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0IntroductionWith the rapid developmentof modern manufacturing,applications of aluminum alloy welded structures with bigthickness are becoming more and more widely. As a kindof efficient welding method, twin wire welding has suchmerits as big deposition rate, little heat input and narrowheat-affected zone. At the same time, the defects such asincomplete penetration, discontinuous beam or undercutcan be avoided effectively[1 -5]. 2219 aluminum alloy hasthe wider application foreground due to it… 相似文献
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From the viewpoint of welding mechanics, two new welding methods-welding with trailing peening and welding with trailing impactive rolling were introduced. For aluminum alloy thin-shell structures with high strength, welding will lead to hot cracking, poor joint and distortion. In order to solve them, trailing impactive device was used behind welding torch to impact the different positions of welded joints, thus realizing the welding with free-hot cracking, low distortion and join tstrengthening. By use of impactive rolling wheels instead of peening heads, the outlook of welded specimen can be improved and stress concentration at weld toes can be reduced. Equipment of this technology is simple and portable. It can used to weld sheets, longitudinal and ring-like beams of tube-like structures, as well as the thin-shell structures with closed welds such as flanges and hatches. So the technology has the wide application foreground in the fields of aviation and aerospace. 相似文献
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基于无源性的异步机自适应控制 总被引:2,自引:0,他引:2
对近年来出现的一种异步机控制方法--基于无源性的控制(简称PBC)进行了发
展,从理论上取消了对定子电流反馈的要求,并针对转子电阻变化,增加了参数自调整的自
适应控制和转子磁链闭环控制.该控制器保留了PBC方法的简单、无奇异点等优点,而且抑
制了由于转子电阻变化引起的转速和磁链跟踪误差. 相似文献
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点模式匹配是计算机视觉和模式识别领域中的一个重要问题 .通过研究 ,在假定待匹配的两个点模式中已知有三对点整体对应的前提下 ,基于射影坐标以及对投影变换和排序变换同时保持不变的 p2 -不变量等理论 ,通过定义一种广义距离 ,给出了一种求解透视变换下 ,点数不等的两个平面点模式匹配问题的新算法 .理论分析和仿真实验表明 ,该算法是快速、有效的 相似文献
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点模式匹配是计算机视觉和模式识别领域中的一个重要问题。通过研究,在假定待匹配的两个点模式中已知有三对点整体对应的前提下,基于射影坐标以及对投景变换和排序变换同时保持不变的p^2--不变量等理论,通过定义一种广义距离,给出了一种求解透视变换下,点数不等的两个平面点模式匹配问题的新算法。理论分析和仿真实验表明,该算法是快速、有效的。 相似文献
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刚体连杆电驱动机器人的分散鲁棒跟踪控制 总被引:1,自引:0,他引:1
该文针对不确定刚体连杆电驱动机器人的跟踪控制问题,提出了一种新的分散控制器设计方法:首先设计标称控制器使标称闭环系统具有理想的跟踪性能;然后设计鲁棒补偿器以抑制非线性耦合、关节摩擦、参数不确定性和外扰等因素的影响。理论分析及仿真结果表明,在具有足够带宽的情况下,不需要测量电枢电流,该控制器可以保证跟踪误差局部终值有界,并具有可在线调整的特点。 相似文献