中文摘要：

排列熵是信号复杂性的一种度量.文章提出利用排列熵值确定平面欠驱动五杆机构的混沌边缘.首先利用MATLAB中Simmechanics模块建立欠驱动五杆机构动力学模型,提取随杆长变化的位移、速度的多组时间序列,然后计算排列熵并绘制熵值随杆长变化的曲线,根据排列熵曲线的变化趋势确定机构运动的混沌边缘.最后利用相图和最大李雅普诺夫指数法对确定的混沌边缘进行了验证.研究表明利用排列熵值曲线可以正确地确定出机构的混沌边缘.

英文摘要：

The permutation entropy is a measure for analysing the complexity of signal set. In this paper it is proposed to employ the permutation entropy for finding the chaos edge of a planar five-bar underactuated mechanism. Firstly, Simmechanics of MATLAB is utilized to get the time series of velocity and displacement, and calculate the permutation entropy. Then with the variation of the one length of the mechanism, the curve of permutation entropy with respect to the change of length is plotted, by which the chaos edge can be found. Finally the chaos edge is verified by the phase diagram and maximum Lyapunov exponent. As a whole, by means of permutation entropy curve, the chaos edge of a mechanism can be precisely determined.