考虑电磁铁故障的磁浮列车单悬浮模块的容错控制

本文针对参数具有不确定性的磁浮列车单模块悬浮系统,利用线性矩阵不等式(LMI)方法,设计了对执行器失效具有完整性的容错控制器.同时考虑到工程实际的需要,引入权重概念对控制律进行修改,并利用数值方法对新控制律作用下闭环系统的稳定性进行验证.对不同执行器故障模式下悬浮间隙的变化进行了仿真分析,结果表明该方法对闭环系统的参数不确定性具有鲁棒性,对部分执行器失效具有容错能力.     

连铸过程结晶器液面控制的模糊控制方法

对连铸过程结晶器液面控制提出一种新的模糊控制方法。该方法采用一种简化的模糊 PID结构 ,结合了传统模糊 PI与模糊 PD控制方法的优点。仿真结果表明 ,该方法对周期性扰动具有良好的抑制效果 ,对过程参数的变化具有很强的鲁棒性     

抄纸过程定量水分控制仿真研究

抄纸过程定量水分系统既存在强耦合,又具有很大纯延迟;应用Bristol方法了对定量水分系统进行了解耦,对传统Smith预估控制进行了改进并对其鲁棒性进行了分析;提出一种基于Bristol解耦控制和改进Smith预估控制的定量水分优化控制方法,该方法同时解决了耦合和纯延迟两个问题;对直接反馈控制、Bristol解耦控制、改进Smith预估控制、解耦预估优化控制方法的控制效果进行了仿真和比较,结果表明该方法具有良好的控制效果;对解耦预估控制进行了鲁棒性仿真,证明该方法具有很强的鲁棒性,具有一定的工程应用价值.     

Dijkstra和矩阵迭代两种算法的对比研究

Dijkstra算法和矩阵迭代算法都是最短路径问题中的重要方法,然而两种方法中哪种方法具有更高计算效率?为了找到问题答案,文章通过对两种方法的介绍,另外通过MatLab平台对两种方法分别编程,同时进行实例的计算,然后通过各项指标对实验结果比较,得出结论,矩阵迭代算法较dijkstra算法具有更高效的计算能力,其简洁计算方式更便于计算机编程。此次研究有利于对两种最短路径方法有更深刻的认识,便于今后在实际应用中选择具有针对性的方法。     

基于矩的图像变化检测

传统的线性预测的方法在遥感图像变化检测不具有很好的普适性,基于矩的遥感图像的变化检测方法具有对光照,噪声的稳健性.Gaussian-Hermite矩是正交矩,叠加了高斯平滑,但是计算量大.Circular shift矩具有光照不敏感性,但是不是正交矩,具有明显的分块效应.采取将Gaussian-Hermite矩和Circular shift矩相结合,采用由粗到精的策略,应用到遥感图像的变化检测中.将其同单独用Circular shift矩,线性预测的方法进行比较,实验表明提出的方法计算量小,对噪声,光照具有不敏感性.     

基于最小变量的B-样条移动机器人路径规划研究

为解决移动机器人在避障时的曲线优化问题,提出了基于最小变量的B-样条路径规划方法。对该方法从数学模型上进行了推导,指出了该方法相对于其它B-样条方法的优点,并对该方法进行了优化,给出了相应的优化算法。研究表明：具有最小变量的B-样条函数比只用B-样条函数定义的曲线具有更优化的线性约束,其曲线具有更好的光滑性。     

基于最小变量的B-样条移动机器人路径规划研究

为解决移动机器人在避障时的曲线优化问题,提出了基于最小变量的B-样条路径规划方法.对该方法从数学模型上进行了推导,指出了该方法相对于其它B-样条方法的优点,并对该方法进行了优化,给出了相应的优化算法.研究表明:具有最小变量的B-样条函数比只用B-样条函数定义的曲线具有更优化的线性约束,其曲线具有更好的光滑性.     

用DDE实现非固定格式的报表制作

本文介绍了一种利用DDE 实现非固定格式报表生成的方法,该方法具有较好的通用性和实用性,对MIS 开发人员具有很好的参考价值。     

基于小波多分辨率分析的间谐波检测方法

间谐波是电力系统中一种特殊的谐波,大量存在于电网中,对电网的危害很大,对它进行检测和分析具有重要的意义.针对傅立叶(DFT)方法只能检测出整数倍的基波频率,而对间谐波无能为力的缺点,文章提出了一种基于小波多分辨率分析的间谐波检测方法.仿真结果表明该方法具有较好的分辨率,可以很好地对间谐波进行分析,在电力系统间谐波分析方面具有经典DFT方法无可比拟的优点.     

改进的自适应阈值区域图像分割方法在飞机目标识别中的应用

阈值分割是图像分割的常用方法。本文提出采用基于改进的自适应阈值区域分割方法,提高了对飞机目标遥感图像的分割效果。结果表明,该分割方法具有针对性,比传统方法具有明显的优势。     

模型跟踪广义预测鲁棒自适应控制器

本文采用滤波CARMA模型,基于内模原理,提出了一种新的广义预测鲁棒自适应控制器,并分析了闭环系统性能,在新的控制器中,引入适当的前馈作用,使得跟踪和调节问题解耦,利用部分状态跟踪、模型参考以及极点配置方法解决跟踪问题,利用多步预测滚动优化方法解决调节问题;适当选择滤波器可以保证对平稳随机扰动有满意的响应,减少可调参数对闭环系统响应的影响,增强系统对未建模动态的鲁棒性,仿真结果表明:该控制器对确定性和非平稳随机扰动具有不变性,对系统时延和阶次变化具有鲁棒性,适用于非最小相位和开环不稳定系统。     

Multivariable PID control by decoupling

This paper presents a new methodology to design multivariable proportional-integral-derivative (PID) controllers based on decoupling control. The method is presented for general n × n processes. In the design procedure, an ideal decoupling control with integral action is designed to minimise interactions. It depends on the desired open-loop processes that are specified according to realisability conditions and desired closed-loop performance specifications. These realisability conditions are stated and three common cases to define the open-loop processes are studied and proposed. Then, controller elements are approximated to PID structure. From a practical point of view, the wind-up problem is also considered and a new anti-wind-up scheme for multivariable PID controller is proposed. Comparisons with other works demonstrate the effectiveness of the methodology through the use of several simulation examples and an experimental lab process.     

Feedforward output-feedback control for continuous exothermic reactors with isotonic kinetics

The robust feedforward (FF) output-feedback (OF) control problem of (possibly open-loop unstable) continuous exothermic jacketed reactors with isotonic kinetics with respect to reactant concentration is considered. The volume, temperature, and concentration must be regulated by manipulating the feed, exit and coolant flowrates on the basis of volume and temperature measurements. The problem is addressed as an interlaced controller-observer design within a constructive control framework. The result is a quasi linear-decentralized (qLD) FF-OF dynamic controller which: (i) recovers (up to observer convergence) the behavior of a robust nonlinear FF-SF controller, (ii) has closed-loop stability conditions coupled with conventional-like tuning guidelines, and (iii) constitutes an add-on to the PI control scheme commonly employed in industrial reactors. The approach is tested with an open-loop unstable reactor example through simulations.     

A three-loop model-following control structure: theory and implementation

This article presents a novel three-loop control system, which supplements control structures known from the literature as model following control (MFC). The major advantage of the proposed system is its high robustness to process parameter variations; it is much higher than that offered by single-loop or two-loop control systems. Features of the new structure are revealed by a theoretical analysis that has been carried out from the viewpoint of requirements for a force/pose controller of a Stäubli RX60 manipulator. This article shows how the proposed control structure responds to such strong process parameter variations and makes a comparison to results yielded by single-loop control structures.     

Stabilization of robot motion and contact force interaction for third-order motor dynamics

An approach to the synthesis of control laws stabilizing motion and force in contact tasks, based on the exponential stability of the closed-loop control system, is described. When using the synthesized control laws, simultaneous stabilization of both motion and force is achieved with a preset quality of the transient responses. The task is solved in a most general form, taking into account the constraints on robot control, its position and the force of interaction of the robot and the environment, and the external perturbations and inaccuracies of the measuring sensors, when the environment dynamics is being described by nonlinear second-order differential equation, and the robot dynamics includes the third-order equations of the robot actuators dynamics.     

A two-degree-of-freedom PI controller based on events

In this paper, a completely event-based two-degree-of-freedom proportional-integral controller is presented. The architecture of the controller is based on event-based decoupled solutions for the set-point following and the load disturbance rejection tasks. For the first task, the solution is a design procedure that, by considering a first-order-plus-dead-time model of the process and a predesigned open-loop control action, produces an event-based feedforward controller that provides the required process variable transition with just two events. The second task is solved by applying two separate event-based proportional and integral control actions. Because the two tasks are initially solved independently, two solutions for coupling them are described. Illustrative examples of the performance of the controller are included as well as experimental results.     

Generalized terminal state constraint for model predictive control

A terminal state equality constraint for Model Predictive Control (MPC) laws is investigated, where the terminal state/input pair is not fixed a priori but it is a free variable in the optimization. The approach, named “generalized” terminal state constraint, can be used for both tracking MPC (i.e. when the objective is to track a given steady state) and economic MPC (i.e. when the objective is to minimize a cost function which does not necessarily attains its minimum at a steady state). It is shown that the proposed technique provides, in general, a larger feasibility set with respect to the existing approaches, given the same prediction horizon. Moreover, a new receding horizon strategy is introduced, exploiting the generalized terminal state constraint. Under mild assumptions, the new strategy is guaranteed to converge in finite time, with arbitrarily good accuracy, to an MPC law with an optimally-chosen terminal state constraint, while still enjoying a larger feasibility set. The features of the new technique are illustrated by an inverted pendulum example in both the tracking and the economic contexts.     

Decentralized control of the Tennessee Eastman Challenge Process

A decentralized control system is developed for the Tennessee Eastman Challenge Process (TE problem). The design procedure begins with the selection of the method for production-rate control, to which inventory controls and other functions are then coordinated. Results show that production rate can be maximized at any of the three standard product compositions, even when the feed of reactant A is lost. All specifications of the challenge problem are satisfied despite large disturbances in feed composition and reaction kinetics. Variability in product rate and quality is less than that seen in previous studies. The process can operate on-spec for long periods without feedback from composition measurements. Setpoints for certain variables (such as reactor temperature and concentrations of A and C in the reactor feed) must be chosen a priori, and the effect on operating cost is estimated. The performance of the proposed decentralized control is compared to that of a nonlinear model predictive control (NMPC) developed previously. There appears to be little, if any, advantage to the use of NMPC in this application. In particular, the decentralized strategy does a better job of handling constraints - an area in which NMPC is reputed to excel. Reasons for this are discussed.     

A New Control Scheme of Single-link Flexible Manipulators Robust to Payload Changes

A new scheme is presented in this paper to control single-link flexiblemanipulators. The objective is to control the tip position of the flexiblearm in the presence of joint friction and payload changes. The controlscheme is based on two nested loops: an inner feedback loop to control themotor position which is robust to joint friction, and an outer loop tocontrol the tip position which is robust to payload changes. This outer loopis composed of a feedforward term and a feedback term. This results in asimple control law that needs minimal computing effort and, thus, can beused for real time control of flexible arms. The proposed method is generalin the sense that it can be applied to very different arm structures anddiverse sensor systems configurations. Results corresponding to twodifferent arm setups are presented.     

高频增益符号未知时的变结构模型参考自适应控制:任意相对阶的控制律设计

讨论被控对象相对阶大于1且高频增益符号未知时的变结构模型参考自适应控制问题,从而将相对阶为1时的结果推广到任意相对阶.首先对关键信号构造监控函数,并在此基础上提出了一种控制信号切换律.进而证明,当被控对象相对阶大于1、高频增益符号未知时,在监控函数的监测下,相关控制信号经至多有限次切换后将停止切换,跟踪误差将收敛到一个残集内,且该残集可通过减小某些设计参数而变得任意小.特别,本文证明,与相对阶为1时相同,当对象相对阶大于1时,若系统的某些初始条件为零,则至多只需要一次切换.