热电偶检定炉炉温模型参考自适应控制的研究

热电偶校检定炉在对热偶进行高温点的校验时,炉温难于稳定,主要原因在于控高温时加热时间较长环境温度产生较大变化,从而造成检定炉加热模型产生时变,导致控制器效果明显变差,本文利用模型参考自适应控制方法在线调整PID控制器参数以适应环境温度变化而造成的加热炉模型时变,试验结果表明该方法适应性良好,从而为热电偶检定炉的温度控制提供了新的方法。     

粗轧机开式机架连接锁紧装置的改进

针对我公司高线厂粗轧机开式机架,连接装置存在的问题,在结构分析、强度分析的基础上对此装置进行了改造,取得了很好效果。对于同类轧机开式机架连接具有一定的借鉴和参考价值。     

鞍钢无缝钢管厂总体改造框架探讨

介绍了鞍钢无缝钢管厂发展的历程,阐述了必须对其进行技术改造的理由,提出了改造的具体原则及设想.     

嵌入式LCD控制器的设计和实现

介绍了一种嵌入式LCD控制器的设计和实现方案。提出了实现对LCD控制器的两种设计方案构思，其中：一种方案采用一片CPLD和两片帧存的控制器设计方案；另一种只采用一片CPLD和一片帧存的控制器设计方案。分析了两种方案的优点和弊端，详细介绍了后一种方案，并给出了它的实现方法。该方案只要稍作改动就能应用到其他的LCD上。     

基于DotNET平台的应用程序开发框架的研究

介绍了基于Web的分布式应用系统的框架结构模型,讨论了数据库访问、用户安全、通用的用户控件、工作流和工作任务等的功能与实现。研究成果已经用于资产管理、人力资源管理等产品的开发,应用实践表明该框架的设计技术先进,性能优良,功能强大,完全满足分布式应用系统的开发需要。     

A new approach to adaptive control: no nonlinearities

In adaptive control the goal is to design a controller to control an uncertain system whose parameters may be changing with time. Typically the controller consists of an identifier (or tuner) which is used to adjust the parameters of a linear time-invariant (LTI) compensator, and under suitable assumptions on the plant model uncertainty it is proven that good asymptotic behaviour is achieved, such as model matching (for minimum phase systems) or stability. However, a typical adaptive controller does not track time-varying parameters very well, and it is often highly nonlinear, which can result in undesirable behaviour, such as large transients or a large control signal. Furthermore, most adaptive controllers provide only asymptotic tracking, with no ability to design for a pre-specified settling time.Here we propose an alternative approach, which yields a linear periodic controller. Rather than estimating the plant or compensator parameters, instead we estimate what the control signal would be if the plant parameters were known. In this paper we argue the utility of this approach and then examine the first order case in detail, including a simulation. We also explore the benefits and limitations of the approach.     

Model reference adaptive robust fuzzy control for ship steering autopilot with uncertain nonlinear systems

A novel model reference adaptive robust fuzzy control algorithm is presented for ship steering autopilot, which is an uncertain nonlinear system. In the proposed algorithm, fuzzy logic systems have been used to approximate lumped unknown function in the ship steering systems and the adaptive mechanism with minimal learning parameter, i.e. only one parameter, has been achieved by use of Lyapunov approach. The proposed methodology is verified using the simulation mode of the Dalian Maritime University's ocean-going training ship named Yulong. It is shown that the proposed algorithm guarantees that the ship steering autopilot system is asymptotically stable and its tracking error can approach to zero.     

Trajectory tuning for the tracking problem of the underactuated mechanical systems: application to the PVTOL aircraft

The Planer vertical take-off and landing (PVTOL) aircraft is a typical example of an underactuated mechanical system and has a nonminimum-phase nature. When considering output tracking control, the Input/Output (I/O) linearization method is not appropriate since the stability of the internal dynamics is not guaranteed. Hauser et al. regarded this system as a slightly nonminimum-phase system which approximates to a minimum-phase one. Their control scheme yielded good results when the coupling factor was small, but the results were not acceptable when the coupling factor increased. In this article, we propose two approaches to improve the control performance. First, we consider the approximation error of Hauser's scheme as uncertainty, and apply the Linear Quadratic Regulator (LQR) method, which possesses robustness against uncertainty, to determine the stabilizing feedback coefficients. Second, from the fact that the tracking error is unavoidable, we use the “virtual reference trajectory” to design the tracking control law, and optimize this trajectory to reduce the tracking error between the “actual reference trajectory” and the “resulting trajectory”. This optimization also improves the control performance by choosing a suitable performance index. By using our approach, we achieve better performance even if the coupling factor is increased. We show these results by numerical simulation. This work was presented, in part, at the Seventh International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

基于事件框架的事件相关文档的智能检索研究

在事件相关文档的检索中,事件主题的迁移和分化与相似事件的干扰是影响系统性能的两个主要因素。本文提出了一种基于事件框架知识和事件主体信息的检索方法。该方法对事件相关评价函数进行了的改进:首先,从事件语料中提炼出事件的框架知识、从事件文档中挖掘出表达事件主体的信息,然后将这些知识和信息进行向量化,最后利用向量化的结果对相关度评价函数进行优化。实验结果表明该方法是有效的,明显提高了事件相关文档的检索性能。     

基于主存访问相关解决等技术的高带宽主存控制器设计

随着现代处理器和缓存技术的发展,当代计算机系统的性能日益受到主存系统的制约,对主存带宽的需求将越来越大。论文提出主存访问相关解决、主存访问动态调度和地址重映射三项技术,利用主存访问自身的特性(局部性)、同步DRAM自身的物理特性(操作的并行性)和二者之间的关系(地址映射),设计了新型、高带宽主存控制器,有效地提高了主存系统的带宽。