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1.
研究了压电智能板结构的H∞振动控制问题。先采用4节点矩形弯曲薄板单元(含12个位移自由度,2个电自由度)的有限元模型,利用Ham ilton原理得到了智能板结构的运动微分方程,然后综合运用模态截断法、最小实现法和平衡降阶法,对压电智能板结构的系统状态方程进行了降阶处理,得到了可观可控且低阶的近似状态方程,针对该降阶后的系统,利用H∞控制理论求解出能抑制干扰的动态输出反馈控制器,并将该控制器作用到降阶处理前的原系统中,从而能实现原系统抗干扰的振动控制。最后,以智能悬臂薄板结构为例,讨论了降阶过程中出现的一些问题和结论,并求出了相应的动态输出反馈控制器。仿真结果表明,文中的方法可实现压电智能板结构对干扰的抑制。  相似文献   

2.
对桁架结构系统的模型降阶和主动控制进行了研究。系统模型采用有限元方法进行建模;模型降阶分别采用模态价值分析方法和内平衡降阶方法;控制设计采用最优控制方法。同时详细给出了模态价值分析方法和内平衡降阶方法的降阶过程,并将两者的结果进行了数值对比。仿真结果显示,两种降阶方法均能够有效地对桁架系统进行模型降阶,本文采用的最优控制律能够有效地抑制结构的振动。  相似文献   

3.
土木工程结构振动控制由于模型的自由度数目较大,结构控制中控制器阶次较高,导致主动控制和半主动控制实施过程中时滞效应十分突出.本文在采用均衡实现技术对结构模型的状态变量重新排序形成内部均衡系统的基础上,对系统二次型性能指标泛函进行内平衡变换,略去对内平衡系统能量影响较小的状态变量,进行结构模型的降阶.通过对20层钢框架结构振动控制Benchmark模型二班型性能指标泛函进行内平衡变换,得到降阶的振动控制模型,计算表明本文方法是可行和有效的.  相似文献   

4.
基于气动力辨识的ASE模型降阶研究   总被引:1,自引:0,他引:1  
CFD/CSD耦合计算能够准确预测跨音速段飞行器弹性振动的非定常气动力, 但其带来的巨大 计算量及高阶维数不利于气动弹性系统的分析与综合. 针对于此,采用系统辨识及 均衡截断技术对高阶气动伺服弹性模型进行降阶处理,并利用所得到的低阶模型进行系统综 合:(1) 基于Volterra级数气动力辨识技术,得到非定常气动力的时域降阶模型(ROM), 耦合结构动力学模型及控制机构动力学模型获得气动伺服弹性(ASE)状态空间方 程;(2) 利用均衡截段法对时域ASE模型进行进一步降阶,得到能够较真实反映所关心频域内系统响应 的低阶ASE模型;(3) 针对建模误差和降阶误差存在造成的系统不确定性问题,结合降阶模型 采用混合灵敏度$H_{\infty}$控制方法设计颤振主动抑制鲁棒控制律,保证其作用 于真实系统的有效性;对控制器进行 均衡阶段降阶并保持其鲁棒性,得到低阶鲁棒的颤振抑制控制器. 最后利用典型的BACT模型 进行气动伺服弹性的降阶及主动颤振抑制控制,仿真结果表明,基于ROM建立的低阶气动弹 性模型能够较真实地反应系统的颤振特性;而基于截断后的降阶模型所设计的低阶鲁棒控制 器能够有效应用于存在不确定性摄动的实际系统,并将系统颤振速度提高36%.  相似文献   

5.
采用分布式压电驱动器升力面的颤振主动抑制   总被引:1,自引:0,他引:1  
陈伟民  管德  李敏  诸德超 《力学学报》2002,34(5):756-763
对采用分布式压电驱动器升力面的颤振主动抑制进行了理论与试验研究.应用 LQG最优控制法设计了主动控制律,在控制律降阶时提出了平衡实现与LK法结合使用的新途径,在对不定常气动力进行有理函数拟合时对LS法进行了改进.试验中利用激光测速仪非接触测量模型的速度响应并在地面共振试验中用压电驱动器激振模型.颤振风洞试验结果表明,理论计算合理并与试验结果吻合良好.  相似文献   

6.
平台是一个耦合系统 ,表现在转动惯量耦合和力矩耦合。在设计稳定回路时平台模型与实际物理模型有差别 ,因此要求所设计的控制器具有鲁棒稳定性。 H∞ 控制理论是目前解决鲁棒控制问题比较成功且比较完善的理论体系 ,本文利用 H∞ 控制理论 ,研究了平台稳定回路多输入多输出 ( MIMO)控制器的设计。最后通过计算机仿真 ,验证了控制器的正确性。  相似文献   

7.
可控约束阻尼层梁的H∞控制实验研究   总被引:4,自引:0,他引:4  
谢石林  张希农 《实验力学》1999,14(2):157-164
建立了可控约束阻尼层悬臂梁的动力学模型,分析了模型中的不确定性.针对模态溢出问题,研究了可控约束阻尼层梁结构的H∞鲁棒控制设计,并进行了数值仿真与控制实验研究.结果表明,与位移比例反馈控制相比,H∞控制能有效抑制可控约束阻尼层梁结构的模态振动,且对被截断模态不产生控制溢出,具有良好的鲁棒稳定性.  相似文献   

8.
振动控制系统的可靠性可以反映出主动控制的效果,本文提出了一种适合于确定框架结构控制系统可靠性的计算方法。该方法利用模态变换,把系统变为模态独立的振动方程,根据Field提出的假设,先定义阈值,假设控制后系统响应对阈值的穿阈率服从泊松分布,然后根据各模态的控制结果确定相应的可靠性,最后根据Veneziano提出的方法给出系统的可靠性。文中提出针对框架最大位移的控制输出来确定系统可靠性概念;此外,在系统降阶和控制方法方面,选择了基于系统可控性的平衡降阶法和针对系统不确定性具有较好控制效果的广义预测控制,最后给出了计算实例,算例表明这一方法是有效的。  相似文献   

9.
吴志刚  高强 《力学学报》2004,36(6):757-761
系统的H∞范数表征其对外界干扰的抑制能力. 根据控制系统最小H∞范数与Hamilton微分系统两点边值问题一阶特征值之间的对应关系,利用微分方程特征值的摄动法估计由区间参数描述的不确定性系统的最小H∞范数.  相似文献   

10.
土木工程结构振动控制由于模型的自由度数目很大,控制器阶次非常高,从而导致主动控制和半主动控制实施过程中时滞效应十分的突出。本文在采用均衡实现技术对结构模型进行降阶的基础上,进行LQ控制器的设计,考虑了对应较小奇异值的状态变量对低阶控制器的影响,对LQ控制器的设计进行改进,优化了控制效果。本文通过对Highway Bridge的Benchmark模型进行LQ控制器设计的改进研究,验证了本文方法的改进效果。  相似文献   

11.
When using H ∞ techniques to design decentralized controllers for large systems,the whole system is divided into subsystems, which are analysed using H ∞ control theory before being recombined. An analogy was established with substructural analysis in structural mechanics, in which H∞ decentralized control theory corresponds to substructural modal synthesis theory so that the optimal H∞ norm of the whole system corresponds to the fundamental vibration frequency of the whole structure. Hence, modal synthesis methodology and the extended Wittrick-Williams algorithm were transplanted from structural mechanics to compute the optimal H ∞ norm of the control system. The orthogonality and the expansion theorem of eigenfunctions of the subsystems H∞ control are presented in part ( Ⅰ ) of the paper. The modal synthesis method for computation of the optimal H∞ norm of decentralized control systems and numerical examples are presented in part ( Ⅱ ).  相似文献   

12.
When using H ∞ techniques to design decentralized controllers for large systems,the whole system is divided into subsystems, which are analysed using H∞ control theory before being recombined. An analogy was established with substructural analysis in structural mechanics, in which H ∞ decentralized control theory corresponds to substructural modal synthesis theory so that the optimal H ∞ norm of the whole system corresponds to the fundamental vibration frequency of the whole structure. Hence, modal synthesis methodology and the extended Wittrick-Williams algorithm were transplanted from structural mechanics to compute the optimal H∞ norm of the control system. The orthogonality and the expansion theorem of eigenfunctions of the subsystems H∞ control are presented in part (Ⅰ)of the paper. The modal synthesis method for computation of the optimal H ∞ norm of decentralized control systems and numerical examples are presented in part (Ⅱ).  相似文献   

13.
Active control for nonlinear aeroelastic structures is an attractive innovative technology. The design of classic active flutter controllers has often been based on low-fidelity and low-accuracy linear aerodynamic models. Multi-physics high-fidelity reduced order model (ROM) was used to design active control laws. In order to provide a lower-order model for controllers design, a balanced proper orthogonal decomposition ROM (POD-BT/ROM) was investigated. A state-space aeroservoelastic model and the active flutter suppression control law design method based on POD-BT/ROM were proposed. The effectiveness of the proposed method was then demonstrated by NACA 0012 airfoil, AGARD 445.6 wing and the Goland wing+ aeroelastic model.  相似文献   

14.
The present nonlinear model reduction methods unfit the nonlinear benchmark buildings as their vibration equations belong to a non-affine system. Meanwhile, the controllers designed directly by the nonlinear control strategy have a high order, and they are difficult to be applied actually. Therefore, a new active vibration control way which fits the nonlinear buildings is proposed. The idea of the proposed way is based on the model identification and structural model linearization, and exerting the control force to the built model according to the force action principle. This proposed way has a better practicability as the built model can be reduced by the balance reduction method based on the empirical Grammian matrix. A three-story benchmark structure is presented and the simulation results illustrate that the proposed method is viable for the civil engineering structures.  相似文献   

15.
This paper discusses the design of fuzzy PID type controllers (FPIDC) to improve seismic control performance of a nonlinear structural system with an active tuned mass damper (ATMD) against earthquakes. Since structural systems have nonlinearities and uncertainties, fuzzy-based controllers are adequate because of their robust character and satisfactory performance in active structural control. The main advantages of this controller are the ability to handle nonlinearities and uncertainties effectively. In the literature, various structures for fuzzy PID (including PI and PD) controllers have been proposed. In order to obtain proportional, integral and derivative control actions altogether, it is intuitive and convenient to combine PI and PD actions to form a fuzzy PID controller. The simulated system has fifteen degrees of freedom and is modeled using nonlinear behavior of the base–structure interaction. The system is then simulated against the ground motion of the Northridge earthquake (M w =6.7) in USA on 17 January, 1994. Finally, the time history of the storey displacements, accelerations, ATMD displacements, control voltage and frequency responses of both the uncontrolled and controlled cases are presented. The ground motion recorded of the El-Centro and Kocaeli earthquakes has been used to evaluate the effectiveness of the proposed control algorithm. The robustness of the controller has been checked through the uncertainty in stiffness of the structure. Simulation results exhibit that superior vibration suppression is achieved by the use of designed fuzzy PID type controllers.  相似文献   

16.
针对线性离散时间系统,研究其时域硬约束下的H∞输出反馈控制问题。假定外界扰动能量有限,基于线性矩阵不等式处理方法,提出并证明了时域硬约束下H∞输出反馈控制器存在的充分条件,并应用于车辆主动悬架设计。四分之一车辆模型数值仿真结果表明,即使车辆模型参数存在不确定性,本文提出的控制器在提高车辆乘坐舒适性的同时,仍能很好地兼顾车辆的其他性能要求。  相似文献   

17.
ABSTRACT

The simultaneous design of scruccure and active controls is considered for structures equipped with force controllers. Both requirements for mission control (prescribed terminal conditions) and for the control of structural response (control damping) are reflected in developments for the design of

distributed parameter and large scale structures. As an example of problems with simple modal control, the optimal design is predicted for a cantilevered beam and for the feedback gains and actuator positions of its discrete controllers. Also the additional criterion to limit control spillover is incorporated into the formulation for modal control with a prescribed number of controlled modes. Computational results indicate that in some cases the use of a fully coupled model for the design of structure and its control devices leads to a considerable improvement in performance.  相似文献   

18.
Nonlinear aeroelastic characteristics of sandwich beams with pyramidal lattice core are investigated, and the active flutter control of the nonlinear structural system is also studied using the piezoelectric actuator/sensor pair. In the structural modeling, Reddy’s third-order shear deformation theory is applied. Aerodynamic pressure is evaluated by the supersonic piston theory. Hamilton’s principle and the assumed mode method are used to derive the equation of motion. The proportional feedback and the optimal H control methods are performed to design the controller. In the robust control, the uncertainty caused by omitting the nonlinear terms of the control equation is taken into account, and the mixed sensitivity method is used to solve the problem. The nonlinear aeroelastic property of the sandwich beam is analyzed and is compared with that of the equivalent isotropic beam with the same weight to show the superior aeroelastic characteristics of the lattice sandwich beam. Controlled vibration responses under the two different controllers are calculated and compared. Simulation results show that the robust controller is much more effective than the proportional feedback controller in the flutter suppression of the nonlinear sandwich beam.  相似文献   

19.
本文以二自由度四分之一汽车悬架系统为研究对象,采用不同控制策略对考虑时滞的悬架系统控制特性进行研究,并对控制效果进行对比分析.首先,采用第二类拉氏方程建立考虑时滞的二自由度悬架控制系统的动力学模型;然后分别基于状态变换法和H控制理论,设计系统的时滞反馈控制律.其中状态变换法主要通过系统状态变量的转换,将系统时滞控制方程转换成不显含时滞的动力学方程,然后采用传统的二次型最优控制方法对系统进行控制.H控制主要通过使用Lyapunov-Krasovskii泛函和自由权矩阵法,设计考虑时滞的H控制律;最后在Matlab/Simulink平台上对控制系统进行仿真分析,并在相同时滞下对两种控制结果进行对比.研究表明,两种控制策略在考虑时滞的情况下均可保证系统的稳定性,且H控制相比于状态变换法有更好的控制效果.  相似文献   

20.
宋建筑  李宏男 《力学学报》2016,48(2):430-436
系统建模不可避免地要忽略一些因素从而造成模型误差,因此基于不确定性的非精确模型来设计控制器显得尤为重要.随着各国学者的不断研究,在线性系统H_∞控制方面取得了很大的发展,但仍存在求解过程繁琐、系统的保守性不强、结构复杂和控制器阶数较高等问题.运用计算结构力学与最优控制相模拟的理论来试图完善存在的问题.导引模就是结构力学中的本征值问题,即弹性稳定的欧拉(Euler)临界力或结构振动的本征频率;通过引入区段混合能的概念,采用精细积分和扩展的威廉姆斯(W-W)算法计算导引模,将此方法引入到基于市场机制的控制(market-based control,MBC)理论中,提出了线性结构基于市场机制的鲁棒控制策略.同时给出了在鲁棒控制下,采用李雅普诺夫(Lyapunov)直接法证明了结构基于市场机制的鲁棒控制器的稳定性及参数的确定方法.最后对一高层受控结构进行数值计算与分析,并与H_∞鲁棒算法的控制效果进行了对比.结果表明,导引模不能取到临界值,否则会导致控制输入趋于无穷大.基于市场机制的鲁棒控制效果要好于H_∞鲁棒算法,并且具有较强的应变能力和在线计算时间短等优点,能较好地适用于高层和大跨结构.  相似文献   

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