Abstract: Multiple weft yarns are arranged in shuttles at different heights during the formation of three-dimensional carbon fiber fabrics. To ensure that each layer of weft yarns can withstand a uniform beating-up force, the reed must move horizontally in the front dead center, simultaneously feeding each layer of weft yarn into the weaving mouth. Traditional beating-up methods, such as linkage and conjugate cam mechanisms, cannot meet the requirements of multi-layer three-dimensional fabric weaving technology because they can only achieve circular arc trajectory movement of the reed. To solve the problem of uniform force on each layer of weft yarns in three-dimensional fabrics, this paper proposed a parallel beating-up mechanism composed of a conjugate cam and a planar linkage.
In this paper, through an analysis of the form and mechanism principle of beating-up, a modified trapezoidal acceleration motion law was applied to the parallel beating-up of a reed. A reverse design program was compiled in the Matlab environment for the swing arm motion law and the conjugate cam theoretical profile. The Step function was used to simulate the beating-up resistance caused by multi-layer three-dimensional fabrics, and a functional prototype simulation model of the parallel beating-up system was constructed by Adams/View software. The kinematic and dynamic performance of the system were simulated and analyzed, taking into account factors such as beating-up resistance, contact collision, and conjugate clearance. A parallel beating-up mechanism suitable for multi-layer three-dimensional fabrics was developed by effectively connecting conjugate cam and planar linkages through mechanism combination. A calculation method and simulation idea for the beating-up resistance of multi-layer three-dimensional fabrics were also proposed. It is found that near the front dead center, the angular acceleration of the rocker shaft reaches its maximum, and the reed undergoes stable horizontal motion along the X direction, which can well meet the requirements of parallel beating-up technology. Due to conjugate clearance, high-frequency collisions between the main and auxiliary cams and rollers can cause mechanical vibration, adversely affecting the dynamic accuracy of parallel beating-up. 
The new beating-up mechanism has good process applicability and practical application prospects. It provides technical ideas for the design innovation of parallel beating-up for multi-layer three-dimensional fabrics made of carbon fibers.

Key words: carbon fiber, reed, conjugate cam, parallel beating-up, conjugate gap, three-dimensional fabric, beating-up resistance

摘要： 为提升碳纤维立体织物各层打纬力分布的均匀性，通过机构串联对共轭凸轮与平面四连杆进行功能配置，设计了一种适用于多层立体织造的组合式平行打纬构型。根据修正梯形加速运动规律，在Matlab环境中对主、副凸轮理论廓线进行数值分析与编程反求，提出了适用于多层立体织物的打纬阻力计算方法，构建了基于Adams/View的高精度平行打纬系统数字化仿真模型，并针对其运动特性、共轭精度及接触碰撞等进行了动态模拟与分析。结果显示：钢筘在前死心位置(凸轮轴转角为72°时)附近能够很好地实现水平打纬运动；摇轴与摆臂具有较高的角运动匹配精度，且两者负角加速度在前死心处均达到瞬时最大，有利于同步打紧各层纬纱；当凸轮机构存在共轭间隙时，摇轴角位移、角加速度会产生明显的偏离与振荡，同时主、副凸轮与滚子之间亦存在高频次接触和碰撞，并将导致摇轴与筘座发生振动，不利于提升平行打纬动力精度。文章为高品质多层立体织物打纬构型的设计与应用提供了借鉴。

关键词: 碳纤维, 钢筘, 共轭凸轮, 平行打纬, 共轭间隙, 立体织物, 打纬阻力