排序方式: 共有183条查询结果,搜索用时 31 毫秒
31.
针对基于磁流变液阻尼器的半主动控制系统中存在的时滞问题, 采用了一种将可控的时滞变量引入半主动控制切换条件的控制策略, 研究了考虑时滞的天棚阻尼控制切换条件对半主动阻尼减振系统的影响, 分析了含有分数阶Bingham模型的线性刚度系统在基础激励下的振动特性. 利用平均法得到了系统在含时滞半主动控制策略下主共振响应的近似解析解, 根据Lyapunov理论分析了系统的稳定性. 通过数值解验证了近似解析解的准确性, 二者具有较好的一致性. 利用近似解析解分析了固定激励频率下时滞对系统幅频响应特性的影响, 以及主共振峰值响应和共振频率随时滞变化的特性规律. 结果表明, 含时滞的半主动控制系统存在一个小时滞区间, 使得系统的振幅在主共振峰对应的频率附近低于不考虑时滞时系统的振幅, 且存在最优时滞使得系统的振幅大幅度降低; 而大时滞的引入会加剧系统的振动, 导致系统的颤振. 确定了基于分数阶Bingham模型的线性刚度系统在天棚阻尼半主动控制下的时滞选取原则, 为振动系统半主动阻尼控制中的时滞选取提供了参考. 相似文献
32.
In this paper, the fractional-order Genesio--Tesi system showing chaotic
behaviours is introduced, and the corresponding one in an integer-order form
is studied intensively. Based on the harmonic balance principle, which is
widely used in the frequency analysis of nonlinear control systems, a
theoretical approach is used to investigate the conditions of system
parameters under which this fractional-order system can give rise to a
chaotic attractor. Finally, the numerical simulation is used to verify the
validity of the theoretical results. 相似文献
33.
In this paper, chaotic behaviours in the fractional-order Liu system
are studied. Based on the approximation theory of fractional-order
operator, circuits are designed to simulate the fractional- order
Liu system with $q=0.1-0.9$ in a step of 0.1, and an experiment has
demonstrated the 2.7-order Liu system. The simulation results prove
that the chaos exists indeed in the fractional-order Liu system with
an order as low as 0.3. The experimental results prove that the
fractional-order chaotic system can be realized by using hardware
devices, which lays the foundation for its practical applications. 相似文献
34.
Optimization Design of Holding Poles Based on the Response Surface Methodology and the Improved Arithmetic Optimization Algorithm北大核心CSCD
下载免费PDF全文
![点击此处可从《应用数学和力学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
抱杆优化设计需要耗费大量有限元分析计算时间,难以确定可行域.该文采用响应面法(response surface method,RSM)来模拟抱杆结构的真实响应,提出了改进的算术优化算法(improved arithmetic optimization algorithm,IAOA)对抱杆结构进行优化设计.将分数阶积分引入算术优化算法(arithmetic optimization algorithm,AOA),改善了算法的开发能力.采用拉丁超立方抽样,选取抱杆结构杆件截面试验样本,利用最小二乘法对样本点进行分析,构建了抱杆结构应力和位移关于杆件截面尺寸的二阶响应面代理模型.建立以抱杆质量最小化为优化目标,许用应力和位移为约束条件的优化模型,采用IAOA对其进行求解.结果表明:二阶响应面模型能够准确预测抱杆结构的响应值,IAOA的求解精度得到显著提升,代理模型可大幅降低有限元分析所需的计算代价,优化后抱杆结构质量减轻了8.2%.联合使用RSM和IAOA可有效求解大型空间杆系结构的优化设计问题. 相似文献
35.
Juanping Yang Hong-Li Li Long Zhang Cheng Hu Haijun Jiang 《Mathematical Methods in the Applied Sciences》2023,46(1):197-214
This paper deals with the problems of quasi-projective synchronization (QPS) and finite-time synchronization (FTS) for a kind of delayed fractional-order BAM neural networks (DFOBAMNNs). In order to reach the goals of synchronization and more accurately gauge of settling time and error level, several fresh quantized controllers are structured to make the utmost of confined communication resources. Then, based on the finite-time theorem, quantized control strategy, Lyapunov function theory and properties of Mittag–Leffler function as well as inequality analysis techniques, some plentiful criteria are formed to set up a relation between control gains and quantization parameters. In addition, the corresponding error bound of QPS and guages of the settling time on FTS are also given. Finally, a few numerical examples are introduced to validate the effectiveness of the presented control protocols. 相似文献
36.
Enkelejd Hashorva Anthony G. Pakes 《Journal of Mathematical Analysis and Applications》2010,372(2):496-514
Let X,Y,B be three independent random variables such that X has the same distribution function as YB. Assume that B is a beta random variable with positive parameters α,β and Y has distribution function H with H(0)=0. In this paper we derive a recursive formula for calculation of H, if the distribution function Hα,β of X is known. Furthermore, we investigate the relation between the tail asymptotic behaviour of X and Y, which is closely related to asymptotics of Weyl fractional-order integral operators. We present three applications of our asymptotic results concerning the extremes of two random samples with underlying distribution functions H and Hα,β, respectively, and the conditional limiting distribution of bivariate elliptical distributions. 相似文献
37.
本文对一类具有多重时滞的Caputo分数阶中立型微分控制系统的相对可控性和相对U可控性进行了研究.首先利用Laplace变换得到系统解的一个新的表达式,接着由Grammian矩阵得出系统相对可控的充分必要条件.最后给出了一类非线性分数阶中立型微分控制系统相对U可控的充分必要条件. 相似文献
38.
This paper proposes a new chaotic system and its fractional-order chaotic system. The necessary condition for the existence of chaotic attractors in this new fractional-order system is obtained. It finds that this new fractional-order system is chaotic for q 〉 0.783 if the system parameter m=6. The chaotic attractors for q=0.8, and q=0.9 are obtained. A circuit is designed to realize its fractional-order chaos system for q=0.9 by electronic workbench. 相似文献
39.
A new circuit unit for the analysis and the synthesis of the chaotic behaviours in a fractional-order Liu system is proposed in this paper. Based on the approximation theory of fractional-order operator, an electronic circuit is designed to describe the dynamic behaviours of the fractional-order Liu system with α = 0.9. The results between simulation and experiment are in good agreement with each other, thereby proving that the chaos exists indeed in the fractional-order Liu system. 相似文献
40.
Concepción A. Monje Antonio J. Calderon Blas M. Vinagre Yangquan Chen Vicente Feliu 《Nonlinear dynamics》2004,38(1-2):369-381
The objective of this work is to find out optimum settings for a fractional PI controller in order to fulfill three different robustness specifications of design for the compensated system, taking advantage of the fractional order, . Since this fractional controller has one parameter more than the conventional PI controller, one more specification can be fulfilled, improving the performance of the system and making it more robust to plant uncertainties, such as gain and time constant changes. For the tuning of the controller an iterative optimization method has been used, based on a nonlinear function minimization. Two real examples of application are presented and simulation results are shown to illustrate the effectiveness of this kind of unconventional controllers. 相似文献