Integration of batching and scheduling for hot rolling production in the steel industry

This paper investigates the hot rolling production scheduling problem in the steel industry and proposes a new mixed integer programming model for this problem based on the monolithic modeling strategy that integrates batching and scheduling. Using this strategy, the new model can simultaneously schedule multiple turns and simultaneously determine the production timetable of these turns in a global optimal view. A long-term tabu search heuristic using frequency-based memory is developed to obtain near-optimal solutions for this problem. Three kinds of speed-up strategies are developed to accelerate the search procedure of the proposed tabu search. A practical scheduling system combining the proposed mathematical model and the tabu search heuristic has been developed and tested on instances collected from practical production data. The experimental results show that the proposed mathematical model and the tabu search heuristic outperform both the current manual scheduling method and the traditional serial method.     

Disposal of Waste Plastics With Traditional Coking Process

A new technology for treating waste plastics （WP） by traditional coking process was introduced. With a thermo-balance and a 10 g atmospheric fixed bed reactor, the thermo-gravimetric behavior and product were studied during co-coking of WP with blended coal. And then, using a coke-oven with capacity of 200 kg, the characteristics of products were assessed. The results showed that there is an overlapping temperature range （200-550℃ ） of decomposition between WP and blended coal, and the pyrolysis synergism index η and synergism strength β proposed could evaluate the synergism between them. 1% of added WP results in the maximum synergism in all series experiments. The increase of added WP decreases the synergism. Tar yield in co-coking is increased with the decrease of water yield for synergism. Moreover, it was also found that the quality indexes of coke, such as M10, M40, CRI and CSR, are degraded with the increase of WP until 4%, though the quality of tar and gas is optimized for WP addition.     

基于颜色空间映射的自适应足球机器人视觉系统

为了解决足球机器人比赛中视觉信息检测问题,给出基于嵌入式多处理器体系结构的视觉系统框架,并研究了一种自适应阈值目标分割方法。该方法将视觉系统采集的图像从YCbCr颜色空间转换为一维颜色映射图像,并提出基于竞争学习的空间映射方法。同时使用小波变换方法来平滑颜色映射空间直方图和降低阈值搜索维数。然后使用基于映射图像直方图动态搜索阈值的方法来分割图像。最后,通过实验表明研究的视觉系统的有效性,能够实时准确地完成视觉处理任务。     

动态滑模控制在EAF电极调节系统中的应用

针对电弧炉电极调节系统的非线性、时变、模型不确定、大滞后等特点,结合高阶滑模和动态滑模控制的设计思想为其设计了一种动态滑模控制器,即通过微分环节构成新的切换函数,将不连续项转移到控制的一阶中,得到本质连续的动态滑模控制律,并将其应用到电弧炉电极调节系统中。对系统的阶跃响应和跟踪特性分别进行了仿真,仿真结果表明,所设计的动态滑模控制器不仅能使系统具有良好的动态性能和较强的跟踪特性,同时能有效地抑制系统的抖振,达到控制系统的动态品质要求。     

基于集成神经网络的多故障诊断方法

铝电解过程是一个非线性、多耦合、时变和大时滞过程,受强电场、强磁场、强热场交互干扰,形成了复杂多变的槽况特征,故障种类繁多,发生频繁,有效地故障预报和诊断,对电解系列平稳供电,节约电能、提高铝的产量和质量有重要意义。根据铝电解过程故障特点,提出了基于主成分分析的集成神经网络铝电解多故障诊断方法,建立分层故障诊断模型结构,包括子神经网络层和决策融合神经网络层,子神经网络模块采用了改进型的Elman神经网络,强化信息的记忆功能,并通过主成分分析优化了神经网络结构;决策融合神经网络通过各子网络传递的相关信息,进一步验证对子神经网络诊断结果和复合故障进行综合决策。仿真结果表明,具有良好的诊断效果,验证了该故障诊断方法的可行性和有效性。     

A new admissibility condition of discrete-time singular systems with time-varying delays

This paper gives a novel delay-dependent admissibility condition of discrete-time singular systems with time-varying delays. For convenience, the time-varying delay is assumed to be the sum of delay lower bound and the integral multiples of a constant delay. Specially, if the constant delay is of unit length, the delay is an interval-like time-varying delay. The proposed admissibility condition is presented and expressed in terms of linear matrix inequality (LMI) by Lyapunov approach. Generally, the uncertainty of time-varying delay would lead to conservatism. In this paper, this critical issue is tackled by accurately estimating the time-varying delay. Consequently, the proposed admissibility condition is less conservative than the existing results, which is demonstrated by a numerical example.     

Adaptive fault detection and isolation approach for actuator stuck faults in closed-loop systems

This paper addresses the fault detection and isolation (FDI) problem for linear time-invariant (LTI) systems under feedback control. Considered all the possible actuator stuck faults, the closed-loop systems are modeled via multiple models, i.e., fault-free model and faulty models. A fault detection observer and a bank of fault isolation observers are designed by using adaptive estimation techniques. The explicit fault detectability and isolability conditions are derived for determining the class of faults that are detectable and isolable. An F-18 aircraft model is employed to illustrate the effectiveness of the proposed FDI approach.     

Fault tolerant H ∞ control for a class of polynomial non-linear discrete-time systems

This paper studies the fault tolerant control (FTC) problem for a class of polynomial nonlinear discrete-time systems with guaranteed H _∞ performance in the presence of actuator faults. The concerned fault is considered as a multi-model of the typical aberration in actuators’ effectiveness. A quadratic-like polynomial Lyapunov function is presented for the H _∞ specification. The main contribution of this paper is that the effect of the nonlinear terms appear in FTC analysis is described as an index in order to transform the controller design into a semi-definite programming (SDP). A numerical example is given to verify the applicability of this new approach for the nonlinear FTC synthesis.     

铸造镍基高温合金的蠕变阻力

在对颗粒强化理论和位错蠕变理论进行回顾、评价基础上，发展了一个位错蠕变阻力模型，认为蠕变阻力是影响铸造镍基高温合金蠕变机制的重要因素。当施加应力足以使位错切入γ′相时，主要蠕变机制是位错切割γ′相过程，蠕变阻力就是位错切入γ′相的临界门槛应力。在低施加应力区，位错只能借助于热激活攀移过程通过γ′相。蠕变阻力包括两部分：第一项是位错攀移临界门槛应力，与施加应力无关；第二项是与施加应力有关的阻力项，代表了其他强化机制的贡献。位错攀移机制蠕变阻力的上限是切割机制门槛应力。在3种铸造镍基高温合金中（定向凝固DZ17G合金，IN100合金和IN738合金），对上述模型进行了验证，理论计算应用了SL强化理论，与实测值符合较好。