四自由度棒料搬运机械手设计开题报告

编号无锡太湖学院毕业设计（论文）相关资料题目： 四自由度棒料搬运机械手设计 信机 系 机械工程及其自动化 专业2013年5月25日目 录一、毕业设计（论文）开题报告二、毕业设计（论文）外文资料翻译及原文三、学生“毕业论文（论文）计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计（论文）开题报告题目： 四自由度棒料搬运机械手设计 机电系 机械工程及其自动化 专业学 号： 0923076 学生姓名： 陈 华 指导教师： 冯 鲜 （职称：讲 师 ） （职称： ）2012年11月26日课题来源随着世界经济的快速发展和现代科学技术的进步,物流产业作为国民经济中一个新兴的服务部门,正在全球范围内迅速发展.在国际上,物流产业被认为是国民经济发展的动脉和基础产业,其发展程度成为衡量一国现代化程度和综合国力的重要标志之一,被喻为促进经济发展的“加速器”.物流产业是指铁路、公路、水路、航空等基础设施,以及工业生产、商业批发零售和第三方仓储运输及综合物流企业为实现商品的实体位移所形成的产业.国民经济各个领域的物流经济实体从横向构成了物流产业.这个产业由铁道、公路、水运、空运、仓储、托运等行业为主体组成,同时还包含了商业、物资业、供销、粮食、外贸等行业中的一半领域,还涉及到机械、电器业中的物流装备生产行业和国民经济所有行业的供应、生产、销售中的物流活动。 近年来工业自动化的发展机械器件逐渐成为一门新兴的学科,并得到了较快的发展。工业现场的很多重体力劳动必将由机器代替,这一方面可以减轻工人的劳动强度,另一方面可以大大提高劳动生产率。例如,目前在我国的许多中小型生产行业中,往往冲压成形这一工序还需人工上下料,既费时费力,又影响效率。为此我们研制了一套上下料机械手模拟装置，以此为基础,为进一步实用化做好充分准备。机械手是工业自动控制领域中经常遇到的一种控制对象. 是一种模仿人手动作，并按设定程序，轨迹和要求代替人手抓（吸）取，搬运工件或工具进行操作的自动化装置。其可以完成许多工作,如搬物、装配、切割、喷染等等,应用面非常广泛。工业生产中常用的进行水平/垂直位移的机械设备的动作由气缸驱动，气缸又又相应的电磁阀控制，该机械手除外形尺寸比实物小些以外,其结构、原理及功能与实际的机械手是完全一致的。科学依据机器人（又称机械手，机械人，英文名称：Robot），在人类科技发展史上其来有自，早在三国时代，诸葛亮发明的木牛流马即是古代中国人的智能结晶。随着近代的工业革命，机器产业的不断发展成为近代工业的主要支柱。 机器人的研究从一开始就是拟人化的，所以才有机械手、机械臂的开发与制作，也是为了以机械来代替人去做人力所无法完成的劳作或探险。但近十几年来，机器人的开发不仅越来越优化，而且涵盖了许多领域，应用的范畴十分广阔。 工业机器人是典型的机电一体化高技术产品。在许多生产领域，它对于提高生产自动化水平，提高劳动生产率、产品质量和经济效益，改善工人劳动条件的作用日见显著。不少劳动条件恶劣、生产要求苛刻的场合，工业机器人代替人力劳动已是必然的趋势。 工业机器人是一种机体独立，动作自由度较多，程序可灵活变更，能任意定位，自动化程度高的自动操作机械。主要用于加工自动线和柔性制造系统中传递和装卸工件或夹具。工业机器人以刚性高的手臂为主体，与人相比，可以有更快的运动速度，可以搬运更重的东西，而且定位精度相当高，它可以根据外部来的信号，自动进行各种操作。国内现状及发展趋势 物流这一概念的形成和物流管理学科的建立只不过几十年的历史,引入我国也仅十几年时间。但是物流这一概念赖以形成的流通行业却已历史久远,早在人类社会出现商品交换的时期就已经出现了。随着时间的流逝，物流的发展趋势大致可以归纳为以下几点： 物流需求弹性逐年增高,经济增长越来越依赖于物流的发展。 第三方物流的比重逐年增加。 进一步加快国际化进程。 物流体系综合化； 三流一体化。 国外机械手工业、铁路工业中不仅在单机、专机上采用机械手上下料，减轻工人的劳动强度，而且在铁路工业中应用机械手以加工铁路车轴、轮等大、中批零件。并和机床共同组成一个综合的数控加工系统。采用机械手进行装配更始目前研究的重点，国外已研究采用摄象机和力传感装置和微型计算机连在一起，能确定零件的方位达到镶装的目的。 国外机械手的发展趋势是大力研制具有某种智能的机械手。使它具有一定的传感能力，能反馈外界条件的变化，作相应的变更。视觉功能即在机械手上安装有电视照相机和光学测距仪（即距离传感器）以及微型计算机。 触觉功能即是在机械手上安装有触觉反馈控制装置。工作时机械手首先伸出手指寻找工作，通过安装在手指内的压力敏感元件产生触觉作用，然后伸向前方，抓住工件。 总之，随着传感技术的发展机械手装配作业的能力也将进一步提高。更重要的是将机械手、柔性制造系统和柔性制造单元相结合，从而根本改变目前机械制造系统的人工操作状态。研究内容本设计中的四自由度棒料搬运机械手，主要是针对圆形棒料的搬运。本设计中的机械手有四个自由度，由底座的旋转，手臂的升降，手臂的伸缩，手爪 的旋转组成。本设计中的机械手是一种通用型棒料搬运机械手。通过气爪手指的不同选择可满足不同直径的棒料的搬运。通过示教再现或程序的直接控制可实现在机械手工作范围内把棒料从指定点搬运到另一指定点，并把棒料翻转过来。通过对机械手的相应控制还可实现对棒料的排列。拟采取的研究方法、技术路线、实验方案及可行性分析由设计要求本设计机械手实现的作用：自动线上有A,B两条输送带，之间距离为0.7米，现设计机械手将一棒料翻转过来。确定为四自由度的机械手。其中2个为旋转，两个为平移。在工业机器人的诸多功能中，抓取和移动是最只要的功能。这两项功能的实现的技术基础是精巧的机械结构设计和良好的伺服控制驱动。 本次设计就是在这一思维下展开的。根据设计内容和需求确定机械手，利用步进电机驱动和谐波齿轮传动来实现机器人的旋转运动；利用另一台步进电机驱动滚珠丝杠旋转，从而使与滚珠丝杠螺母副固连在一起的手臂实现上下运动；考虑到本设计中的机械手工作范围不大，故利用气缸驱动实现手臂的伸缩运动；末端夹持器则选用气爪来做夹持器，用小型气缸驱动夹紧。气爪的旋转则由与气爪连接的摆动气缸实现。研究计划及预期成果研究计划：2012年11月12日2012年11月18日：按照任务书要求查阅论文相关参考资料，填写毕业设计开题报告书。2012年11月19日2012年11月24日：填写毕业实习报告。2012年11月25日2012年12月2日：按照要求修改毕业设计开题报告。2013年12月3日2013年12月17日：学习并翻译一篇与毕业设计相关的英文材料。2013年1月11日2013年1月15日：PLC程序设计。2013年1月21日2013年2月2日：CAD设计。2013年3月6日2013年5月25日：毕业论文撰写和修改工作。预期成果： 通过气爪手指的不同选择可满足小于直径60mm的棒料的搬运。通过示教再现或程序的直接控制可实现在机械手工作范围内把棒料从指定点搬运到另一指定点，并把棒料翻转过来。通过对机械手的相应控制还可实现对棒料的排列。特色或创新之处采用多自由度，可一定程度的模拟人手动作。可配合一些简单的工具并行使用。已具备的条件和尚需解决的问题机械爪通用性不强，有一定的限制。指导教师意见 指导教师签名：年 月 日教研室（学科组、研究所）意见 教研室主任签名： 年 月 日系意见 主管领导签名： 年 月 日英文原文Spin control for carsStability control systems are the latest in a string of technologies focusing on improved diriving safety. Such systems detect the initial phases of a skid and restore directional control in 40 milliseconds, seven times faster than the reaction time of the average human. They correct vehicle paths by adjusting engine torque or applying the left- or-right-side brakes, or both, as needed. The technology has already been applied to the Mercedes-Benz S600 coupe.Automatic stability systems can detect the onset of a skid and bring a fishtailing vehicle back on course even before its driver can react. Safety glass, seat belts, crumple zones, air bags, antilock brakes, traction control, and now stability control. The continuing progression of safety systems for cars has yielded yet another device designed to keep occupants from injury. Stability control systems help drivers recover from uncontrolled skids in curves, thus avoiding spinouts and accidents. Using computers and an array of sensors, a stability control system detects the onset of a skid and restores directional control more quickly than a human driver can. Every microsecond, the system takes a snapshot, calculating whether a car is going exactly in the direction it is being steered. If there is the slightest difference between where the driver is steering and where the vehicle is going, the system corrects its path in a split-second by adjusting engine torque and/or applying the cats left- or right-side brakes as needed. Typical reaction time is 40 milliseconds - seven times faster than that of the average human. A stability control system senses the drivers desired motion from the steering angle, the accelerator pedal position, and the brake pressure while determining the vehicles actual motion from the yaw rate (vehicle rotation about its vertical axis) and lateral acceleration, explained Anton van Zanten, project leader of the Robert Bosch engineering team. Van Zantens group and a team of engineers from Mercedes-Benz, led by project manager Armin Muller, developed the first fully effective stability control system, which regulates engine torque and wheel brake pressures using traction control components to minimize the difference between the desired and actual motion. Automotive safety experts believe that stability control systems will reduce the number of accidents, or at least the severity of damage. Safety statistics say that most of the deadly accidents in which a single car spins out (accounting for four percent of all deadly collisions) could be avoided using the new technology. The additional cost of the new systems are on the order of the increasingly popular antilock brake/traction control units now available for cars. The debut of stability control technology took place in Europe on the Mercedes-Benz S600 coupe this spring. Developed jointly during the past few years by Robert Bosch GmbH and Mercedes-Benz AG, both of Stuttgart, Germany, Vehicle Dynamics Control (VDC). in Bosch terminology, or the Electronic Stability Program (ESP), as Mercedes calls it, maintains vehicle stability in most driving situations. Bosch developed the system, and Mercedes-Benz integrated it into the vehicle. Mercedes engineers used the state-of-the-art Daimler-Benz virtual-reality driving simulator in Berlin to evaluate the system under extreme conditions, such as strong crosswinds. They then put the system through its paces on the slick ice of Lake Hornavan near Arjeplog, Sweden. Work is currently under way to adapt the technology to buses and large trucks, to avoid jack-knifing, for example. Stability control systems will first appear in mid-1995 on some European S-Class models and will reach the U.S. market during the 1996 model year (November 1995 introduction). It will be available as a $750 option on Mercedes models with V8 engines, and the following year it will be a $2400 option on six-cylinder $1650 of the latter price is for the traction control system, a prerequisite for stability control.Bosch is not alone in developing such a safety system. ITT Automotive of Auburn Hills, Mich., introduced its Automotive Stability Management System (ASMS) in January at the 1995 North American International Auto Show in Detroit. ASMS is a quantum leap in the evolution of antilock brake systems, combining the best attributes of ABS and traction control into a total vehicle dynamics management system, said Timothy D. Leuliette, ITT Automotives president and chief executive officer. ASMS monitors what the vehicle controls indicate should be happening, compares that to what is actually happening, then works to compensate for the difference, said Johannes Graber, ASMS program manager at ITT Automotive Europe. ITTs system should begin appearing on vehicles worldwide near the end of the decade, according to Tom Mathues, director of engineering of Brake & Chassis Systems at ITT Automotive North America. Company engineers are now adapting the system to specific car models from six original equipment manufacturers. A less-sophisticated and less-effective Bosch stability control system already appears on the 1995 750iL and 850Ci V-12 models from Munich-based BMW AG. The BMW Dynamic Stability Control (DSC) system uses the same wheel-speed sensors as traction control and standard anti-lock brake (ABS) systems to recognize conditions that can destabilize a vehicle in curves and corners. To detect such potentially dangerous cornering situations, DSC measures differences in rotational speed between the two front wheels. The DSC system also adds a sensor for steering angle, Utilizes an existing one for vehicle velocity, and introduces its own software control elements in the over allantilock-brake/traction-control/stability-control system. The new Bosch and ITT Automotive stability control systems benefit from advanced technology developed for the aerospace industry. Just as in a supersonic fighter, the automotive stability control units use a sensor-based computer system to mediate between the human controller and the environment - in this case, the interface between tire and road. In addition, the system is built around a gyroscopelike sensor design used for missile guidance. Beyond abs and traction controlStability control is the logical extension of ABS and traction control, according to a Society of Automotive Engineers paper written by van Zanten and Bosch colleagues Rainer Erhardt and Georg Pfaff. Whereas ABS intervenes when wheel lock is imminent during braking, and traction control prevents wheel slippage when accelerating, stability control operates independently of the drivers actions even when the car is free-rolling. Depending on the particular driving situation, the system may activate an individual wheel brake or any combination of the four and adjust engine torque, stabilizing the car and severely reducing the danger of an uncontrolled skid. The new systems control the motion not only during full braking but also during partial braking, coasting, acceleration, and engine drag on the driven wheels, circumstances well beyond what ABS and traction control can handle. The idea behind the three active safety systems is the same: One wheel locking or slipping significantly decreases directional stability or makes steering a vehicle more difficult. If a car must brake on a low-friction surface, locking its wheels should be avoided to maintain stability and steerability. Whereas ABS and traction control prevent undesired longitudinal slip, stability control reduces loss of lateral stability. If the lateral forces of a moving vehicle are no longer adequate at one or more wheels, the vehicle may lose stability, particularly in curves. What the drive fishtailing is primarily a turning or spinning around the vehicles axis. A separate sensor must recognize this spinning, because unlike ABS and traction control, a cars lateral movement cannot be calculated from its wheel speeds. Spin handlers The new systems measure any tendency toward understeer (when a car responds slowly to steering changes), or over-steer (when the rear wheels try to swing around). If a car understeers and swerves off course when driven in a curve, the stability control system will correct the error by braking the inner (with respect to the curve) rear wheel. This enables the driver, as in the case of ABS, to approach the locking limit of the road-tire interface without losing control of the vehicle. The stability control system may reduce the vehicles drive momentum by throttling back the engine and/or by braking on individual wheels. Conversely, if the hteral stabilizing force on the rear axle is insufficient, the danger of oversteering may result in rear-end breakaway or spin-out. Here, the system acts as a stabilizer by applying the outer-front wheel brake. The influence of side slip angle on maneuverability, the Bosch researchers explained, shows that the sensitivity of the yaw moment on the vehicle, with respect to changes in the steering angle, decreases rapidly as the slip angle of the vehicle increases. Once the slip angle grows beyond a certain limit, the driver has a much harder time recovering by steering. On dry surfaces, maneuverability is lost at slip-angle values larger than approximately 10 degrees, and on packed snow at approximately 4 degrees. Most drivers have little experience recovering from skids. They arent aware of the coefficient of friction between the tires and the road and have no idea of their vehicles lateral stability margin. When the limit of adhesion is reached, the driver is usually caught by surprise and very often reacts in the wrong way, steering too much. Oversteering, ITTs Graber explained, causes the car to fishtail, throwing the vehicle even further out of control. ASMS sensors, he said, can quickly detect the beginning of a skid and momentarily activate the brakes at individual wheels to help return the vehicle to a stable line. It is important that stability control systems be user-friendly at the limit of adhesion - that is, to act predictably in a way similar to normal driving. The biggest advantage of stability control is its speed - it can respond immediately not only to skids but also to shifting vehicle conditions (such as changes in weight or tire wear) and road quality. Thus, the systems achieve optimum driving stability by changing the lateral stabilizing forces. For a stability control system to recognize the difference between what the driver wants (desired course) and the actual movement of the vehicle (actual course), current cars require an efficient set of sensors and a greater computer capacity for processing information. The Bosch VDC/ESP electronic control unit contains a conventional circuit board with two partly redundant microcontrollers using 48 kilobytes of ROM each. The 48-kB memory capacity is representative of the large amount of intelligence required to perform the design task, van Zanten said. ABS alone, he wrote in the SAE paper, would require one-quarter of this capacity, while ABS and traction control together require only one half of this software capacity. In addition to ABS and traction control systems and related sensors, VDC/ESP uses sensors for yaw rate, lateral acceleration, steering angle, and braking pressure as well as information on whether the car is accelerating, freely rolling, or braking. It obtains the necessary information on the current load condition of the engine from the engine controller. The steering-wheel angle sensor is based on a set of LED and photodiodes mounted in the steering wheel. A silicon-micromachine pressure sensor indicates the master cylinders braking pressure by measuring the brake fluid pressure in the brake circuit of the front wheels (and, therefore, the brake pressure induced by the driver). Determining the actual course of the vehicle is a more complicated task. Wheel speed signals, which are provided for antilock brakes/traction control by inductive wheel speed sensors, are required to derive longitudinal slip. For an exact analysis of possible movement, however, variables describing lateral motion are needed, so the system must be expanded with two additional sensors - yaw rate sensors and lateral acceleration sensors. A lateral accelerometer monitors the forces occurring in curves. This analog sensor operates according to a damped spring-mass mechanism, by which a linear Hall generator transforms the spring displacement into an electrical signal. The sensor must be very sensitive, with an operating range of plus or minus 1.4 g. Yaw rate gyro At the heart of the latest stability control system type is the yaw rate sensor, which is similar in function to a gyroscope. The sensor measures the speed at which the car rotates about its vertical axis. This measuring principle originated in the aviation industry and was further developed by Bosch for large-scale vehicle production. The existing gyro market offers two widely different categories of devices: $6000 units for aerospace and navigation systems (supplied by firms such as GEC Marconi Avionics Ltd., of Rochester, Kent, U.K.) and $160 units for videocameras. Bosch chose a vibrating cylinder design that provides the highest performance at the lowest cost, according to the SAE paper. A large investment was necessary to develop this sensor so that it could withstand the extreme environmental conditions of automotive use. At the same time, the cost for the yaw rate sensor had to be reduced so that it would be sufficiently affordable for vehicle use. The yaw rate sensor has a complex internal structure centered around a small hollow steel cylinder that serves as the measuring element. The thin wall of the cylinder is excited with piezoelectric elements that vibrate at a frequency of 15 kilohertz. Four pairs of these piezo elements are arranged on the circumference of the cylinder, with paired elements positioned opposite each other. One of these pairs brings the open cylinder into resonance vibration by applying a sinusoidal vo