswind-induced turbulence during complex maneuvers such as turning,which can significantly compromise control and reduce autopilot effectiveness.This paper presents a nove...Unmanned aircraft are highly vulnerable to crosswind-induced turbulence during complex maneuvers such as turning,which can significantly compromise control and reduce autopilot effectiveness.This paper presents a novel control strategy to improve the controllability of unmanned aircraft in challenging wind conditions.First,the equations of motion for the aircraft are reformulated as a system of stochastic differential equations,which are subsequently transformed into a deterministic form.By modeling turbulence as a Gaussian random process and incorporating it directly into the control system,the proposed method proactively compensates for the adverse effects of turbulence.The transformation is achieved using semi-invariant techniques.Second,the control problem is formulated as an optimization task,aiming to minimize the deviation between the actual and desired turn characteristics,specifically the angular velocity.Finally,a new numerical method with proven global convergence is employed to compute the optimal autopilot parameters.Simulation results using a medium-range unmanned aircraft model under continuous turbulent gusts demonstrate that the proposed method significantly outperforms existing approaches,ensuring both stability and precision in turbulent wind conditions.展开更多
This study explores the nonlinear resonance of a rotating solar sail membrane exposed to time-varying solar thermal and solar radiation pressure.The sail membrane is modeled using a cantilever membrane,applying the vo...This study explores the nonlinear resonance of a rotating solar sail membrane exposed to time-varying solar thermal and solar radiation pressure.The sail membrane is modeled using a cantilever membrane,applying the von Kármán theory for membrane large deflection.The membrane’s nonlinear equation is derived by employing the Lagrange equation while accounting for excitations from solar thermal and radiation pressure.The equation is solved via the Rayleigh-Ritz method.The bifurcation diagram of membrane motion is applied to reveal membrane resonance responses under different solar sail rotating frequencies.The displacement time history,phase portrait,Poincarémap,frequency spectrum,and the largest Lyapunov exponent are used to study nonlinear vibrations that occur near resonance regions.The results indicate that time-varying thermal loading excites membrane motions with multiple natural frequencies by the parametric resonance mechanics,leading to the onset of membrane chaotic motion.The membrane’s primary resonance is stimulated in harmonic oscillation by the time-varying radiation pressure.The divergence instability caused by thermal excitation is also illustrated by comparing the membrane’s vibration amplitude with and without thermal excitation.The membrane’s nonlinear vibration characteristics vary significantly with solar illumination angles,the membrane’s thermal expansion coefficients,and structural damping.展开更多
文摘在国家全面推进实现乡村振兴和“双碳”目标的背景下,提升乡村建设品质与风貌特色成为核心任务。文章研究聚焦乡村参数化木结构装配式建筑设计展开研究,对国家政策和地方政策进行考察,并通过中国学术期刊全文数据库和Web of Science搜集整理了国内外相关论文文献,借助CiteSpace文献工具对乡村装配式木结构参数化设计研究数据进行可视化分析。研究针对2000—2025年乡村建设研究趋势,提出在乡村振兴背景下利用Grasshopper和Revit等BIM技术探索乡村参数化建设新途径的设计策略,为乡村参数化木结构装配式建设发展提供参考依据。
基金co-supported by the Fund of Robot Technology Used for Special Environment Key Laboratory of Sichuan Province(No.22kftk01)the Key Research and Development Program of Heilongjiang,China(No.2024ZXJ07B05)the National Natural Science Foundation of China(No.92471103)。
文摘Unmanned aircraft are highly vulnerable to crosswind-induced turbulence during complex maneuvers such as turning,which can significantly compromise control and reduce autopilot effectiveness.This paper presents a novel control strategy to improve the controllability of unmanned aircraft in challenging wind conditions.First,the equations of motion for the aircraft are reformulated as a system of stochastic differential equations,which are subsequently transformed into a deterministic form.By modeling turbulence as a Gaussian random process and incorporating it directly into the control system,the proposed method proactively compensates for the adverse effects of turbulence.The transformation is achieved using semi-invariant techniques.Second,the control problem is formulated as an optimization task,aiming to minimize the deviation between the actual and desired turn characteristics,specifically the angular velocity.Finally,a new numerical method with proven global convergence is employed to compute the optimal autopilot parameters.Simulation results using a medium-range unmanned aircraft model under continuous turbulent gusts demonstrate that the proposed method significantly outperforms existing approaches,ensuring both stability and precision in turbulent wind conditions.
基金supported by the Science Fund of NPU-Duke China Seeds Program(Grant No.119003067)the CAST-BISEE Fund(Grant No.MC010175)+1 种基金the Project of National Natural Science Foundation of China(Grant No.12372233)the“111”project of China(Grant No.B17037).
文摘This study explores the nonlinear resonance of a rotating solar sail membrane exposed to time-varying solar thermal and solar radiation pressure.The sail membrane is modeled using a cantilever membrane,applying the von Kármán theory for membrane large deflection.The membrane’s nonlinear equation is derived by employing the Lagrange equation while accounting for excitations from solar thermal and radiation pressure.The equation is solved via the Rayleigh-Ritz method.The bifurcation diagram of membrane motion is applied to reveal membrane resonance responses under different solar sail rotating frequencies.The displacement time history,phase portrait,Poincarémap,frequency spectrum,and the largest Lyapunov exponent are used to study nonlinear vibrations that occur near resonance regions.The results indicate that time-varying thermal loading excites membrane motions with multiple natural frequencies by the parametric resonance mechanics,leading to the onset of membrane chaotic motion.The membrane’s primary resonance is stimulated in harmonic oscillation by the time-varying radiation pressure.The divergence instability caused by thermal excitation is also illustrated by comparing the membrane’s vibration amplitude with and without thermal excitation.The membrane’s nonlinear vibration characteristics vary significantly with solar illumination angles,the membrane’s thermal expansion coefficients,and structural damping.
