共查询到20条相似文献,搜索用时 15 毫秒
1.
The dynamic behavior of electro-mechanical gyrostat system subjected to external disturbance is studied in this paper. By applying numerical results, phase diagrams, power spectrum, Period-T maps, and Lyapunov exponents are presented to observe periodic and chaotic motions. The effect of the parameters changed in the system can be found in the bifurcation and parametric diagrams. Several methods, the delayed feedback control, adaptive control algorithm (ACA) control are used to control chaos effectively. Anticontrol of chaos destroyed the periodic motions and replaced by chaotic motion effectively by adding constant motor torque and adding periodic motor torque. Finally, synchronization of chaos in the electro-mechanical gyrostat system is studied. 相似文献
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《中国物理快报》2021,(3)
Ehrenfest time depends differently on the Planck constant in integrable motion and chaotic motion. We study how its dependence on the Planck constant changes when there is a continuous transition from regular motion to chaotic motion. We find that the dependence is a weighted compromise between its two distinct dependences in regular and chaotic motions. The study is carried out with the system of periodically driven anharmonic oscillator. As the system is quite typical, the result may apply generally. 相似文献
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The three-dimensional (3-D) dynamics of a fluid-conveying cantilevered pipe fitted with an end-mass and additional intra-span spring-support is investigated in this paper, both theoretically and experimentally. The main objective is to examine how the dynamics of a cantilevered pipe with additional spring-support is modified by the presence of a small mass attached at the free end. In the theoretical study, the nonlinear three-dimensional equations of motion are discretized via Galerkin's method, and the resulting equations are solved by a finite difference method. For the cases studied, the system was found to lose stability by planar flutter; as the flow velocity is increased beyond that point, a sequence of higher order bifurcations ensue, involving 2-D and 3-D periodic and quasiperiodic motions, as well as chaotic ones. In the experiments, performed with elastomer pipes and water flow, similarly 2-D and 3-D periodic, quasiperiodic and chaotic oscillations were observed. Theory and experiments have been shown to be in good qualitative and quantitative agreement. The experimental behaviour is illustrated by video clips (electronic annexes). Moreover, the effects of (i) small stiffness imperfections and (ii) excitation by a point-force are explored theoretically in a preliminary way. 相似文献
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A backstepping control system is proposed to control and synchronize the attitude dynamics of a satellite subjected to deterministic external perturbations which induce chaotic motion when no control is affected in this paper. The proposed method is a systematic recursive design approach based on the choice of Lyapunov functions for constructing feedback control laws. The effectiveness of the proposed control scheme is verified by the simulated results. 相似文献
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H.-K. CHEN 《Journal of sound and vibration》2002,255(4):719-740
The dynamic behavior of a symmetric gyro with linear-plus-cubic damping, which is subjected to a harmonic excitation, is studied in this paper. The Liapunov direct method has been used to obtain the sufficient conditions of the stability of the equilibrium points of the system. By applying numerical results, time history, phase diagrams, Poincaré maps, Liapunov exponents and Liapunov dimensions are presented to observe periodic and chaotic motions. Besides, several control methods, the delayed feedback control, the addition of constant motor torque, the addition of period force, and adaptive control algorithm (ACA), have been used to control chaos effectively. Finally, attention is shifted to the synchronization of chaos in the two identical chaotic motions of symmetric gyros. The results show that one can make two identical chaotic systems to synchronize through applying four different kinds of one-way coupling. Furthermore, the synchronization time is also examined. 相似文献
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通过增加外腔反馈式半导体激光器的激光反馈时间,使系统处于混沌状态,再采用滑模变结构控制方法实现这种激光器的混沌控制.该方法的优点是系统既能很快地获得稳定的输出激光,又能根据工程需要实现激光输出功率强度的灵活调整.理论分析和数值计算结果表明控制结果具有很强的稳定性和鲁棒性.研究结果对改善实际激光系统稳态输出的快速性、输出功率的灵活可调性和能量转换效率有较好的参考价值.
关键词:
混沌
外腔反馈式半导体激光器
滑模变结构控制
外腔长度 相似文献
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Chaos and chaotic control in a relative rotation nonlinear dynamical system under parametric excitation 下载免费PDF全文
This paper studies the chaotic behaviours of a relative rotation nonlinear dynamical system under parametric excitation and its control. The dynamical equation of relative rotation nonlinear dynamical system under parametric excitation is deduced by using the dissipation Lagrange equation. The criterion of existence of chaos under parametric excitation is given by using the Melnikov theory. The chaotic behaviours are detected by numerical simulations including bifurcation diagrams, Poincar map and maximal Lyapunov exponent. Furthermore, it implements chaotic control using non-feedback method. It obtains the parameter condition of chaotic control by the Melnikov theory. Numerical simulation results show the consistence with the theoretical analysis. The chaotic motions can be controlled to period-motions by adding an excitation term. 相似文献
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The stability of the rolling motion of near space hypersonic vehicles with rudder control is studied using method of qualitative analysis of nonlinear differential equations, and the stability criteria of the deflected rolling motions are improved. The outcomes can serve as the basis for further study regarding the influence of pitching and lateral motion on the stability of rolling motion. To validate the theoretical results, numerical simulations were done for the rolling motion of two hypersonic vehicles with typical configurations. Also, wind tunnel experiments for four aircraft models with typical configurations have been done. The results show that: 1) there exist two dynamic patterns of the rolling motion under statically stable condition. The first one is point attractor, for which the motion of aircraft returns to the original state. The second is periodic attractor, for which the aircraft rolls periodically. 2) Under statically unstable condition, there exist three dynamic patterns of rolling motion, namely, the point attractor, periodic attractor around deflected state of rolling motion, and double periodic attractors or chaotic attractors. 相似文献
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本文把混沌神经动力学行为应用到了一个多自由度的机器人手臂,利用一种简单的神经编码方法使高维的神经网络模式转化成了低维的运动参数。虽然只在神经网络中嵌入了三种简单的姿势动作,但是在混沌神经动力学行为出现时,机器人手臂呈现出复杂的组合运动。利用这一点,提出了一个简单的控制算法用来解决病态问题(不一定有解或者确定的解无法保证的问题)。实装实验进一步表明,尽管只有粗略甚至不确定的光源信息,利用提出的算法机器人手臂可以成功的寻找到光源。 相似文献
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Bifurcation and chaos analysis for aeroelastic airfoil with freeplay structural nonlinearity in pitch 下载免费PDF全文
The dynamics character of a two degree-of-freedom
aeroelastic airfoil with combined freeplay and cubic stiffness
nonlinearities in pitch submitted to supersonic and hypersonic flow
has been gaining significant attention. The Poincaré mapping
method and Floquet theory are adopted to analyse the limit cycle
oscillation flutter and chaotic motion of this system. The result
shows that the limit cycle oscillation flutter can be accurately
predicted by the Floquet multiplier. The phase trajectories of both
the pitch and plunge motion are obtained and the results show that
the plunge motion is much more complex than the pitch motion. It is
also proved that initial conditions have important influences on the
dynamics character of the airfoil system. In a certain range of
airspeed and with the same system parameters, the stable limit cycle
oscillation, chaotic and multi-periodic motions can be detected
under different initial conditions. The figure of the Poincaré
section also approves the previous conclusion. 相似文献
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Yuan-Zhao Yin He-Jun Yin 《International Journal of Infrared and Millimeter Waves》1994,15(7):1263-1274
The motion of a relativistic electron is analyzed in the field configuration consisting of a circular wiggler magnetic field, an axial magnetic field, and the equilibrium self-electric and self-magnetic fields produced by the non-neutral electron ring. By generating Poincare surface-of-section maps, it is shown that when the equilibrium self-fields is strong enough, the electron motions become chaotic. Although the realistic circular wiggler magnetic field destroys the integrability of the electron motion as the equilibrium self-fields do, the role the latter plays to make the motions become chaotic is stronger than the former. In addition, the axial magnetic field can restrain the occurrence of the chaoticity. 相似文献
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《Physica A》2006,371(2):683-691
We study the dynamical behavior of a few shuttle buses when they pass each other freely and control the speed to retrieve the loading's delay. The dynamics of the buses is expressed in terms of the nonlinear maps. The tour times of buses and the time headway between buses exhibit the complex behavior with varying trips. The buses exhibit deterministic chaos even if there are no noises. Bus speeds up to retrieve the delay induced by loading the passengers on its bus. The bus chaos is controlled by varying the degree of speedup. The chaotic motion depends on both loading and speedup's parameters. The shuttle bus schedule is connected with the complex motions of shuttle buses. The region map (phase diagram) is shown to control the complex motions of buses. 相似文献
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《Physics letters. A》2005,338(2):128-140
The mechanisms leading to chaotic behavior in the Lorenz system are well understood. Basically, homoclinic connections induce a strange invariant set around the zero fluid motion stationary point. This set, associated with a Smale horseshoe, is in the heart of chaotic attractors. This Letter examines the application of a simple feedback controller to eliminate the chaotic behavior in a controlled Lorenz system. The main idea is to stabilize certain stationary points to destroy the homoclinic connections. In this way, stabilization of the Lorenz trajectories about non-chaotic motion is achieved. The effectivity of the feedback control strategy is illustrated by means of numerical simulations. 相似文献