共查询到20条相似文献,搜索用时 15 毫秒
1.
R. Yamapi M.A. Aziz-Alaoui 《Communications in Nonlinear Science & Numerical Simulation》2007,12(8):1534-1549
We consider in this paper the dynamics of the self-sustained electromechanical system with multiple functions, consisting of an electrical Rayleigh–Duffing oscillator, magnetically coupled with linear mechanical oscillators. The averaging and the harmonic balance method are used to find the amplitudes of the oscillatory states respectively in the autonomous and nonautonomous cases, and analyze the condition in which the quenching of self-sustained oscillations appears. The influence of system parameters as well as the number of linear mechanical oscillators on the bifurcations in the response of this electromechanical system is investigated. Various bifurcation structures, the stability chart and the variation of the Lyapunov exponent are obtained, using numerical simulations of the equations of motion. 相似文献
2.
Ren Yamapi 《Communications in Nonlinear Science & Numerical Simulation》2006,11(8):907-921
In this paper, we analyze the dynamics of an electromechanical damping device, which consist of an electrical system coupled magnetically to a mechanical structure, and that works by transferring the vibration energy of the mechanical system to the electrical system. We study the instability issues which limit the performance of the device. An analysis of the effective range of the coupling parameter for which a good reduction of the amplitude of the mechanical system occurs is presented. The effects of the coupling parameter on the bifurcation structures are found and it appears that with the appropriate choosing coupling parameter, the quenching of mechanical chaotic vibrations takes place. 相似文献
3.
《Communications in Nonlinear Science & Numerical Simulation》2006,11(3):355-375
In this paper, we consider the dynamics and chaos control of the self-sustained electromechanical device with and without discontinuity. The amplitude equations are derived in the general case using the harmonic balance method. The model without discontinuity is first considered. The effects of the amplitude of the parametric modulation and some particular coefficients are found in the response curves. The transition to chaotic behavior is found using numerical simulations of the equations of motion. We find that chaos appears in the model between the quasi-periodic and periodic orbits when the amplitude of the external excitation E0 vary. An adaptive Lyapunov control strategy enables us to drive the system from the chaotic states to a targeting periodic orbit. The effects of elasticity and damping on the dynamics of the self-sustained electromechanical system are also derived. 相似文献
4.
Xiao-Lan Xie 《商业与工业应用随机模型》1991,7(4):343-360
A hierarchical production control framework for a flexible manufacturing system is proposed. The machines in the system are subject to failures in a wide spectrum band. At first, failures are clustered near some discrete points on the failure spectrum in order to define the hierarchical model. Each level in the hierarchy corresponds to a discrete point on the failure spectrum. At each level, faster varying failures are modelled by their mean behaviour, and more slowly varying failures are treated as static. Then, a hierarchical controller of multiple time scale type is proposed. System control at each level is based on the work of Kimemia and Gershwin. Simulation results conclude the paper. 相似文献
5.
The coupling vibration characteristics of a flexible shaft-disk-blades system with mistuned features
The purpose of this paper is to investigate the coupling vibration characteristics of a flexible shaft-disk-blades system with mistuned features. There are some new phenomena due to the coupling effects of shaft-bending, shaft-torsion, disk-transverse and blade-bending. In this investigation, this paper mainly focuses on the influence of mistuned features of the blade's length and the stagger angle. It is found that there are four types of coupling modes: the coupling mode of shaft bending, disk transverse and blade bending (SDB), the coupling mode of shaft torsion disk transverse-blade bending (TDB), the coupling mode of disk transverse and blade bending (DB), the repeated mode of blade bending-blade bending (BB). With the effect of mistuned features, the natural frequencies and the coupling mode type will change correspondingly. With the mistuning value of blade length employed in this study, the TDB mode in the tuned system will disappear and shift into TSDB mode instead, and one of the repeated SDB modes will be replaced by STDB modes. Due to this mistuned features, the blades and disk experience a certain degree of vibration localization phenomenon. Different from the length feature, the influence of mistuning values of blade's stagger angle mainly take effect on the coupling modes. At last, by inspection on the Campbell diagrams, the influence of rotational speed on the transformation of natural frequencies is illustrated on the tuned/mistuned flexible shaft-disk-blades coupling structure. 相似文献
6.
Viktor Levandovskyy 《Journal of Differential Equations》2009,246(3):1274-1287
We present a method for investigating the cyclicity of an elementary focus or center of a polynomial system of differential equations by means of complexification of the system and application of algorithms of computational algebra, showing an approach to treating the case that the Bautin ideal B of focus quantities is not a radical ideal (more precisely, when the ideal BK is not radical, where BK is the ideal generated by the shortest initial string of focus quantities that, like the Bautin ideal, determines the center variety). We illustrate the method with a family of cubic systems. 相似文献
7.
具有一类三次曲线解的Kolmogorov三次系统的极限环的存在性 总被引:1,自引:1,他引:1
证明了具有三次曲线解y=-x(x-1)2 4/24的Kolmogorov三次系统是有存在极限环可能的. 相似文献
8.
This paper is concerned with mathematical modeling and optimal motion designing of flexible mobile manipulators. The system is composed of a multiple flexible links and flexible revolute joints manipulator mounted on a mobile platform. First, analyzing on kinematics and dynamics of the model is carried out then; open-loop optimal control approach is presented for optimal motion designing of the system. The problem is known to be complex since combined motion of the base and manipulator, non-holonomic constraint of the base and highly non-linear and complicated dynamic equations as a result of the flexible nature of both links and joints are taken into account. In the proposed method, the generalized coordinates and additional kinematic constraints are selected in such a way that the base motion coordination along the predefined path is guaranteed while the optimal motion trajectory of the end-effector is generated. This method by using Pontryagin’s minimum principle and deriving the optimality conditions converts the optimal control problem into a two point boundary value problem. A comparative assessment of the dynamic model is validated through computer simulations, and then additional simulations are done for trajectory planning of a two-link flexible mobile manipulator to demonstrate effectiveness and capability of the proposed approach. 相似文献
9.
Reenu Rani Sunita Gakkhar Ali Moussaoui 《Mathematical Methods in the Applied Sciences》2019,42(18):7192-7209
In this paper, a stock‐effort dynamical model with two fishing zones is discussed. The nonlinear harvesting function is assumed depending upon stock size as well as fishing effort. The migration of fish is considered between two zones. The harvesting vessels also move between zones to increase their revenue. The movements of fish and fishing vessels between zones are assumed to take place at a faster time scale as compared with processes involving growth and harvesting occurring at a slow time scale. The aggregated model is obtained for total fish stock and fishing effort. This aggregated (reduced) model is analyzed analytically as well as numerically. Biological and bionomic equilibria of the system are obtained, and criteria for local stability or instability of the system are derived. The impact of levels of taxation T on the fish population and on the revenue earned by the fishery is investigated. An optimal harvesting policy is also discussed using the Pontryagin's maximum principle. The aggregated model also exhibits Hopf and transcritical bifurcation with respect to the bifurcation parameter tax T. Numerical simulations are presented to illustrate the results. 相似文献
10.
Synchronization of a chaotic finance system 总被引:1,自引:0,他引:1
Synchronization strategies of a three-dimensional chaotic finance system are investigated in this paper. Based on Lyapunov stability theory and Routh-Hurwitz criteria, some effective controllers are designed for the global asymptotic synchronization on different conditions. When the system parameters are known, the hybrid feedback control and a method based on special matrix structure are adopted respectively, to realize the synchronization of the chaotic finance system. When the parameters are unknown, the active control is extended and introduced to realize the synchronization. Numerical simulations show the validity and feasibility of the synchronization schemes. 相似文献
11.
C. G. Cassandras 《Annals of Operations Research》1985,3(8):427-447
A real-time hierarchical routing control scheme for a large class of material handling systems is presented. The higher level (coordinator) performs resource allocation tasks and supplies parameter values to the lower (local control) level. The lower level operates in an autonomous (without continuous supervision) and distributed fashion. If state information is made available to the coordinator, the routing strategy can furthermore be adaptively adjusted. 相似文献
12.
G. A. Chumakov 《Siberian Mathematical Journal》2007,48(5):949-960
This is a qualitative analysis of a system of two nonlinear ordinary differential equations which arises in modeling the self-oscillations of the rate of heterogeneous catalytic reaction. The kinetic model under study accounts for the influence of the reaction environment on the catalyst; namely, we consider the reaction rate constant to be an exponential function of the surface concentration of oxygen with an exponent μ. We study the necessary and sufficient conditions for the existence of periodic solutions of differential equations as depending on μ. We formulate some sufficient conditions for all trajectories to converge to a steady state and study global behavior of the stable manifolds of singular saddle points. 相似文献
13.
14.
煤炭城市是由人口、资源、经济与环境四个子系统构成的复杂系统.其可持续发展依赖于各子系统的合理结构和发展模式以及对系统的有效控制.将可持续发展思想与系统动力学模拟方法相结合,在分析了煤炭城市系统结构基础上,构建了煤炭城市系统动力学模型:确定生育指数、各产业投资比例、资源循环利用率等为调控参数,以典型煤炭城市鸡西市为例进行了5种发展模式的模拟和调控.结果表明:可持续发展模式与其他四种发展模式相比,取得的经济、资源、环境整体效益最大,是鸡西市发展的相对最佳方案. 相似文献
15.
In this paper, a competitive Lotka-Volterra system with three delays is investigated. By choosing the sum τ of three delays as a bifurcation parameter, we show that in the above system, Hopf bifurcation at the positive equilibrium can occur as τ crosses some critical values. And we obtain the formulae determining direction of Hopf bifurcation and stability of the bifurcating periodic solutions by using the normal form theory and center manifold theorem. Finally, numerical simulations supporting our theoretical results are also included. 相似文献
16.
In this paper, by using qualitative analysis, we investigate the number of limit cycles of perturbed cubic Hamiltonian system with perturbation in the form of (2n+2m) or (2n+2m+1)th degree polynomials . We show that the perturbed systems has at most (n+m) limit cycles, and has at most n limit cycles if m=1. If m=1, n=1 and m=1, n=2, the general conditions for the number of existing limit cycles and the stability of the limit cycles will be established, respectively. Such conditions depend on the coefficients of the perturbed terms. In order to illustrate our results, two numerical examples on the location and stability of the limit cycles are given. 相似文献
17.
一类三次系统极限环的惟一性 总被引:2,自引:0,他引:2
讨论三次系统x=x(A0+A1x+A2y+A3xy-A4y2)y=y(x-1)的极限环问题.得到了该系统不存在极限环和存在惟一极限环的条件. 相似文献
18.
Tsuyoshi Katayama 《Queueing Systems》2007,57(4):169-178
We consider a multi-class priority queueing system with a non-preemptive time-limited service controlled by an exponential
timer and multiple (or single) vacations. By reducing the service discipline to the Bernoulli schedule, we obtain an expression
for the Laplace-Stieltjes transform (LST) of the waiting time distribution via an iteration procedure, and a recursive scheme
to calculate the first two moments. It is noted that we have to select embedded Markov points based on the service beginning
epochs instead of the service completion epochs adopted for most of M/G/1 queueing analyses. Through the queue-length analysis, we obtain a decomposition form for the LST of the waiting time in
each queue having the exhaustive service.
相似文献
19.
In the present investigation, we develop queueing model for the performance prediction of flexible manufacturing systems (FMSs) with a multiple discrete material-handling devices (MHD). An iterative method has been suggested using mean value analysis (MVA) for the state-dependent routing. Two queueing network models are considered to determine the material-handling device interference. In the first one, we model the interference from the MHD by inflating the station service times but neglect queueing at the MHD. In another network, the queueing for the MHD is taken into consideration. The performance of FMS configuration is obtained by iterating between two networks. The suggested algorithms demonstrate better results than the algorithm used by earlier workers for single MHD. Some performance indices viz. throughput, mean service time, mean waiting time, etc. are obtained. Numerical results are provided to highlight the effect of the system parameters on performance indices, which are further evaluated by using neuro-fuzzy controller system to validate the tactability of soft computing approach. 相似文献
20.
Hamid HamicheKarim Kemih Malek GhanesGang Zhang Saïd Djennoune 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(4):1146-1154
This paper studies the synchronization problem for a new chaotic four-dimensional system presented by Qi et al. Two different methods, the passive control method and the impulsive control method, are used to control the synchronization of the four-dimensional chaotic system. Numerical simulations show the effectiveness of the two different methods. 相似文献