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| 1 | 一种新型并联灌注机器人运动学分析和多目标优化显示文摘针对大型航天器蜂窝结构灌注需求,提出一种新型串并混联灌注机器人机构,主要对并联机构进行分析研究。首先,对3PSS-PU并联机构进行了运动学分析,建立了运动学反解数学模型和雅可比矩阵;其次,确定了影响机构工作空间主要因素的约束条件,求解出了机构的工作空间;然后,建立了机构的刚度模型,求得机构在运动过程中的刚度变化分布;最后,利用遗传算法,以工作空间和全局刚度为目标对机构结构参数进行优化分析,确定了最终的机构尺寸参数,为蜂窝灌注机器人应用奠定基础。 | 杨会 房海蓉 李典 方跃法 | 2018 | 北京航空航天大学学报2018,44,3: | 8 |
| 2 | 一种新型并联灌注机器人动力学分析与仿真显示文摘针对用于大型航天器防热层灌注的3PSS?PU并联灌注机器人,进行动力学分析与仿真验证。建立并联机构逆运动学模型,通过对数学模型求导,分别求解并联机构驱动滑块和连杆的速度、加速度与动平台速度、加速度之间的映射关系,得到并联机构的支链雅克比矩阵。在此基础上,利用虚功原理建立并联机构的动力学模型,并通过Mathematica和Adams软件,在动平台沿zb轴移动和沿yb轴转动2种运动轨迹下,分别对比3个驱动滑块的位移、速度、加速度以及驱动力等运动参数的理论曲线和仿真变化曲线。研究结果表明:所建立并联机构运动学和动力学模型正确,并联机构不仅具有良好的移动性能,而且具有较好的转动性能,为并联灌注机构动力学性能进一步研究以及控制系统的设计提供了理论依据。 | 杨会 房海蓉 方跃法 | 2019 | 中南大学学报(自然科学版)2019,50,9: | 4 |
| 3 | Dimensional synthesis of a novel 5-DOF reconfigurable hybrid perfusion manipulator for large-scale spherical honeycomb perfusion显示文摘A novel hybrid perfusion manipulator(HPM)with five degrees of freedom(DOFs)is introduced by combining the 5PUS-PRPU(P,R,U and S represent prismatic,revolute,universal and spherical joint,respectively)parallel mechanism with the 5PRR reconfigurable base to enhance the perfusion efficiency of the large-scale spherical honeycomb thermal protection layer.This study mainly presents the dimensional synthesis of the proposed HPM.First,the inverse kinematics,including the analytic expression of the rotation angles of the U joint in the PUS limb,is obtained,and mobility analysis is conducted based on screw theory.The Jacobian matrix of 5PUS-PRPU is also determined with screw theory and used for the establishment of the objective function.Second,a global and comprehensive objective function(GCOF)is proposed to represent the Jacobian matrix’s condition number.With the genetic algorithm,dimensional synthesis is conducted by minimizing GCOF subject to the given variable constraints.The values of the designed variables corresponding to different configurations of the reconfigurable base are then obtained.Lastly,the optimal structure parameters of the proposed 5-DOF HPM are determined.Results show that the HPM with the optimized parameters has an enlarged orientation workspace,and the maximum angle of the reconfigurable base is decreased,which is conducive to improving the overall stiffness of HPM. | Hui YANG Hairong FANG Yuefa FANG Xiangyun LI | 2021 | Frontiers of Mechanical Engineering2021,16,1: | 2 |
| 4 | Analytical design of effective thermal conductivity for fluid-saturated prismatic cellular metal honeycombs显示文摘A comparative optimal design of fluid-saturated prismatic cellular metal honeycombs(PCMHs) having different cell shapes is presented for thermal management applications. Based on the periodic topology of each PCMH, a unit cell(UC) for thermal transport analysis was selected to calculate its effective thermal conductivity. Without introducing any empirical coefficient, we modified and extended the analytical model of parallel–series thermal–electric network to a wider porosity range(0.7 ~ 0.98) by considering the effects of two-dimensional local heat conduction in solid ligaments inside each UC. Good agreement was achieved between analytical predictions and numerical simulations based on the method of finite volume. The concept of ligament heat conduction efficiency(LTCE) was proposed to physically explain the mechanisms underlying the effects of ligament configuration on effective thermal conductivity(ETC).Based upon the proposed theory, a construct strategy was developed for designing the ETC by altering the equivalent interaction angle with the direction of heat flow: relatively small average interaction angle for thermal conduction and relatively large one for thermal insulation. | Wenbin Wang Xiaohu Yang Bin Han Qiancheng Zhang Xiangfei Wang Tianjian Lu | 2016 | Theoretical & Applied Mechanics Letters2016,6,2: | 2 |
| 5 | Improving the thermal shock resistance of ceramics by crack arrest blocks显示文摘Ceramics used in the high temperature environment are inevitably subjected to sudden temperature change, which may lead to catastrophic thermal shock failure due to the intrinsic brittleness of ceramics. In this paper, an experimental platform is designed to realize the in-situ observation during the thermal shock experiments. Experimental results show that all the cracks initiate from one of the edge midpoints and propagate to another one for square specimens. Such experimental observation is consistent with the maximum tensile stress zone with the maximum temperature gradient given by the finite element method(FEM). The different crack modes resulting from different heating rates after thermal shock experiments are observed and analyzed. Comparison between different clamping methods is conducted to study the effects of boundary conditions on the thermal shock experiments. Furthermore, in order to improve the thermal shock performance of alumina ceramics, crack arrest blocks are added near the edge midpoint. The thickness, shape and arrangement of the blocks are systematically investigated to understand the mechanism of improvement of thermal shock resistance. | WANG Yan Wei XIA Biao SU Hong Hong CHEN Hang FENG Xue | 2016 | Science China(Technological Sciences)2016,59,6: | 0 |
| 6 | 一种大型球冠蜂窝灌注机器人结构设计与分析显示文摘针对航天器中大型球冠蜂窝防热层结构自动灌注问题,设计了一种3自由度混联灌注机器人,并建立灌注机器人的机构模型.该混联机器人结构紧凑、驱动简单、占地面积小,末端灌注装置始终垂直于球冠面移动,有利于蜂窝结构的灌注;采用多机器人操作模式,提高了灌注效率.通过建立运动学约束方程,分析了机构的运动学反解,同时建立了机构的速度雅可比矩阵,在此基础上,利用一种高效的数值正解算法分析了运动学正解,并通过对位置正解的分析得出灌注机器人的整个工作空间,并基于速度雅可比矩阵对机构的灵巧性和奇异性进行分析.结果表明灌注机器人能够实现对蜂窝结构的精确定位,且工作空间能够达到整个球冠面,满足蜂窝防热层结构的灌注要求. | 杨会 房海蓉 周昌春 曲海波 | 2017 | 北京交通大学学报2017,41,1: | 0 |