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Adaptive fuzzy sliding mode control of Lorenz chaotic system


By using the exponential reaching law technology, a sliding mode controller was designed for Lorenz chaotic system subject to an unknown external disturbance.


Furthermore, to eliminate the chattering resulting from the discontinuous switch controller and to guarantee system transient performance, a new adaptive fuzzy sliding mode controller was designed.


Then the sliding average least squares (SALS) method was adopted to determine the mass, damp, and stiffness of the remote environment and use this information to amend the dynamic model of the environment.


A sliding mode perturbation observer (SPO) is designed to estimate unmeasurable states and system perturbations that involve system nonlinearities, disturbances and unmodelled dynamics.

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 This paper deals primarily with derivation of computation equations for seepage through earth dam having a less pervious upstream sloping core and a blanket on pervious foundation. With these equations, the hydraulic heads at several key points along the percolation path can be obtained simultaneously, and the hydraulic gradient line can be plotted. The seepage discharge through various parts and through the entire section can also be calculated. In the derivation of the equations, it is assumed that the variationof... This paper deals primarily with derivation of computation equations for seepage through earth dam having a less pervious upstream sloping core and a blanket on pervious foundation. With these equations, the hydraulic heads at several key points along the percolation path can be obtained simultaneously, and the hydraulic gradient line can be plotted. The seepage discharge through various parts and through the entire section can also be calculated. In the derivation of the equations, it is assumed that the variationof the loss of head underneath the blanket is linear and that the saturation line in the dam is a parabola. It is also assumed that the seepage through the unsaturatedpercolation region between the sloping core and the saturation line is supplied vertically, as in actual case. Consequently, the final results of the derivation appearing as equations (3) & (1) are elementary functions, a computation of which can be easily made with a slide rule. All the equations are checked by the electrical analogy of resistance networks, with a discrepancy less than 5%. The paper in another respect gives, from equations (13) and (15), a method of calculation of the upper and lower limit lengths of the blanket for both of the cases of uniform and nonuniform thickness. A subsequent suggestion is made as regards the determination of the reasonable design length of the blanket, once the two limiting lengths have been computed. It also presents a method of designing the blanket of equal strength to prevent seepage, and the thickness is given by the approximate equation (17). It is pointed out that the determination of the thickness of the upstream blanket should not only suit the construction convenience but also be comfortable to the entrance head loss as given by equation (18).  本文主要推导了鋪盖斜墙土坝的渗流計算公式,利用該項公式可以同时計算出各关鍵点的水头,画出水力坡綫及浸潤綫,并可計算出各分段的渗流量以及总渗流量。推导公式时,主要假定鋪盖下面受压渗流的水头損失是直綫变化,坝体內的浸潤綫是拋物綫变化,并且考虑了浸潤綫起点以上斜墙段渗漏水非飽和渗流区域的沿程补給条件。最后引証所得的方程組:計算水头的式(3)和計算流量的式(1),是用較簡单的初等函数的代数式表示的,在設計計算时只需要一把計算尺。計算公式經过电阻网模型(电力积分仪)試驗的驗証,誤差一般小于5％,比目前文献中的公式精度都高。本文明确了鋪盖长度的上限和下限,推导出不等厚鋪盖和等厚鋪盖的极限长度計算式(13)及(15)。并在极限长度的基础上提出經济合理的适宜长度約为极限长度的1/3～2/3。此外本文并明确了鋪盖和斜墙的等抗渗强度設計方法,推导出直綫变化的厚度計算式(17)。同时指出一般认为鋪盖前端决定于施工厚度的片面性,也应滿足进口損失水头,需要按式(18)核算确定。  The protective layer of the Paiho earthdam at the Miyun Reservoir slid during an earthquake in 1976. The scope and features of the slide are described in this paper. An analysis of the accelerograph obtained at the dam site and the earthquake response of the dam is also presented. According to the component and density of the sandygravel material of the protective layer, and the results of dynamic triaxial tests conducted on its fine parts, it has been indicated that the material is of the type... The protective layer of the Paiho earthdam at the Miyun Reservoir slid during an earthquake in 1976. The scope and features of the slide are described in this paper. An analysis of the accelerograph obtained at the dam site and the earthquake response of the dam is also presented. According to the component and density of the sandygravel material of the protective layer, and the results of dynamic triaxial tests conducted on its fine parts, it has been indicated that the material is of the type that is easily susceptible to uefaction. Under seismic loadings its shear strength decreases considerably as the porewater pressure Increases. This is proved to be the main cause of the slide. The stability analysis taking into consideration the liquefaction effect confirms this conclusion. Finally, the remedial and strengthening measures for the dam are recommended, In addition, some suggestions as to the problem of using sandygravel materials in the construction of earthdams in the seismic region are given.  １９７６年地震时密云水库白河土坝保护层发生滑坡。文中阐述滑坡的范围和形态，对坝上取得的地震记录和地震过程中大坝的反应做了分析。 根据保护层砂砾料的组成、密度和细料的三轴动力试验成果指出这种料属于易液化料，在地震荷载作用下由于孔隙水压力的升高而使抗剪强度大幅度降低是这次滑坡的主要原因。考虑砂砾料液化的边坡稳定分析资料证实这一结论。 文中最后介绍了大坝的加固措施，并对地震区砂砾料筑坝问题提出了若干观点和建议。  In this paper a discussion on the adoption of the seismic coefficients and on safety evaluation in aseismatic design of gravity dams on rock foundations is presented.The discussion is based on further investigations the seismic response of the Xinfengjiang Dam, the Koyna Dam and some other gravity dams selected.In aseismatic design of gravity dams, usually based on static method or socalled pseudostatic method using conventional seismic coefficients and static parameters for calculating the shearing strength,... In this paper a discussion on the adoption of the seismic coefficients and on safety evaluation in aseismatic design of gravity dams on rock foundations is presented.The discussion is based on further investigations the seismic response of the Xinfengjiang Dam, the Koyna Dam and some other gravity dams selected.In aseismatic design of gravity dams, usually based on static method or socalled pseudostatic method using conventional seismic coefficients and static parameters for calculating the shearing strength, a basic evaluation of the overall stability against sliding of the dam subjected to earthquake, though far from being satisfactory, can usually be obtained. Stress calculation based on such methods, however, is often misleading. Therefore, it is advisable to take a different approach.Applicating the method of dynamic analysis and adopting a design seismic coefficient for the expected ground motion of the dam foundation to estimate the earthquake loadings and stresses, combining them with those produced by normal loads and comparing them with the paremeters for static strength, one may then arrive at a reasonable safety evaluation of a dam.This paper deals mainly with the problem of stability against sliding.The authors present the concept of relative seismic stability, which shall be helpful to indicate the rule of stability against sliding of dams subjected to earthquake and, consequently, to make sure the safety of the dam.In the investigation the dynamic coupling action between the dam and the reservoir water was taken into consideration,the dam and the reservoir water being treated as an assemble of finite elements.The analysis was carried by both the methods of response spectrum and timehistory. And the combined effects of dynamic and static loadings were introduced.  本文在通过对新丰江和柯依那(Koyna)大坝的震害情况进一步分析,和选择了其它一些重力坝进行研究后,提出了岩基上重力坝抗震设计地震系数的采用及安全性估算的意见. 在重力坝的抗震设计中,按照静力法或拟静力法和经验的地震系数、抗剪强度的静力指标检验大坝的抗滑稳定性,是可以得到基本估计的,但还存在某些问题;尤其是,在进行坝体强度校核时,往往会使人产生误解.因此,作者认为有必要采用动力分析法和预计的设计坝基地震系数,以估算地震荷载和应力,并与正常荷载的情况组合,取强度的静力指标作出比较,才能得到近乎合理的安全估算. 文中着重研究了大坝滑动稳定性问题,提出了抗震的稳定相对安全率的概念,它有助于揭示地震时大坝抗滑稳定的变化规律,并作出安全的估算. 在分析时,将坝体和库水作为有限单元的集合体,考虑了坝体与库水在振动时耦合作用,按反应谱法和时程法进行动力分析,得出了动力和静力的综合成果.   << 更多相关文摘 
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