《信号与系统》中复频域法分析求解电路响应探讨

介绍了复频域分析法求解电路的依据、求解过程,通过两道例题分析复频域法在求解电路时的解题思路、画S域等效电路图需注意的问题,表明复频域法在分析求解电路的全响应、零状态响应等时具有一定的优越性。     

无人机纵向H_∞状态反馈控制律设计及仿真

研究了H∞状态反馈方法在无人机纵向控制律设计中的应用.建立了无人机纵向运动的小扰动方程,适当地选取广义状态变量建立了系统广义被控对象,在matlab中用基于线性矩阵不等式(LMI)的求解方法设计了系统H∞状态反馈控制器,并进行了数字仿真验证.以无人机纵向运动中俯仰控制通道的等俯仰角爬升模态为例,给出了设计过程和结果,并与PID控制器的控制效果进行比较,表明H∞控制器有更好的控制效果,它可以兼顾系统响应的动态和稳态性能,有效地解决了PID控制器设计中某些性能指标相互矛盾的问题.     

基于传输线模型的动态电路建模与仿真分析

针对利用数值分析法求解高阶电路时难于列写系统状态空间方程,且计算复杂烦琐的问题,阐述了一种不需要列写状态空间方程,并且能够直接从动态电路元件得到电路计算模型的建模法(传输线模型(TLM)建模法),同时对一个含耦合元件的动态电路进行了建模和仿真,与常用的其它两种常用的数值分析法进行了比较分析.仿真结果表明.方法简单实用,物理概念清晰,能有效对各种动态电路特别足高阶电路进行求解,并且具有无条件的数值稳定性.     

非线性末制导系统参数灵敏度分析

末制导系统参数随着飞行环境及飞行条件的改变而存在摄动,针对这一问题本文提出根据动态灵敏度来分析参数摄动对脱靶量的影响.基于伴随法推导出与系统动态方程相同规模的伴随方程,并通过一次伴随求解计算得到脱靶量对所有可调参数及摄动参数的动态灵敏度,有效的提高了计算效率.传统的直接分析法是将系统状态变量直接对参数变量进行微分,需要对每个参数变量求解一组代数或微分方程,对于状态变量及参数变量较多的情况效率较低.本文基于两种方法对末制导系统的参数灵敏度进行分析,分析结果揭示了参数摄动对脱靶量的影响程度,较小的参数灵敏度为提高系统的鲁棒性提供了依据.     

一类非线性LC电路的分析与模拟

给出一类非线性LC电路的状态分析和数值模拟：将电容的电荷表示为相位角的简谐函数,电路的响应频率表示为相位角关于时间的变化率;以电路的响应频率为未知函数,对状态方程进行近似求解;算出时间随相位角变化的近似关系式;给出电路的相图、电容的电荷以及电感的磁通链随时间变化关系式及数值模拟,结果与数值积分法吻合良好。     

非线性末制导系统参数灵敏度分析（英文）

末制导系统参数随着飞行环境及飞行条件的改变而存在摄动,针对这一问题本文提出根据动态灵敏度来分析参数摄动对脱靶量的影响.基于伴随法推导出与系统动态方程相同规模的伴随方程,并通过一次伴随求解计算得到脱靶量对所有可调参数及摄动参数的动态灵敏度,有效的提高了计算效率.传统的直接分析法是将系统状态变量直接对参数变量进行微分,需要对每个参数变量求解一组代数或微分方程,对于状态变量及参数变量较多的情况效率较低.本文基于两种方法对末制导系统的参数灵敏度进行分析,分析结果揭示了参数摄动对脱靶量的影响程度,较小的参数灵敏度为提高系统的鲁棒性提供了依据.     

基于改进RLS的传感器动态特性校正方法

在动态测试中为了消除传感器谐振频率处振动产生的误差,针对传感器高阶系统的补偿问题提出一种改进RLS算法优化补偿滤波器。采用梯度下降法产生滤波器参数初值,再用RLS算法对参数进行修正。在matlab平台上对算法进行了仿真验证,分析了补偿前后传感器系统的时域响应和频域响应。对实际压电传感器CY-YD-205进行了补偿,工程实验表明采用改进RLS算法设计的补偿滤波器可以大大改善传感器系统的动态特性。     

直流激励下一阶线性动态电路三要素法解题探讨

电工学中分析一阶线性动态电路的方法有经典法和三要素法两种,但经典法的解题过程较复杂,学生不易理解和掌握。本文主要探讨了三要素法分析电路响应的思路及使用该方法时的注意之处。     

无人机侧向运动H_∞控制器设计及仿真

研究了鲁棒控制中H_∞状态反馈方法在无人机侧向控制律设计中的应用;建立了无人机侧向运动的小扰动方程,根据控制目标选取了合适的广义状态变量,建立了广义被控对象,应用matlab鲁棒控制工具箱中线性矩阵不等式(LMI)的求解方法设计了系统H_∞状态反馈控制器,并进行了数字仿真验证;以无人机侧向运动中滚转控制通道的H_∞鲁棒控制器设计为例,给出设计过程及仿真结果;与PID控制器的控制效果进行比较,说明控制器能够使系统有更好的动态和稳态性能,且比PID控制器对外界噪声干扰有较好的抑制作用,现已成功应用于某型无人机。     

动力伞伞翼阵风响应的数值模拟

采用有限体积法求解非定常Euler方程,并通过引入动态网格方法模拟阵风条件,对不同风速下水平和垂直阵风的伞翼气动力响应进行动态模拟与计算,针对动力伞伞翼柔性结构和飞行速度慢的特点,运用动态仿真方法求解阵风响应的附加气动力与力矩。结果表明:遇水平阵风时,伞翼气动力表现为多周期不同幅度的主动颤振运动;遇垂直阵风时,气动力响应基本与阵风速度变化趋势保持一致,最终稳定后气动力相对于阵风加载前变化不大。     

新型脉冲电源等效电路动态特性研究

研究电感储能的新型脉冲电源提高效能问题,采用脉冲电容储能型电源,制造复杂。采用开关控制,限制了发展,同时由于给出了脉冲电源的等效电路并导出电路对应的变系数微分方程,方程的解析求解较为复杂。为解决上述问题,建立了电感储能型等效电路的模型,进行仿真,结果明确了电路各元件参数对输出脉冲特性的影响,验证了计算结果的可靠性。研究电感储能型脉冲电源电路参数的取值对输出脉冲电压的特性有着较明显的控制效果,通过适当选择各元件参数的取值,可以获得较小脉冲电压脉宽的同时又有较高的电压幅度。仿真结果为新型脉冲电源系统设计过程中参数的选择提供了可靠的依据。     

基于动态模糊聚类分析的模糊集划分新方法

由于模拟电路具有容差特征,用故障字典法进行故障诊断时,传统的模糊集划分方法就存在弊端.针对这种弊端;采用模糊理论中的动态聚类分析法来改善传统模糊集的划分;首先用蒙特卡罗分析法进行电路容差分析,然后用动态模糊聚类分析方法,对电路故障状态进行分类,形成新的模糊集划分方法;实验结果证明了新划分方法的可行性和有效性,并显著提高电路故障的检测率和隔离率.     

Analysing the Robustness of Surfing Circuits

Surfing is a technique for implementing high-speed digital pipelines that exploits the analog dynamics of the underlying circuits. Thus, verification must consider the analog behaviour of the design. We have presented a method for analysing the robustness of surfing circuits. We formulate noise margin analysis as a non-linear optimization problem where we find the smallest disturbance waveform that results in a qualitative change in the behavior of the circuit. We present a practical method for solving these optimization problems based on deriving a sensitivity matrix for the small-signal response of the circuit.     

Dynamic response of frameworks by fast fourier transform

A general numerical method for determining the dynamic response of linear elastic plane frameworks to dynamic shocks, wind forces or earthquake excitations is presented. The method consists of formulating and solving the dynamic problem in the frequency domain by the finite element method and of obtaining the response by a numerical inversion of the transformed solution with the aid of the fast Fourier transform algorithm. The formulation is based on the exact solution of the transformed governing equation of motion of a beam element and it consequently leads to the exact solution of the problem. Flexural, and axial motion of the framework members are considered. The effects of damping (external viscous or internal viscoelastic), axial forces on bending, rotatory inertia and shear deformation on the dynamic response are also taken into account. Numerical examples to illustrate the method and demonstrate its advantages over other methods are presented.     

Thermally induced vibrations of beam structures

A general numerical method is developed for determining the dynamic response of beam structures to rapidly applied thermal loads. The method consists of formulating and solving the dynamic problem in the Laplace transform domain with the aid of dynamic stiffness influence coefficients defined for a beam element in that domain and of obtaining the response by a numerical inversion of the transformed solution. Thus, the solution of the associated heat conduction problem, usually obtained by Laplace transform and needed for the computation of the thermal load, can be used in its transformed form. The effects of damping and of axial compressive forces on the structural response are also studied. Three examples are presented in detail to illustrate the proposed method and demonstrate its advantages.     

Dynamic routing and admission control for virtual circuit networks

The dynamic joint routing and admission control problem in multiple class multiple source-destination virtual circuit networks is considered. A nonlinear dynamic queueing model for virtual circuit networks that considers the dynamic interaction among the virtual circuit and packet processes is introduced. Then a multi-objective cost function of rejecting and maintaining virtual circuits, as well as of delaying and servicing packets is defined. The combined problem is formulated as an optimal control problem. Necessary optimality conditions are provided by Pontryagin's maximum principle. Sufficient optimality conditions based on the convexity of the Hamiltonian function are also given. For the finite horizon, the optimal controls can be found after numerically solving a Two-Point Boundary-Value Problem. For the longrun stationary equilibrium, the state-dependent routing and admission controls are derived.This work was supported by the National Science Foundation under Grant DMC-8452002 together with matching funds from AT&T Information Systems.     

Uncontrollable Perturbations of Nonlinear Dynamic Systems: Estimation on Moving Modes

A method of decomposition analysis and design is developed for estimating the unmeasurable components of the state vector and external perturbations of a wide class by the methods of design of systems with discontinuous controls in the correction circuit of the dynamic observer. It is helpful in identifying the observable subspace of maximal dimension of the state vector and observable combinations of the components of the state vector, and in solving the estimation problem in a finite time without the need for joint analysis and design of a closed system with an observer.     

一个非自治电路混沌特性的计算机分析与研究

该文首先分析了Logistic映射的一些典型的混沌特性，然后运用与其相类比的分析研究方法，诸如时间序列分析方法、相图分析方法和分岔图分析方法，对一个非自治电路进行了计算机分析与研究。通过对描述该非自治电路的非线性微分方程进行求解和计算机分析，可以看到，当输入电压的幅值改变时，该电路系统的动力学特性对输入电压幅值有很强的敏感性。在对该非自治电路的分岔图进行了详细的计算机分析后，指出了该非自治电路从倍周期通向混沌的分岔点。以此，说明了该非自治电路是典型的具有混沌特性的非线性电路。     

Dynamic response of frameworks by numerical laplace transform

A general method for determining the dynamic response of complex three-dimensional frameworks to dynamic shocks, wind forces or earthquake excitations is presented. The method consists of formulating and solving the dynamic problem in the Laplace transform domain by the finite element method and of obtaining the response by a numerical inversion of the transformed solution. The formulation is based on the exact solution of the transformed governing equation of motion of a beam element, and it consequently leads to the exact solution of the problem. Flexural, axial and torsional motion of the framework members are considered. The effects of damping (external viscous or internal viscoelastic), axial forces on bending, rotatory inertia and shear deformation on the dynamic response are also taken into account. Numerical examples to illustrate the method and demonstrate its merits are presented.