资源目录
压缩包内文档预览：(预览前20页/共51页)
编号：20771461
类型：共享资源
大小：15.56MB
格式：ZIP
上传时间：2019-07-11
上传人：QQ24****1780
认证信息
个人认证
王**（实名认证）
浙江
IP属地：浙江
150
积分
- 关 键 词：
-
平行运动机构的机构分析与构型设计
- 资源描述：
-
平行运动机构的机构分析与构型设计,平行运动机构的机构分析与构型设计
- 内容简介：
-
上海工程技术大学毕业设计（毕业论文）开题报告学 院机械工程学院专 业机械工程及自动化班级学号011115105学 生王淼指导教师程武山教授 题 目 平行运动机构的机构分析与构型设计 任务实际进行日期 自 年月 日起，至 年 月 日止1课题背景及意义齿轮 连杆机构因具有多种优良输出特性，故被 广泛应用于工业生产中。其中，有一种传递等速运动 的特殊机构，即齿轮 平行四边形机构( 以下简称 GPM) ，目前也越来越受到青睐，三环减速器就是一例。对一类形式的 GPM，即 平动齿轮机构的传动性能进行了研究，但对外啮合式 GPM 研究甚少。本文中论述了该组合机构的组成规 则，并对外啮合式和内啮合式 GPM 的传动性能进行 了分析与比较。而且，在寻找最佳性能组合机构的同 时，对如何改变不同形式 GPM 的传动比进行了总结。2文献综述2.1平行四边形机构的运动性能及应用研究该组合机构由平行四边形机构和齿轮机构组合 而成。选择平行四边形机构作为基础机构，是因为它 有以下两个显著特点: 两曲柄以相同速度同向转动; 连杆作平动( 即角速度为零) 。 齿轮机构，即装载在平行四边形机构上依次啮合 的齿轮串( 包括只有一对齿轮啮合的情况) 。为了使 装在各构件上的齿轮能够始终保持啮合，齿轮应装在 连杆机构转动副中心的销轴上。另外，若无一个齿轮 与基础机构固连，那么组合机构的自由度将大于1，如 图1a 中的机构，其自由度 F =2，一般要求组合机构的 自由度等于1，故至少有一个齿轮与基础机构固连。 经分析，固连齿轮必为齿轮串两端的齿轮，且与 它固连的构件只能是由它向外延伸仅有一个转动副 中心的销轴装有齿轮的构件，否则将破坏原先 机构的结构性质。如图 1a 中，端部齿轮 5 只能与机 架4 固连; 端部齿轮 7 只能与构件 1 固连。在图 1a 中，若将不在齿轮串端部的齿轮 6 与基础机构的构件 固连，那么它可能与构件2 或构件 3 固连。当齿轮 6 与构件2 固连时，齿轮6、齿轮7 和构件2 构成刚性构 件，机构变成图1b 所示的机构，此时齿轮 7 已不起作用; 当齿轮6 与构件3 固连时，齿轮5、齿轮6 和构件3 构成刚性构件，机构变成图 1c 所示的机构。当端部 齿轮5 与构件3 固连时，同理，构件5、构件6 和构件3 也构成刚性构件，得到与图1c 所示相同的结果。由文献可知，在装载上齿轮机构后，自由 度的增减值F =1 ，其中 表示固连的端部齿轮 数目。由此可知，F 与齿轮串中的齿轮数目无关， 仅与固连的端部齿轮的数目 有关。由于平行四边 形机构的自由度为 1，那么使F = 0，即固连一个端 部齿轮即可满足运动确定性要求。当然，上述的组成 规则也适用于一般齿轮 四杆机构。2.2平行四杆仿形机构设计及运动仿真如图 1 所示，本机构主要由前支架、上拉杆、下拉杆、 后支架、限位杆、运输钩等组成。前支架通过 U 型卡丝与 机架主梁固结，后支架与排种器、开沟器、双圆盘开沟器、覆土镇压轮固结。上 拉杆与下拉杆平行 且相等， A 点与 B 点 铰接在前支架上构 成四杆机构的前杆， C 点与 D 点铰接在 后支架上构成四杆 机构的后杆。机具在 工作过程中，上拉杆 AC、CD 杆、下拉杆 BD 构成的连杆系统 绕 A 点和 B 点转动。 由平行四边形的运动特点可知，在上下仿形过程中，上拉 杆 AC 和下拉杆 BD 始终做平行运动，从而使刚性连接在 后拉杆 CD（后支架）上的开沟器在免耕作业过程当中一 直作平行运动，进而保证了开沟器在工作过程中的入土 角恒定不变，开出深浅一致的种沟，为种子出苗的一致性 和作物生长的整齐性提供了条件。2.3双平行四杆型远程运动中心机构的设计双平行四杆 RCM 机构是指通过对两组平行四 杆结构进行平面耦合，以实现末端执行器绕虚拟中 心转动的一类 RCM 机构。 双平行四杆 RCM 机构的一维构型可以归纳如 图1所示， 图1a为平行四杆RCM机构的基本构型。 由于机构中 BCDE 回路有冗余约束，通过去除不同 的约束，可以衍生出其他几种结构形式(图 1b1f )。 此外，还可通过改变固定端，得到如图 1g1j 所示 的几种不同构型。 图 1 一维双平行四杆型 RCM 机构的 10 种构型 双平行四杆型 RCM 机构具有如下优点：结 构简单，驱动器可放置在基座处。可通过连杆的 弯折变形灵活安排 RCM 的位置以适应不同的应用 要求。缺点在于由于杆件之间的干涉以及平行四杆 存在奇异位型，影响运动范围；另外，由于铰链数 目多造成机构刚度较差。 由于安装时必须考虑到安装末端执行器以及 与底座固定的铰链或者电动机等需要占据一定的空 间。为了保证末端执行器轴线通过虚拟中心点，一 般有如图 2 所示的两种方法，这里以安装末端执行 器为例。图 2a 中将末端执行器相对末端杆件倾斜放 置，从而使末端执行器通过虚拟中心。图 2b 通过杆 件弯折，使得虚拟中心移动一定距离，以满足安装 需要。这两种方法都有应用，这里主要对后一种方 案进行讨论。2.4双曲柄环板式针摆行星传动中 平行四杆机构运动性能分析双曲柄环板式针摆行星传动是一种新型摆线针轮行星传动,其结构原理如图 1,由两个主动曲柄 (1、3)、带针轮的环板(2即连杆)与机架(4)构成平行四杆 机构 ABCD, 环板上的针轮中心 Op 位于连杆 BC的中点,与 环板 2上针轮相啮合的摆线轮 5中心Oc位于两个主动曲柄 回转中心 A、D 连线 AD 的中点, 针轮与摆线轮的中心距 OpOc的大小等于曲柄的长度 e . 在常规的环板式齿轮减速 器结构设计中,为便于分析计算连杆铰链处的总反力,通常 做以下假定:平行四杆机构 ABCD的杆长尺寸误差 忽略不计; 连杆惯性力不计;连杆做平面运动. 但对高 速及重型机械,因其惯性力很大故必须考虑惯性力,此外由 于机构在加工和装配过程中,机构中各杆长的实际尺寸都呈现出一定的随机性,影响着机构的运动性 能,使得机构的真实运动与设计预定的理想运动之间出现一定的偏差. 因此在实际应用中. 双曲柄平行 四杆机构的连杆并不能真正做到匀速平动,而是存在着角加速度,由角加速度引起的惯性力矩造成连杆 上铰链的实际支反力与理论支反力不一样. 而研究二者之间的差别,对分析机构实际运动的稳定性和可靠性、计算铰链的寿命具有重要意义. 本文分析双曲柄平行四杆机构的杆长尺寸误差对机构特性的影响,为研究运动副间隙对机构的杆 长误差的补偿作用提供依据.3 研究方法主要按照以下几个步骤进行1机床的特点2机床的位置分析3平行机构的位置分析4平行机构的速度分析5平行机构的加速度分析6实例仿真7 结论4 进度安排（1） 1.第14周：文献检索，资料收集，整理有关平行运动机构的资料,写出开题报告，完成外文资料翻译。（2） 2.第58周：设计方案讨论，设计方案确定，进行设计计算。（3） 3.第912周：电气图设计、绘图。（4） 4.第1314周：对电子器件特性分析，进行相应传感器实验（5） 5.第1517周：撰写论文。参考文献 1. 姚九成，赵国军 平动齿轮机构的演化与创新J 江汉石油学 院学报2. 张春林，胡荣晖，姚九成 平动齿轮机构的同性变异法J 机械 设计3. 张春林，荣辉，黄祖德 圆平动齿轮传动机构的研究J 北京理 工大学学报4. 吕庸厚，沈爱红 组合机构设计与应用创新M 北京: 机械工 业出版社赵自强，张春林，程爱明 平动齿轮传动啮合效率的理论研究 J 机械传动5. 齿轮 平行四边形机构的运动性能及应用研究 陈海文 王 忠6. 双平行四杆型远程运动中心机构的设计* 宗光华 裴 旭 于靖军 毕树生 孙明磊7. 平行四杆仿形机构设计及运动仿真 马华永 1， 2， 王卫兵 1， 王坤 1， 翟庆钟 1， 郭德卿 18. 何卫东, 李 欣,李力行. 双曲柄环板式针摆行星传动的研究 J . 机械工程学报, 2000, 36(5)9. GB中华人民共和国国家标准齿轮热功率 第二部分: 热承载能力计算 S. 中华人民共和国国家质量监督检验 检疫总局.10. GB中华人民共和国国家标准齿轮热功率 第一部分: 油池温度在 95时齿轮装置的热平衡计算 S. 中华人民 共和国国家质量监督检验检疫总局.11. 胡如夫, 周哲波. 齿轮减速器的热功率试验及提高热功率的措施 J . 机械科学与技术, 1998, (3) 5胡如夫, 赵伟敏. 新型齿轮减速器散热装置 J. 机械工程师, 2000 , (2)12. 何卫东, 李 欣,李力行. 双曲柄环板式针摆行星传动的研究 J . 机械工程学报, 2000, (5): 8487 . 13. 葛宰林, 何卫东. 加工精度对双曲柄环板式针摆行星传动动态性能的作用分析 J. 中国机械工程, 2003 , 14(12): 10591061 .14. 孙 恒. 机械原理(第六版)M. 北京: 高等教育出版社, 2000 .15. 赵竹青. 平面四杆机构的可靠性分析 J . 机械设计, 2002 . (11) 16. 杨基厚. 机构运动学与动力学 M. 北京: 机械工业出版社, 1987 . 17. TAYLOR R H, FUNDA J, LAROSE D, et al. A telerobotic system for augmentation of endoscopic surgeryC/ 14th IEEE Medicine & Biology Conf., October 29- November 1, 1992, Paris. USA：IEEE, 1992 18. TAYLOR R H, FUNDA J, ELDRIDGE B, et al. A telerobotic assistant for laparoscopic surgeryJ. Enginee- ring in Medicine and Biology Magazine, 199519. TAYLOR R H, JENSEN P, WHITCOMB L, et al. A steady-hand robotic system for microsurgical augmenta- tionJ. The International Journal of Robotics Research, 1999, 18(12)20. KIM D, KOBAYASHI E, DOHI T, et al. A new, compact MR-compatible surgical manipulator for minimally invasive liver surgeryC/ 5th International Conference on Medical Image Computing and Computer-Assisted Intervention, September 25-28, 2002, Tokyo, Japan. Heidelberg：LNCS 2489, 200221. FARAZ A, PAYANDEH S. A robotic case study：optimal design for laparoscopic positioning standsC/ Interna- tional Conference on Robotics and Automation, April 20-25, 1997, Albuquerque, New Mexico. USA：IEEE, 199722. PEI Xu, YU Jingjun, BI Shusheng, et al. Enumeration and type synthesis of one-DOF remote-center-of-motion mechanismsC/ The 12th world congress in mechanism an machine science, June 18-21, 2007, Besancon, France. England：IFToMM, 2007. Mechanism Design and Simulation Analysis of Multifunctional Nursing BedLizong Lin, Song Zhang, Xinglong Hu School of Mechanical and Power Engineering East China University of Science and Technology, Shanghai, China E-mail: lizonglin E-mail: Abstract-This research develops a new multifunctional nursing bed that can realize the movements of turning left and right sides and defecating on the bed for clinical use. And use the ADAMS to analysis the effects to the motor torque from the force on the rotated board, friction of contact pair and space position. By analysis of dynamic on the model of the main mechanism can get the curves and the influences of torque, which plays an important guiding role in selecting appropriate motor and installation structure.Keywords- nursing bed, ADAMS, virtual prototyping, dynamic analysisI. INTRODUCTIONNursing beds as parts of medical equipments are necessary for hospital care, and has been widely used in hospitals, nursing homes, retirement homes and many other fields. However, the prices of good quality nursing beds are expensive, the new study can reduce the cost and the difficulty of care, for example, to the patients resting on the bed for a long time, their turning over and lifting back required nurses have sufficient physical strength. Common beds just have head up, leg flexion and extension functions, this bed adds the function as rolling around, defecating on the bed and so on as needed 1.II. MECHANISM DESIGNThe nursing bed can be divided into four parts by the structure and function as: bed body, control cabinet, a framework for activities, removable bedpan. Block diagram as in Fig. 1In the control cubicle, the installment has the master control board, the motor-driven board, the transformer, the switching power supply and so on. The control cubicle connects with the nursing bed by the connection. Except the fixed mechanism, the bed body also includes the drive motor and the vane organization. The active frame installment has the wheels, which may be separated from the nursing bed. In the frame there are the water tank, stool which can rise and fall and the hot air blower. The transportable bed pan also installs wheels and can insert into the activity frame. In addition, the control system also includes the wire operators, the LCD and so on. In the system there are six DC motors which complete the actions of rising and falling of the head, the flexion of the leg, rolling around of the left and right, opening and closing of the vane and rising and falling of the stool and so on.A. Bed Function.The bed activity functions including the rising and falling of the head, the flexion of the leg and the bed body tum sides which satisfied patients active request basically, favors the patients to improve their blood circulation and prevents the bedsore. This nursing bed has designed the flexion of the leg conforms to human bodys movement characteristic. The bed body side turns may divide into three movements: the left side to tum, the right side to tum and the even side. Fig. 2, Fig. 3, Fig. 4 is the bed bodys three movements. B. Nursing Function The defecation function is rare in other electric nursing bed which suits the paralysis patient especially. In the middle of the bed body there is a rectangular opening, where can only seen two vanes in the normal condition. When defecating, the vane turns down to makes a breach, then the defecation device rise. After the defecation completed, the vane upturns continues to fill the gap. The defecation device is composed of the active frame and the motion bed pan which can inserts into the frame, and the entire frame can coordinate to load the bed body. The nursing bed can also provide the functions of spraying water and drying. In the active frame installed the water tank, the hot air blower and the solenoid valve. The water tank has a water pump, heater, the temperature sensor and the water level sensor. It can be realized that the water temperature establishment, the water temperature maintains and the water tank volume automatic increase and so on under the controllers control. The patient who is sick bed in long-term is the major recipients of this nursing bed. Before defecate, press the key stool raise on the remote control, two vanes open, and then the stool raise, plate of the stool erects automatically, and so as to the bed pan. The patient can defecate after these movements completed. After the defecation completes, press corresponding key, carries on the flushing first, then uses hot blast drying, which has manifested the human nursing function. The water for flushing is preserved in the tank, and use heating wire to maintain the temperature. Its needed to gather and process of the temperature in order to realize the control of it, the gather can completed by the sensor, the process and control can completed by the monolithic integrated circuit. As a result of the patients defecate time is uncertainty, and requests maintains the temperature constant, for the aim of providing appropriate temperature momentarily.III. SYSTEM MODELINGA. Modelling Nursing bed is a very complex structure, which can divided into the mechanical component of the bed body, the active frame, the transportable bed pan, the electronic control system and the motor driven system by the structure and the function. Fig. 5 is the geometric modeling graph of the vane 2.I Right rotated board 2 lever of right rotated board 3 Driving arm of right rotated board 4 Motor of right rotated board 5 Motor of left rotated board 6 Driving arm of left rotated board 7 lever of left rotated board 8 Left rotated board 9 Door axis of rotated boardFigure 6 Lever and driving arm of rotated board I Lever of rotated board 2 Driving arm of boardB. Contact Pairs Processing Fig. 6 is the geometric modeling graph of the vane lever and actuating arm. The axis of one of the vane lever ends fixed with the vane, the other end has a curve groove. Both sides of the vane actuating arm are round axes, whose axle centers are parallel. One axis is linked with the motor and fixed, the other coordinated with the curve groove to form a contact. The motor caused the actuating arm to reverse, which can realize opening and closing of the vane.III. SIMULATION ANALYSIS The purpose of dynamics simulation of the vane is to analysis the influence to the torque in the different condition, and guide to improve the design and select the appropriate drive motor 3. A. !influence to Torque from Action The sizes of the left and right vanes are not equal, but the motors are same. Select the right one which has a greater area and force to analysis 4. Select the action point in middle of the two vanes, and the arm of the force is 15 cm. The friction coefficient of the steel is 1.2 to 1.4, and 0.02 to 0.05 after lubricated, takes the friction coefficient of 0.05.The curves are not smooth seen from Fig.7 and Fig.8, as the high frequency component coupling to them analyzed mathematically, which were considered to be vibration in actual. It is also discovered that the vane has a phenomenon of vibration, which meet with the simulated data when testing. The vibration has a relation to the stress, nature of material, rigidity of material, osculating curve of rigid body, friction coefficient and so on. It is inferred from the simulation analysis that the bigger stress the smaller vibration. Make sure the contact surfaces are smooth when design the curve groove of the vane lever to reduces the nonessential vibration. Fig.9 is the angular velocity when the stress is SOON, the vibration situation can be observed obviously 5.The actual action to the vane from the patient is not constant but increases gradually when the vane turns to the level position nearby. So that, select the larger motor torque as far as possible to prevent overloading.B. lrifluence to Torque from Friction CoefficienttThere are three kinds of restraints altogether in the vane simulation: fixed restraint, hinge restraint and contact restraint. The fixed restraint cannot cause the friction force, but the hinge restraint and the contact restraint can. The hinge to the hinge restraint can be processed as sliding bearing. The friction coefficient of sliding bearing is small. The dynamic friction coefficient of sliding bearings is 3.0xl0-3 and the static friction coefficient is 4 .0 x 10 - 3 Although the contact restraint is also a kind of sliding friction, but it cannot simply processed as sliding bearing, because the contact is complex, and the stress is also big. Fig. 10 represents the contact force when lever axis and curve groove of actuating arm have a stress of SOON, where the biggest can reach 1800N.Fig. 11 and Fig. 12 respectively represent the torque chart in the friction coefficient of 0.07 and 0.31, and the stress of SOON.Compared with Fig. 11 and Fig. 12, it cannot obviously see the changes of the torque, so as the curve. The biggest diversity is that the vibration reduces when friction coefficient is 0.31. The friction coefficient f.I. has not caused the biggest moment of force change obviously, only has a tendency of enlargement, after the process of filter smooth correlative value 6.C. lrifluence toTtorque from Space PositionWhen design the vane, not only consider the actual installment space and the request size, but also need to pay attention to the relations in the space position between the revolution axis of the vane lever and the revolution axis of the actuating arm. Because their positions are not only relating whether the vane can operation normally, but also affects the biggest driving force. Use the coordinates system as Fig. 13 when establish the coordinate. Fig. 14, Fig. 15 and Fig. 16 are the changing graph of biggest torque in VI-452 Volume I 2010 2nd International Conference on Mechanical and Electronics Engineering (ICMEE 2010) different space position 7. And the stress is SOON, friction coefficient is 0.03.Comparing the data in the different condition may see that the time and the biggest torque have changed remarkably. And the movement time is the smallest in condition 3, so as the force moment. In the condition 2, the lever arm separated from the drive shaft in the moving procession. When actually determine the data, should consider about the motor of torque, size and structure and so on, the best effort may not be the most suitable 8. Through the analysis of dynamics simulation to the vane that: 1) The motor driven torque is small. In the process of simulation analysis, exerted 500N force to the vane and calculates the biggest torque of the motor is 25Nm, but actually the torque is 18Nm, therefore present the phenomenon of the vane asthenia when raising. Here takes 500N force, it is only the average action size in the normal condition. When actual use, possibly bigger than 500 N, so that it must be considered that the motor should have a sufficient remainder actuation torque to satisfY the request under the dissimilar condition. 2) The influence of the friction coefficient is not big to the torque. Under the condition of constant action, its indicated that the friction coefficient has a very small influence to the torque, through takes different friction coefficient to calculate the biggest torque. 3) The space position of the rotation axis has a bigger influence to the torque, the condition 1 and 3 have a difference of 1 ONm, and the movement time also changing.V. CONCLUSION Discussed the
- 温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。
川公网安备: 51019002004831号