论文标题:建筑结构最优控制理论及其应用研究
Civil Structure Optimal Control Theory and Application Studies
论文作者
论文导师 邓子辰,论文学位 硕士,论文专业 一般力学与力学基础
论文单位 西北工业大学,点击次数 93,论文页数 83页File Size3558K
2007-03-01论文网 http://www.lw23.com/lunwen_848744037/
structure control; stability; instantaneous optimal control; open-closed loop; prediction instantaneous optimal control
控制是结构对策发展的最高阶段，结构振动控制是当前结构工程的高科技领域之一。1972年美国普渡大学J．T．P．Yao教授提出结构控制的概念以来，确定反馈与控制增益最优关系的算法始终是持续研究的热点课题，不断的改进已有算法弥补已有算法的缺陷也是科技工作者的重要工作，本文的选题也正是建立在此基础之上的。 第1章首先从现在的建筑结构设计思想，即延性结构设计体系中出现的问题入手，引出结构设计的一种新概念——结构控制。接下来对建筑结构控制的任务及实现途径做了系统的分析，介绍了建筑结构控制的分类，讨论了结构主动控制及其发展现状，最后引出本文的主要工作。 系统的模型是整个结构控制的前提条件，第2章讨论了动态系统及其主要特性，包括系统的数学描述、稳定性、能控性和能观性，这些性质是评价一个控制系统的最基本的要求，并且指出了这些性质的判别方法。 第3章介绍了工程中常用的线性二次型最优控制的算法，即LQ、LQG和瞬时最优控制，讨论了它们各自的优点以及共同存在的问题，即开闭环控制作为一种较理想的控制策略却无法在工程中应用的难题。 第4章提出了一种瞬时最优预测控制方法，该方法在性能指标中综合考虑下一时刻位移、控制律输入能量和地震波能量的影响，并对下一时刻的地震激励进行预测，解决了第3章中算法的共同存在的问题，并且讨论了算法的稳定性、能控性和能观性；针对算法中的指数矩阵的数值计算，引入精细算法，在满足足够精度的情况下，解决了指数矩阵计算困难的问题；最后讨论了算法的时滞影响。 第5章对第4章提出了算法进行了实例仿真，将该方法与工程中采用较多的LQG方法进行了对比，结果显示采用瞬时最优预测控制方法取得的控制效果优于LQG方法；对存在时滞时的系统进行了仿真分析，结果显示在存在0.06s时滞时，算法仍然有效，说明了算法的鲁棒性较好。 第6章对整个论文进行了总结，并且对振动控制及其本文提出的瞬时最优预测控制的应用前景进行了展望，并进一步指出本文提出的算法如果要应用到工程实际当中尚需要深入进行大量的工作。
Control is the top stage of structure countermeasure, and the structure vibration control is one of the high-tech fields of structure engineering nowadays. Since professor J.T.P.Yao from Purdue University proposed the concept of structure control in 1972, research for new algorithm about optimal relation between feedback and control gain is a continuously hot topic which is valuable in study, and improving on the existing algorithm or remedying bugs in existing algorithm is also an important work for scientists and engineers, which is the basic point studied in this dissertation. The main research works of the present dissertation can be described as follows:In the first chapter, the problem in the traditional concept called flexible structure design in civil structure design is presented. Then, a new structure design concept called structure control is introduced. Next, the task and approach of structure control are analyzed. In addition, the structure control types and its development are presented. At last, the primary works in this dissertation is pointed out.The system model is the premise condition of structure control, so the second chapter discusses the dynamical system and the mainly system properties, including mathematics model, stability, controllability and observability. These properties are the basic conditions to evaluate a control system.In the third chapter, three optimal control algorithms about structure control are presented, which are classical Linear Quadratic optimal control, Linear Quadratic Gauss optimal control and instantaneous optimal control. Next, their merits and bugs are evaluated, and their same bug is pointed out especially, which is as a perfect control strategy, open-closed control can"t be applied in project because of the uncertainty of Seismic Excitation.In the fourth chapter, a new algorithm called Instantaneous Optimal Prediction control is proposed. During the closed-open loop control, the algorithm includes one step ahead corresponding to the discrete expression of governing equation, the input energy of control force and Seismic Excitation, thereby it can solve the problem that we must know the information of Seismic excitation. Then next, its dynamical properties including stability, controllability and observability are discussed. The calculation of matrix exponent is quite difficult, especially when the dimension is more. In order to solve the problem, a precise calculation method is introduced. The influence of time delay is discussed briefly in the last section.
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