共查询到20条相似文献,搜索用时 15 毫秒
1.
Jacob Tal 《Automatica》1977,13(2):153-159
This paper considers the problem of synchronizing a controllable oscillator with some external frequency and determines the conditions for synchronization. The requirements are determined analytically and the results are applied to several examples in various fields. 相似文献
2.
The describing function method has played a leading role in the prediction of limit cycles in scalar systems; in recent years this approach has been extended to the multivariable case. Derived techniques assume the nonlinearity inputs to be sinusoidal. However, this condition is not always satisfied, and as an alternative, the present paper considers the use of a method which is based on a set of non-sinusoidal functions. Novel concepts related to the characteristic loci are defined and employed for the derivation of new graphical tests. 相似文献
3.
This paper derives a differential contraction condition for the existence of an orbitally-stable limit cycle in an autonomous system. This transverse contraction condition can be represented as a pointwise linear matrix inequality (LMI), thus allowing convex optimisation tools such as sum-of-squares programming to be used to search for certificates of the existence of a stable limit cycle. Many desirable properties of contracting dynamics are extended to this context, including the preservation of contraction under a broad class of interconnections. In addition, by introducing the concepts of differential dissipativity and transverse differential dissipativity, contraction and transverse contraction can be established for interconnected systems via LMI conditions on component subsystems. 相似文献
4.
This paper studies synchronization of coupled second-order linear harmonic oscillators with local interaction. We analyze convergence conditions over, respectively, directed fixed and switching network topologies by using tools from algebraic graph theory, matrix theory, and nonsmooth analysis. It is shown that the coupled harmonic oscillators can be synchronized under mild network connectivity conditions. Examples are given to validate the convergence conditions. The theoretical result is also applied to synchronized motion coordination of multi-agent systems as a proof of concept. 相似文献
5.
Housheng Su Author Vitae 《Automatica》2009,45(10):2286-182
In this paper, we revisit the synchronization problems for coupled harmonic oscillators in a dynamic proximity network. Unlike many existing algorithms for distributed control of complex dynamical networks that require explicit assumptions on the network connectivity, we show that the coupled harmonic oscillators can always be synchronized, without imposing any network connectivity assumption. Moreover, we also investigate the synchronization with a leader and show that all harmonic oscillators can asymptotically attain the position and velocity of the leader, again without any assumption on connectivity of the followers. Numerical simulation illustrates the theoretical results. 相似文献
6.
In a supermarket refrigeration, the temperature in a display case, surprisingly, influences the temperature in other display cases. This leads to a synchronous operation of all display cases, in which the expansion valves in the display cases turn on and off at exactly the same time. This behavior increases both the energy consumption and the wear of components. Besides this practical importance, from the theoretical point of view, synchronization, likewise stability, Zeno phenomenon, and chaos, is an interesting dynamical phenomenon. The study of synchronization in the supermarket refrigeration systems is the subject matter of this work. For this purpose, we model it as a hybrid system, for which synchronization corresponds to a periodic trajectory.To examine whether it is stable, we transform the hybrid system to a single dynamical system defined on a torus. Consequently,we apply a Poincar ′e map to determine whether this periodic trajectory is asymptotically stable. To illustrate, this procedure is applied for a refrigeration system with two display-cases. 相似文献
7.
In this paper, the presence of limit cycles in the behaviour of antagonistically coupled magneto-rheological (MR) actuators is investigated. The actuator considered in this paper offers high torque-to-mass and torque-to-inertia ratios, for inherent safe actuation. While the antagonistic arrangement is beneficial in improving the actuator performance and eliminating backlash, it may result in limit cycles when the actuator operates in a position control loop. The occurrence of a limit cycle depends on the parameters of the actuator as well as the controller. An in-depth analysis is carried out in this paper to establish a connection between the system parameters and the limit cycle occurrence. Moreover, sufficient conditions for avoiding limit cycles are derived specifically for a proportional-derivative (PD) controller. Simulations and experimental results validate the analysis and provide insights into conditions under which limit cycles are observed in the operation of antagonistic MR actuators. 相似文献
8.
In this paper we prove that any controllable linear systems , admits a polynomial feedback u= u(x) such that the closed-loop system admits an orbitally asymptotically stable limit cycle.Moreover, we prove that for any positive integer n, there exists an nth-order polynomial, autonomous, ordinary differential equation with a unique limit cycle. 相似文献
9.
The emergence of synchronization in a network of coupled oscillators is a fascinating subject of multidisciplinary research. This survey reviews the vast literature on the theory and the applications of complex oscillator networks. We focus on phase oscillator models that are widespread in real-world synchronization phenomena, that generalize the celebrated Kuramoto model, and that feature a rich phenomenology. We review the history and the countless applications of this model throughout science and engineering. We justify the importance of the widespread coupled oscillator model as a locally canonical model and describe some selected applications relevant to control scientists, including vehicle coordination, electric power networks, and clock synchronization. We introduce the reader to several synchronization notions and performance estimates. We propose analysis approaches to phase and frequency synchronization, phase balancing, pattern formation, and partial synchronization. We present the sharpest known results about synchronization in networks of homogeneous and heterogeneous oscillators, with complete or sparse interconnection topologies, and in finite-dimensional and infinite-dimensional settings. We conclude by summarizing the limitations of existing analysis methods and by highlighting some directions for future research. 相似文献
10.
This paper studies the problem of finding the initial states for which the solution of a class of switched systems consisting of unstable second-order nonlinear subsystems is convergent. A method is described and applied to establish the regions in the plane where it is possible to define a switching law such that the solution of a class of switched nonlinear systems converges to the origin. We prove that, under certain conditions, these regions are delimited by closed curve solutions of the switched system. Furthermore, a sufficient condition for the closed curve solution to be a limit cycle is presented. Finally, a numerical example is included in order to illustrate the results. 相似文献
11.
We introduce time-varying parameters in a multi-agent clustering model and we derive necessary and sufficient conditions for the occurrence of clustering behavior with respect to a given cluster structure. For periodically varying parameters the clustering conditions may be formulated in a similar way as for the time-invariant model. The results require the individual weights assigned to the agents to be constant. For time-varying weights we illustrate with an example that the obtained results can no longer be applied. 相似文献
12.
μ analysis is one of the most efficient techniques to evaluate the stability margins and the performance levels of linear time-invariant systems in the presence of structured time-invariant uncertainties. The exact computation of the structured singular value μ is known to be NP hard in the general case, but several methods have been developed in the last 30 years to compute accurate and reliable bounds. In this paper, all existing μ lower bound algorithms are reviewed and the most relevant ones are evaluated on a wide set of real-world benchmarks, corresponding to various fields of application, system dimensions and structures of the uncertainties. The results are thoroughly analyzed and simple improvements to the existing algorithms are proposed to approach the exact value of μ with a reasonable computation cost. Conclusions show that non-conservative values can be obtained in almost all cases. A brief extension to skew-μ analysis confirms the good results obtained in the classical μ case. 相似文献
13.
通过对一类混合系统仿真中的连续系统、离散事件系统及推理决策系统各自仿真时钟的分析,得出了推理决策系统仿真依赖于其两个系统的结果,继而提出了用其中的离散事件 系统仿真时钟云同步具有等步长策略的连续系统仿真时钟改进的等步长方法,并给出了相应的软件实现方法与性能评价准则,解决了该类混合记真时钟的同步问题,减少了仿真误差,从而为该类混合系统的仿真提供理论依据。 相似文献
14.
Prediction error methods are considered for identification of the forward linear dynamics of nonlinear feedback closed-loop systems which operate in a perturbed stable limit cycle. A model of the signals measured in a neighborhood of the limit cycle is presented and shown to satisfy a quasistationarity property. Quasistationarity is then used to prove that prediction error methods are both convergent and consistent for our data model. 相似文献
15.
在大型超市制冷系统耗能问题的研究中,由于系统通常采用分布式控制,控制方式往往忽视了各子系统之间的交互干扰而导致系统出现同步现象.将系统的非线性数学模型简化为一个二阶仿射切换系统模型,并在Matlab环境下进行了仿真,对系统的同步现象进行了分析.仿真结果表明,系统在运行过程中出现了同步现象,即各陈列柜温度趋于一致,各陈列柜蒸发器入口阀门的开闭状态趋于同步.通过分析,同步现象的出现使吸气总管的吸气压力出现了周期性较大的波动,容易造成压缩机频繁启停,增加了压缩机的损耗,不利于超市制冷系统的节能降耗. 相似文献
16.
Performance robustness with multiple objectives of linear control systems having structured norm-bounded uncertainty is considered. In order to deal with any two objective functions Ψ1 and Ψ2 associated with a single feedback control system, the combined criterion Ψ[Ψ1 ψ2]Ψ S 1 is often used. The paper, however, considers Ψ ψ1 Ψ 1 and Ψ W, 11 1 directly. It is shown that it is possible to assess robust performance of two objectives by a single μ test if repeated nonscalar blocks are adequately introduced in the structure of μ. In other words, a performance robustness problem with multiple objectives is proved to be equivalent to a stability robustness problem with extra repeated uncertainty blocks. This equivalence theorem is applicable to various system and norm setups including sampled-data systems. 相似文献
17.
针对一类具有不确定参数的非线性混沌系统,在对现有一些混沌同步方法比较总结的基础上,提出了一种混沌通信同步的新方法。通过合理的假设,将该类系统转化为在可观测输出端由附加白噪声驱动的线性时变系统。然后通过最优滤波来处理同步问题,可应用Kalman滤波的方法进行估计,响应系统的状态能够渐近收敛于驱动系统,并且在输出端加入干扰噪声的情况下,仍能保持良好的跟踪轨迹。 相似文献
18.
Jesús Chacón José Sánchez Antonio Visioli Luis Yebra Sebastián Dormido 《Journal of Process Control》2013,23(6):826-838
This work is focused on the study of limit cycles that appear in a control scheme which is based on the use of a PI controller with an event-based send-on-delta sampling (SOD). The processes investigated are integrator processes plus time delay (IPTD) and first and second order processes plus time delay, which are of interest because they are frequently used to model many industrial processes. The SOD sampling is characterized as a non-linearity of n levels with hysteresis. An algorithm to calculate the limit cycles properties is proposed, and then the results obtained in simulations are compared with experiments performed on a real plant, a distributed solar collector field at the Solar Platform of Almería (PSA, Spain). 相似文献
19.
Jeff S. Shamma 《Systems & Control Letters》1995,24(1)
We consider the robust stability of time-varying linear systems subject to structured time-varying uncertainty. We provide an alternate proof of the result that robust stability holds if and only if a scaled small-gain condition holds asymptotically. The new proof employs an extension of the so-called S-procedure losslessness theorem to time-varying quadratic forms which is of independent interest. 相似文献
20.
1引言Doyle在1982年提出的结构奇异值(μ)方法是分析和综合结构式不确定系统的有力工具[1,2].基于结构奇异值分析的小μ定理[2]给出了具有多个摄动块的线性动态系统鲁棒稳定的充要条件.而鲁棒性能定理[2]则进一步地将鲁棒稳定性问题和鲁棒性能问题统一成μ分析问题.然而.我们注意到,在所有研究结构奇异值的文献中,均要求块对角摄动矩阵中每个子摄动块是方的.这一要求无疑大大限制了μ方法的应用,因为非方摄动块在系统中是经常存在的.此时对Doyle给出的结构奇异值的上界函数[1]必须进行修正.2非方… 相似文献