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多变量滑动平均模型参数估计两段最小二乘法
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作者 杜洪越 邓自立 《黑龙江大学自然科学学报》 CAS 2003年第2期55-58,共4页
提出了多变量滑动平均(MA)模型参数估计的两段最小二乘法。第一段将多变量MA模型用高阶多变量自回归(AR)模型近似代替,用多变量递推最小二乘法(MRLS)估计高阶AR模型参数。第二段用最小二乘法解不相容矩阵代数方程组得MA参数估值。同多... 提出了多变量滑动平均(MA)模型参数估计的两段最小二乘法。第一段将多变量MA模型用高阶多变量自回归(AR)模型近似代替,用多变量递推最小二乘法(MRLS)估计高阶AR模型参数。第二段用最小二乘法解不相容矩阵代数方程组得MA参数估值。同多变量递推增广最小二乘法相比,可提高精度,仿真例子说明了其有效性。 展开更多
关键词 变量滑动平均模型 参数估计 两段最小二乘法
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串联工业机器人的自适应稳态增益调整技术
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作者 牛鑫 冯洪宁 《机械设计与制造》 北大核心 2024年第6期338-341,347,共5页
由于时滞控制具有模型无关性、简单性和鲁棒性等优点,在工业机器人控制中得到了广泛的应用。然而,过高的增益会导致系统响应不稳定或振荡。为了解决这一问题,提出了一种用于串联机械臂时滞控制的自适应增益调整算法。首先,通过机器人机... 由于时滞控制具有模型无关性、简单性和鲁棒性等优点,在工业机器人控制中得到了广泛的应用。然而,过高的增益会导致系统响应不稳定或振荡。为了解决这一问题,提出了一种用于串联机械臂时滞控制的自适应增益调整算法。首先,通过机器人机械臂时滞控制原理分析表明了恒定增益存在的缺陷。然后,采用滑动变量和边界条件为时滞控制设计了一种自适应增益调整算法,能够在无需大量的调整参数的条件下,自动将增益调整到满足时滞控制稳定性条件的稳定值。仿真和实验结果验证了所提自适应增益调整算法的有效性。研究结果表明,与传统的时滞控制(大增益)相比,所提算法将机械手跟踪的均方根误差和最大误差分别减小了31.2%和61.4%,并且即使在初始值不稳定的情况下,仍可以提供稳定的增益,控制性能显著提高。 展开更多
关键词 机器人机械臂 时滞控制 自适应 滑动变量 边界条件
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A new method to calculate lateral force acting on stabilizing piles based on multi-wedge translation mechanism 被引量:2
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作者 罗渝 许强 +3 位作者 何思明 李新坡 何尽川 吴永 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期654-661,共8页
A new method based on the multi-wedge translation mechanism is presented to calculate the lateral force acting on the stabilizing piles. At first, there is no assumption for the shape of potential sliding surface, it ... A new method based on the multi-wedge translation mechanism is presented to calculate the lateral force acting on the stabilizing piles. At first, there is no assumption for the shape of potential sliding surface, it is just considered that the potential sliding surface is a composite of a number of straight lines. And then, the potential sliding mass is divided into a number of triangular wedges take with these straight lines as its base. The kinematic theorem of limit analysis is adopted to calculate the rate of external work and the rate of energy dissipation for each triangular wedge, respectively. Furthermore, the multivariate functions are established to calculate the lateral force acting on the stabilizing piles. The lateral force and the corresponding potential sliding surfaces can be obtained by an optimizational technique. At last, an example is taken to illustrate the method. The effect of soil strength parameters, slope angle and pile roughness on the lateral force and the corresponding potential sliding surface are analyzed.The result are compared with those obtained using other methods. 展开更多
关键词 PILE sliding surface limit analysis multi-wedge mechanism
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Late Quaternary Activity and Paleoearthquakes along the Nanyukou Segment of the Northern Piedmont Fault of Wutai Mountain
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作者 Ding Rui Ren Junjie Zhang Shimin 《Earthquake Research in China》 2010年第1期82-96,共15页
The northern piedmont fault of Wutai Mountain is located at the north of the Shanxi Graben system, which is the dominating fault of the south boundary of the Fanshi-Daixian depression. This paper discusses the fault a... The northern piedmont fault of Wutai Mountain is located at the north of the Shanxi Graben system, which is the dominating fault of the south boundary of the Fanshi-Daixian depression. This paper discusses the fault activity and paleoearthquakes around the Nanyukou segment of the northern piedmont fault of Wutai Mountain during the late Quaternary through field investigation along the fault, measuring geomorphic deformation and excavating trenches at some important sites. From Nanyukou to the southwest of Shanhui, we find obviously dislocated alluvial fans, with strong neotectonic movement at these sites. Since nearly 20ka, the vertical average slip rate is 1.55mm/a to 2.0mm/a. However,since nearly 6ka,it has reached as high as 2.3mm/a, which is twice that on other segments. 2 trenches were excavated around Nanyukou with 6 events discovered. The referenced ages of the events are before 7600a, 6700a - 7600a, 5321a - 5575a, 4400a - 5400a,420Oa-4400a and after 1600a B.P. with approximate recurrence interval 1400a. The latest event is likely to be the earthquake occurring at 512 A. D. ,so it is necessary to do further work to verify this in the future. 展开更多
关键词 The northern piedmont fault of the Wutai Mountain Late Quaternary Fault scarp PALEOEARTHQUAKE Slip rate
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不确定Gray-Scott系统的参数辨识与时空混沌同步 被引量:2
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作者 吕翎 李义 郭治安 《中国科学(G辑)》 CSCD 北大核心 2009年第1期77-82,共6页
将离散控制系统的滑动变量零渐近的性质扩展为连续的,应用于描述时空混沌的偏微分方程中,提出了一种实现时空混沌同步和参数辨识的方法.设计了参数辨识器和同步控制器.以不确定Gray-Scott系统为例,验证其有效性.仿真结果表明,参数辨识... 将离散控制系统的滑动变量零渐近的性质扩展为连续的,应用于描述时空混沌的偏微分方程中,提出了一种实现时空混沌同步和参数辨识的方法.设计了参数辨识器和同步控制器.以不确定Gray-Scott系统为例,验证其有效性.仿真结果表明,参数辨识器中的辨识量能够有效地替代目标系统和响应系统中的未知参数.施加控制器后,两个未知参数的时空混沌系统迅速地达到完全同步. 展开更多
关键词 时空混沌 滑动变量 参数辨识 同步 不确定Gray-Scott系统
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Determination of Euler parameters of Philippine Sea plate and the inferences
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作者 臧绍先 沈正康 +2 位作者 陈起永 刘永刚 宁杰远 《Science China Earth Sciences》 SCIE EI CAS 2002年第2期133-142,共10页
Euler vectors of 12 plates, including Philippine Sea plate (PH), relative to a randomly fixed Pacific plate(PA) were determined by inverting the 1122 data from NUVEL-1 global plate motion model, earthquake slip vector... Euler vectors of 12 plates, including Philippine Sea plate (PH), relative to a randomly fixed Pacific plate(PA) were determined by inverting the 1122 data from NUVEL-1 global plate motion model, earthquake slip vectors along Philippine Sea plate boundary, and GPS observed velocities. Euler vectors of Philippine Sea plate relative to adjacent plates are also gained. Our results are well consistent with observed data and can satisfy the geological and geophysical constraints along the Caroline(CR)-PH and PA-CR boundaries. Deformation of Philippine Sea plate is also discussed by using the plate motion Euler parameters. 展开更多
关键词 Philippine Sea plate earthquake slip vectors intraplate deformation relative plate motion plate motion parameters
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