参数变化
- 与 参数变化 相关的网络例句 [注:此内容来源于网络,仅供参考]
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The common method, that all strong-correlation terms of the model are eliminated, can bring the loss in the engineering application, so the new method is proposed that the identified model reserves some correlation. The augmented matrix A is constructed by the outputΔW and the matrix S. The"determinating order based on ratio of determinant"is brought out to screen the strong-correlation terms in the structure identification. The latent root estimation is improved in screening the eigenvalues and eigenvectors. Thus the estimation precision is improved greatly.The consistence check of guidance instrument error coefficients of flight test and ground test is the purpose of flight experiment. The causes of inconsistency of the two models are analyzed. The hypothesis test of linear regression model based on F statistics is proposed to check the consistence.Finally, the instability of error coefficients is probably caused by the change of the flight environments, therefore, the relation between the error coefficients and flight environment is analyzed. The approach is presented to identify SINS guidance instrument error models and compensate the error in the segmented sections corresponding to the change of vertical acceleration of aircraft.
在结构辨识中,常用的方法由于将模型中的强相关项全部剔除而给工程应用带来损失,因此,本文提出了新的有益思想,即在保留一定相关性的基础上进行辨识:将输出向量ΔW与环境函数矩阵S构成增广矩阵A,然后采用"比定阶行列式"来剔除相关向量的方法,这样既可以尽可能多地保留了对落点影响大的强相关参数,又可以对落点影响小的强相关参数给予剔除;在参数估计中,改进了特征根估计中特征根和特征向量的筛选方法,提出"近零"准则,从而大大提高了参数估计的精度;再者,鉴于天地模型"一致性"检验是飞行试验和SINS制导工具误差系数分离的主要目的,因此,本文又深入分析了造成天地模型不一致的原因,提出了采用基于F统计的线性回归模型假设检验方法来进行捷联制导工具误差模型的天地"一致性"检验;最后,鉴于飞行环境剧烈变化可能会对惯性仪表误差系数稳定性带来一定的影响,因此本文深入地分析了SINS制导工具误差系数与外界环境的关系,提出了基于过载变化大小的分段辨识和分段实时补偿的算法。
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On the basis of dual porosity theory,the well test interpretation model which considers the variation of krg versus the volume of liquid is also established and resolved by the implicit method numerically.
摘要通过分析凝析气藏的相图,建立了凝析液饱和度随压力降的变化规律,并回归得出了相应的公式;同时通过对气体压缩因子、黏度随压力、温度的变化,建立了这些参数和无因次压力的关系;在双重介质地层假设的基础上,建立了在试井过程中凝析气相对渗透率随凝析液饱和度变化的凝析气藏试井解释数学模型,采用隐式迭代的方法进行了求解并进行了参数敏感性分析;结果表明:凝析液的饱和度对凝析气藏试井的压力及压力导数曲线有着很大的影响,早期由于凝析液的析出,阻碍了气藏的流动,导致压力及压力导数曲线上升;在凝析液饱和度达到峰值之后,随着凝析液的挥发,凝析气的相对渗透率逐渐恢复,压力及压力导数曲线又回归到正常的径向流位置;由于裂缝和基岩之间的压力差,使得裂缝弹性储容比在测试过程中发生变化,进而影响了压力及压力导数;窜流系数和裂缝弹性储容比的变化决定了窜流段发生的早晚和程度;而基岩中气体黏度的变化使得窜流的发生稍微滞后。
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The major results are summarized as follows: When there is initial error only or model parameter error only in the Lorenz system, the error growth and predictability limit are comparable between two kinds of error problems. This result holds basically for the wide range of parameter space of Lorenz system.
结果表明:在初始误差和参数误差单独存在时,系统的可预报期限随误差大小的变化规律基本上相同;对于相同的误差大小,初始误差和参数误差对系统可预报期限的影响几乎相同,这一结果基本上不随参数范围的变化而变化。
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ABSTRACT Aiming at problems of trans-vector controller in a vehicle-carried induction motor such as variable rotor and stator resistance following motor temperature, and their inductance varying with flux saturation degrees. Firstly, CSI and VSI are introduced, for CSI, it can hold the advantages both FOC and DTC using stator flux directional, PI parameter and simulation are also introduced. Secondly, equations of IM in the synchronous rotary frame and its static counterpart, as figuring in the saturation condition of magnetic field, are dealt in this paper and the simulation results are presented. Thereafter, the parameter designing of PI trans-vector controller is processed, which features the non-linear model. In practical realization, as neglecting the dynamical change of motor inductance, this paper employs online modification of inductance parameters, according to the flux saturation, then transforms the non-linear equations into linear ones, and so compacts the structure of controller. Thirdly, in view of the maximum torque output is extraordinary requisite when Electrical Vehicle start up, accelerate, and overtake, this paper issues the maximum torque when both inverter and battery capacity is corporeally definite. Fourthly, on-line differentiating and analyzing both rotor's time constants and its flux by using the expanding order reduction and discrete Kalman filter equation are fathomed, in order to realize high-performance trans-vector algorithm, and also the simulation results are presented. Fifthly, the close-loop regenerative brake system, when the EV's torque is set constant, is deduced; at the same time, unification of electric drive model and brake model is executed. Combined with maximum charge current demands, the mathematical model for online yielding torque as a demand.
本论文针对车载异步电机在矢量控制器所遇到的问题:定转子电阻随温度变化及随电机饱和程度变化的转子电感及定子电感而影响电机调速性能提出一套完整的解决方案:分析了电流型逆变器和电压型逆变器在实现矢量控制时控制器参数的计算,分析出对于电流型逆变器在采用定子磁场定向时,其性能同时具有矢量控制和直接转矩控制两者的优势,并对电压型逆变器在转子磁场定向下的模型进行了仿真研究;建立异步电机非线性模型,推导出考虑磁饱和时异步电机在同步旋转坐标系及静止坐标系下的方程,并做出了仿真结果,建立异步电机在非线性模型下的矢量控制调节器的PI参数设计,在实际应用中,若忽略电机电感的动态变化,可以根据当前的磁路饱和状态而在线修正电感参数,从而将非线性方程线性化,降低控制器的复杂度;考虑到电动汽车在起动和加速超车时需要电机有最大转矩输出,本文讨论在逆变器容量一定和电池供电能力有限的情况下电机最大转矩输出问题;推导了异步电机扩展降阶、离散卡尔曼滤波方程在线辨识转子时间常数和转子磁通,用于实现高性能的矢量控制算法,并给出了仿真结果;推导出了电动汽车恒转矩给定的闭环回馈制动系统,实现了电动控制模型和制动模型的统一,而且结合铅酸电池最大充电电流的要求,为制动转矩在线给定建立了数学模型;设计了基于双DSP系统的高性能矢量控制器软硬件框图,并以大量实验数据说明矢量控制在电动汽车应用的实际应用状况。
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In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.
这章具体研究了基于三种极化散射特性描述的相应的目标识别方法:①基于极化参数平面描述的目标识别方法,将目标回波极化状态投影到以极化椭圆参数,即椭圆率角ε和倾角τ表征的极化状态平面上,参数随观测频率的变化就形成了图,根据图的变化特点构造了目标的多维极化特征空间,并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构;②基于Poincare极化球面描述的目标识别方法,采用Stokes矢量表征目标回波的极化状态,并将其投影到描述极化状态的Poincare极化球面上,定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息,提取了准方位不变性的目标极化特征,最后设计了目标的识别器结构;③基于频率敏感性描述的目标识别方法,通过在Poincare极化球面上所定义的极化状态距离的概念,研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题,获得了在极化状态距离下的频率分布特性曲线,采用最小二乘估计曲线拟合方法,它既用于极化特征的降维,同时又直接将拟合参数作为目标的分类特征。
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The method of prediction on stochastical simulating 3D parameter field of rock mechanics is brought forward in this paper. Namely, rock mechanics parameters- curve obtained by known and limited conventional log materials is took as inputs of hard data;and seismic attribute data body, hydrating of mud shale and rock environmental parameters data is took as constraint of soft data. By simulating stochastically through optimizing algorithm of Sequential Gauss Simulation,dynamical data field of rock mechanics parameter of three-dimensional space are gotten, then log response of rock mechanics parameters in position of any point in space is predicted.
提出三维岩石力学参数场随机模拟预测的方法,即以已知有限的常规测井资料计算出来的岩石力学参数曲线作为硬数据输入,以已知地震属性数据体及泥页岩水化和岩石环境参数数据作为软数据约束,选择序贯高斯模拟方法,随机模拟得到动态规律变化的岩石力学参数的三维空间数据场,然后由岩石力学参数的三维空间数据场预测空间任一位置的岩石力学参数在井上的测井响应,并把该反映动态规律变化的测井响应按照油田勘探开发的要求输出成特定格式,供生产和工程上使用。
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This algorithm is based on Ref[1,2] and perfectly improves the method for choosing forgetting factor, and in the algorithm the auto-regulation factor is introduced so as to cope with parameter estimation of fast time varying systems such as missile control system, etc., Digital simulation results show that this algorithm is satisfactory for identifying the parameters which change in the form of some typical functions (e.g., exponential, slide, step, sine, square or their combination).
这种方法主要是在文献 [1,2]的基础上改进了遗忘因子的选取方法,引入了自动调整遗忘因子,以适应导弹控制系统等快速时变系统的参数估计要求。数字仿真结果表明,这种辨识方法对于诸如参数的指数变化、斜坡变化、阶跃变化、正弦变化、方波变化以及由这些变化形式构成的混合变化,都有比较好的辨识效果。
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The authors analyze the operation characteristic of distance protection of transmission line connecting wind farm with power grid under the variation of parameters such as the amplitude ratio of electromotive force at both sides, the phase difference of electromotive force at both sides, equivalent impedance of sources, system frequency and so on; based on the real-time current and electromotive force at wind farm side as well as the information of wind power generators participating power generation, a method to adaptively set the operation boundary of distance protection by use of the information at wind farm side only is proposed.
文章分析了风电场和电网联络线的距离保护随电源电势幅值比、电势相位差、电源等效阻抗、系统频率等参数变化时的动作特性,并基于风电场侧的实时电流和电势与参与发电的发电机信息,提出了仅利用风电场侧信息量自适应整定保护动作边界的方法。
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Then, aerodynamic parameters in different flight conditions are used to imitate the uncertainty of the system, and the digital simulation of closed-loop system designed is performed. The results show that the system can accomplish asymptotic decoupling of roll angle, sideslip angle and head-on angle for aircraft, and the system is provided with the function for restraining uncertainty in the system. This illustrates that the flight control system designed has not only good decoupling characteristic, but also better robustness.
然后用不同飞行条件下的空气动力参数变化来模拟系统的不确定性,并进行闭环系统数字仿真,结果表明,所设计的控制律不仅可实现对飞机滚转角、侧滑角、迎角等的渐近解耦控制,而且对系统不确定性具有较强的抑制作用,说明系统具有较好的解耦性和较强的鲁棒性。
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The results indicate that winter SSWs are catastrophes due to the variations of model parameters and are stratospheric responses on the bottom boundary forcings, and that the SSW is very sensitive to the initial state of stratospheric zonal wind.
结果表明,冬季平流层增温是由于模型参数变化而导致系统灾变的结果,是冬季平流层对底部强迫的响应,它同时对平流层基本流的剖面十分敏感。
- 推荐网络例句
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According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.
曝气设备的动力效率在叶轮转速为120rpm~150rpm时取得最大值,此时氧利用率和充氧能力也具有较高值。
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The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.
稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世,形体几无变化。
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When I was in school, the rabbi explained everythingin the Bible two different ways.
当我上学的时候,老师解释《圣经》用两种不同的方法。