Advanced Textile Technology ›› 2024, Vol. 32 ›› Issue (8): 91-99.

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Collaborative reverse design and numerical implementation of heald frame lifting and selection cams on a rotary electronic dobby

  

  1. School of Mechanical Engineering, Xijing University, Xi'an 710123, China
  • Online:2024-08-10 Published:2024-09-02

旋转式电子多臂开口提选综凸轮协同反求及数值实现

  

  1. 西京学院机械工程学院,西安 710123

Abstract: The rotary electronic dobby has many advantages, such as compact structure, high efficiency, and good stability. In order to control the lifting motion of multi-page healed frames precisely, the current mechanical system of electronic dobby chooses a cam drive in both lifting and selection units. Designing high-precision lifting and selection cams with good dynamic characteristics has always been problematic in developing high-speed electronic dobby. In addition, the motion control of the lifting and selection systems for the heald frame is complementary, so it is necessary to consider the cooperating factors of the lifting and selection process from the process level. This paper combines the composition and operating principle of the rotary electronic dobby and realizes the joint reverse design of the lifting and selecting cams in Matlab software, which is conducive to a deep understanding of the rotary electronic dobby's lifting and selection coordination mechanism. 
By analyzing the process, designing the mechanism, deducing equations, and conducting theoretical calculations, the cycloidal, corrected and constant velocity motion law was applied to the rotation output of the slider rod. A reverse design program for the profile curve of the lifting conjugate cam was developed by Matlab software. The "bisection method" was used to iteratively calculate the coordination parameters of the lifting and selection cams, thereby determining the safety angle of the large disk, the lifting angle, and the return angle of the selection cam. On this basis, combined with the requirements of selection and control, a swinging rod motion law based on a quintic polynomial was constructed, and the theoretical profile curve of the selection conjugate cam was designed and generated through Matlab software. The joint development of the lifting and selection conjugate cams was achieved, and the feasibility of the cooperation between the lifting and selection system was verified. The lifting and selecting cam mechanism has good motion performance and coordination relationship when the motion laws of cycloidal, corrected and constant velocity and the quintic polynomial are employed.
The reverse design ideas and numerical implementation method of lifting and selecting conjugate cams have been clarified, providing an essential reference for designing and developing high-precision rotary electronic dobby.

Key words: electronic dobby, bisection method, conjugate cam, heald frame, collaboration, safe angle

摘要: 针对高速电子多臂开口复杂的机械控制构成,通过旋转式多臂机的功能原理解析和数值运算,实现提综变速系统与选综控制单元驱动凸轮的协同设计。将摆线修正等速运动规律应用于滑块架回转输出,利用Matlab对提综共轭凸轮工作轮廓进行设计计算,结果显示:当滑块架预设停顿角度为25°时,主、副凸轮最大压力角约为40.8°,提综摆臂行程角约为41.2°,满足旋转变速模式下的提综工艺要求。采用“二分法”对提综与选综配合参数进行迭代计算,确定大转盘安全转角约为38.79°、选综凸轮升程角与回程角约为83°。根据选综机构条件及控制要求,构建基于五次多项式的摆杆运动规律,并在Matlab环境下计算生成选综共轭凸轮理论轮廓曲线。从数值分析层面验证了提选综凸轮的运动配合机制,为高精度电子多臂开口的协同设计与开发提供了一定理论基础。

关键词: 多臂开口, 二分法, 共轭凸轮, 综框, 协同, 安全角

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