在间隙函数为分段线性函数的单对齿轮系统非线性微分方程量纲一化的基础上 ,给出了系统的精确解析解。直接从 L yapunov指数的定义出发 ,给出了计算最大 Lyapunov指数的数值方法 ,作出了系统随激励频率变化时的 L yapunov指数图 ,并据...在间隙函数为分段线性函数的单对齿轮系统非线性微分方程量纲一化的基础上 ,给出了系统的精确解析解。直接从 L yapunov指数的定义出发 ,给出了计算最大 Lyapunov指数的数值方法 ,作出了系统随激励频率变化时的 L yapunov指数图 ,并据此判别了系统中所存在的周期和混沌吸引子。研究结果表明 。展开更多
Through the research into the characteristics of 7-DoF high dimensional nonlinear dynamics of a vehicle on bumpy road, the periodic movement and chaotic behavior of the vehicle were found.The methods of nonlinear freq...Through the research into the characteristics of 7-DoF high dimensional nonlinear dynamics of a vehicle on bumpy road, the periodic movement and chaotic behavior of the vehicle were found.The methods of nonlinear frequency response analysis, global bifurcation, frequency chart and Poincaré maps were used simultaneously to derive strange super chaotic attractor.According to Lyapunov exponents calculated by Gram-Schmidt method, the unstable region was compartmentalized and the super chaotic characteristic of the nonlinear system was verified.Numerical results by 4-order Runge-Kutta method presented the multiform dynamic behavior of the system.展开更多
The main research motive is to analysis and to veiny the inherent nonlinear character of MPEG-4 video. The power spectral density estimation of the video trafiic describes its 1/f^β and periodic characteristics.The p...The main research motive is to analysis and to veiny the inherent nonlinear character of MPEG-4 video. The power spectral density estimation of the video trafiic describes its 1/f^β and periodic characteristics.The priraeipal compohems analysis of the reconstructed space dimension shows only several principal components can be the representation of all dimensions. The correlation dimension analysis proves its fractal characteristic. To accurately compute the largest Lyapunov exponent, the video traffic is divided into many parts.So the largest Lyapunov exponent spectrum is separately calculated using the small data sets method. The largest Lyapunov exponent spectrum shows there exists abundant nonlinear chaos in MPEG-4 video traffic. The conclusion can be made that MPEG-4 video traffic have complex nonlinear be havior and can be characterized by its power spectral density,principal components, correlation dimension and the largest Lyapunov exponent besides its common statistics.展开更多
The aim of this article is to detect the detachment between the cam and the follower using the largest Lyapunov exponent parameter,the power density function of fast Fourier transform,and Poinarémaps due to the n...The aim of this article is to detect the detachment between the cam and the follower using the largest Lyapunov exponent parameter,the power density function of fast Fourier transform,and Poinarémaps due to the nonlinear dynamics phenomenon of the follower.The detachment between the cam and the follower was investigated for different cam speeds and different internal distances of the follower guide from inside.This study focuses on the use of the cam–follower system with a bionic quadruped robot through a linkage mechanism.Multishock absorber(spring–damper–mass)systems at the very end of the follower were used to improve the dynamic performance and to reduce the detachment between the cam and the follower.The SolidWorks program was used in the numerical solution,while a high‐speed camera at the foreground of the OPTOTRAK 30/20 equipment was used to identify the follower position.The friction and impact were considered between the cam and the follower and between the follower and its guide.In general,when the cam and the follower are in permanent contact,there is no loss in potential energy,and no impact or restitution.The detachment between the cam and the follower increases with increasing coefficient of restitution in the presence of the impact.展开更多
文摘Through the research into the characteristics of 7-DoF high dimensional nonlinear dynamics of a vehicle on bumpy road, the periodic movement and chaotic behavior of the vehicle were found.The methods of nonlinear frequency response analysis, global bifurcation, frequency chart and Poincaré maps were used simultaneously to derive strange super chaotic attractor.According to Lyapunov exponents calculated by Gram-Schmidt method, the unstable region was compartmentalized and the super chaotic characteristic of the nonlinear system was verified.Numerical results by 4-order Runge-Kutta method presented the multiform dynamic behavior of the system.
基金Supported by the National Natural Science Founda-tion of China (60132030)
文摘The main research motive is to analysis and to veiny the inherent nonlinear character of MPEG-4 video. The power spectral density estimation of the video trafiic describes its 1/f^β and periodic characteristics.The priraeipal compohems analysis of the reconstructed space dimension shows only several principal components can be the representation of all dimensions. The correlation dimension analysis proves its fractal characteristic. To accurately compute the largest Lyapunov exponent, the video traffic is divided into many parts.So the largest Lyapunov exponent spectrum is separately calculated using the small data sets method. The largest Lyapunov exponent spectrum shows there exists abundant nonlinear chaos in MPEG-4 video traffic. The conclusion can be made that MPEG-4 video traffic have complex nonlinear be havior and can be characterized by its power spectral density,principal components, correlation dimension and the largest Lyapunov exponent besides its common statistics.
文摘The aim of this article is to detect the detachment between the cam and the follower using the largest Lyapunov exponent parameter,the power density function of fast Fourier transform,and Poinarémaps due to the nonlinear dynamics phenomenon of the follower.The detachment between the cam and the follower was investigated for different cam speeds and different internal distances of the follower guide from inside.This study focuses on the use of the cam–follower system with a bionic quadruped robot through a linkage mechanism.Multishock absorber(spring–damper–mass)systems at the very end of the follower were used to improve the dynamic performance and to reduce the detachment between the cam and the follower.The SolidWorks program was used in the numerical solution,while a high‐speed camera at the foreground of the OPTOTRAK 30/20 equipment was used to identify the follower position.The friction and impact were considered between the cam and the follower and between the follower and its guide.In general,when the cam and the follower are in permanent contact,there is no loss in potential energy,and no impact or restitution.The detachment between the cam and the follower increases with increasing coefficient of restitution in the presence of the impact.
