Wavelet-Based Algorithms for Control of Smart Civil Structures - Phase Two Study

PI：Hojjat Adeli，俄亥俄州这是一个由两部分组成的研究工作的第二阶段，旨在研究小波作为土木结构控制手段的作用。技术工作与确定为第一阶段工作一部分的工作范围相结合。项目摘要尽管经典的反馈控制算法，如线性二次型调节器(LQR)和线性二次型高斯(LQG)算法可以用来减少振动，但它们存在许多根本缺陷。它们在结构的固有频率附近实现了显著的衰减，但当外部干扰的频率与结构的固有频率略有不同时，它们无法抑制振动。经典最优控制算法的局限性在于输入激励必须是先验的，而对于地震或风荷载作用下的土木结构则不是这样。智力优势：拟议研究的主要目标是探索基于小波的算法，以创建一种新的控制模型，用于承受地震和风等动态力的土木结构的主动、半主动和混合控制，克服现有反馈控制算法的一些缺点。新的控制模型将a)具有在一定输入频率范围内抑制振动的能力，b)不太容易受到结构建模近似和误差的影响，以及c)包括外部激励项。这是通过巧妙地集成反馈控制算法来实现的，例如LQR或LQG算法、滤波x最小均方(LMS)算法和小波。目标是在外部动态扰动下实时实现最优控制。建议的研究重点将是利用小波的滤波和变换特性以及基于小波的算法来开发最优控制策略。这项研究的第二个目标是探索通过将被动辅助减振系统和半主动调谐液柱阻尼器(TLCD)系统合理地结合起来来开发一种混合控制系统。新模型利用了被动和半主动控制系统的优点，从而提高了控制系统在正常运行以及电源或计算机故障时的整体性能、可靠性和可操作性。采用鲁棒小波-混合反馈LMS控制算法寻找控制参数的最优值。所提出的混合控制系统不同于其他所提出的将主动系统和被动系统相结合的混合控制系统，从而消除了对大功率要求的需要。更广泛的影响：拟议研究对整个社会的潜在好处将是创造新一代智能民用结构，提高安全性和可靠性，以抵御该国大部分地区遭遇的地震和强风等自然灾害。拟议的研究将a)导致新的控制技术，以减轻结构在动态地震和风荷载作用下的危害，b)对振动控制的一般领域，包括机械和航空航天结构的控制，以及c)在使用小波来解决其他智能民用基础设施系统方面产生新的见解。

PI: Hojjat Adeli, Ohio StateThis is the second phase of a two-part research effort aimed at examining wavelets as a means of control for civil structures. The technical effort is integrated with the scope of work identified as part of the phase 1 effort. Project Summary Even though classical feedback control algorithms such as the Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian (LQG) algorithms can be used to reduce vibrations, they suffer from a number of fundamental shortcomings. They achieve a significant level of attenuation in the vicinity of the natural frequencies of the structure, but fail to suppress the vibrations when frequency of the external disturbance differs even slightly from the natural frequencies of the structure. A limitation of classical optimal control algorithms is due to the fact that the input excitation must be known a priori which is not the case for civil structures subjected to earthquake or wind loading. Intellectual Merits: The primary objective of the proposed research is to explore wavelet- based algorithms for creation of a new control model for active, semi-active, and hybrid control of civil structures subjected to dynamic forces such as earthquakes and winds overcoming some of the shortcomings of the existing feedback control algorithms. The new control model will a) have the ability to suppress vibrations over a range of input frequencies, b) be less susceptible to structural modeling approximations and errors, and c) include the external excitation term. This is achieved through adroit integration of a feedback control algorithm such as the LQR or LQG algorithm, the filtered-x Least Mean Square (LMS) algorithm, and wavelets. The goal is to achieve optimum control under external dynamic disturbances in real time. A focus of the proposed research will be development of optimal control strategies utilizing the filtering and transformation characteristics of wavelets and wavelet-based algorithms. A secondary objective of the proposed research is to explore the development of a hybrid control system through judicious integration of a passive supplementary damping system with a semi-active tuned liquid column damper (TLCD) system. The new model utilizes the advantages of both passive and semi-active control systems, thereby improving the overall performance, reliability, and operability of the control system during normal operations as well as a power or computer failure. The robust wavelet-hybrid feedback LMS control algorithm will be used to find optimal values of the control parameters. The proposed hybrid control system eliminates the need for a large power requirement, unlike other proposed hybrid control systems where active and passive systems are combined. Broader Impacts:The potential benefits of the proposed research to society at large will be creation of a new generation of smart civil structures with improved safety and reliability against natural hazards such as earthquakes and strong winds encountered in most of the country. The proposed research will a) lead to new control techniques for hazard mitigation of structures subjected to dynamic seismic and wind loading, b) be of value to the general domain of vibration control including control of mechanical and aerospace structures, and c) result in new insights in the use of wavelets for solution of other intelligent civil infrastructure systems.