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针对目前气动人工肌肉数学模型建模过程较为复杂的问题,提出一种气动人工肌肉的实验模型辨识方法。以气动人工肌肉-质量系统为实验对象,对其输入气压与气动肌肉收缩量之间的关系模型进行实验辨识研究。采用欠阻尼二阶系统来描述气动人工肌肉充气与排气过程的动态响应,并利用实验数据对模型参数进行辨识。最后基于辨识得到的模型进行气动人工肌肉的位置控制,实验结果验证了模型的有效性。 相似文献
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某气动单向弯曲关节柔性手指由人工肌肉和弹性钢板并联组成,弯曲变形时具有大变形和非线性特点,静力学模型十分复杂且不利于控制。为便于实时精准控制,进一步简化手指静力学模型,并对其静力学特性进行实验研究。搭建静力学实验平台,对单肌肉驱动和双肌肉驱动两种不同驱动类型的柔性手指在不同限位面和等外载荷工况下分别进行夹持力和弯曲角度的对比实验。利用MATLAB对实验数据进行处理分析,得到手指夹持力和弯曲角度的经验模型。结果表明:气动单向弯曲关节柔性手指夹持力与弯曲角度、工作气压和驱动肌肉数目之间存在非线性关系;与静力学理论模型相比,该经验模型具有更高的精度,夹持力模型预测误差能控制在0.76 N内,弯曲角度模型误差可控制在6.9°内。 相似文献
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采用自主研发的气动柔性关节,仿人手外形研制了一种新型柔性灵巧手。该机械手为人手的1.5倍,每根柔性手指由两个气动柔性关节组成,通过调节关节内气压控制手指形变实现机械手抓取物体。利用三维运动捕捉系统和机械手气动实验平台进行了不同气压下柔性手指的运动学实验,分析了机械手工作空间,并进行了机械手抓取实验。实验结果表明:该机械手具有较好的柔性和物形适应性可实现多种抓取模式和完成不同类型物体抓取;五指握取时可抓持最大物体直径为220 mm,最小物体直径为50 mm,质量为1 kg的物品。 相似文献
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对薄壁铝合金管材的充液弯曲进行数值模拟与实验研究;讨论内压与管端约束对成形结果的影响;分析在管端约束的情况下充液弯曲过程中管材典型点的应力状态。结果表明:在充液内压较高的情况下,管材内侧的起皱现象得到减轻;但是,当内压超过管材发生塑性变形的内压时,管材会在弯曲合模过程中被挤出型腔。由于管端约束而产生的拉应力抵消了弯曲过程中内侧的压应力,管端约束情况下弯曲质量更好。 相似文献
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湿式离合器动密封装配间隙是车辆传动系统中的重要装配要求,直接影响车辆运行性能与行驶安全。为保障实际工况下其装配间隙符合设计要求,基于有限元分析方法与雅可比旋量理论,提出考虑实际工况的湿式离合器动密封装配间隙分析方法。针对某湿式离合器动密封装配间隙问题,计算转动状态下的最小装配间隙分布区间,并定量分析各载荷变形对装配间隙的贡献度。结果表明:实际运行状态下最小装配间隙分布区间为[-0.022,0.098] mm,与设计要求[0.025,0.207] mm严重不符;采用装配后再对内孔精加工的工艺对贡献度为74.22%的配流套内孔过盈装配变形进行调控后,最小装配间隙分布区间提升至[0.027,0.139] mm,符合设计要求,车辆运行性能得到有效保障。 相似文献
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黄永明 《中国有色金属学会会刊》2008,18(3):665-673
The flow rule of Prandtl-Reuss was adopted and incremental elasto-plastic finite-element analysis formulation of Coulomb's friction law combining the finite deformation theory was established, and Lagrangian formulation for simulating the squaring process of circular tube was updated. Incremental Coulomb's friction law was used in the global stiffness matrix to solve the sliding-sticking state of friction at the boundary contact interface. During the squaring process, the linear factor rmin was adopted to solve the non-linear boundary problems of changing node contact and separation, elasto-plastic transient situation in an element and the non-linear constitutive behavior of material so as to make each reasonable increment of the punch meet the demand of calculation for linear increment. The squaring process of circular tube, load distribution and final shape of work piece after unloading were simulated by this mode and compared with research data. It is known that the circular tube with higher geometrical ratio (R/t) could be pressed into symmetric square tube without collapse. This result can provide reference for the analysis of this process and evaluation and improvement of product defects. 相似文献
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《Journal of Materials Processing Technology》2014,214(7):1341-1351
In this paper, in order to explore the deformation behavior of double-sided tube hydroforming in square-section die, effect of external pressure on the critical effective strain was theoretically analyzed firstly. And then a special experimental setup was designed for double-sided tube hydroforming in which the difficulty of simultaneous loading was overcome using two independent intensifiers and servo controlling while the sealing of external pressure was guaranteed by the O rings assembled in the interfaces of mandrel/base plate and outer cylinder/base plate. Furthermore, 5A02-O aluminum alloy tubes with outer diameter of 63 mm and thickness of 2 mm were investigated under different external pressures varying from 0 to 80 MPa. At the same time, numerical simulation was conducted using the Abaqus/Explicit software. It is shown that increasing of external pressure has an effect on the fraction of grain boundaries, the number and size of the microvoids and the microhardness in the transition zone, and thus increases the critical effective strain in the transition zone. It can be concluded that the deformation ability of the transition zone is improved by the external pressure in double-sided tube hydroforming of square-section. This investigation shows that double-sided tube hydroforming is a potential forming method for the fabrication of lightweight hollow structures using the tubes with low ductility. 相似文献
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TiC颗粒增强钛基复合材料的形变 总被引:2,自引:0,他引:2
研究了TiC颗粒增强钛基复合材料增强颗料和基体之间的不均匀形变,得出颗粒和基体之间的形变过程中产生形变摩擦阻力,通过弹塑性力学计算出的TiC/Ti界面上颗粒阻碍基体变形力为TiC强度的0.6倍,阻碍基体中滑移的进行,使基体得到强化。另一方面,当界面上的形变应力同基体的某个晶面形成位错源时,可放出位错环,使应力得到释放,同时增加基体的位错密度,位错互相缠绕形成胞状亚结构,强化基体。 相似文献
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Ta—10W衬管与钢管段的爆炸复合 总被引:2,自引:0,他引:2
研究了Ta-10W全金衬管与CrNiMo钢管段的爆炸复合,观察了爆炸复合界面,讨论了装药量与管段变形量的关系。分析了爆炸复合对管段力学性能的影响,结果表明,取相同条件下平板复合炸药厚度的60%左右作为圆内复工艺参数的方法是可行的,在装药质量比R=0.8条件下,已将0.4mm厚Ta-10W合金衬管可靠地内复在CrNiMo钢管段内,结合界面是波状结合。 相似文献
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通过单向拉伸试验获得7种规格的21-6-9不锈钢管及3种规格的321不锈钢管的基本力学性能参数,21-6-9不锈钢管强度高、塑性差,其力学性能特征不利于拉深、弯曲等塑性成形;与21-6-9不锈钢管相比,321不锈钢管强度低、塑性好。分别通过弧形试样拉伸试验和管段试样拉伸试验,获取了Φ1.25mm×0.02mm厚的规格21-6-9不锈钢管的力学性能参数,发现由管段试样获得的延伸率大于弧形试样获得的延伸率,其屈服强度及抗拉强度略小于弧形试样获得的屈服强度及抗拉强度。由于弧形试样拉伸过程中,试样受到的并不是单向应力状态,因此管段试样获得的结果更准确。 相似文献
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V. I. Zel’dovich N. Yu. Frolova A. E. Kheifets S. M. Dolgikh K. V. Gaan E. V. Shorokhov 《The Physics of Metals and Metallography》2018,119(6):542-550
A bulky copper cylindrical shell with an internal diameter of 118 mm and a wall thickness of 5.9 mm has been exposed to an explosion of a cylindrical explosive charge uniformly distributed around it. A cylinder with a diameter of 57–58 mm has been obtained as a result of high-speed deformation caused by the explosion. A metallographic analysis of the cylinder structure shows that the shell collapses under the influence of axially symmetric radial deformation, which is accomplished by both twinning and sliding mechanisms. It is determined that axial deformation occurs along with the radial deformation. The microstructure of the cross-section consists of three zones. A wide annular deformation zone is formed on the outside, an annular recrystallization zone is formed closer to the center, and a circular region with a dendritic structure is formed at the center. The presence of dendrites indicates that the temperature at the boundary of this region reaches the melting point of copper. The temperature change along the radius of the cylinder has been calculated. 相似文献
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为了研究约束条件、压头尺寸等外部因素对金属圆管径向压缩力学性能的影响,采用圆柱形压头,对6组钢管试件进行径向压缩试验,对比分析结构变形、承载力及吸能特性;试验结果表明:V形约束的设置对钢管的塑性变形模式有显著的影响,延长了钢管内凹曲塌陷变形接触行程,使接触点两侧腔体封闭效果得到较大提高;结构承载力、平均压溃荷载及总变形能与约束体角度、压头直径、V形体间距成正比,与加载速率成反比。最后针对石油井井喷失控抢险救援,提出了一种新型内防喷装置的结构设计方案,可实现管柱内、外同时阻喷、事后处置更加安全、便捷的目的。 相似文献