共查询到20条相似文献，搜索用时 15 毫秒
1.
We studied the response of harmonically and stochastically excited strongly nonlinear oscillators with delayed feedback bang-bang control using the stochastic averaging method. First, the time-delayed feedback bang-bang control force is expressed approximately in terms of the system state variables without time delay. Then the averaged It6 stochastic differential equations for the system are derived using the stochastic averaging method. Finally, the response of the system is obtained by solving the Fokker-Plank-Kolmogorov （FPK） equation associated with the averaged lt6 equations. A Duffing oscillator with time-delayed feedback bang-bang control under combined harmonic and white noise excitations is taken as an example to illus- trate the proposed method. The analytical results are confirmed by digital simulation. We found that the time delay in feedback bang-bang control will deteriorate the control effectiveness and cause bifurcation of stochastic jump of Duffing oscillator. 相似文献
2.
A stochastic optimal control strategy for partially observable nonlinear quasi Hamiltonian systems is proposed.The optimal control forces consist of two parts. The first part is determined by the conditions under which the stochastic optimal control problem of a partially observable nonlinear system is converted into that of a completely observable linear system. The second part is determined by solving the dynamical programming equation derived by applying the stochastic averaging method and stochastic dynamical programming principle to the completely observable linear control system. The response of the optimally controlled quasi Hamiltonian system is predicted by solving the averaged Fokker-Planck-Kolmogorov equation associated with the optimally controlled completely observable linear system and solving the Riccati equation for the estimated error of system states. An example is given to illustrate the procedure and effectiveness of the proposed control strategy. 相似文献
3.
On stochastic optimal control of partially observable nonlinear quasi Hamiltonian systems 总被引：1，自引：0，他引：1
INTRODUCTION Since many actual control systems such asthose in structural engineering are subjected torandom excitations and the system states are esti-mated from measurements with random noise,stochastic optimal control of partially observablesystems is a research subject of much significance.One basic approach to this problem is to convert itinto the stochastic optimal control of completelyobservable systems using separation theorem(Wonham, 1968; Fleming and Rishel, 1975; Ben-so… 相似文献
4.
对有限频段内汽车悬架系统的时滞反馈控制参数优化问题进行研究。首先,建立时滞加速度反馈控制下 1/4 汽车悬架系统力学模型,推导出车身和车轮加速度幅值的解析表达式;其次,通过对系统稳定性分析,得到关于反馈增益系数和时滞的稳定性分区图,以数值计算验证稳定性分析的正确性;最后,在有限频段内以最大车身加速度变化的百分比为优化目标,以反馈增益系数和时滞为优化参数,利用粒子群优化算法获得有限频段内最优反馈增益系数和时滞。实验结果表明,与被动汽车悬架系统相比较,最优时滞反馈控制下汽车悬架系统的隔振性能获得了明显提高,在最优时滞反馈控制参数取值下,有限频段内车身加速度幅值至少降低37.27%。 相似文献
5.
A rectangular thin plate vibration model subjected to inplane stochastic excitation is simplified to a quasinonintegrable Hamiltonian system with two degrees of freedom. Subsequently a one-dimensional Ito? stochastic differential equation for the system is obtained by applying the stochastic averaging method for quasi-nonintegrable Hamiltonian systems. The conditional reliability function and conditional probability density are both gained by solving the backward Kolmogorov equation numerically. Finally, a stochastic optimal control model is proposed and solved. The numerical results show the effectiveness of this method. 相似文献
6.
本文研究变周期采样的网络控制系统模型的随机最优反馈控制。假设网络诱导延时服从某一个区间的均匀分布,设计一个依赖延时的状态反馈控制器,使得所建立的变周期采样的NCS模型指数均方稳定。利用动态规划思想结合Bellman方程通过优化所给定的性能指标,得到了随机最优反馈控制器设计方法,并通过仿真实例验证了本章提出方法的有效性。 相似文献
7.
针对国内民机系统纵向稳定性较差、飞机纵向短周期模态响应稳定性不足等问题,以某大型民机为研究对象,基于特征结构配置方法,利用逆模型的思路确定控制系统前馈增益系数,并基于某典型配平状态点,利用线性模型设计该飞机纵向控制律。线性仿真分析中,利用俯仰角速率q响应准则评价控制方案效果。仿真结果表明,采用特征结构配置方法设计的纵向飞行控制律具有良好控制效果,可以改善系统飞行品质使其达到一级飞行品质要求,相比于经典控制理论,通过特征结构配置方法进行纵向Nz控制律设计可以一次性确定反馈增益系数,缩短控制律设计时间。 相似文献
8.
运用ＭＴＭＤｓ系统对高层建筑的地震反应进行多模态控制研究．首先描述了ＭＴＭＤｓ系统的构造及其主要参数,建立了高层建筑－ＭＴＭＤｓ系统耦联体系的运动方程,并对简谐地面运动激励下的多模态控制进行了参数优化,最后应用ＭＴＭＤｓ系统对受１９４０年Ｅｌ－Ｃｅｎｔｒｏ（ＮＳ方向）地震波激励的某１１层框架建筑进行了数值模拟,其结果显示多模态控制下该框架建筑的顶层位移幅值比单模态控制时降低了２０％左右;从而得出结论：ＭＴＭＤｓ系统是高层建筑地震反应控制的一种有效、可靠并实用的被动控制措施,且多模态控制比单模态控制具有更好的实用性和可靠性,因而展示了更广阔的应用前景． 相似文献
9.
针对网络控制系统的数据丢包问题,提出将网络控制系统中的丢包问题等价地转换为k采样周期网络控制问题,进而通过变换将k采样周期的网络控制系统等价转化为变时延网络控制系统。在此基础上,将李雅普诺夫稳定性理论与线性矩阵不等式方法相结合,给出这种变时延网络控制系统的稳定性判据和控制器设计方法。最后通过仿真结果验证了文中方法的有效性。 相似文献
10.
针对电力市场中一类非线性博弈模型的混沌问题,通过加入脉冲时间延迟反馈控制,对其稳定性进行研究。第一种形式是对一家投资商引入系统变量的时间延迟反馈控制法,第二种形式是对整个系统引入系统变量的时间延迟反馈控制,并利用Matlab软件对该系统进行数值模拟,验证该方法的有效性。结果表明：时间延迟反馈控制可以有效控制系统的稳定性。 相似文献
11.
LI Gen guo 《上海大学学报(英文版)》1999,3(4):263-269
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｃｏｎｓｉｄｅｒｔｈｅｍｏｄｅｌｘ ¨＋ｘ（１－ｘ）（ｘ－ａ）＝０,（１）ｗｈｅｒｅａｉｓａｃｏｎｓｔａｎｔ．Ａｓａ＝－１,Ｅｑ．（１）ｒｅｄｕｃｅｓｔｏｔｈｅＤｕｆｆｉｎｇｅｑｕａｔｉｏｎｆｏｒｔｈｅｓｙｓｔｅｍｏｆｓｏｆｔｓｐｒｉｎｇｗｉｔｈｏｕｔｄａｍｐｉｎｇｘ ¨＋ｘ－ｘ３＝０．（２） ＴｈｅＤｕｆｆｉｎｇｓｙｓｔｅｍｈａｓｂｒｏａｄｅｎｇｉｎｅｅｒｉｎｇｂａｃｋｇｒｏｕｎｄ．Ｔｈｅｒｅａｒｅｐａｐｅｒｓ［１～４］ｒｅｌａｔｅｄｔｏｔｈｅｄｙｎａｍｉｃ… 相似文献
12.
张江林 《邢台职业技术学院学报》2010,27(1):61-65
应用有限元方法在机体结构模态分析的基础上,对某四缸内燃机曲轴各主轴承在曲轴轴颈作用力激励下的结构振动进行了计算,得到了曲轴各主轴承在不同方向上的结构振动响应曲线,并对其响应特征进行了分析。在此基础上,对轴承结构动力响应与机体结构模态特征间的关系以及主轴承结构振动与机体结构振动和噪声辐射之间的关系也作了进一步的讨论。结果表明作用在主轴承上的径向力可以激起主轴承的轴向往复振动,该轴向振动传播到机体裙部并产生噪声辐射。 相似文献
13.
Based on the modal analysis theory and by using the dynamics finite element analysis model of a three-dimensional assembly circuit module, dynamic characteristics of circuit module have been studied, including both natural characteristics analysis and dynamic responses analysis. Using a subspace method, modal analysis is first carried out. The first 6 orders of natural frequencies and vibration modes are obtained. Influence of the number of the Z-shaped metal slices on dynamic characteristics of the entire structure is also studied.Harmonic response analysis is then conducted. The steady-state response when the circuit module is subjected to harmonic excitation is determined. A curve of the response values against frequencies is obtained. As a result, the optimal number of Z-shaped metal slices can be determined, and it can be assured that the three-dimensional assembly circuit module has good performance in terms of the dynamic characteristics. 相似文献
14.
A minimax optimal control strategy for quasi-Hamiltonian systems with bounded parametric and/or external disturbances is proposed based on the stochastic averaging method and stochastic differential game. To conduct the system energy control, the partially averaged Ito stochastic differential equations for the energy processes are first derived by using the stochastic averaging method for quasi-Hamiltonian systems. Combining the above equations with an appropriate performance index, the proposed strategy is searching for an optimal worst-case controller by solving a stochastic differential game problem. The worst-case disturbances and the optimal controls are obtained by solving a Hamilton-Jacobi-Isaacs （HJI） equation. Numerical results for a controlled and stochastically excited DulTlng oscillator with uncertain disturbances exhibit the efficacy of the proposed control strategy. 相似文献
15.
针对一类具有时变状态时滞和参数不确定性的线性不确定时滞系统,研究了闭环极点具有α-稳定性限制的鲁棒H∞控制器设计问题.对所有容许的不确定,首先给出判断系统鲁棒α-稳定且具有干扰衰减γ的充分条件;而后基于线性矩阵不等式方法,分别提出了状态反馈和动态输出反馈控制器存在的充分条件及相应的控制器设计方法.数值算例验证了所给结果的有效性. 相似文献
16.
Rong-hua HUAN Wei-qiu ZHU Yong-jun WU 《浙江大学学报(A卷英文版)》2008,9(3):351-357
A modified nonlinear stochastic optimal bounded control strategy for random excited hysteretic systems with actuator saturation is proposed. First, a controlled hysteretic system is converted into an equivalent nonlinear nonhysteretic stochastic system. Then, the partially averaged Itoe stochastic differential equation and dynamical programming equation are established, respectively, by using the stochastic averaging method for quasi non-integrable Hamiltonian systems and stochastic dynamical programming principle, from which the optimal control law consisting of optimal unbounded control and bang-bang control is derived. Finally, the response of optimally controlled system is predicted by solving the Fokker-Planck-Kolmogorov （FPK） equation associated with the fully averaged Itoe equation. Numerical results show that the proposed control strategy has high control effectiveness and efficiency. 相似文献
17.
针对一类具有状态时滞的不确定离散系统,研究了其时滞依赖的保成本与鲁棒H∞控制问题.通过引入状态变换,提取出时滞因子,基于Lyapunov稳定性理论和线性矩阵不等式（LMI）方法,得到了保成本H∞状态反馈控制器存在的一个充分条件,以LMI的可行解构造出相应的状态反馈控制律.算例验证了该设计方法的有效性,并且可以通过调节时滞相关度因子得到不同的时滞界限和控制器增益K. 相似文献
18.
In this paper,the control of complex delayed networks with different nodes is proposed.Firstly,the stabilization of coupled networks with time delay is investigated.By constructing a Lyapunov function,a linear feedback controller design procedure for the networks is converted to the problem of solving a set of linear matrix inequalities.Then the results are extended to networks with both delayed dynamical nodes and delayed couplings.It is shown that the stabilization of complex networks is determined by the dynamics of each uncoupled node,coupling matrix and feedback gain matrix of networks.Two examples are simulated.In the first example,a network with 10 nodes consisting of Lorenz systems and systems proposed by Zhang in 2009 is given.It is found that the network states are divergent without control,and convergent under designed linear feedback controllers.In the second example,a larger network with 100 nodes consisting of delayed Chen systems and delayed Lorenz systems is given.The proposed method is also effective for large scale networks. 相似文献
19.
A dynamic finite element method combined with finite element mixed formula for contact problem is used to analyze the dynamic characteristics of gear system. Considering the stiffness excitation, error excitation and meshing shock excitation, the dynamic finite element model is established for the entire gear system which includes gears, shafts, bearings and gearbox housing. By the software of I-DEAS, the natural frequency, normal mode, dynamic time-domain response, frequency-domain response and one-third octave velocity grade structure borne noise of gear system are studied by the method of theoretical modal analysis and dynamic response analysis. The maximum values of vibration and structure borne noise are occurred at the mesh frequency of output grade gearing. 相似文献
20.
We investigate the best performance for linear feedback control systems in the case that plant uncertainty is to be considered. First, we define an average integral square criterion of tracking error over a class of stochastic model errors. By utilizing spectral factorization to minimize the performance index, we derive an optimal controller design method and further study best performance in the presence of stochastic perturbation. The results can be used to evaluate optimal performance in practical control system designs. 相似文献