【作者】 夏风林；

【导师】 葛明桥；

【作者基本信息】 江南大学 ， 纺织工程， 2010， 博士

【摘要】 高速经编机一般具有梳栉数少、机号高、生产速度快等特点,其产品广泛应用于服装、装饰和产业等各个领域。高速经编机的梳栉横移运动规律是影响梳栉横移平稳性、精确性最重要的因素,直接关系到经编机的运转性能。传统的高速经编机主要采用花盘凸轮式横移机构,推动梳栉完成针前、针背横移。花盘凸轮式横移机构能适应经编机的高速运转,但更换织物组织不便,不利于产品开发。本课题研究和开发了一种新的基于直线伺服控制的经编电子横移系统,以增强高速经编机的起花性能。首先,论文从带有电子横移系统的高速经编机产品花型结构入手,归纳了这类机器的结构特点;根据经编机梳栉横移工艺要求,分析了高速经编机梳栉横移允许时间,根据实测的几种高速经编机梳栉横移对应的主轴转角,推算了横移时间,其中前梳针前横移时间极短,一般仅为几毫秒到十几毫秒。接着,论文结合高速经编机横移运动的高速度、高精度、高频率和间歇式运动特点,运用凸轮机构运动原理,对常用运动规律的特性值进行分析,并通过数学模糊综合评判方法,将修正梯形加速度运动规律选定为电子横移系统的伺服驱动曲线。在此基础上对梳栉横移运动进行深入研究,表明横移允许主轴转角、横移针距数、针距和经编机主轴转速等是影响横移特性值的4个因素。由此对梳栉横移进行优化设计,在确保横移安全的前提下有效地延长了针前横移时间,大大降低了横移的最大速度、加速度和跃度,显著改善了梳栉横移的运动平稳性和精确性。然后,论文研究了一种新的基于直线伺服控制的经编电子横移系统的实现方法,架构了一种由上位机、下位机和直线伺服执行机构组成的三级分布式高速经编机集成控制系统。上位机采用控制界面友好、功能强的工控机,便于实现电子送经、电子横移、电子贾卡等集成控制和网络生产管理;下位机采用具有电子凸轮控制功能的高性能PLC,控制稳定可靠,实现横移的平稳无冲击;伺服执行机构选用了执行周期较短的伺服驱动器和推力大、动态响应快、传动机构简洁的直线伺服电机。上位机与下位机通过Internet网络通信,下位机与伺服驱动器之间通过EtherCAT网络进行通信。系统具有实时性强、动态响应快、驱动平稳等特点。最后,论文对这一基于直线伺服控制的经编电子横移系统的性能进行了研究,测试了经编机在600～1200r/min不同转速时的指令信号曲线与电机实际运动曲线,随着经编机转速提高,两者在针前横移结束时的吻合性变差;研究了梳栉横移的平稳性,建立了一种梳栉横移的动力学模型,分析了梳栉横移时的振动及其影响,阐明限制电子横移系统适应更高经编机转速的主要因素是梳栉横移结束时的余振;讨论了梳栉横移精确性及其影响因素。论文对所架构的基于直线伺服控制的经编电子横移系统性能测试与研究,将有助于提高高速经编机装备技术水平,促进高档经编起花产品研发。更多还原

【Abstract】 High speed warp knitting machine has the characteristics of few guide bars, fine gauge, high production speed, and its products are widely used in clothing, decorative and technical fields. The motion law of shogging of guide bars on high speed warp knitting machine is the most important factor that affects the motion smoothness and shog accuracy of guide bars and is related to the working performance of the machine directly. Traditional high speed warp knitting machine mainly uses cam as pattern drive mechanism, making guide bars accomplish overlap and underlap. Warp knitting machines with cam pattern drive mechanisms can run at a very high speed of, but changing pattern is inconvenience, which is not conducive to product development. This paper researches and develops a new kind of electronic shogging system based on linear servo control, in order to enhance the patterning performance of high speed warp knitting machine.Firstly, starting from pattern structures of fabric knitted by this machine, the characteristics of high speed warp knitting machine with electronic shogging system was summed up. It analyzed the allowable time for shogging based on shogging requirements of guide bar. By measuring rotational angle of mainshaft which corresponds to shogging movement of various high speed warp knitting machines, the shogging time has been calculated, and it is proved that the front guide bar has a very short time to overlap, generally only a few milliseconds to dozen milliseconds depend on the speed of mainshaft of the machine.Secondly, the motion law of shogging has been studied. High speed, high precision, high frequency, intermittent characteristics of shogging movement of warp knitting machine were integrated, and the characteristic value of common curve was analyzed by cam follower movement theory. The motion law of modified trapezoidal acceleration curve was chosen as the driving law of linear servo in electronic shogging system by using Mathematical Fuzzy Comprehensive Evaluation Method. Further work was carried out based on the result of former research on guide bar shogging movement. It showed that allowed shogging period, lapping needle, machine gauge and running speed of mainshaft of machine are the four factors that affecting the motion characteristic value of guide bar. By optimizing the shogging motion like this, the overlay time was effectively extends much under the premise of ensuring the safety of shogging. The maximum value of the shogging speed, acceleration and jerk could be deduced down respectively. Thus, the performances of motion smoothness and shog accuracy of guide bars are improved obviously.Next, it is studied that a kind of electronic shogging system based on linear servo control for high speed warp knitting machine, and constitutes the three-level distributed control system composed of upper-bit computer, under-bit controller and linear servo implementing agencies. An industrial computer which has a strong ability in program execution, friendly control interface and easy to operate was used as upper-bit computer. It facilitated the realization of electronic let-off, electronic take-up, electronic jacquard and so on to control integrated and network-based production management. Under-bit controller uses a strong PLC with control stability and reliability, and control functions of an electronic cam curve to create a smooth shogging motion without any shock. Linear servo implementing agencies selects a kind of servo drives with short executing period, and a permanent magnet synchronous linear motor with strong thrust, good dynamics and simple frame. Under-bit controller communicates with upper-bit computer via internet network and with servo drives via EtherCAT network. This control system obtains characteristics of real-time processing, high dynamic responsiveness and driving smoothly.Finally, the performance of electronic shogging system based on linear servo control for high speed warp knitting machine was tested at the speed range of 600-1200r/min of machine. The command signal curve and the actual movement curve of linear motor are obtained on monitor. The difference between them become bigger while machine speed going up. A kind of dynamic model is set up to analyze the vibration of guide bar during or/and after shogging, and it is indicated that the vibration of guide bar after overlapping is the main factor which makes a limit speed of machine. Further research focused on performance and the factors which affects the shogging accuracy.The research on the performance of electronic shogging system based on linear servo control should be helpful to improve the technological level of high speed warp knitting machine and be useful to develop high quality warp knitting pattern products.更多还原