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1、圆型经编机的伪造伺服系统摘要经编技术通常都是运用在直丝(线性)经编机上的。使用一种新概念的锥形针床并附上凸轮驱动模式圆环的圆型经编机，最近成为一种可能。这需要一个机械联动传递的凸轮运动模式,但很容易产生环振动的不良水平。新一代的设计中取代机械凸轮和联动高速无刷直流伺服电机，使图案的精确成为无限可能。经报道，方法选择的基于最大程度的减少了伺服电机的功率以及完成最快的运动要求。通过选择最小合适的指定应用伺服电机驱动的方法保证了成本最小化。经报道,一个圆型经编机采用伺服电机以及其驱动机器使用方法的选定设计、建造,并测试使用成功。2001科学出版社有限公司。保留所有权利。简介:模式机制概述直丝经编机使
2、用了三个主要机制产生制针过程。针织机制针即是前边垂直摆动筒子纱的机制从前线移动到后面的针和一个移针距机制产生重叠，然后和从下面露出的平面针进行平行铺设。这台机器的模式在最大程度上取决于动作的难易修改它的每个移针距形成的机理和字符串的长度链。经编针周期在针织机上可以被描述成六个阶段(见图1)。从针在他们的最高位置,有以前的循环圆自己干,在阶段(1)从后面纱线摆动到前面的针。在阶段(2)下一个线程被铺设的钩子表演,而一针一针从侧身空间到下一个的重叠。然后摆动的纱线的回到了针的平台(3)。然后就开始移动针向下,旧的环路的每一针被锁住的,导致柜子的关闭。这些针继续向下移动,直到老循环到达山顶的针,(阶
3、段(4),拉动了织物张力。在阶段(5),下面织针的线程再一次,这一次后面的针重复。(阶段(6),线程在钩子上打开柜子,成为下一个循环。在圆型经编机上，纱线接头都是通过非穿孔环。旋转运动的成为与图案,这些环链是由多种旋转运动与圆环在同步的主要机制负责往复式针纵向(见图2),戒指必须履行的两种截然不同的轮换和两个住在机器周期。今后的研究方向和幅值的旋转将取决于织物结构产生的吧。然而,一份重叠总是会进行过超过一针,而一个只可在几针并且可以因此需要一个更大的轮换的戒指。大的数目的戒指,可能性更大的模式。然而,一定数量的空间放置他们和纱线的路径的复杂度的数量一般限制环中存在模式的机器。系统要求第一次设计
4、原型被用来当作工业针织机生产包装面料、长统袜绷带材料和其他技术纺织品。产品设计规格为机器覆盖所有这些市场中实施,从而建立起企业终端产品的要求。研究发现,大多数应用程序不需要多于一个4倍下去针距。此外,最小规格(每英寸的针数)在相关应用四岁。气缸的直径是不重要的,这种情况在组网应用的范围为75100毫米的长统袜,这完全是因人而异的应用和广泛的应用于医学应用。为第一原型,75mm直径缸使用。这个尺寸缸、四针空间四针每英寸相当于38气缸。一个4针距将可能需要的旋转8针空间,相当于76。这也正是决定向以及系统的要求,即模式机制必须能完成多达80的旋转,在一个单一的下针距。设计师可以改变织物的编织周期的
5、一部分分配给模式和企业生态位重叠动作。在初步设计圆形的助燃机,三分之一的机器周期被认为是sucient为针的运动。这使得三分之二的针织周期来执行120和重叠互相矛盾。假设的最大速度是1000转数,这台机器单一针织循环发生在60岁的女士。这样只剩下20 ms履行重叠和20的旋转。机械解决办法其专利模式机制2、5都是机械控制模式,使用两个凸轮控制的开放,面对环模式和有最大长度的12机周期。人数限制周期是由于空间限制。较大数量的机器周期模式里需要一个更大的凸轮的空间,但在凸轮的大小是有限的。主要的进步达到与机械方法解决建设作为本研究之部分:(1)使用封闭模式凸轮凸轮追随者,减少冲击和振使用开放,面对
6、凸轮时形成的,(2)改进的生产工艺模式的凸轮通过开发一个特制的工具建立出铣削程序的模式,(3)凸轮机构的凸轮性能提高利用摆线针轮箴les的每一个片段。摆线针轮剖面进行已知能给你最好的结果为高速应用3相比其他基本位移曲线,因为它们提供了三种有限的衍生品的位移。给出了摆线针轮位移。唯一的缺点,使用这种类型的职业乐为当前的应用是基于混球曲线的结束点的各运动。也就是说,在节点处上升(或收益)期间结束时期开始和居住。这是因为第三种派生的位移不为零,而在终点的住。如果有必要,运动曲线可能会有进一步的优化利用poly-nomial档案,来确保位移及其三个衍生物是连续贯穿始终。研制了一种特制的计算机应用程序,
7、创造出一种凸轮廓线,然后再下载到一个数控铣床。一旦在针织机、凸轮运动中是使用高速lmed录像机(200帧每秒)。没有过多的振动;即使追随者帧观看时都已经看到,跟随者的没有离开一侧的轨道上,这是滚动。机械系统的作用是:将创造的直线移动模式的旋转凸轮进一环通过模式有一定数量的枢纽和机械连接(见图2)。组件和长度的联系在很大程度上取决于身体的可用空间和尺寸对机器零件的制造和销售。例如,为了创造出一个长循环运动的模式由环,同时保持适当的压力角的凸轮、基线半径等一定增加。虽然凸轮机构跑光滑,高速的视频显示过度振动模式的戒指。对比的平稳运行和不规则的凸轮机构从动件运动圆环表明,后者是由弹性机械连接。机器的
8、速度会因此总是会受到其力学性能和尺寸的连接。证明了这种机械的设计概念的圆形经编机制是可行的。伺服控制系统一种全新的方法是控制模式的机理问题采用伺服电机的环。虽然更昂贵的解决方案,它具有潜在地产生模式链条,只是大小限制的记忆(i.e.hundreds用五机械周期而不是12个机械周期)和缩短了时间和部分从一个模式需要改变到另一个地方。此外,伺服电机,会产生一种旋转运动,当耦滑轮组可以驾驶模式环直接。没有必要机械转型到一个旋转的一个直线移动,则可能是要求如果其他的电子控制线性驱动的机械设备,使用,如线性气动执行机构。被选择的伺服电机的步进电机由于反应的速度和位置控制要求给出的针织的申请。本文涉及的伺
9、服控制的模式机制而已。但是,主要机制,即针织负责针运动也可以通过伺服系统给予更多的控制之间的同步针和纱线。6提出一种提高动态特性,通过控制的凸轮机构从动件凸轮的使用伺服电机的速度。基于直线电机的经编机横移控制系统设计摘要 本文以三相永磁无刷直流直线电机及驱动控制系统为主要研究对象，采用数字信号处理器(DsP)为控制核心对经编机横移机构进行实用设计。文中给出了系统的总体设计方案，阐述了该系统的基本结构、工作原理、运行特性及其设计方法。另外，文中还对各硬件模块(直线电机驱动电路、位置检测电路、电流检测等)电路设计以及各软件模块进行了详细的分析。关键词：经编机；横移运动；直线电机；DsP；PwM；P
10、ID1 引言经编丁业是纺织工业的一个重要组成部分，经编产业的快速发展推动了经编机设备制造技术的不断更新。开发和研制出技术含量高、生产效率高、可靠性高的高档智能化经编机，核心技术是需要经编机梳栉横移精度高，因为高精度的横移机构在回复运动过程中，可以保证织针回摆过相应的导纱针时，一个横移时间就完成。因此开发和研制出智能化的高精度经编机意义深远。2 当前的经编机横移机构控制系统21机械式经编机横移机构 机械式多梳栉提花经编机是由高低尺寸不一的链块纵横排列成链带，编织花型时该链带循环走动，按照花型的要求控制着梳栉的行程以达到编织花型的目的。这种横移机构的缺点是一种花型就要一种凸轮(或花纹链条)，凸轮(
11、或花纹链条)加工成本高，花型变化品种有限，且代价昂贵。另外，由于人们对花型要求越来越高，梳栉数进一步增加，生产和改变花型已经变得越来越困难。在多品种、小批量的买方市场下，用链条来进行花型生产非常费事、费时，且成本很高。22新型电子横移机构新型的EL(electronic guide baf control system)横移机构、su(summe blech)横移机构、钢丝花梳横移机构、地梳和贾卡梳横移机构均采用伺服电机控制。EL适用于连续的、快速的花型变换。机器速度受到限制。Su横移机构借助滑动组件来控制花梳，通过电磁元件来控制滑动组件，从而可按照确定的路径来形成横移路径距离。但是它的极限是
12、最大47针的横移距离和每分钟450转的最大转速。新型的钢丝花梳、地梳和贾卡梳横移机构都采用了伺服电机控制。每个钢丝花梳连接一个伺服电机，由伺服电机执行横移运动，钢丝梳通过空气压缩机进行回复。另一端的反向平衡装置(气动张力调整器)保证钢丝梳在整个横移区间的张力均匀一致。导纱针按照花型进行运动，一个方向借助压缩空气，另一个方向通过机械动力，大小由伺服电机控制(如图2)。另外，Karl Mayer公司新近研制出了匹艾州压电式贾卡装置。它是由压电陶瓷及贾卡导纱针组成。压电式贾卡导纱技术彻底改变了贾卡装置，无需通丝、移位针等繁杂部件，使贾卡经编机提花部分的机构大大简化，有助提高速度。但是横移距离较小。3
13、 系统总体结构设计31系统方案的选取针对上面所阐述的当前几种经编机横移机构，本文采用基于直线电机的横移控制系统，利用直线电机取代花纹链块直接驱动导纱梳(如图3)。由直线电机驱动的传动装置，不需要任何转换装置而直接产生推力，因此，它可以省去中间转换机构，简化了整个装置或系统，保证了运行的可靠性，提高了传递效率，降低了制造成本。另外，由DsP构成的电机控制系统相对于单片机或微机具有更高的精度和速度，而且存储量大，具有逻辑控制功能和各种中断处理能力，丰富的数输入输出口、通信口、专用电机控制PwM输出口，各种硬件集成在同一芯片中，从而简化硬件设计，提高软件编程的灵活性。整个系统结构简单、体积小、可靠性
14、高，实现真正意义上的机电一体化新型高精度经编机横移机构控制系统。32系统总体结构框图本系统采用直线电机型号为深圳大族精密机电有限公司生产的LMcuM20420，其最大行程为300mm，连续推力可达73N，最大电流18A。可以很好的满足经编机横移的要求。控制器采用采用TI公司生产专用于电机控制的TMs320LF2407A。基于DsP的直流直线电机控制系统的系统框图如图4所示，DsP负责处理采集到的数据和发送控制命令并通过捕获单元捕捉电动机动子位置传感器上的脉冲信号，判断动子位置，输出合适的驱动逻辑电平至星型全桥MOsFET电路，再由MOsFET功率驱动电路驱动电机做直线运动；DsP的捕获单元根据
15、捕获的位置传感器脉冲信号的宽度，计算出电机的当前转速，与电机的设定转速比较后，利用PID算法产生合适的脉宽调制信号(PwM)控制电机的转速跟随转速的设定值；驱动保护电路可完成电机的过载、欠压、过压等异常故障保护。4系统硬件电路实现41直线电机驱动电路驱动电路设计采用三相星型全桥电路。全桥逆变电路采用六个IRF640搭建，在每个管子的基极和发射极之间并接一个嵌位电阻。电机前置功率管驱动电路采用IR2130，IR2130芯片的每6路输出控制驱动电路的上半桥和下半桥导通关断，从而控制控制电机的转速和正反方向横移，同时起到过载、欠压、过压等异常故薛保护。由IR2130和MOSFET组成的电机驱动电路如
16、图5所示。图5三相星型全桥式电机驱动电路图42位置检测电路在直线电机的控制系统中，要实现对直线位移的精确控制，就必须通过高精度的检测装置对它进行检测，将检测结果转换成数字量反馈给DsP，由DsP对这些数据进行处理。系统使用直线光栅传感器进行电机位置检测。光栅位置检测装置由光源、两块光栅(长光栅、短光栅)和光敏元件等组成。如果将指示光栅在其自身的平面内转过一个很小的角度0，这样两光栅的刻线相交，则在相交处出现黑色条纹，称为莫尔条纹。由于两块光栅的刻线密度相等，即栅距w相等，而产生的莫尔条纹的方向和光栅刻线方向大致垂直，所以当O很小时，其条纹间B和光栅栅距w及2条光栅刻线夹角关系为：当光栅相对移动
17、时，莫尔条纹将沿着刻线方向移动。光栅移动一个栅距，莫尔条纹也移动一个间距B，同时；在指示光栅上的光敏元件接收到一次光脉冲的照射，并相应输出1个电脉冲。通过计数电脉冲的数目，就可以测量标尺光栅的位移x，即： x=iw （2）43电流检测电路采用wBl414电流传感器作为电流检测装置，由于三相绕组采用的是星形连接，中点悬空，也就是说，电流的3个变量不完全独立，只要知道其中两个，设为Ia和Ib，另一个变量Ic就可以算出：因而实现电动机相电流的精确检测，只需两路检测电路，将Ia和Ib的电流值经转换后分别送往DsP的ADcINO和ADCINl。电流检测原理图如图6所示。位置检测不但用于换向控制，而且还用
18、于产生速度控制量。每个周期内有6次换相，电机的动子每走过一块磁铁都有一次换相(每块磁铁的长度15mm)，这样测得两次换相的时间间隔为t，就可以根据式(31)计算出两次换相间隔期间的平均角速度。两次换相的时间间隔t可以通过捕捉中断发生时读出定时器2的值来获得。图6 电流检测电路图5 DSP控制系统软件实现主程序的主要功能足完成系统的初始化，如系统RAM的映射(存储空间的分配)、看门狗初始化、中断初始化、I0引脚功能初始化、事件管理器EvA的PwM，ADc初始化、事件管理器EVB的CAP初始化、异步串行口初始化等。初始化完成后，主程序在RAM中建立基准正弦函数表，该正弦酾数表是对幅值为l正弦函数正
19、半周期采样900个点得到的。图7主程序流程框图6 结论本文以TMs320LF2407A作为控制器。对纺织机械电子横移系统的电子凸轮机构进行了实用设计。系统充分利用直线电机的优点，采用电流环、速度环的双闭环控制电极的位置和速度，PID算法对参数进行反复优化，使系统达到预期的位移控制精度和频率响应，并且在经编机电子横移系统上运行可靠。Patterning servo-mechanism for a circular warp knitting machineAbstractWarp knitting is always performed on flat (linear) knitting mac
20、hines. A circular warp-knitting machine is recently made possible by using a novel concept of a conical needle bed and patterning cams with enclosed cam followers to drive the patterning rings. This also requires a mechanical linkage to transmit the motion from the patterning cam to the patterning r
21、ings, which is prone to vibration at undesirable levels. A new generation design replaces the mechanical cam and linkage with high-speed AC brushless servomotors enabling limitless precision patterning possibilities. A method of selecting servomotors based on minimising the power required to perform
22、 the fastest motion required for a given application is reported. This method ensures cost minimising by selecting the smallest servomotor suitable for a given application. A circular warp-knitting machine using servomotor to drives selected using the method reported is designed, built and successfu
23、lly tested.2001 Elsevier Science Ltd. All rights reserved.Introduction: patterning mechanism overviewFlat warp knitting machines employ three main mechanisms to produce stitches.Namely, a knitting mechanism that reciprocates the needles vertically, a swingingmechanism to move the yarns from the fron
24、t to the back of the needles and ashogging mechanism to produce the overlaps and underlaps parallel to the plane on which the needles are laid.A pattern consists of a chain of dierent length underlaps and hence theexibilityof the machine patterning depends on the ease of modifying the movements per-
25、formed by its shogging mechanism and the length of the pattern chain.The warp knitting needle cycle for a at knitting machine can be described ascomprising six stages (see Fig. 1). Starting with the needles at their highest position and having the previous loops round their stem, in stage (1) the ya
26、rns are swung from the back to the front of the needles. At stage (2), the overlap, a thread is laid under the hook of the needle by performing a sideways shog from one needle space to the next. The yarns are then swung to the back of the needle in stage (3). The needles then start to move downwards
27、, the old loops are caught under each needle latch and cause the latches to close. The needles continue moving down until the old loops reach the top of the needle, are cast-o (stage (4) and pulled by fabric tension. At stage (5), theunderlap, the threads are shogged again, this time behind the need
28、les.As the needles rise again (stage (6), the threads in the hooks open the latches and become the next loops.On a circular machine, the yarns are threaded through radially perforated rings.The shogging movement becomes a rotation of these rings and a pattern chain comprises a number of rotational m
29、ovements of the rings in synchronisation with the main mechanism responsible for reciprocating the needles vertically (see Fig. 2).The rings must perform two distinct rotations and two dwells during a machine cycle. The direction and amplitude of the rotations will depend upon the fabric structure b
30、eing created. However, an overlap will always be carried out over one needle only, while an underlap can be under several needles and could therefore require a larger rotation of the ring.The larger the number of rings, the greater the patterning possibilities. However,the amount of space to place t
31、hem and the complexity of the yarn paths generally restricts the number of patterning rings present in a machine.System requirementsThe first design prototype was used as an industrial knitting machine to produce packaging fabrics, stockings bandage materials and other technical textiles. A product
32、design specification for a machine to cover all these markets was carried out in order to establish the end products requirements. It was found that most applications would not require more than a 4-needle underlap. In addition, the minimum gauge (number of needles per inch) in the relevant applicat
33、ions was 4. The cylinder diameter is not critical for the netting applications; this varies in the range of 75100mm for the stockings application and it varies widely for medical applications. For the first prototype, a 75-mm diameter cylinder was used. For this size cylinder, four needle spaces at
34、four needles per inch are equivalent to 38 of the cylinder. A 4-needle underlap will probably require a rotation of 8 needle spaces, which is equivalent to 76.It was therefore decided to set as system requirement that the patterning mechanism must be able to perform a rotation of up to 80 in a singl
35、e underlap.The fabric designer can alter the portion of the knitting cycle allocated to the patterning ring movements (underlap and overlap). In the initial design of the circular warp-knitting machine, one-third of the machine cycle was deemed to be sucient for the needles movement. This leaves two
36、 thirds of the knitting cycle to perform the underlap and overlap; 120 each.Assuming that the maximum speed of the machine is 1000 rpm, a single knitting cycle takes place in 60 ms. This leaves only 20 ms to perform the underlap and 20 ms for the overlap rotation.Mechanical solutionThe patented patt
37、erning mechanisms 2,5 are all mechanically controlled, use two patterning rings controlled by open face cams and have a maximum pattern length of 12 machine cycles. The restriction on the number of cycles is due to space limitation.A larger number of machine cycles in a pattern would require a large
38、r cam, but the space in which the cam ts in is limited.The main progress achieved with the mechanical solution built as part of this research was: (1) the use of enclosed cam followers in the patterning cams, reducing shock and vibration eects created when using open face cams, (2) improvements of t
39、he manufacturing process of the patterning cams by developing a tailor-made tool to create the milling programs of the patterning cam, and (3) enhancement of the cam performance by using cycloidal proles for each segment. Cycloidal profiles are known to give the best results for high-speed applicati
40、ons 3when compared to other basic displacement curves, because they provide three finite derivatives of displacement. The cycloidal displacement is given by:The only drawback to using this type of prole for the current application is the non-continuous jerk curve at the end points of each motion. Th
41、at is, at the point where the rise (or return) period ends and the dwell period begins. This is because the third derivative of the displacement is not zero at the end point, whereas that of a dwell is. If necessary, the motion curves could be further optimised by using poly-nomial profiles to ensur
42、e that the displacement and its three derivatives are continuous throughout.A tailor-made computer application was developed to create the cam profile program, which is then downloaded into a NC milling machine. Once on the knitting machine, the cam in motion was lmed using a high-speed video record
43、er (200 frames per second). There was no excessive vibration of the follower in the cam-track; even when viewed frame by frame it was seen that the follower did not leave the side of the track on which it was rolling.The mechanical system converts a translational motion created by the patterning cam
44、 into a rotation of the patterning ring by means of a number of pivots and mechanical linkages (see Fig. 2). The conguration and length of the linkage components depend on the physical space available and the dimensions of the machine elements. For example, in order to create a longer pattern by cir
45、cular motion of the ring, while maintaining appropriate pressure angles in the cam, the baseline radius of the cam must increase.Although the cam-follower mechanism ran smoothly, the high-speed video showed excessive vibration of the patterning rings. The contrast between the smooth running of the c
46、am follower and irregular motion of the rings suggests that the latter is created by the elasticity of the mechanical linkages. The speed of the machine would therefore always be constrained by the mechanical properties and the dimensions of the linkages.This mechanical design proved the circular wa
47、rp knitting mechanism concept to be feasible (see Fig. 3). However, a design that allowed for more patterning exibility and ultimately higher operational speed was required in order to manufacture the more complex fabric designs used in the medical and stockings industries.Servo-controlledsolutionAn
48、 entirely new approach to the patterning mechanism problem was to control the rings using servomotors. Although a more costly solution, it has the potential of creating pattern chains that are only restricted by the size of the memory of the hardware used (i.e.hundreds of machines cycles rather than 12) and reducing the time and parts required to change from one pattern to another.In addition, a servomotor would produce a rotational motion, when coupled viatiming belts and pulleys could drive the patterning rings dire