簇绒提花地毯纱线束动态张力分析

 为控制纱线张力波动，提高毯面质量，有必要研究提花罗拉控制下纱线张力波动的形成及影响因素。本文假设地毯纱线束为线性弹性，且截面为圆形。在离合器吸合和释放瞬间，以作用在提花罗拉上的阻力矩作为输入，纱线的动态张力为输出，对提花罗拉与牵引罗拉间纱线束的动态张力进行理论分析。根据动量矩定理和纱线束质量守恒定律，建立了提花罗拉作用下纱线束动态张力模型。假设输入为阶跃信号，应用拉普拉斯变换，求出纱线张力波动的幅度、频率及阻尼比，并进行仿真。结果显示，阻力矩对纱线束张力波动有很重要的影响。因此为降低纱线张力的波动，有必要对提花罗拉的结构、离合器摩擦片进行精密设计。同时，分析了纱线束长度对张力波动固有频率和系统阻尼系数的影响。

Dynamic tension analysis of yarn strand in tufting jacquard carpets

It is essential to research the forming of yarn tension and its effects during tufting process for controlling its vibration due to the control of jacquard roller and improving the carpet quality.Assuming that the yarn strand is linearly elastic with a circular cross section,taking the dynamic tension as an output and the braking moment applied on the jacquard roller as an input,at a moment of clutch operating and releasing,the dynamic tension fluctuations of yarn strand during transmitting between the jacquard roller and drag roller are theoretically analyzed.A mathematical model describing the yarn strand tension fluctuation is derived from the law of moment of momentum and yarn strand mass conservation law.The dynamic tension is obtained by applying Laplace′s transformation and provided that the input braking moment is a step response.The amplitude,frequency and damping coefficient of yarn tension fluctuation are obtained.The results show that the braking moment has an important influence on the yarn strand tension fluctuations,suggesting a necessity of precise design and control of jacquard roller and friction plate of clutch.At the same time,the effect of the length of yarn strand from jacquard rollers to drag rollers on natural frequency and damping coefficient of fluctuation of yarn strand tension are analyzed.