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一种新型的自动售货机用取物箱的设计【15张CAD图纸+毕业论文】【答辩通过】

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关键词：: 一种新型自动售货机用取物箱设计

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摘要

论文主要介绍了一种新型的自动售货机用取物箱的设计过程。在设计过程中还综合各方面因素对设计做了多次改进,简述了自动售货机的原理、分类以及内部结构与电子元件和国内外发展概况。就实际使用中所出现的因防盗板运动方式的不同所引起的取物箱高度过高而导致的取物箱体积增大的问题，提出了解决方法。运用PLC对自动售货机的控制系统做了设计。新型的防盗板联动机构具有结构简单、运动平稳、受力情况好、成本低、加工容易等优点。新型取物箱的结构设计运用了机械设计、机械原理、材料力学、创新思维等多方面的知识，是对所学知识的一次综合考验。此次设计的取物箱大多数零件都是钣金件，因此，为了完成这一设计，我学会了运用Solid Edge三维绘图软件，此软件最大的优点就是具有强大的钣金件建模能力。此外，我还充分利用了AutoCAD软件强大的参数化特征将设计图形显而易懂的呈现在大家面前。

关键词:自动售货机;取物箱;防盗板;钣金;Solid Edge;AutoCAD;PLC

Abstract

This paper mainly introduced a new type of vending machine in the design process of take content box. Also synthesized various aspects factor in the design process to design does improved many times, has summarized the limiting condition and the domestic development survey which the vending machines，classification , the internal structure and electronic components ,the domestic and foreign development situation. According to the practical use of guard against theft occurred because of the different ways of plate movement caused by the content box highly exorbitant and take the lead to take content box the increase in size, solutions are put forward. I did the application of PLC control system of the vending machine to do the design The new security board linkage mechanism possesses simple structure, smooth movement, force of good, Low cost, easy processing. Take the new content box structure design using a mechanical design, mechanical principle, material mechanics, innovative thinking and so on various knowledge, is the knowledge of a comprehensive test.The design of the take content box is most parts metal sheet, Therefore, in order to finish the design, I learned to use Solid Edge 3D drawing software. Besides that I fully design the graph using the AutoCAD software formidable parametrization characteristic to reveal easy to understand present in front of us.

Key words:Vending machine ;Take content box ;Security board;Sheet metal parts ;Solid Edge ;AutoCAD;PLC

摘要III

AbstractIV

1 绪论1

1.1 课题来源1

1.2 本课题的研究内容和意义1

1.2.2 设计意义1

1.3 自动售货机的起源、兴起和普及1

1.3.1 起源1

1.3.2 兴起2

1.3.3 自动售货机产业的普及2

1.4 自动售货机在国内的发展2

1.5 自动售货机在国外的应用3

1.6 自动售货机在国外的市场发展4

1.7 新型自动售货机的新增功能4

2 自动售货机的分类6

3 自动售货机的结构与功能分析7

3.1 结构7

3.2 功能分析8

4 自动售货机的控制技术10

4.1 PLC的系统结构11

4.2 I/O分配表11

4.3 PLC外部接线图12

4.4 梯形图程序13

5 取物箱的结构与作用16

5.1 结构16

6 取物箱不同防盗结构的比较18

6.1 传统取物箱防盗结构18

6.2 改进后取物箱防盗机构18

7 取物箱箱体结构的设计20

8 取物箱材料的选择21

8.1 箱体材料的选择21

8.2 取物门与防盗板材料的选择21

8.3 取物门固定套材料的选择21

9 取物箱中力的计算22

10 联动轴扭矩计算24

11 取物门旋转角度的选择25

12 取物箱的三维效果27

13 结论与展望31

13.1 结论31

13.2 存在的不足及对未来的展望31

致谢32

参考文献33

1 绪论

1.1 课题来源

自动售货机是可完成无人自动售货,集光、机、电一体化的商业自动化设备。自动售货机不受任何场地限制,方便快捷,很多城市的公共场所里面都放置有自动售货机。从自动售货机的发展趋势来看，它的出现是由于劳动密集型的产业构造向技术密集型社会转变的产物。大量生产、大量消费以及消费模式和销售环境的变化，要求出现新的流通渠道；而相对的超市、百货购物中心等新的流通渠道的产生，人工费用也不断上升；再加上场地的局限性以及购物的便利性等这些因素的制约，无人自动售货机作为一种必须的机器便应运而生了。可编程序控制器(PLC)是综合了计算机技术、自动控制技术和通讯技术而发展起来的一种新型的工业控制装置,它具有可靠性高、编程简单、维护方便等优点,已在工业控制领域得到广泛地应用。本课题实现自动售货机的取物箱的防盗装置和联动机构的设计更为紧凑，比较大程度的减少取物箱的体积。自动售货机行业长期以来在美国、日本等国家得到迅猛发展，目前已在45个国家得到广泛普及。据业内人士估计，中国的自动售货机拥有量仅有2万台，相对于13亿的人口大国和零售业态发展的趋势而言，中国自动售货机行业的发展空间将更加广阔。可编程序控制器( PLC)是综合了计算机技术、自动控制技术和通讯技术而发展起来的一种新型的工业控制装置，它具有可靠性高、程序简单、维护方便等优点，已在工业控制领域得到广泛地应用，因为自动售货机作为社会上完成商品零售和综合服务的独立设施，要求它的结构必须可靠、稳定和执行效率高。一种新型的自动售货机用取物箱的设计保证自动售货机能够长期安全稳定运行。本文就详细地介绍PLC实现的自动售货机控制系统的硬件设计和软件设计，新型的取物箱的设计过程。

1.2 本课题的研究内容和意义

1.2.1 研究内容

设计一种新型的自动售货机用取物箱，主要是将传统的向上翻转的防盗板改变为平移式防盗板，该取物箱可以有效的降低设计高度，有效节约设计空间，适用于售货机比较紧凑的内部空间，从而可有效降低取物箱的高度。

1.2.2 设计意义

降低取物箱的高度可以减少它所占的体积，从而可以为物品展示区和储物箱腾出更多的空间，这样一来，自动售货机可以为消费者提供更多的商品，提高单台售货机的销售量，为企业创造更多的经济利润！

1.3 自动售货机的起源、兴起和普及

1.3.1 起源

自动售货机的历史，可一直追溯到远古时代的埃及。亚历山大的科学家HERON在其所著的《气体装置(PNEUMATIKA)》中描述，只要将钱币投入该装置，水就会自动流出来。这就是自动售货机的起源，大约在公元前215年左右，埃及寺院中就安装了这种装置，用来销售“神圣之水(圣水)”。

1.3.2 兴起

日常生活中最重要的是方便，自动售货机最早出现在二十世纪五六十年代的西欧，当时在美国的地铁中，人们可以用1美分在自动售货机上买到一块口香糖。

第二次世界大战后，经济开始复兴的1957年，以日本作为代表，开发出了饮料自动售货机。只要在饮料自动售货机中投入10日元，就会在纸杯内注入一定量的果汁。由于机器的上部安装有引人注目的喷水装置，所以该自动售货机被称为“喷水型果汁自动售货机”，自此出现了爆发性的自动售货机狂潮。此种喷水型果汁自动售货机为消费者带来了新奇、前卫的购买方式，并对之后日本的自动售货机高度普及起到了很大的作用。之后登场的是可乐自动售货机。随着美国大型可乐公司正式进驻日本市场，到了1960年代中期，罐装饮料自动售货机也登场了。自动售货机的活跃表现对可乐销量的惊人增长贡献巨大。同时，优秀的自动售货机市场战略、操作技巧等都对日本的自动售货机产业的发展产生了很大的影响。1962年，作为流通领域革命的使者，拉开了自动售货机的序幕。一开始是瓶装饮料自动售货机。1967年，100日元单位以下的货币全部改为硬币，从而促进了自动售货机产业的发展。

自动售货机在日本被亲切地称为“微型小店”。“微型小店”出售的商品，从咖啡、香烟、各种酒类已经发展到部分日常生活用品，就连报纸、大米、邮票、明信片、电池、录像带等也可以自动出售。现在，自动售货机除路旁以外，已进入学校、工厂、医院、游戏厅、麻将馆、影剧院等公共场所。作为世界上最大的自动售货市场，日本已有560万台，通过自动售货机出售的商品多达6000余种，年营业额7兆1122亿日。每年，仅饮料的销售额相当于1593亿元人民币，按人口计算，每23人就拥有1台自动售货机，平均每人在自动售货机上的消费达56000日元。

1.3.3 自动售货机产业的普及

随着经济的发展、人们对富裕生活的不断追求，自动售货机开始迅速普及。由于经济的高度成长，建立了消费物品的大量生产体制，同时需要与之相适应的大规模物流方式，满足这一需求的就是自动售货机和超级市场。在作为主力商品的饮料领域中，随着罐装咖啡的出现，诞生出了世界首例可销售冷、热饮料的冷热罐装饮料自动售货机，这向普及迈出了一大步。由于冷热罐装饮料自动售货机的推广，流通行业可提高设备设置的空间利用率，并能在全年内取得均衡的销售额。在原料加工后用纸杯等进行销售的杯式自动售货机领域中，从速溶咖啡机、普通咖啡机、甚至是能够在机器内部磨好咖啡豆后加牛奶的普通咖啡机，快速应对着消费者嗜好的变化。

1.4 自动售货机在国内的发展

随着我国经济的快速发展，人们的生活方式发生了巨大的变化，人们的生活节奏也越来越快！于是一种既节约时间又方便快捷的消费理念出现在了我们的面前，那就是自动售货。在这一思想的指导下，自动售货机应运而生，它的出现极大的方便了我们的生活。自动售货机是能根据投入的钱币自动付货的机器。自动售货机是商业自动化的常用设备，它不受时间、地点的限制，能节省人力、方便交易。是一种全新的商业零售形式，又被称为24小时营业的微型超市。能分为三种：饮料自动售货机、食品自动售货机、综合自动售货机。

在许多公共场所都能看到它的身影，比如，机场、车站、码头、地铁口、商业街、校园、办公写字楼、居民生活小区、游乐场以及一些大型的公司内部。

适销的商品更是五花八门、种类繁多，只要是各种标准化的商品，都可通过自动售货机予以销售。我们相信，随着我国经济的持续发展，人民消费水平的不断提高，对自动售货机的需求必将越来越多、越来越广泛。

现在，自动售货机产业正在走向信息化并进一步实现合理化。例如实行联机方式，通过电话线路将自动售货机内的库存信息及时地传送各营业点的电脑中，从而确保了商品的发送、补充以及商品选定的顺利进行。并且，为防止地球暖化，自动售货机的开发致力于能源的节省，节能型清凉饮料自动售货机成为该行业的主流。在夏季电力消费高峰时，这种机型的自动售货机即使在关掉冷却器的状况下也能保持低温，与以往的自动售货机相比，它能够节约10－15%的电力。进入21世纪时，自动售货机也将进一步向节省资源和能源以及高功能化的方向发展。

除此之外，自动售货机内部空间的布局也发生了很多变化，为了追求储物空间的最大化，必须控制其余部件所占的体积，取物箱的结构设计就是其中之一。传统取物箱结构的最大缺点就是高度过高，占用了自动售货机内部过多的空间，这主要是由防盗方式所引起的，现阶段市场上自动售货机的取物箱主要的防盗方式是使位于取物箱后部的防盗板向上翻转来封闭取物箱上部开口。此种方式的优点是实现方式简单可靠，缺点是在同等条件下取物箱实现功能所需的设计高度比较高（必须留出取物门与防盗板翻转所需的高度空间）不适宜现在越来越紧凑的设计要求。鉴于此类情况现需设计一新型的自动售货机用取物箱，此次我的毕业设计就是重新设计取物箱的防盗机构，该取物箱主要由取物箱箱体、取物门、防盗板、联动机构、运动辅助部件（滑动轨道等）组成。主要实现的运动过程是当向内推动取物门时，通过联动机构的传动使防盗板由后向前平移，并封闭整个取物箱上部开口，在整个运动过程中要使防盗板的平移速度尽可能的快于取物门的开启速度。

1.5 自动售货机在国外的应用

自动售货机是劳动密集型的产业构造向技术密集型社会转变的产物。大量生产、大量消费以及消费模式和销售环境的变化，要求出现新的流通渠道;而相对的超市、百货购物中心等新的流通渠道的产生，人工费用也不断上升;再加上场地的局限性以及购物的便利性等这些因素的制约，无人自动售货机作为一种必须的机器便应运而生了。

　　自动售货机在国外早已很普及，大街上、公寓里到处都是。在美国、日本和整个欧洲，自动售货机的应用领域已经扩展至小食品、冷热饮料、快餐、游戏软件、香烟、报纸、邮票、电话磁卡以及个人卫生用品等各个方面。其中，日本的自动售货机应用方面具有代表性。自动售货机已成为日本城市喧嚣街头的一个标志。这种机器已不仅限于销售香烟等各类商品，还提供许多新的服务功能，例如把零钱捐给某非政府组织，或者通过观看小屏幕播放的广告信息而获得打折等。通过一种新的自动售货机，消费者哪怕只购买一杯热咖啡也可获得折扣，因为在机器加热咖啡的过程中，液晶显示屏上会播放一段广告，消费者只需耐心看完广告就可获得打折。还有一些新机型可以接受向非政府组织的捐款。目前，日本街头已有1万多台可接受捐款的自动售货机，但需求量依然很大。还有一种机型，当身体健康处于危险状态的使用者按动按键时，机器就会发出警报声。此外，日本最主要的一家饮料分销商还与政府签订协议，推出了“灾害应急型”自动售货机。当地震等自然灾害发生时，中心电脑处理系统会向自动售货机发出指令，市民可从机器中免费提取饮料和食品。

1.6 自动售货机在国外的市场发展

目前，自动售货机作为一种不同于传统的零售方式进入四十五个国家市场。在这四十五个国家中，美国和日本发展最快。在国外主要是以饮料厂家引导，带动自动售货机的发展。作为世界上最大的自动售货市场，日本通过自动售货机出售的商品多达6000余种。在欧洲每台自动售货机日销售额达到50到100美元不等，以巴黎地铁车站为例，在各个站点总计摆放了1500台，每月销售额达600万法郎。美国自动售货机的零售营业额高达293亿美元，日本每个消费者每年在自动售货机上的消费金额达5.5万日元。全世界每年通过自动售货机销售商品的总额已达2000亿美元。

1.7 新型自动售货机的新增功能

1.7.1 多种货币识别功能：

电控系统可以配合纸币、硬币识别器增加代金券功能，可以识别纸质和硬币。

1.7.2 USB功能：

　应用USB技术，使用一个优盘，就能轻松下载售货机的运营信息，然后使用PC机对下载的数据进行处理，便于运营商掌握不同地区、不同机器、不同商品的售卖情况。

1.7.3 无线网络运营管理功能：

　　将自动售货机当前运营的数据，包括系统状态、系统故障、料道故障、缺货情况、销售数据通过安装在自动售货机上的GPRS模块无线传输到售货机网络服务器，运营人员可以在任何一台联网的电脑上掌握售货机的这些信息，实现自动售货机的大规模运营和网络化管理。

1.7.4 带有摄像头：

一些装有监视摄像头的自动售货机已开始试用，它们除了可监控针对售货机的犯罪外，还对周边起到了警戒作用。此外，有关部门计划给自动售货机装上电子公告牌，使其能在自然灾害等紧急情况发生时，为公众提供信息服务。

1.7.5 语音功能：

自动语音叫卖功能,真正做到了代替营业员的叫卖,从而引起更多的消费者的关注。

1.7.6 故障诊断:

能自动快速诊断机器本身、纸币接收器、硬币接收器等模块的故障，并将故障信息提示操作者，便于有效的日常维护。

伴随收入水平的提高，人们追求灵活、方便、快捷以及自助式服务是自动售货机得以如此迅猛发展的主要原因。在发达国家自动售货机已经成为零售业一个不可分割的部分，特别是对青年一代，这种伴随其成长的前卫零售方式更可谓是一种新的消费时尚。现代都市生活的节奏日趋加快，追求方便、快捷的服务成为人们的一种时尚，以麦当劳、肯德基为代表的的西式快餐在我国的迅速发展就是很好的例子。随着对外开放的不断扩大，传统的零售业发展成百货商店、连锁超市、电视直销、厂家直销等多种方式并存的局面，极大地方便了人们的生活。

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内容简介：: 英文原文Kinematic and dynamic synthesis of a parallel kinematic high speeddrilling machineAbstractTypically, the termhigh speed drilling is related to spindle capability of high cutting speeds. The suggested high speed drilling machine (HSDM) extends this term to include very fast and accurate point-to-point motions. The new HSDM is composed of a planar parallel mechanism with two linear motors as the inputs. The paper is focused on the kinematic and dynamic synthesis of this parallel kinematic machine (PKM). The kinematic synthesis introduces a new methodology of input motion planning for ideal drilling operation and accurate point-to-point positioning. The dynamic synthesis aims at reducing the input power of the PKM using a spring element. Keywords: Parallel kinematic machine; High speed drilling; Kinematic and dynamic synthesis1. IntroductionDuring the recent years, a large variety of PKMs were introduced by research institutes and by industries. Most, but not all, of these machines were based on the well-known Stewart platform 1 configuration. The advantages of these parallel structures are high nominal load to weight ratio, good positional accuracy and a rigid structure 2. The main disadvantages of Stewart type PKMs are the small workspace relative to the overall size of the machine and relatively slow operation speed 3,4. Workspace of a machine tool is defined as the volume where the tip of the tool can move and cut material. The design of a planar Stewart platform was mentioned in 5 as an affordable way of retrofitting non-CNC machines required for plastic moulds machining. The design of the PKM 5 allowed adjustable geometry that could have been optimally reconfigured for any prescribed path. Typically, changing the length of one or more links in a controlled sequence does the adjustment of PKM geometry.The application of the PKMs with constant-length links for the design of machine tools is less common than the type with varying-length links. An excellent example of a constant-length links type of machine is shown in 6. Renault-Automation Comau has built the machine named Urane SX. The HSDM described herein utilizes a parallel mechanism with constant-length links.Drilling operations are well introduced in the literature 7. An extensive experimental study of highspeed drilling operations for the automotive industry is reported in 8. Data was collected fromhundreds controlled drilling experiments in order to specify the parameters required for quality drilling. Ideal drilling motions and guidelines for performing high quality drilling were presented in 9 through theoretical and experimental studies. In the synthesis of the suggested PKM, we follow the suggestions in 9.The detailed mechanical structures of the proposed new PKM were introduced in 10,11. One possible configuration of the machine is shown in Fig. 1; it has large workspace, highspeed point-to-point motion and very high drilling speed. The parallel mechanism provides Y, and Z axes motions. The X axis motion is provided by the table. For achieving highspeed performance, two linear motors are used for driving the mechanism and a highspeed spindle is used for drilling. The purpose of this paper is to describe new kinematic and dynamic synthesis methods that are developed for improving the performance of the machine. Through input motion planning for drilling and point-to-point positioning, the machining error will be reduced and the quality of the finished holes can be greatly improved. By adding a well-tuned spring element to the PKM, the input power can be minimized so that the size the machine and the energy consumption can be reduced. Numerical simulations verify the correctness and effectiveness of the methods presented in this paper.2. Kinematic and dynamic equations of motion of the PKM moduleThe schematic diagram of the PKM module is shown in Fig. 2. In consistent with the machine tool conventions, the z-axis is along the direction of tool movement. The PKM module has two inputs (two linear motors) indicated as part 1 and part 6, and one output motion of the tool. The positioning and drilling motion of the PKM module in this application is characterized by (y axis motion for point-to-point positioning) and (z axis motion for drilling). Motion equations for both rigid body and elastic body PKM module are developed. The rigid body equations are used for the synthesis of input motion planning of drilling and input power reduction. The elastic body equations are used for residual vibration control after point-to-point positioning of the tool.2.1. Equations of motion of the PKM module with rigid links Using complex-number representation of mechanisms 12, the kinematic equations of the tool unit (indicated as part 3 which includes the platform, the spindleand the tool) are developed as follows. The displacement of the tool is andwhere b is the distance between point B and point C, r is the length of link AB (the lengths of link AB, CD and CE are equal). The velocity of the tool iswhereThe acceleration of the tool iswhereThe dynamic equations of the PKM module are developed using Lagranges equation of the second kind 13 as shown in Eq. (7).echanism can be derived using the finite element method and take the form ofwhere M, C and K are system mass, damping and stiffness matrix, respectively; D is the set of generalized coordinates representing the translation and rotation deformations at each element node in global coordinate system; R is the set of generalized external forces corresponding to D; n is the number of the generalized coordinates (elastic degrees of freedom of the mechanism). In our FEA model, we use frame element shown in Fig. 3 in which EIe is the bending stiffness (E is the modulus of elasticity of the material, Ie is the moment of inertia), q is the material density, le isthe original length of the element. are nodal displacements expressed in local coordinate system(x, y). The mass matrix and stiffness matrix for the frame element will be 66 symmetric matrices which can be derived fromthe kinetic energy and strain energy expressions as Eqs. (12) and (13)where T is the kinetic energy and U is the strain energy of the element; are the linear 1 2 3 4 5 6 and angular deformations of the node at the element local coordinate system. Detailed derivations can be found in 14. Typically, a compliant mechanism is discretized into many elements as in finite element analysis. Each element is associated with a mass and a stiffness matrix. Each element has its own local coordinate system. We combine the element mass and stiffness matrices of all elements and perform coordinate transformations necessary to transform the element local coordinate systemto global coordinate system. This gives the systemmass M and stiffness K matrices. Capturing the damping characteristics in a compliant systemis not so straightforward. Even though, in many applications, damping may be small but its effect on the systemstability and dynamic response, especially in the resonance region, can be significant. The damping matrix C can be written as a linear combination of the mass and stiffness matrices 15 to form the proportional damping C which is expressed aswhere a and b are two positive coefficients which are usually determined by experiment. An alternate method 16 of representing the damping matrix is expressing CasThe element of C is defined as,where signKij=(Kij/|Kij|), Kij and Mij are the elements of K and M, is the damping ratio of the material.The generalized force in a frame element is defined as where Fj and Mj are the jth external force and moment including the inertia force and moment on the element acting at (xj ,yj), and m is the number of the externalforces acting on the element. The element generalized forces,are then combined to formthe systemgeneralized force R. The second order ordinary differential equations of motion of the system, Eq. (11), can be directly integrated with a numerical method such as Runge-Kutta method. For the PKM we studied, each link was discreted as 15 frame elements. Both Matlab and ADAMS software are used for programming and solving these equations.3. Input motion planning for drillingSuppose we know the ideal motion function of the drilling tool. How to determine the input motor motion so that the ideal tool motion can be realized is critical for high quality drillings. The created explicit input motion function also provides the necessary information for machine controls. According to the study done in 9, the drilling process can be divided into three phases: entrance phase, middle phase, and exit phase. In order to increase the productivity and quality of the drilling, many operation constraints such as minimum tool life constraint, hole location error constraint, exit burr constraint, drill torsion breakage constraint, etc. must be considered and satisfied. Under these conditions, the feed velocity of the tool should be slow at the entrance phase to reduce the hole location errors. The tool velocity should also be slow at the exit phase to reduce the exit burr. At the middle phase, the tool drilling velocity should be fast and kept constant. The retraction of the tool after finishing the drilling should be done as quickly as possible to increase the productivity. Based on these considerations, we assume that the ideal drilling and retracting velocities of the tool are given by Eq. (17).where vT1 is the maximum drilling velocity, T1, T2,and T3 are the times corresponding to the entrance phase, the middle phase and the exit phase. vT2 is the maximum retracting velocity. T4, T5, and T6 are corresponding to accelerating, constant velocity, and decelerating times for retracting operation. is the cycle time for a single drilling. As a numerical example, suppose we drill a 25.4 mm (1 in) deep hole with Tc=0.4s, 0.3s for drilling, 0.1s for retracting. Set T1=T3 0.06s, T4=T6=0.03s. Under these con-ditions, vT1=106(mm/s), vT2=-363(mm/s). The graphical expression of the ideal tool motion is shown in Fig. 4. If the link length in PKM r=500 mm, the angle=53 at the starting point of drilling, the corresponding input motor velocity relative to the idealtool motion is shown in Fig. 5. Generally, the curve fitting method can be used to create the input motion function. But according to the shape of the curve shown in Fig. 5, we create the linear motor velocity function manually section by section as shown in Eq. (18).where vB=143.48mm/s, vC=165.77mm/s, vE=-557.36mm/s, vF=-499.44mm/s. When plotting the velocity curve with Eq. (18), no visual difference can be found with the curve shown in Fig. 5. Eq. (18) is composed of six parts with four cycloidal functions and two linear functions. If we control the two linear motors to have the same motion as described in Eq. (18), the drilling and retracting velocity of the tool will be almost the same as shown in Fig. 4. The absolute errors between the ideal and real tool velocity are shown in Fig. 6, in which the maximum error is less than 8 mm/s, the relative error is less than 1.5%. At the start and the end positions of the drilling, the errors are zero. These small absolute and relative errors illustrate the created input motion and are quite acceptable. The derived function is simple enough to be integrated into the control algorithmof the PKM.4. Input motion planning for point-to-point positioningIn order to achieve fast and accurate positioning operation in the whole drilling process, the input motion should be appropriately planned so that the residual vibration of the tool tip can be minimized. Conventionally the constant acceleration motion function is commonly used for driving the axes motions in machine tools. Although this kind of motion function is simple to be controlled, it may excite the elastic vibration of the systemdue to the sudden changes in acceleration. Take the same PKM module used in previous for example. A FEA model is built using ADMAS with frame elements. The positioning motion is the y-axis motion, which isrealized by the two linear motors moving in the same direction. Suppose the positioning distance between the two holes is 75mm, the constant acceleration is 3g(approximated as 30m/s here). The input motion of the linear motors with constant acceleration and deceleration is shown in Fig. 7, in which the maximum velocity is 1500 mm/s, the positioning time is 0.1 s. Assuming the material damping ratio as 0.01, the residual vibration of the tool tip is shown in Fig. 8. In order to reduce the residual vibration and make the positioning motion smoother, a six order polynomial input motion function is built as Eq. (19)where the coeffcients ci are the design variables which have to be determined by minimizing the residual vibration of the tool tip. Selecting the boundary conditions as that when t=0, sin=0, vin=0, ain=0;and when t=Tp, sin=h, vin=0, ain=0, where Tp is the point-to-point positioning time, the first six coeffcients are resulted:Logically, set the optimization objective aswhere c6 is the independent design variable; is the maximum fluctuation of residual vibrations of the tool tip after the point-to-point positioning. Set and start the calculation from c6=0. The optimization results in c6=-10mm/s . Consequently, c5=7.510mm/s , c4 =-1.42510mm/s , c3=8.510mm/s , c2=c1=c0=0. It can be seen that the optimization calculation brought the design variable c6 to the boundary. If further loosing the limit for c6, the objective will continue reduce in value, but the maximum value of acceleration of the input motion will become too big. The optimal input motions after the optimization are shown in Fig. 9. The corresponding residual vibration of the tool tip is shown in Fig. 10. It is seen from comparing Fig. 8 and Fig. 10 that the amplitude and tool tip residual vibration was reduced by 30 times after optimization. Smaller residual vibration will be very useful for increasing the positioning accuracy. It should be mentioned that only link elasticity is included in above calculation. The residual vibration after optimization will still be very small if the compliance from other sources such as bearings and drive systems caused it 10 times higher than the result shown in Fig. 10.5. Input power reduction by adding spring elementsReducing the input power is one of many considerations in machine tool design. For the PKM we studied, two linear motors are the input units which drive the PKM module to perform drilling and positioning operations. One factor to be considered in selecting a linear motor is its maximum required power. The input power of the PKM module is determined by the input forces multiplying the input velocities of the two linear motors. Omitting the friction in the joints, the input forces are determined from balancing the drilling force and inertia forces of the links and the spindle unit. Adding an energy storage element such as a spring to the PKM may be possible to reduce the input power if the stiffness and the initial (free) length of the spring are selected properly. The reduction of the maximum input power results in smaller linear motors to drive the PKM module. This will in turn reduce the energy consumption and the size of the machine structure. A linear spring can be added in the middle of the two links as shown in Fig. 11(a). Or two torsional springs can be added at points B and C as shown in Fig. 11(b). The synthesis process is the same for the linear or torsional springs. We will take the linear spring as an example to illustrate the design process. The generalized force in Eq. (10) has the form ofwhere l0 and k are the initial length and the stiffness of the linear spring. The input power of the linear motors is determined byIn order to reduce the input power, we set the optimization objective as follows:where v is a vector of design variables including the length and the stiffness of the spring, . For the PKM module we studied, the mass properties are listed in Table 1. The initial values of the design variables are set as . The domains for design variables are set as lmin;lmax=400, 500 mm, kmin; kmax=1,20 N/mm. The PKM module is driven by the input motion function described as Eq. (18). Through minimizing objective (24), the optimal spring parameters are obtained as and k=14.99 N/mm. The input powers of the linear motors with and without the optimized spring are shown in Fig. 12, in which the solid lines represents the input power without spring, the dotted lines represents the input power with the optimal spring. It can be seen from the result that the maximum input power of the right linear motor is reduced from 122.37 to 70.43 W. A 42.45% reduction is achieved. For the left linear motor, the maximum input power is reduced from 114.44 to 62.72 W. A 45.19% reduction is achieved. The effectiveness of the presented method by adding a spring element to reduce the input power of the machine is verified. Torsional springs may be sued to reduce the inertial effect and the size of the spring attachment.6. ConclusionsThe paper presents a new type of high speed drilling machine based on a planar PKM module. The study introduces synthesis technology for planning the desirable motion functions of the PKM. The method allows both the point-to-point positioning motion and the up-and-down motion required for drilling operations. The result has shown that it is possible to reduce substantially the residual vibration of the tool tip by optimizing a polynomial motion function. Reducing residual vibration is critical when tool positioning requirement for the HSDM is in the range of several microns. By adding a well-tuned optimal spring to the structure, it was possible to reduce the required input power for driving the linear motors. The simulation has demonstrated that more than 40% reduction in the required input power is achieved relative to the structure without the spring. The reduction of required input power may allow choosing smaller motors and as a result reducing costs of hardware and operations.In order to better understand the properties of the HSDM and to complete its design, further study is required. It will include error analysis of the machine as well as the control strategies and control design of the system. 7. AcknowledgementsThe authors gratefully acknowledge the financial support of the NSF Engineering Research Center for Reconfigurable Machining Systems (US NSF Grant EEC95-92125) at the University of Michigan and the valuable input fromthe Centers industrial partners.中文翻译高速钻床的动力学分析摘要通常情况下，术语“高速钻床”就是指具有较高切削速率的钻床。高速钻床(HSDM)也是指具有非常快的和正确的点到点运动的钻床。新的HSDM是由带有两个直线电动机的平面并联机构组成。本文主要就是对并联机器(PKM)的动力学分析。运动合成是为了介绍一种新方法，它能够完善钻孔操作和点到点定位的准确性。动态合成旨在减少因使用弹簧机械时PKM的输入功率。关键词: 并联运动机床; 高速钻床; 动力学的合成1.介绍在最近的几年里，研究所和工业协会介绍了各式各样的PKM。其中大部分（但不是所有）,以众所周知的斯图尔特月台1为基础结构。这一做法的好处是高公称的负载重量比，良好的位置精度和结构刚性2。斯图尔特式PKM的主要缺点是相对小的工作空间和相对慢的操作速度 3,4。机床刀具的工作空间是指刀尖能够移动和切削材料所需要的容积。平面的斯图尔特月台的设计在5中被提到，像是对无CNC机器作翻新改进的方法需要塑料的铸模机制一样。PKM5的设计允许可以调整几何学已经被规定了的最佳的再配置的任何路径。一般的，改变一根或较多连杆的长度是以PKM受约束的顺序来做几何学的调整。在机床设计中，“定长度连杆”的PKM应用比“不定长度连杆”的共同点要少的多。一个优秀“定长度连杆”型的机器例子被显示在6。Renault-Automation Comau已经建造叫做“Urane SX”的机器。在此HSDM被描述成是一个采用“定长度连杆”组成的并联机械装置。钻床操作在文学7中被很好的介绍了。汽车工业中，一项关于高速钻孔的操作的广泛的实验研究在8中被报告。数据从数百个钻床控制实验上收集起来，是为了具体指定钻床质量所必须的参数。理想的钻床运动和制造高质量钻床的指导方针通过理论和实验的研究被呈现在9中。在被建议的PKM综合中，我们遵循9中的结论。新推出的PKM的详细机械结构在10,11被介绍，机器的大致结构显示在图1中；它有很大的工作空间，点到点的高速运动和非常高的钻速。并联的机械装置提供给了Y和Z轴的动作，X轴动作是由工作台提供的。为了达成高速的运转，用了两个线性马达来驱驶机械装置和用一个高速的主轴来钻孔。这篇文章的目的就是描述新的运动学的和动力学合成的方法的发展，为了改良机器的运转。通过输入运动，规划钻井和点对点定位，机器的误差将会被减少，而且完成孔的质量能被极大的提高。通过增加一个弹簧机械要素到PKM，输入动力就能被最小，以便机器的尺寸和能量损耗降低。数字模拟的正确查证和热交换率的方法呈现在这篇文章中。2.PKM模型的运动学和动力学的运动方程式PKM模型的概要线图在图2中被显示。由于机床刀具库的一致，Z轴是沿着工具运动的方向的。PKM模型有部分1和部分6二个输入指示(二个线性电机)，和一个刀具的输出动作。在PKM模型应用中，定位和钻孔运动分别通过 ( y 轴动作相对点到点的定位)和 (z轴动作相对钻孔)表示。刚体和柔性体的PKM模型运动方程式都被发展了。刚体方程式被用于合成输入钻床的动作计划和输入力量还原。柔性体方程式被用来在刀具点到点定位之后的剩余振动控制。2.1.刚性连杆的PKM模型的运动方程式机械装置12的特点是使用了数字集成,刀具设备(含工作台，主轴和刀具3部份)。它的运动学方程式的发展依下列各项。刀具的变位是且其中b是点B和点C之间的距离,r是连杆AB的长度(连杆AB、CD和CE的长度是相等的)。刀具的速度是其中刀具的加速度是其中 PKM模型的动力学方程式的发展如方程（7）所示，使用了拉格朗日的第二个类型的方程式13。其中t是系统的总动能；和是总坐标值和速度值;是总力对应到的的值。k是坐标系中总的独立数目。在这里,k=2，q1= y1和q2=y6，引出之后，公式(7)可被表达成其中n是移动连杆的数目；是连杆i的大量惯性矩；是连杆i的质量中心坐标；是PKM模型中连杆i的旋转角。总力的值通过（9）决定其中V是势能，是没有势能的力。为了对PKM模型的钻孔操作，我们有其中是切削力, F1和F6是线性马达在PKM上输入的力。情绪商数。公式(1)到公式(10)构成了刚性连杆PKM模型的运动学和动力学方程式。2.2.柔性连杆的PKM模型的动作方程式顺从的机械装置的动微分方程式能用有限的机械要素方法和以下的公式得到其中M、C和K分别是系统质量，阻尼和刚性母体；D是在全球同等坐标系中的每个机械要素平移和旋转变形表现的总坐标值；R是总外力值，与D保持一致；n是坐标的总数目值(机械装置的柔性自由度)。在我们的FEA模型中，我们使用在图3中被显示的机械要素结构，其中EIe是弯曲刚性(E是材料的柔性系数,Ie是惯性矩),是物质的密度,le是机械要素的最初长度。是(x,y)坐标系统中表现的结点变位。机械要素的大众基地和刚性基地将会是66个对称的矩阵，能从动能和应变能中得到，表达在公式（12）和（13）中其中t是动能，U是机械要素的应变能；是机械要素基本坐标系中线性的123456和角变形节。详细的推论能在14被发现。典型地，在有限的机械要素分析中，一个顺从的机械装置是被离散成许多个机械要素的。每个机械要素与一个质量和一个刚性母体有关。每个机械要素有它自己的基本坐标系。我们结合机械要素质量和所有机械要素的刚性矩阵运行坐标转换时，必须把机械要素的基本坐标系转换成世界坐标系，这就提供了系统质量M和刚性K矩阵。在一个顺从的系统中捕获阻尼特性不是这么顺利的。即使, 在许多应用中，阻尼可能很小，但是它能作用在系统安全性和动力的频率响应中，尤其在共振区域中,可能是重要的。阻尼基地C能被写做一种质量和刚性矩阵15的线性结合，构成比例阻尼C如下式表达所示其中和是二个通常由实验决定的正系数。一个表现阻尼基地的交互方法16 表达成C如下机械要素C被定义为,其中,和是K和M的机械要素, 是材料的阻尼比。机械要素结构中的总力被定义为其中和是的外力和力矩，包括在上动作的机械要素的惯性力和力矩,m 是在机械要素上动作的外力数目。机械要素的总力,组合构成了系统总力R。系统动作的第二次序普通微分方程式，如公式(11), 用一个数字能直接被整合的方法,就像是Runge- Kutta的方法那样。对于我们研究的PKM,每个连杆被分离成15个机械要素结构。Matlab和ADAMS软件都被用来规划和解决这些方程式。3.为钻床输入动作计划假如我们知道钻床理想的动作功能。高质量钻床的关键是如何决定输入电动机动作以便刀具的理想动作能被了解。创建明白的输入动作功能时也为机器控制提供了必需的数据。依照研究在9中所做的,钻孔的过程能分为三个时期: 入口期,中间期和出口期。为了增加生产能力和钻孔的质量，许多操作限制，例如最小刀具的寿命限制，孔位置误差限制,退出毛边限

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