基于SVC的硅锰炉谐波抑制研究

针对吉林铁合金16 500 kVA硅锰炉运行时引起闪变和产生大量谐波的现状,分析硅锰炉运行特性,对工厂供电系统的性能参数进行现场测试与分析,提出一种基于SVC的硅锰炉谐波抑制方案,具体设计了4支路固定电容滤波器和TCR回路及其控制系统.模拟运行结果表明:该谐波治理方案可行、实用,有效地抑制了电网的闪变和谐波,改善了电网的电能质量.     

武钢硅钢SVC的设计原理与特性分析

武钢硅钢扩建工程将对电网产生电压波动大、功率因数低、高次谐波电流大等危害。因此必须装设一套静止型无功补偿装置（ＳＶＣ）来抑制上述不利影响，本文介绍了这套ＳＶＣ装置的设计原理及技术特点。     

欠驱动2DTORA基于部分反馈线性化的非线性控制设计

具有旋转激励的两自由度平移振荡器(2DTORA)由未驱动的具有2个自由度直线运动的小车和安装在小车上的驱动旋转小球组成,针对这一新型的欠驱动系统,分析其动力学,研究其稳定控制方案.基于拉格朗日方程,建立系统的动力学模型,通过分析动力学的耦合,说明旋转小球目标转角设定在小车2个自由度直线运动方向上时系统是不可控的.采用部分反馈线性化技术,将系统动力学的直接驱动部分线性化,将其未直接驱动部分作为系统的内部动态考虑;选择直接驱动的自由度作为系统输出,进行反馈控制设计;通过分析系统的内部动态,证明了系统零动态的渐近稳定性,保证了整个控制系统的稳定性.最后,通过仿真实验验证了控制器的有效性.     

基于Varela免疫模型的免疫控制器的设计与仿真

Varela免疫网络模型是继Jerne独特性网络模型之后的第二代网络模型,Varela免疫网络模型描述的是没有外来抗原作用时的T、B细胞因子的动态平衡关系.本文在此基础上建立了一种考虑抗原的改进的Varela免疫网络模型.然后基于这种能够在一定程度上合理描述生物免疫特性的改进Varela免疫网络模型,构造了一类与被控对象无关的免疫控制器模型.以大惯性大滞后模型为被控对象,采用仿真的方法研究了该免疫控制器的特性.仿真研究与分析表明:该免疫控制器具有一定的记忆和自学习能力,具有较好的抗纯滞后及参数自适应性能.文中将这种免疫控制器的参数变化对控制系统的影响也作了仿真研究.     

组合柔性结构非线性柔性模型

根据组合柔性结构的结构参数对其变形特性的影响,对组合柔性结构进行了分类,并给出了组合柔性结构中柔性杆存在非线性变形的条件.考虑柔性结构的变截面特征和非线性变形的问题,对组合柔性结构的变形特性进行了分析,建立了变形求解的非线性柔性模型.最后设计并加工了一种柔性铰链-柔性杆组合结构,分别采用伪刚体模型、拟柔性模型和非线性柔性模型对其变形进行理论计算,同时采用静电驱动方式对组合柔性结构的变形进行测试.结果表明,非线性柔性模型的计算结果与实验测试结果最接近,证明了此模型和分析方法的有效性.     

基于Ethernet的网络控制系统LQG最优控制器的设计

实时控制网络通常指现场总线,但由于多种现场总线难以集成,阻碍了它的进一步发展.为了解决这一难题,本文提出了基于以太网的网络控制系统.针对以太网作为控制网络存在的数据传输时延给控制品质带来不良影响问题,提出运用通信技术对网络时延进行在线估计.在此基础上,应用控制理论中的李亚普诺夫稳定性定理以及最优控制理论为网络控制系统设计最优控制器--LQG控制器.通过实验证明了上述设计的有效性,从而说明了以太网作为控制网络的可行性.     

基于分段线性化模型的冷连轧机PID解耦控制

针对冷连轧机采用基于工作点的线性化模型进行动态规格变换控制时系统误差和张力波动较大的问题,提出了一种基于递推分段线性化模型的PID解耦控制方案。通过对五机架冷连轧机进行动态规格变换仿真表明,该方案可保证系统的控制精度,满足动态规格变换的控制要求。     

基于非线性规划模型的旋风除尘器设计优化北大核心

作为工业生产应用中一种重要气固两相分离装置,旋风除尘器的应用广泛分布于船舶制造、石油化工、煤炭发电、资源开发等产业领域。基于经典Leith-Licht理论所提出的旋风除尘器半经验设计方法,依据紊流混掺层流分离理论,结合实际含尘空气及其中颗粒物理参数,以旋风除尘器的结构尺寸为变量,建立相应捕集效率数学模型。根据数学模型选择优化目标函数,以自编代码为工具,利用优化设计的思想,采用非线性规划模型对旋风除尘器尺寸进行设计。最后结合计算流体力学(CFD)方法对优化后的尺寸模型进行除尘效率验证。仿真结果表明,改进后的数学模型理论计算与建立的仿真模型计算结果相吻合,误差仅为1.41%。该方法克服了传统设计方法实验验证周期长、经济性差等缺点,对旋风除尘器的优化设计具有重要的工程应用价值。     

基于SV利率期限结构模型的国债价差研究

利用sV利率期限结构模型,本文选取上海证券交易所和银行间债券市场多个交易日的国债数据,运用遗传算法求解模型参数,得到两个市场的国债收益率曲线.结果表明,使用sv模型拟合出的国债理论价格与实际价格之间误差较小,适用于我国国债市场;在两个市场上相同剩余到期期限的国债收益率之间存在价差,而且价差随着国债的到期期限的增加先变小后变大.可能是由于市场分割、流动性差异和交易机制的不同引起的.     

AGC系统控制模型与结构的研究

针对几种厚度自动控制系统（ＡＧＣ系统）控制模型的特点，分析，研究了各种ＡＧＣ控制模型对系统结构的特殊要求，并给出基本的系统结构。对各种ＡＧＣ控制模型及系统之间的关系做了推导和比较。     

Nonlinear Control of Open-Channel Water Flow Based on Collocation Control Model

This paper is devoted to the nonlinear control of open-channel water flow dynamics via a one-dimensional collocation control model for irrigation canals or dam-river systems. Open channel dynamics are based on the well-known Saint-Venant nonlinear partial differential equations. In order to obtain a finite-dimensional model an orthogonal collocation method is used, together with functional approximation of the solutions of Saint-Venant equations based on Lagrange polynomials. This method can give a more tractable model than those obtained from classical finite-difference or finite-element methods (from the viewpoint of both state dimension and structure), and is well suited for control purposes. In particular it is shown how such a model can be used to design a nonlinear controller by techniques of dynamic input–output linearization with the goal of controlling water levels along an open-channel reach. Controller performance and robustness are illustrated in simulations, with a simulated model for the canal chosen as more accurate than the one used for control design.     

Optimal Nonlinear Stochastic Control of Hysteretic Systems

A strategy for optimal nonlinear stochastic control of hysteretic systems with parametrically and∕or externally random excitations is proposed and illustrated with an example of a single-degree-of-freedom system. A hysteretic system subject to random excitation is first replaced by a nonlinear nonhysteretic stochastic system, from which an It? equation for the averaged total energy of the system as a 1D controlled diffusion process is derived by using the stochastic averaging method of energy envelope. For a given performance index, a Hamilton-Jacobi-Bellman equation is then established based on the stochastic dynamical programming principle and solved to yield the optimal control force. Finally, the statistics of the responses of uncontrolled and controlled systems and those of the optimal control force are predicted analytically. Comparison with the modified optimal polynomial controller indicates that the proposed strategy is more effective and efficient.     

基于非线性预测模型的单神经元自适应PID板形控制

为了解决传统PID板形控制精度低、速度慢、抗干扰能力差等问题,将BP神经网络和单神经元引入到板形的控制中,提出一种基于BP神经网络预测模型的单神经元自适应PID控制的板形控制策略。利用BP神经网络的非线性逼近能力和单神经元的自学习、自适应能力,通过两者的有机结合寻找一个最佳的P、I、D非线性组合控制律,实现对带钢板形缺陷的有效控制。仿真实验结果表明,该控制算法能很好地跟踪板形的目标设定值,提高了系统的控制精度,加快了系统的响应速度,并且具备较强的抗干扰能力。     

Robust Control of PVTOL Aircraft with a Nonlinear Optimal Control Solution

In this paper, a new nonlinear control strategy is proposed for hovering control of planar vertical takeoff and landing (PVTOL) aircraft. The control of this typical nonlinear, nonminimum-phase system is treated as a robust control problem. The robust control design is then converted to an equivalent optimal control design so that both stabilization and performance can be guaranteed. The primary contribution of this work is to provide a closed-form solution to the resultant nonlinear optimal control problem by employing a recently emerging nonlinear control approach, called the θ?D technique. The θ?D technique is based on optimal control theory and derived from an approximate solution to the Hamilton-Jacobi-Bellman equation via a perturbation process. This formulation will not only enhance the system performance but also simplify the design process in that robustness and optimality are integrated in one unified optimal control framework. Furthermore, the closed-form control law is very suitable for onboard implementation. The effectiveness of the proposed method is demonstrated by simulation results and comparison studies with a similar linearization based optimal control formulation.     

基于角色的动态分级权限控制模型

企业级WEB ERP应用系统中,对于业务管理层级分明、用户多而分散、权限难以集中管理的系统,传统的RBAC（Role-based Access Control）模型难以满足实际业务系统的需求。基于RBAC模型的基本思想,对角色概念进行了扩展和增强,提出了一种通过资源和角色的分级分层定义,权限分布式逐级控制模型,优化企业管理流程。在实现技术上,定义了人力资源管理区树结构,更加直观地体现了层次结构,简化了授权配置。     

Robust Nonlinear Optimal Solution to the Lunar Landing Guidance by Using Neighboring Optimal Control

A closed-loop time-optimal control strategy for the highly nonlinear problem of the lunar landing mission by using the perturbation technique is developed in this study. The first part of the study considers analytical solution for an optimal control policy of variable mass spacecraft, while it descents on the surface of the moon in the variable gravitational field of it. To validate the accuracy of perturbation solution, a numerical approach based on steepest descent method is employed. The second part considers analytical derivation of an optimal feedback guidance solution by employing the neighboring optimal control (NOC) law when effects of imperfection in the dynamic model or disturbing noises have been taken into account. The technique of NOC produces time-varying feedback gains that minimize the performance index to the second order for perturbations from a nominal optimal path. The robustness of the designed NOC law is examined with applying sinusoidal noises. From the study of the simulation results, it may be concluded that the developed optimal guidance laws may be used in real world spacecraft applications.     

基于非线性方程法的齿轮钢淬透性计算模型

采用非线性回归方程计算方法,结合实际生产的齿轮钢淬透性数据对数学模型进行修正。在此基础上,开发了齿轮钢淬透性的计算预报平台,实现根据成分和预设的晶粒度级别预报任意端淬距离的淬透性值。模型预测精度高于传统的多元线性回归方法。     

基于非线性方程法的齿轮钢淬透性计算模型

采用非线性回归方程计算方法,结合实际生产的齿轮钢淬透性数据对数学模型进行修正。在此基础上,开发了齿轮钢淬透性的计算预报平台,实现根据成分和预设的晶粒度级别预报任意端淬距离的淬透性值。模型预测精度高于传统的多元线性回归方法。     

Nonlinear Dynamical Model for Hysteresis Based on Nonconvex Potential Energy

A model for hysteretic dynamics is proposed in the current paper. Hysteresis is treated as an input–output relation for a dynamic system. The Lagrangian of the dynamic system is constructed on the basis of a nonconvex potential energy and governing equations of the system dynamics are obtained using the Lagrangian equation. Bifurcations will be induced in the nonlinear dynamics due to the nonconvexity of the potential energy. It is shown that when the coefficients are chosen appropriately, the bifurcation diagram will lead to hysteretic behavior. Both the third- and fifth-order nonlinear terms are investigated and it is shown that the fifth-order nonlinearity is able to give a perfect prediction of experimental hysteretic behaviors. Hysteretic damping force of a magneto-rheological fluid damper and polarization hysteresis in piezoelectric materials are modeled successfully using the current model. The parameter identification for the model is also presented.     

基于工程最佳化指标的PID自校正控制

根据模拟调节器中的典型系统工程最佳化指标,直接设置和整定了数字调节器的结构和参数.给出了其中二阶、三阶最佳化设计指标.当对象模型参数时变时,采用自适应控制技术,在线闭环辨识对象模型.数字PID调节器参数被自动整定.