Flatness Control Based on Dynamic Effective Matrix for Cold Strip Mills

Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.

Dynamic matrix predictive control for a hydraulic looper system in hot strip mills

Controlling the looper height and strip tension is important in hot strip mills because these variables affect both the strip quality and strip threading. Many researchers have proposed and applied a variety of control schemes for this problem, but the increasingly strict market demand for strip quality requires further improvements. This work describes a dynamic matrix predictive control(DMC) strategy that realizes the optimal control of a hydraulic looper multivariable system. Simulation experiments for a traditional controller and the proposed DMC controller were conducted using MATLAB/Simulink software. The simulation results show that both controllers acquire good control effects with model matching. However, when the model is mismatched, the traditional controller produces an overshoot of 32.4% and a rising time of up to 2120.2 ms, which is unacceptable in a hydraulic looper system. The DMC controller restricts the overshoot to less than 0.08%, and the rising time is less than 48.6 ms in all cases.

Vector control of permanent magnet synchronous motor based on dynamic matrix control

Aiming at the control problem of strongly nonlinear and coupled permanent magnet synchronous motor(PMSM)oil rig,this paper presents a predictive control method based on dynamic matrix model.In this method,the dynamic matrix algorithm using multistep prediction technique is applied to the speed loop control of the motor vector control.And its control effect is compared with the traditional proportional integral(PI)control of the motor.By comparing the initial dynamic response and the steady-state recovery under load interference of the two methods,it is shown that the dynamic response and the robustness of the motor controlled by the new method is better than that controlled by conventional PI method.And the feasibility of new control in the application of PMSM oil rig is verified.

Resilient Fixed-Order Distributed Dynamic Output Feedback Load Frequency Control Design for Interconnected Multi-Area Power Systems

The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.

SYNCHRONIZATION OF MASTER-SLAVE MARKOVIAN SWITCHING COMPLEX DYNAMICAL NETWORKS WITH TIME-VARYING DELAYS IN NONLINEAR FUNCTION VIA SLIDING MODE CONTROL

In this article, a synchronization problem for master-slave Markovian switching complex dynamical networks with time-varying delays in nonlinear function via sliding mode control is investigated. On the basis of the appropriate Lyapunov-Krasovskii functional, introducing some free weighting matrices, new synchronization criteria are derived in terms of linear matrix inequalities （LMIs）. Then, an integral sliding surface is designed to guarantee synchronization of master-slave Markovian switching complex dynamical networks, and the suitable controller is synthesized to ensure that the trajectory of the closed-loop error system can be driven onto the prescribed sliding mode surface. By using Dynkin＇s formula, we established the stochastic stablity of master-slave system. Finally, numerical example is provided to demonstrate the effectiveness of the obtained theoretical results.

基于NNC法和DMC算法的CCHP型微电网两阶段调度

冷热电联产(combined cooling, heating and power,CCHP)系统与微电网的结合有利于促进消纳可再生能源,为了提升CCHP型微电网的经济性、环保性和稳定性,提出了两阶段优化调度模型。离线优化阶段基于需求侧响应策略,建立了基于归一化法向约束法的多目标规划模型,并用熵权-TOPSIS法筛选最优结果。在线优化阶段建立了基于动态矩阵控制算法的有限时域优化模型,对离线优化结果进行跟踪优化和反馈校正,以降低不确定性因素的影响。最后,设计对比方案进行分析,验证了所提优化模型的有效性。

Quantized dynamic output feedback control for networked control systems

The problem of the quantized dynamic output feedback controller design for networked control systems is mainly discussed. By using the quantized information of the system measurement output and the control input, a novel networked control system model is described. This model includes many networkinduced features, such as multi-rate sampled-data, quantized signal, time-varying delay and packet dropout. By constructing suitable Lyapunov-Krasovskii functional, a less conservative stabilization criterion is established in terms of linear matrix inequalities. The quantized control strategy involves the updating values of the quantizer parameters μi（i = 1, 2）（μi take on countable sets of values which dependent on the information of the system measurement outputs and the control inputs）. Furthermore, a numerical example is given to illustrate the effectiveness of the proposed method.

From the new Austrian tunneling method to the geoengineering condition evaluation and dynamic controlling method

The new Austrian tunneling method （NATM） is widely applied in design and construction of underground engineering projects. When the type and distribution of unfavorable geological bodies （UGBs） associated with their influences on geoengineering are complicated or unfortunately are overlooked, we should pay more attentions to internal features of rocks grades IV and V （even in local but mostly controlling zones）. With increasing attentions to the characteristics, mechanism and influences of engineering construction-triggered geohazards, it is crucial to fully understand the disturbance of these geohazards on project construction. A reasonable determination method in construction procedure, i.e. the shape of working face, the type of engineering support and the choice of feasible procedure, should be considered in order to mitigate the construction-triggered geohazards. Due to their high sensitivity to groundwater and in-situ stress, various UGBs exhibit hysteretic nature and failure modes. To give a complete understanding on the internal causes, the emphasis on advanced comprehensive geological forecasting and overall reinforcement treatment is therefore of more practical significance. Compre- hensive evaluation of influential factors, identification of UGB, and measures of discontinuity dynamic controlling comprises the geoengineering condition evaluation and dynamic controlling method. In a case of a cut slope, the variations of UGBs and the impacts of key environmental factors are presented, where more severe construction-triggered geohazards emerged in construction stage than those predicted in design and field investigation stages. As a result, the weight ratios of different influential factors with respect to field investigation, design and construction are obtained.

The H_∞ synchronization of nonlinear Bloch systems via dynamic feedback control approach

We consider an H∞ synchronization problem in nonlinear Bloch systems. Based on Lyapunov stability theory and linear matrix inequality formulation, a dynamic feedback controller is designed to guarantee asymptotic stability of the master-slave synchronization. Moreover, this controller reduces the effect of an external disturbance to the H∞ norm constraint. A numerical example is given to validate the proposed synchronization scheme.

磁悬浮冷水机组冷冻出水温度DMC控制仿真研究

针对磁悬浮冷水机组冷冻水出水温度控制存在时滞、外界干扰而传统PID控制效果不佳的问题,基于动态矩阵控制算法建立控制与仿真模型,通过预测冷水机组出水温度并加以校正,局部动态优化得到控制器最优控制量。仿真结果表明,动态矩阵控制算法能够实现平稳、无超调的控制,出水温度调整速度相比传统PID控制提升3倍以上,抗干扰能力也优于传统PID算法。

基于动态开关表的TLDMC-PMSM零共模电压直接转矩控制

针对三电平直接矩阵变换器-永磁同步电机系统采用直接转矩控制(TLDMC-PMSM-DTC)时出现高共模电压的问题,提出基于动态开关表的TLDMC-PMSM零共模电压直接转矩控制方法。TLDMC的部分旋转矢量共模电压为零,该方法利用这部分旋转矢量去构建DTC的开关表,但是旋转矢量的分布随输入电压相位的变化而变化,这会导致控制结构的复杂度变高,因此此控制算法通过高维开关表来实现TLDMC-PMSM的零共模电压。但是由于所用旋转矢量数目少并且选择的矢量误差大,从而导致电机的转速和转矩脉动大,该文在此基础上,引入动态的旋转矢量和零矢量去构建动态开关表来解决脉动大的问题。仿真和实验结果表明,该方法在保证动态响应能力快、电机的转速和转矩脉动小的基础上,实现了TLDMC-PMSM系统的零共模电压和安全稳定运行。

基于PI-DMC的发电机组主蒸汽温度串级前馈预测控制策略

针对发电机组主蒸汽温度控制系统惯性大、时滞长、扰动大的特点,结合比例积分微分(PI)控制和动态矩阵控制(DMC)的优点,提出一种基于PI-DMC的发电机组主蒸汽温度串级前馈预测控制策略。以控制量为燃料量、被控量为主蒸汽温度,利用遗忘因子递推最小二乘法对主蒸汽温度控制系统模型参数进行辨识;通过对模型施加单位阶跃信号得到预测模型,并通过反馈校正在线修正预测值;对目标函数实时滚动优化得到当前时刻控制量,并设定控制权重对PI和DMC进行优化组合。仿真结果表明:与串级PID和DMC控制相比,提出的控制策略在模型适配且施加干扰时,调节时间约20 s、超调量仅6.47%;在模型失配且施加干扰时,调节时间约30 s、超调量为6.03%。工程应用结果表明:相较于工业现场原控制策略,提出的控制策略控制精度提高了66.91%,同时汽包液位的控制精度提高了47.23%,符合现场设计要求。

双悬臂截割机器人相对动力学建模与力位混合控制研究

双悬臂截割机器人可解决传统单臂掘进机在截割大尺寸断面时效率低下的难题,但其与煤岩的动态交互影响控制性能。现有研究以双臂接触同一对象形成运动闭链为前提,无法满足双悬臂截割机器人双臂运动及末端截割头输出力的控制要求。针对该问题,设计了一种基于机器人相对动力学模型的力位混合控制系统。建立双悬臂截割机器人运动学和动力学模型,基于机器人的相对雅可比矩阵及虚位移与虚功原理推导出机器人的相对动力学模型,通过单一变量同时描述机器人双臂的运动状态,将机器人双臂独立的动力学模型整合为一个整体。基于机器人的相对动力学模型,设计了机器人双臂力位混合控制系统,通过李雅普诺夫函数验证了系统的稳定性和可行性。仿真结果表明:双悬臂截割工艺较单悬臂截割拥有更大的工作空间,具有一次性实现大断面截割的能力;双悬臂截割机器人力位混合控制系统能够完成对期望相对位置和期望相对力的同步跟踪,对截割头期望位置跟踪的绝对误差在0.3132 m以内,均方根误差为0.1447 m。

基于动态矩阵方法的欠驱动AUV运动控制研究

为解决欠驱动自主水下机器人(AUV)在航行过程中的控制问题,提高其抵抗外部干扰的能力,设计一种新型控制器,该控制器以模型预测控制策略中的动态矩阵控制(DMC)方法为主回路控制器,其目的是通过模型预测与反馈校正的特点使AUV获得良好的跟踪能力。此外,副回路控制器采用频率较高的增量式PID的控制方法,通过优化模型预测向量,设计模型调控参数,最终获得反应速度良好的内回路控制器,其作用是快速抑制突发性扰动。最后,将此控制器应用于AUV首向与深度的仿真实验中,通过仿真实验,验证了该控制器不仅能够满足AUV的控制需求,同时在面对外部时变干扰时具有较好的鲁棒性。

高频链矩阵变换器直接功率反步控制策略

针对高频链矩阵变换器(HFLMC)电路前后级耦合导致系统动态性能和鲁棒性降低的问题,提出一种基于直接功率的非线性反步控制策略(BS-DPC)。首先,建立HFLMC非线性数学模型和有功、无功功率动态模型,分析双极性电流空间矢量调制策略;然后,在考虑系统不确定性情况下引入2个解耦控制分量,设计直流输出电流和无功功率反步控制器,实现电池不同工况下输出电流参考值的快速跟踪控制;最后,根据李雅普诺夫稳定性理论证明HFLMC闭环系统全局渐进稳定性,并对比传统PI直接功率控制和BS-DPC策略。仿真和实验结果表明,所提BS-DPC策略控制HFLMC提高了输出电流的动态性能和电网波动及直流滤波电感变化下的鲁棒性,响应时间减少了约78%,网侧THD降低了0.98%。

一种基于DMC的新型预测PID控制器及其整定(英文)

本文提出一种基于动态矩阵控制(DMC)算法预测特性的新型PID控制方法.在考虑将来的输出期望偏差罚函数最小的前提下,由DMC计算出控制变量的值.继而构造基于DMC的预估器用以预测将来时刻的系统输出.根据将来时刻的多步预测偏差,PID控制器产生当前时刻的实际控制增量.文中也给出了基于DMC的预估器及PID控制器的参数整定方法.仿真结果表明,与常规的PID控制和DMC控制相比,所提方法具有良好的控制性能,扰动抑制尤其优良.

锅炉汽包水位系统DMC─PID串级控制仿真研究

给出具有可测干扰系统的动态矩阵控制(DMC)算法,并结合动态矩阵控制、串级调节和PID控制三者的优点,提出了锅炉汽包水位控制系统的DMC-PID控制策略,即内回路采用PID控制快速消除给水流量的扰动,外回路采用带前馈补偿的DMC控制,可有效地克服汽包水位系统的另一主要扰动-蒸汽流量的扰动,同时DMC的强鲁棒性保证了在对象特性变化的情况下仍然获得良好的调节品质。计算机仿真结果显示了该控制策略的有效性和实用性。

动态矩阵(DMC)-PID串级预测控制策略在新型叶片连续回转马达位置伺服系统中的应用

动态矩阵(DMC)预测控制是一种以优化指标确定控制策略的方法。基于DMC的PID串级预测控制是在单纯PID串级控制的基础上,把经过PID校正的伺服系统定义为广义对象,作为DMC的被控对象,用DMC预测算法在线滚动优化控制参数,在优化过程中利用实测信息不断进行反馈校正。通过仿真分析,与单纯的PID控制相比,在新型叶片式连续回转马达位置伺服系统中采用DMC-PID串级预测的一种控制方法控制能够使整个系统的跟踪性能得到进一步提高。