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Accurate closed-form flutter eigensolutions of three-dimensional composite laminates with shear deformation
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作者 Dezhuang PAN Yufeng XING 《Chinese Journal of Aeronautics》 2026年第1期230-246,共17页
According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing ... According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing differential equations are derived by the Hamilton's variational principle,and then solved by the iterative Separation-of-Variable(i SOV)method,which are applicable to arbitrary combinations of homogeneous Boundary Conditions(BCs).However,only the simply-support,clamped and cantilever panels are considered in this work for the sake of clarity.With the closed-form eigensolutions,the flutter frequency,flutter mode and flutter boundary are presented,and the effect of shear deformation and aerodynamic damping on flutter frequencies is investigated.Besides,the relation between panel energy and the work of aerodynamic load is discussed.The numerical comparisons reveal the following.(A)The flutter eigenvalues obtained by the present method are accurate,validated by the Finite Element Method(FEM)and the Galerkin method.(B)When the span-chord ratio is larger than 3,simplifying a 3D panel to 2D(two-dimensional)panel is reasonable and the relative differences of the flutter points predicted by the two models are less than one percent.(C)The reciprocal relationship between the mechanical energy of the panel and the work done by aerodynamic load is verified by using the present flutter eigenvalues and modes,further indicating the high accuracy of the present solutions.(D)The coupling of shear deformation and aerodynamic damping prevents frequency coalescing. 展开更多
关键词 Closed-form eigensolutions The first-order piston theory The Mindlin plate theory three-dimensional panel flutter Separation-of-variable method
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融合Voronoi骨架图RRT算法的防疫机器人路径规划
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作者 伍锡如 吴思明 《电子测量技术》 北大核心 2026年第2期157-168,共12页
针对传统RRT算法在防疫机器人路径规划过程中搜索效率低,路径拐点多,环境适应性不足等问题,提出一种融合Voronoi骨架图的改进RRT路径规划算法。该算法使用广义Voronoi图从地图中构建离线骨架图,并利用Delaunay三角网的空外接圆特性对其... 针对传统RRT算法在防疫机器人路径规划过程中搜索效率低,路径拐点多,环境适应性不足等问题,提出一种融合Voronoi骨架图的改进RRT路径规划算法。该算法使用广义Voronoi图从地图中构建离线骨架图,并利用Delaunay三角网的空外接圆特性对其进行局部实时更新,确保骨架图在未知环境下的时效性;其次,基于骨架图快速获得初始启发式路径,生成关键路径节点作为RRT算法的子目标,在子目标节点之间引入椭圆约束和引力场偏置加速算法收敛,缩短规划时间;最后,设计一种基于双指针的自适应多段剪枝策略,实现路径平滑。仿真实验表明,所提出的算法相比于现有改进算法,在复杂场景下的平均采样节点数减少了55.57%,平均路径长度减少了6.45%,平均规划时间缩短了51.44%;证明了改进算法能够有效减少规划耗时,提高路径规划效率。 展开更多
关键词 防疫机器人 rrt算法 Voronoi骨架图 路径规划
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基于改进RRT算法的无人机航迹规划研究
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作者 姜香菊 杨彦新 《传感技术学报》 北大核心 2026年第1期86-92,共7页
针对无人机航迹规划过程中搜索时间过长,搜索到的路径存在大量冗余点和路径不平滑等问题,提出了一种改进的RRT算法。首先,算法运用并改进了目标偏置和动态变步长策略,能使随机树新节点能更快地朝目标点生长,其次,综合使用冗余点裁剪和3... 针对无人机航迹规划过程中搜索时间过长,搜索到的路径存在大量冗余点和路径不平滑等问题,提出了一种改进的RRT算法。首先,算法运用并改进了目标偏置和动态变步长策略,能使随机树新节点能更快地朝目标点生长,其次,综合使用冗余点裁剪和3次B样条曲线平滑路径的方法,将规划的路径进行平滑处理,得到更适合于无人机飞行的路线。最后将RRT算法、RRT*算法、双向RRT算法和所提出的改进RRT算法在二维和三维环境中进行了仿真实验。结果表明:所提出的改进RRT算法相较于其他三种算法,明显地减少了无人机的搜索时间,使搜索到的路径质量得到了极大提升,能很好地应用于无人机离线航迹规划等场合。 展开更多
关键词 无人机 航迹规划 rrt算法 目标偏置 冗余点裁剪
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基于双向区域RRT*的陪护机器人自主路径规划
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作者 刘树博 张志远 +3 位作者 李智 杨文龙 刘国权 罗先喜 《计算机工程与应用》 北大核心 2026年第2期347-358,共12页
为进一步提高路径规划算法的自主性及实用性,利用陪护机器人非质点模型,提出了基于双向区域RRT*(bidirectional regional RRT*,BR-RRT*)的自主路径规划(autonomous path planning,APP)算法。针对机器人平面中心(robot plane center,RPC... 为进一步提高路径规划算法的自主性及实用性,利用陪护机器人非质点模型,提出了基于双向区域RRT*(bidirectional regional RRT*,BR-RRT*)的自主路径规划(autonomous path planning,APP)算法。针对机器人平面中心(robot plane center,RPC)提出一种包括精英驻停点选择、高效搜索和路径优化的BR-RRT*自主高性能搜索(autonomous high-performance search,AHS)算法,实现对各RPC精英驻停点的路径规划;基于所得RPC精简平滑规划点集,提出最优行进区域获取(optimal travel area acquisition,OTAA)策略,为机器人提供最佳的行进区域。仿真结果表明,在指定机器人起始点和驻停点的前提下,所提BR-RRT*搜索算法在规划路径长度、迭代次数、规划时间和路径平滑度等方面均优于已报道算法;此外,在不同仿真环境及初始位置条件下,基于BR-RRT*的APP算法都能够自主选择合理的驻停点,实现机器人RPC规划路径优化并完成行进区域输出,体现出了较强鲁棒性。 展开更多
关键词 陪护机器人 非质点模型 自主路径规划(APP) BR-rrt*算法 双向目标
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基于改进Informed-RRT^(*)算法的无人机三维路径规划
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作者 张森 庞岩 周福亮 《系统工程与电子技术》 北大核心 2026年第2期660-668,共9页
为满足无人机(unmanned aerial vehicle,UAV)的三维路径规划需求,针对基于启发信息的快速扩展随机树(informed rapidly-exploring random tree,Informed-RRT^(*))算法初始可行路径较长、优化效率低的问题,本文采用动态人工势场来引导树... 为满足无人机(unmanned aerial vehicle,UAV)的三维路径规划需求,针对基于启发信息的快速扩展随机树(informed rapidly-exploring random tree,Informed-RRT^(*))算法初始可行路径较长、优化效率低的问题,本文采用动态人工势场来引导树的生长,降低初始路径的长度;将采样区域限制在分层椭球中,根据障碍物疏密调整采样概率;使用前馈神经网络和遗传算法优化重连区域半径,以降低运行时间。仿真结果显示,在障碍物稀疏和密集环境中,改进算法得到的路径质量相较于Informed-RRT^(*)算法以及A^(*)算法更优,验证了本文算法在无人机三维路径规划中的实用性。 展开更多
关键词 路径规划 无人机 Informed-rrt^(*) 动态人工势场
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基于改进APF-RRT*算法的机械臂路径规划研究
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作者 张鹏飞 章翔峰 +3 位作者 姜宏 马奔驰 李伟达 李坤 《现代电子技术》 北大核心 2026年第5期132-137,共6页
针对机械臂在复杂密集障碍物环境中的路径规划计算资源冗余及搜索效率不高等问题,文中提出一种GF-RRT*算法。首先,基于RRT*算法的核心思想,引入了人工势场法的目标引力,以增强路径搜索的导向性;其次,为了避免算法陷入局部最优解,将人工... 针对机械臂在复杂密集障碍物环境中的路径规划计算资源冗余及搜索效率不高等问题,文中提出一种GF-RRT*算法。首先,基于RRT*算法的核心思想,引入了人工势场法的目标引力,以增强路径搜索的导向性;其次,为了避免算法陷入局部最优解,将人工势场中的斥力场设为0,并设计了合理的碰撞检测机制,确保路径的安全性;此外,采用自适应节点生成优化机制,通过目标偏置策略和节点保留策略,有效减少了冗余节点并优化了路径采样过程;最后,借助三次B样条曲线对路径进行平滑处理,提升了路径的平滑性与实用性。仿真结果显示:相对于RRT算法、RRT*算法和APF-RRT*算法,GF-RRT*算法在路径长度上分别缩短了14.8%、10.6%、3.3%;运行时间分别下降了66.1%、57.7%、38.1%;节点数分别减少了73.2%、61.2%、46.7%;成功率也从87.6%升高到99.8%。通过ROCR6机械臂进行了实际环境实验,进一步验证了GF-RRT*算法在复杂密集障碍物环境下的良好表现,证明了该算法的可行性与有效性。 展开更多
关键词 rrt* 路径规划 机械臂 人工势场法 三次B样条曲线 自适应节点生成
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基于改进RRT算法的机械臂路径规划
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作者 李伟达 姜宏 +3 位作者 章翔峰 马奔驰 陈林 张鹏飞 《现代电子技术》 北大核心 2026年第1期157-162,共6页
针对快速扩展随机树(RRT)算法在机械臂路径规划中存在盲目搜索、计算时间长和冗余过程点比较多的问题,文中提出一种改进RRT算法。首先建立了固定采样函数,使得随机树的扩展更具有方向性;其次在自适应步长基础上加入动态目标偏置策略,通... 针对快速扩展随机树(RRT)算法在机械臂路径规划中存在盲目搜索、计算时间长和冗余过程点比较多的问题,文中提出一种改进RRT算法。首先建立了固定采样函数,使得随机树的扩展更具有方向性;其次在自适应步长基础上加入动态目标偏置策略,通过避免对局部区域过度搜索来提高收敛速度;最后利用固定采样点构造两棵随机树进行搜索,解决了算法扩张速度慢、收敛速度慢和盲目性的问题。简单环境下仿真结果表明:改进RRT算法相对于其他三种算法收敛时间分别减少了18.3%、30%、63.5%,路径长度分别缩短了14.1%、3.5%、41.6%;复杂环境下仿真结果表明:改进RRT算法相对于其他三种算法收敛时间分别减少了56.4%、43.3%、67.6%,路径长度分别缩短了16.1%、9.7%、34.2%。证明了改进后的算法在解决收敛速度慢和导向问题上的有效性,同时算法对复杂环境的适应性也更强。 展开更多
关键词 机械臂 路径规划 rrt算法 固定采样点 自适应步长 动态目标偏置
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基于TR-RRT算法的机械臂路径规划研究 被引量:1
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作者 宋仁捷 葛长青 +1 位作者 张东阳 苗建军 《沈阳理工大学学报》 2026年第1期17-23,共7页
为使机器人在复杂环境中高效执行任务,不仅要求其具备一定的算力基础,还需对路径规划算法进行有效优化。针对传统RRT算法用于复杂环境时存在计算量庞大及路径搜索效率低下等问题,提出一种目标约束RRT(target restraint RRT,TR-RRT)算法... 为使机器人在复杂环境中高效执行任务,不仅要求其具备一定的算力基础,还需对路径规划算法进行有效优化。针对传统RRT算法用于复杂环境时存在计算量庞大及路径搜索效率低下等问题,提出一种目标约束RRT(target restraint RRT,TR-RRT)算法,通过引入目标偏置、约束点引导、冗余点移除、动态步长、三次样条插值等策略,增强搜索能力,提高搜索效率,并对规划的路径进行平滑处理。为验证本文改进算法的性能,分别在二维、三维环境以及Gazebo环境中进行仿真实验,并与RRT、RRT-Connect、Informed-RRT^(*)算法进行比较,结果表明,本文改进算法在不同实验环境下的规划时间和路径长度及节点数量均优于对比算法,显著提高了路径规划的效率与稳定性。 展开更多
关键词 rrt算法 路径规划 目标偏置 动态步长
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基于改进APF-RRT的采摘机械臂运动路径规划 被引量:1
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作者 贾通 潘星宇 +3 位作者 钱振东 路红 李佩娟 张文 《农机化研究》 北大核心 2026年第2期173-182,共10页
在农业自动化快速发展的背景下,机械臂作为果园智能采摘作业的核心设备,其路径规划能力直接影响作业效率。然而果园环境复杂,传统人工势场法(APF)、快速随机搜索树(RRT)等路径规划算法在避障能力与运动平滑等方面仍存在一定不足,难以满... 在农业自动化快速发展的背景下,机械臂作为果园智能采摘作业的核心设备,其路径规划能力直接影响作业效率。然而果园环境复杂,传统人工势场法(APF)、快速随机搜索树(RRT)等路径规划算法在避障能力与运动平滑等方面仍存在一定不足,难以满足高效、安全的采摘需求。针对上述问题,提出了一种基于改进APF-RRT的路径规划算法。通过人工势场引导目标采样方向,增强路径趋近性,并引入非线性斥力场模型平滑势能分布,缓解斥力突变导致的局部震荡;同时,设计了基于最小障碍距离的动态步长策略,自适应调整采样粒度,以兼顾搜索效率和避障精度;通过障碍可行性检测方法去除冗余节点,结合三次B样条曲线实现路径平滑处理,提升路径连续性与执行稳定性。试验表明:在二维空间环境下,改进APF-RRT算法较RRT与APF-RRT算法分别缩短耗时78.75%、58.99%,路径长度减少16.88%、5.93%;在三维空间环境下,耗时缩短88.85%、65.20%,路径长度减少19.60%、5.61%;在机械臂仿真环境中,改进算法生成的路径更加平滑,转折点数量减少。研究结果验证了改进APF-RRT算法在复杂果园下具备良好的全局搜索与避障能力,以及较好的有效性与稳定性。 展开更多
关键词 采摘机械臂 路径规划 人工势场法 快速随机搜索树 改进APF-rrt算法 避障
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基于多策略改进RRT算法的无人船路径规划
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作者 陈小龙 李明智 +3 位作者 张橙橙 汪雅琴 赵弈超 李思奇 《舰船科学技术》 北大核心 2026年第4期155-161,共7页
针对快速扩展随机树(Rapidly-Exploring Random Tree,RRT)算法在结合无人船进行路径规划时存在规划时间长、路径冗余大、路径平滑度不符合欠驱动无人船航行要求等问题,提出一种改进RRT的无人船全局路径规划算法。算法中将贝叶斯优化算... 针对快速扩展随机树(Rapidly-Exploring Random Tree,RRT)算法在结合无人船进行路径规划时存在规划时间长、路径冗余大、路径平滑度不符合欠驱动无人船航行要求等问题,提出一种改进RRT的无人船全局路径规划算法。算法中将贝叶斯优化算法融入目标采样过程,增强目标点采样导向性;引入动态步长和双向贪心剪枝策略作为重要辅助,进一步提升算法效率和路径质量;得到初始路径后采用动态权重3次B样条曲线进一步平滑处理。最后在3种类型障碍物环境下进行仿真实验并与RRT、RRT^(*)算法进行对比。结果表明,改进RRT算法在规划时长、路径长度以及路径质量等方面有明显优势。改进后算法效率更高,路径平滑度更高,研究成果可为无人船自主航行提供参考。 展开更多
关键词 路径规划 改进rrt算法 贝叶斯优化 改进B样条曲线 无人船
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基于改进RRT算法的无人机航迹规划
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作者 揭光亮 张志安 潘孝斌 《机械与电子》 2026年第2期105-111,共7页
针对快速搜索随机树RRT算法在无人机航迹规划时搜索采样效率低、收敛速度慢且平滑性差等问题,提出一种改进RRT算法。改进算法采用快速行进法构建梯度上升场鲁棒引导采样策略,添加树结构引力拓展与局部拓扑特性,融合三次B样条曲线航迹平... 针对快速搜索随机树RRT算法在无人机航迹规划时搜索采样效率低、收敛速度慢且平滑性差等问题,提出一种改进RRT算法。改进算法采用快速行进法构建梯度上升场鲁棒引导采样策略,添加树结构引力拓展与局部拓扑特性,融合三次B样条曲线航迹平滑与改进DWA算法,提升算法的避障与规划能力。仿真实验表明,改进算法同比RRT*算法在二维简易环境、复杂环境及三维环境中的算法规划性能得到明显的提升。 展开更多
关键词 航迹规划 rrt*算法 无人机 FMM
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Three-dimensional line-of-sight-angle-constrained leader-following cooperative interception guidance law with prespecified impact time 被引量:3
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作者 Hao YOU Xinlong CHANG Jiufen ZHAO 《Chinese Journal of Aeronautics》 2025年第1期491-506,共16页
To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D lea... To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance law.First,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact time.Next,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the time-to-go.Then,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy consumption.Moreover,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering applications.Finally,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law. 展开更多
关键词 three-dimensional cooperative interception Leader-following missiles Prespecified impact time LOS-angle-constrained Fixed-time stability Global integral sliding mode
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基于改进RRT Star算法的农机路径规划
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作者 李想 张海峰 +2 位作者 白涛 魏建宝 蔡晓锦 《计算机技术与发展》 2026年第1期170-177,共8页
针对农机路径规划算法中效率低、随机性大、搜索时间长、迭代次数过多、规划出的路径冗长等问题,提出一种基于RRT Star的改进算法。首先,该算法建立目标方位判定准则实现采样空间优化;其次,在改进算法中引入权重动态步长调节函数,使扩... 针对农机路径规划算法中效率低、随机性大、搜索时间长、迭代次数过多、规划出的路径冗长等问题,提出一种基于RRT Star的改进算法。首先,该算法建立目标方位判定准则实现采样空间优化;其次,在改进算法中引入权重动态步长调节函数,使扩展过程具有目标性,并利用CantmullRom插值函数对路径进行平滑处理,根据农田道路情况模拟仿真环境,分别对RRT Star算法、RRT算法、多策略融合的RRT算法和文中算法在性能上进行测试。在三种仿真环境下,文中算法的平均生成时间、平均迭代次数、平均节点数分别较RRT算法提升了44.1%、33.3%、37.4%,较RRT Star算法提升了26.6%、21.2%、17.8%,较多策略融合的RRT算法提升了16.9%、19.0%、14.1%。实验结果表明,文中算法在农机路径规划中具有较高的执行效率和成功率。 展开更多
关键词 路径规划 快速扩展随机树 动态步长 rrt Star CantmullRom插值法
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Global Mapping of Three-Dimensional Urban Structures Reveals Escalating Utilization in the Vertical Dimension and Pronounced Building Space Inequality 被引量:1
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作者 Xiaoping Liu Xinxin Wu +6 位作者 Xuecao Li Xiaocong Xu Weilin Liao Limin Jiao Zhenzhong Zeng Guangzhao Chen Xia Li 《Engineering》 2025年第4期86-99,共14页
Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significan... Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significant gap in detailed and consistent data on 3D building space structures with global coverage due to the challenges inherent in the data collection and model calibration processes.In this study,we constructed a global urban structure(GUS-3D)dataset,including building volume,height,and footprint information,at a 500 m spatial resolution using extensive satellite observation products and numerous reference building samples.Our analysis indicated that the total volume of buildings worldwide in2015 exceeded 1×10^(12)m^(3).Over the 1985 to 2015 period,we observed a slight increase in the magnitude of 3D building volume growth(i.e.,it increased from 166.02 km3 during the 1985–2000 period to 175.08km3 during the 2000–2015 period),while the expansion magnitudes of the two-dimensional(2D)building footprint(22.51×10^(3) vs 13.29×10^(3)km^(2))and urban extent(157×10^(3) vs 133.8×10^(3)km^(2))notably decreased.This trend highlights the significant increase in intensive vertical utilization of urban land.Furthermore,we identified significant heterogeneity in building space provision and inequality across cities worldwide.This inequality is particularly pronounced in many populous Asian cities,which has been overlooked in previous studies on economic inequality.The GUS-3D dataset shows great potential to deepen our understanding of the urban environment and creates new horizons for numerous 3D urban studies. 展开更多
关键词 three-dimensional Global mapping Building volume Building height Building space inequality
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Three-dimensional reconstruction under computed tomography and myopectineal orifice measurement under laparoscopy for quality control of inguinal hernia treatment 被引量:1
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作者 Lei Zhang Jing Chen +7 位作者 Yu-Ying Zhang Lei Liu Han-Dan Wang Ya-Fei Zhang Jun Sheng Qiu-Shi Hu Ming-Liang Liu Yi-Lin Yuan 《World Journal of Gastrointestinal Endoscopy》 2025年第3期50-59,共10页
BACKGROUND Inguinal hernias are common after surgery.Tension-free repair is widely accepted as the main method for managing inguinal hernias.Adequate exposure,coverage,and repair of the myopectineal orifice(MPO)are ne... BACKGROUND Inguinal hernias are common after surgery.Tension-free repair is widely accepted as the main method for managing inguinal hernias.Adequate exposure,coverage,and repair of the myopectineal orifice(MPO)are necessary.However,due to differences in race and sex,people’s body shapes vary.According to European guidelines,the patch should measure 10 cm×15 cm.If any part of the MPO is dissected,injury to the nerves,vascular network,or organs may occur during surgery,thereby leading to inguinal discomfort,pain,and seroma formation after surgery.Therefore,accurate localization and measurement of the boundary of the MPO are crucial for selecting the optimal patch for inguinal hernia repair.AIM To compare the size of the MPO measured on three-dimensional multislice spiral computed tomography(CT)with that measured via laparoscopy and explore the relevant factors influencing the size of the MPO.METHODS Clinical data from 74 patients who underwent laparoscopic tension-free inguinal hernia repair at the General Surgery Department of the First Affiliated Hospital of Anhui University of Science and Technology between September 2022 and July 2024 were collected and analyzed retrospectively.Transabdominal preperitoneal was performed.Sixty-four males and 10 females,with an average age of 58.30±12.32 years,were included.The clinical data of the patients were collected.The boundary of the MPO was measured on three-dimensional CT images before surgery and then again during transabdominal preperitoneal.All the preoperative and intraoperative data were analyzed via paired t-tests.A t-test was used for comparisons of age,body mass index,and sex between the groups.In the comparative analysis,a P value less than 0.05 indicated a significant difference.RESULTS The boundaries of the MPO on 3-dimensional CT images measured 7.05±0.47 cm and 6.27±0.61 cm,and the area of the MPO was 19.54±3.33 cm^(2).The boundaries of the MPO during surgery were 7.18±0.51 cm and 6.17±0.40 cm.The errors were not statistically significant.However,the intraoperative BD(the width of the MPO,P=0.024,P<0.05)and preoperative AC(the length of the MPO,P=0.045,P<0.05)significantly differed according to sex.The AC and BD measurements before and during surgery were not significantly different according to age,body mass index,hernia side or hernia type(P>0.05).CONCLUSION The application of this technology can aid in determining the most appropriate dissection range and patch size. 展开更多
关键词 HERNIA INGUINAL Myopectineal orifice three-dimensional reconstruction Computed tomography Inguinal hernia
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基于人工势场法改进的双向RRT路径规划算法
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作者 郏泽萌 高焕兵 王雪秋 《电子科技》 2026年第3期47-56,共10页
针对RRT(Rapidly-exploring Random Tree)算法在机器人路径规划过程存在采样点随机性高、算法效率低、路径规划时间长以及规划路径冗长等问题,文中提出一种结合人工势场法的双向RRT路径规划算法。将传统RRT算法中单向扩展方式改为由起... 针对RRT(Rapidly-exploring Random Tree)算法在机器人路径规划过程存在采样点随机性高、算法效率低、路径规划时间长以及规划路径冗长等问题,文中提出一种结合人工势场法的双向RRT路径规划算法。将传统RRT算法中单向扩展方式改为由起点和终点同时进行扩展,在节点扩展时加入人工势场法进行引导,增加节点扩展的目的性。将固定步长改换为可变步长,使随机树可以更快地向目标点扩展。对生成路径进行剪枝处理,删除路径中的冗余节点,进一步缩短路径长度。利用MATLAB仿真平台在相同环境下对比所提改进算法与RRT-Connect算法、DRRT-Connect(Dynamic Rapidly-exploring Random Tree Connect)算法、GB(Goal-Biased)-RRT算法、A^(*)算法、PRM(Probabilistic Road Map)算法的路径规划效果。仿真结果表明,所提改进算法与其他改进算法相比最短路径缩短了7%,最短搜索时间降低了65%,提高了算法的规划效率。将所提算法应用于机器人,结果证明了其具有较强可行性。 展开更多
关键词 路径规划 rrt算法 人工势场法 rrt-Connect算法 改进双向rrt算法 贪心算法 可变步长 剪枝优化处理
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改进RRT的救援机械臂路径规划
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作者 董晋 苏东海 《机械工程师》 2026年第2期45-49,共5页
为了改善传统RRT算法在路径规划时搜索效率低、盲目性大的缺点,文中提出了一种改进的RRT算法。首先算法加入了目标偏置的思想,提出了建立虚拟目标点的方法,然后利用变步长的搜索策略,提高了算法的搜索效率。最终将得到的路径进行剪枝处... 为了改善传统RRT算法在路径规划时搜索效率低、盲目性大的缺点,文中提出了一种改进的RRT算法。首先算法加入了目标偏置的思想,提出了建立虚拟目标点的方法,然后利用变步长的搜索策略,提高了算法的搜索效率。最终将得到的路径进行剪枝处理,删除了冗余节点。考虑到机械臂的实际工作情况,将得到的路径用B样条曲线进行平滑处理,让机械臂更加平稳的运行。 展开更多
关键词 rrt 机械臂 变步长 目标偏置 剪枝 平滑处理
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Artificial intelligence-aided semi-automatic joint trace detection from textured three-dimensional models of rock mass 被引量:1
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作者 Seyedahmad Mehrishal Jineon Kim +1 位作者 Yulong Shao Jae Joon Song 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第4期1973-1985,共13页
It is of great importance to obtain precise trace data,as traces are frequently the sole visible and measurable parameter in most outcrops.The manual recognition and detection of traces on high-resolution three-dimens... It is of great importance to obtain precise trace data,as traces are frequently the sole visible and measurable parameter in most outcrops.The manual recognition and detection of traces on high-resolution three-dimensional(3D)models are relatively straightforward but time-consuming.One potential solution to enhance this process is to use machine learning algorithms to detect the 3D traces.In this study,a unique pixel-wise texture mapper algorithm generates a dense point cloud representation of an outcrop with the precise resolution of the original textured 3D model.A virtual digital image rendering was then employed to capture virtual images of selected regions.This technique helps to overcome limitations caused by the surface morphology of the rock mass,such as restricted access,lighting conditions,and shading effects.After AI-powered trace detection on two-dimensional(2D)images,a 3D data structuring technique was applied to the selected trace pixels.In the 3D data structuring,the trace data were structured through 2D thinning,3D reprojection,clustering,segmentation,and segment linking.Finally,the linked segments were exported as 3D polylines,with each polyline in the output corresponding to a trace.The efficacy of the proposed method was assessed using a 3D model of a real-world case study,which was used to compare the results of artificial intelligence(AI)-aided and human intelligence trace detection.Rosette diagrams,which visualize the distribution of trace orientations,confirmed the high similarity between the automatically and manually generated trace maps.In conclusion,the proposed semi-automatic method was easy to use,fast,and accurate in detecting the dominant jointing system of the rock mass. 展开更多
关键词 Automatic trace detection Digital joint mapping Rock discontinuities characterization three-dimensional(3D)trace network
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Dynamic modeling of a three-dimensional braided composite thin plate considering braiding directions 被引量:1
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作者 Chentong GAO Huiyu SUN +1 位作者 Jianping GU W.M.HUANG 《Applied Mathematics and Mechanics(English Edition)》 2025年第1期123-138,共16页
Currently,there are a limited number of dynamic models available for braided composite plates with large overall motions,despite the incorporation of three-dimensional(3D)braided composites into rotating blade compone... Currently,there are a limited number of dynamic models available for braided composite plates with large overall motions,despite the incorporation of three-dimensional(3D)braided composites into rotating blade components.In this paper,a dynamic model of 3D 4-directional braided composite thin plates considering braiding directions is established.Based on Kirchhoff's plate assumptions,the displacement variables of the plate are expressed.By incorporating the braiding directions into the constitutive equation of the braided composites,the dynamic model of the plate considering braiding directions is obtained.The effects of the speeds,braiding directions,and braided angles on the responses of the plate with fixed-axis rotation and translational motion,respectively,are investigated.This paper presents a dynamic theory for calculating the deformation of 3D braided composite structures undergoing both translational and rotational motions.It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications. 展开更多
关键词 three-dimensional(3D)braided composite braiding direction composite thin plate large overall motion dynamic model
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Three-dimensional models:from cell culture to Patient-Derived Organoid and its application to future liposarcoma research
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作者 SAYUMI TAHARA SYDNEY RENTSCH +4 位作者 FERNANDA COSTAS CASAL DE FARIA PATRICIA SARCHET ROMA KARNA FEDERICA CALORE RAPHAEL E.POLLOCK 《Oncology Research》 SCIE 2025年第1期1-13,共13页
Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma ... Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma pathobiology.Conventional cell culture-based research(2D cell culture)is still playing a pivotal role,while several shortcomings have been recently under discussion.In vivo,mouse models are usually adopted for pre-clinical analyses with expectations to overcome the issues of 2D cell culture.However,they do not fully recapitulate human dedifferentiated liposarcoma(DDLPS)characteristics.Therefore,three-dimensional(3D)culture systems have been the recent research focus in the cell biology field with the expectation to overcome at the same time the disadvantages of 2D cell culture and in vivo animal models and fill in the gap between them.Given the liposarcoma rarity,we believe that 3D cell culture techniques,including 3D cell cultures/co-cultures,and Patient-Derived tumor Organoids(PDOs),represent a promising approach to facilitate liposarcoma investigation and elucidate its molecular mechanisms and effective therapy development.In this review,we first provide a general overview of 3D cell cultures compared to 2D cell cultures.We then focus on one of the recent 3D cell culture applications,Patient-Derived Organoids(PDOs),summarizing and discussing several PDO methodologies.Finally,we discuss the current and future applications of PDOs to sarcoma,particularly in the field of liposarcoma. 展开更多
关键词 Cell culture LIPOSARCOMA Patient-Derived Organoid(PDO) SPHEROID three-dimensional(3D)cell culture
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