计数器底座注塑件注塑模具设计【计算器外壳】【一模两腔】

计数器底座注塑件注塑模具设计【计算器外壳】【一模两腔】,计算器外壳,一模两腔,计数器,底座,注塑,模具设计,计算器,外壳 Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.New Cooling Channel Design for I njection Moulding A B M Saifullah, S.H. Masood and Igor SbarskiAbstract Injection moulding is one of the most versatile and important operation for mass production of plastic parts. In this process, cooling system design is very important as it largely determines the cycle time. A good cooling system design can reduce cycle time and achieve dimensional stability of the part.This paper describes a new square sectioned conformal cooling channel system for injection moulding dies. Both simulation and experimental verification have been done with these new cooling channels system. Comparative analysis has been done for an industrial part, a plastic bowel, with conventional cooling channels using the Moldflow simulation software.Experimental verification has been done for a test plastic part with mini injection moulding machine. Comparative results are present ed based on temperature distribution on mould surface and cooling time or freezing time of the plast ic part. The results provide a uniform temperature distribution with reduced freezing time and hence reduction in cycle time for the plastic part. Index TermsConformal cooling channel, Cycle time Moldflow, Square shape. I. INTRODUCTION Injection moulding is a widely used manufacturing process in the production of plastic parts 1. The basic principle of injection moulding is that a solid polymer is molten and injected into a cavity inside a mould which is then cooled and the part is ejected fro m the machine. Therefore the main phases in an injection moulding process involve filling, cooling and ejection. The cost-effectiveness of the process is mainly dependent on the time spent on the moulding cycle in which the cooling phase is the most significant step. Time spent on cooling cycle determines the rate at which parts are produced. Since, in most modern industries, time and costs are strongly linked, the longer is the time to produce parts the more are the costs. A reduction in the time spent on coo ling the part would drastically increase the productio n rate as well as reduce costs. So it is important to understand and optimize the heat transfer process within a typical moulding process. The rate of the heat exchange between the injected plastic and the mo uld is a decisive factor in the economical performance of an injection mould A B M Saifullah is a research doctoral student at Industrial Research Institute Swinburne (IRIS), Swinburne University of Technology, Melbourne, Australia (e-mail- msaifullahswin.edu.au), also Member, IAENG. S. H. Masood is a Professor of Mechanical & Manufacturing Engineering at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia. (Corresponding author, ph:+61-3-9214 8260, fax: +61-3-9214 5050, e-mail: smasoodswin.edu.au) Dr Igor Sbarski is a Senior Lecturer at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia.(e-mail: isbarskiswin.edu.au ). 3.Heat has to be taken away from the plastic material until a stable state has been reached, which permits demolding. The time needed to accomplish this is called cooling time or freezing time of the part. Proper design of cooling system is necessary for optimum heat transfer process between the melted plastic material and the mould. Traditionally, this has been achieved by creating several straight holes inside the mould core and cavity and then forcing a cooling fluid (i.e. water) to circulate and conduct the excess heat away from the molten plastic. The method s used for producing these holes rely on the conventional machining process such as straight drilling, which is incapable of producing complicated contour-like channels or anything vaguely in 3D space. An alternative method of coo ling system that co nforms or fits to the shape of the cavity and core of the mould can provide better heat transfer in injection moulding process, and hence can result in optimum cycle time. This alternative method uses contour-like channels of different cross-section, constructed as close as po ssible to the surface of the mould to increase the heat absorption away from the molten plastic. This ensures that the part is cooled uniformly as well as more efficiently. Now-a-days, with the advent of rapid p rototyping technology such as Direct Metal Deposition (DMD), Direct Metal Laser Sintering (DMLS) and many advanced computer aid ed engineering (CAE) software, more efficient co oling channels can be designed and manufactured in the mould with many complex layout and cross-sections2,3,4. This paper presents a square section conformal co oling channel (SSCCC) for injection moulding die. Simulation has been done for an industrial p lastic part, a circular plastic bowel for these SSCCC and compared with conventional straight cooling channels (CSCC) with Moldflow Plastic Inside (MPI) software. Comparative experimental verification has also been performed with SSCCC and CSCC die for a circular shape test part with mini injectio n moulding machine for two plastic materials. Result shows that SSCCC die gives better cooling time and temperature distribution than that of CSCC dies. II. DESIGN OF THE PART AND MOULDS A. Part design The part circular plastic bowl made of polyprop ylene (PP) thermoplastic, as shown in Fig 1(a) has been designed with Pro -Engineer CAD software. It was then exported to IGES (Initial Graphics Exchange Specification) file surface model to impo rt in MPI for analysis. Material volume of the plastic part is 177.90cm and its weight is 162.3 gm. Experimental test part as shown in Fig 1(b) has also been d esigned with Pro-Engineer software. Experimental ISBN: 978-988-17012-5-1WCE 2009Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.verification has b een done with two types of plastic materials, PP and ABS (Acrylonitrile Butadiene Styrene). Test part volume was 8.8 cm3, and part weight for ABS and PP were 8.68 gm and 8.13gm respectively. (a)(b)(a) (b) Fig-1 CAD model of (a) Circular plastic bowel, (b) Test part. B. Mould Design Mould design has been done using Pro/Moldesign module of the Pro /Engineer system. This mould is then manufactured with Computer Numerical Control (CNC) machine. The mould shown in Fig 2 has two parts, the core and the cavity.Square section conformal cooling channel (SSCCC) has been produced around the cavity by CNC machining of one half of the channel on cavity part and the other half on the core part.Both halves are then joined with screws and sealed with liquid gasket (Permatex) to avoid water leakage.Fig-2 Assembly CAD model of mould with core (top )and two cavity parts. III. ANALYSIS AND RESULTS MPI simulation software has been used for part analysis 5. Analysis sequence was flow-cool-warp. Polyprop ylene plastic material has been used for analysis. Comparative analysis has been done with conventional straight coo ling channel (CSCC) and SSCCC. The diameter of CSCC was 12 mm and the length of SSCCC section size was 12 mm (Fig 3).Fusion meshing with global edge length of 0.995 cm has been used . The numbers of mesh elements used were 12944 and 12291 for CSCC and SSCCC respectively. 3Fig-3 Analysis setting in MPI (a) CSCC (b) SSCCC Both cases used cooling medium as normal water of 25C. Reynolds number was 10000, melting temperature was 230 C. Comparative analysis result from MPI as shown in Fig 4 shows that SSCCC shows better temperature distribution and(a) (b) Fig-4 Comparative freezing or cooling time (a) CSCC(b) SSCCC. less part freezing time than CSCC. In case of CSCC, most of the part cools in about 24 second except the top few areas, while on the other hand SSCCC diagram shows that it is less than 20 seconds. And also CSCC shows the time to freeze range to be 0.4 6-93.7sec and SSCCC shows this to be 0.3-87.15sec. So, using SSCCC, 5 second of cooling time has been reduced which is 3 5% reduction of cooling time. IV. EXPERIMENTAL VERIFICATION AND RESULTS Experimental verification has been done with a circular shap e plastic test part using the machined mould as shown in Fig 5. Part diameter was 40 mm and thickness was 7 mm.The mould dimension was 10x10x2.5 cm . Mould material was mild steel. Experiment has been done with a mini(a) (b) Fig-5 (a) Mild steel Core (left) and cavity with SSCCC (b) CSCC of mild steel. ISBN: 978-988-17012-5-1WCE 2009Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.injection moulding machine of TECHSOFT mini moulder (Fig 6). Two thermocouples TC08 K type of PICO technology have been used to measure temperature of top and bottom surface of the test part. Melting temperature was 250C fo r both ABS and PP. Normal water has been used as a cooling medium, room temperature has been measured as 25 C, so is cooling water. Cooling channel diameter was 5 mm for CSCC and SSCCC section size was 5 mm. With two thermocouples, surface temperature of the test part has been measured for every second.Fig-8 Comparative temperature plot for PPIn experimental tests, twenty samp le test parts have been produced for ABS and PP material for experimental verification and in every case almost the same data has been found. Fig 9 shows the sample test parts in ABS and PP,which have been produced fo r experimental verification. Fig-6 Experimental setup for test injection moulding, left: mini moulder, right: temperature outp ut in PC. Fig 7 and Fig 8 show the comparative temperature distribution for top and bottom surface of the plastic parts for 30 second. Fig-9 Sample test part prod uced for experimental verification Left: ABS right: PP plastic. V. CONCLUSION The cooling process is one o f the most important sub processes in injection moulding because it normally accounts for approximately half of the total cycle time and affects directly the Fig-7 Comparative temperature plot for ABSFrom Fig 7 it is noted that for the ABS plastic, using SSCCC, the top face and bottom face of test part cooled earlier than that with CSCC. In case of SSCCC, maximum top and bottom surface temperature recorded at particular time immediately after injection were 53.36 C and 52.1C. After30 second, this temperature reduced to 42.47 C and 43.07 C, whereas, for CSCC they were 53.24, 52.01 and 47.47, 47.72 C. So in average, 4 to 5 C reduction in temperature happens using the SSCCC. Similar results also have been found when using PP as the part material. From Fig 8, it can be shown that using SSCCC, about 2 to 3 C reduction in temperature can be possible. shrinkage, bending and warp age of the moulded plastic product.Therefore, designing a go od cooling channel system in the mould is crucial since it influences the production rate and quality. The results of MPI simulation and experimental verification show thatusing square shape conformal cooling channels gives up to 35% reduction in cooling time and 20% of the total cycle time can b e obtained, thus greatly improving the production rate and the production quality of injection moulded parts. ACKNOWLEDGMENT These authors are grateful to Mrs. Meredith and Phil Watson of Faculty of Engineering and Industrial Science,Swinburne University of Technology for their technicalsupport for die making with CNC machining.ISBN: 978-988-17012-5-1WCE 2009Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.REFERENCES 1 D.V. Rosato, D.V. Rosato and M.G. Rosato, InjectionMoulding Handbook-3rd ed , Boston, Kluwer Academic Publishers, (2003). 2 X. Xu, E. Sach and S.Allen, The Design of ConformalCooling Channels In Injection Moulding Tooling,Polymer Engineering andScience, 4, 1, pp 1269-1272, (2001). 3 D.E. Dimla, M. Camilotto, and F. Miani: Design and optimization ofconformal cooling channels in injection moulding tools, J. of Mater.Processing Technology, 164-165, pp 1294-1300, (2005). 4 A B M Saifullah and S. H. Masood, Optimum cooling channels design and Thermal analysis of an Injection moulded plastic part mould, Materials ScienceForum, Vols. 561-565, pp. 1999-2002, (2007). 5 A B Saifullah, S. H. Masood and Igor Sbarski, cycle timeoptimization and part quality improvement using novel cooling channels in plastic injection moulding. ANTECNPE 2009, USA. ISBN: 978-988-17012-5-1WCE 2009毕 业 设 计(论文) 外 文 翻 译英文翻译题目一： Application_of_PLC_in_the_Elevator_Control_System_of_Intelligence_Building 英文翻译题目二：Elevator System Based on PLC 学 院 名 称： 机械工程学院 专 业： 材料成型及控制工程 班 级： 成型102班 姓 名： 何足道 学号 10403070234 指 导 教 师： 陈永清 2014年2月8日英文题目一Application_of_PLC_in_the_Elevator_Control_System_of_Intelligence_Building翻译内容指导教师评语 指导教师签字 年 月 日 英文题目二Elevator System Based on PLC 翻译内容指导教师评语 指导教师签字 年 月 日 PLC在智能建筑的电梯控制系统中的应用摘要：本文主要讨论了智能建筑系统的一个子系统：电梯控制系统。 PLC干扰能力强等特点，使电梯行业一个又一个的应用PLC在电梯控制系统，以取代传统的电梯控制系统中正在使用的继电器。 PLC在电梯控制系统中的应用降低了故障率，有效地提高了电梯运行的可靠性与安全性。系统的结构也很简单、紧凑。它的工作原理是：现场控制信息从用户输入设备发送到PLC，然后控制柜需要根据系统要求发出控制信号驱动设备。从而电梯可以根据控制要求来执行相应的行动。 本文选择了OMRON公司的C200HE系列PLC，引进部分信号转播的电梯控制系统和解释功能的控制柜，最后是介绍自动化编程。模拟实验阐述了该设计方法是可行的。PLC在电梯控制系统中的应用是一种有效的方法，它可以使行业管理中心的人员在控制中心远程监控和控制电梯，通过以太网与智能建筑行业管理系统或专用网络的连接，如经度工程。电梯的工作状态也可以及时关注。这不仅能实现科学集中管理的电梯，而且还可以降低电梯的维护费用等，这是智能楼宇的电梯控制系统的发展方向之一。、介绍 在20世纪80年代第一个智能大厦已在美国完成，然后智能建筑已被全世界广泛注意。随着社会的发展，智能建筑的概念已经提出了不同的含义。早期智能建筑被认为等同于智能大厦，但现在智能建筑不仅包括智能化豪宅，也涉及到智能住宅小区。本文主要讨论了智能建筑系统的一个子系统：电梯控制系统。在智能住宅小区中，企业信息管理系统主要负责有关日常生活事情，例如监督区设备，车辆管理，处理危急情况等。对于智能住宅小区来说电梯监控系统也是需要的。如何使人们感到安全，稳定舒适和如何节约能源资源、保护环境等是电梯控制系统的基本要求.。 PLC是一种常见的工业控制装置。它是一种特殊的工业控制计算机，具有完善的功能和简单的框架。PLC干扰能力强等特点，使得电梯行业一个又一个的在电梯控制系统中应用PLC，以取代传统电梯控制系统中正在使用的继电器。PLC在电梯控制系统中的应用降低了电梯的故障率，有效地提高了电梯运行的可靠性与安全性。本文主要讨论电梯控制系统的工作原理，以及系统的软件和硬件实现方法等。 、电梯控制系统的工作原理下图为电梯控制系统的硬件结构图。图1电梯控制系统硬件结构图电梯控制系统的工作原理表述如下：现场控制信息从用户输入设备发送到PLC，然后控制柜需要根据系统要求发出控制信号驱动设备。从而电梯可以根据控制要求来执行相应的行动。有速度反馈系统的装置，其中采用测速发电机提供了电梯速度，一般是安装在尾部的牵引电动机。所以这是一个反馈控制系统，它可以提高系统的控制精度。、该控制系统硬件配置在电梯的控制系统中是没有必要做接口电路的。我们所要做的是发送信号到PLC的数字信号输入端子，包括内部和外部呼叫信号，楼层位置检测信号，限制信号的位置，打开和关闭电梯门信号等的直流电源提供给PLC，可以用作指示灯电源。PLC输出点可以直接用来控制传感器用于电机的正转，反转，停止和控制各段速度等。OMRON公司的C200HE系列PLC已被选定作为主要控制配置，其中主要是根据输入/输出点和用户的程序长度。另一方面，我们也认为，在未来系统的功能可以扩大。C200HE系列PLC，其完善的功能和强大的可靠性，目前能够满足这些要求。此外，除了PLC，系统的主控制装置：输入和输出设备，需要在电梯控制系统中。图2中所示为一部分信号连线的电梯电气控制系统。控制柜是控制中心，从中我们可以发出各种控制命令。控制柜通常是安装在电梯房里。电气设备和信号系统，例如接触器，继电器，电容，电阻，整流器和变压器等，都是集中在控制柜中。电源控制柜的进口电梯前室的主要力量。这股力量也被引入到控制面板中的软电缆里，并与各控制按钮连接。电源线是由控制柜传递给牵引电动机，其他的控制线和信号线分别发送到每个地板接线盒，以形成电梯的执行电路。图2的电梯控制系统的信号连线图3子程序证监会：主叫方在一楼，电梯在三楼、程序设计 该设计包括两部分：硬件和软件。硬件设计是软件的基础。考虑到控制的需求是相对复杂的，我们设计的程序，根据该控制功能分开。此外，我们遵循的原则如下：当电梯上升，必须先执行上升后执行其他要求，当电梯下降，必须执行下降后执行其他要求。在设计过程中采用顺序功能图（SFC）。它是一种专门用于工业顺序控制。证监会的方法可以很详细的描述系统的工作过程。例如，有一个三层智能建筑，子程序的调用，电梯在一楼到三楼，如图 3。当所有SFC制定好和I / O地址列表给出了，我们可以将SFC配对梯形图（LD）。考虑到时间和锁定对方的严格要求，我们引进工作位来记住工作步骤。我们可以写出位控制程序，它可以把每一个步骤连接在一起使上一步骤作为下一步骤的约束条件。因此，实际的输出是这些工作步骤的逻辑组合。、结论 目前，系统程序经过完全的调试。模拟实验表明，该设计方法是可行的。PLC在电梯控制系统中的应用是一种有效的方法，它可以使行业管理中心的人员在控制中心远程监控和控制电梯，通过以太网与智能建筑行业管理系统或专用网络的连接，如经度工程。电梯的工作状态也可以及时关注。这不仅能实现科学集中管理的电梯，而且还可以降低电梯的维护费用等，这是智能楼宇的电梯控制系统的发展方向之一。参考文献1梁剑气，段振刚，何炜。基于PLC的电梯远程监控系统（中国）通讯的实现J北京工商大学学报2003,21（2）:18-212马红倩，张欣应用PLC在大厦电梯控制系统（中国）J。中华辽宁高职学报2002,4（5）：86-88。3崔广元， PLC在电梯控制中的应用. （中国）J - 东北电力技术2003，（7）：50-52。 作者简历 第一作者是目前在太原理工大学的老师。她目前的研究兴趣包括信号处理，智能控制等。第二作者是目前正作为一个老师在太原理工大学从事科学和技术相关课程的教学。她目前的研究兴趣包括电信，智能控制等。PLC控制下的电梯系统由继电器组成的顺序控制系统是最早的一种实现电梯控制的方法。但是，进入九十年代，随着科学技术的发展和计算机技术的广泛应用，人们对电梯的安全性、可靠性的要求越来越高，继电器控制的弱点就越来越明显。 电梯继电器控制系统故障率高，大大降低了电梯的可靠性和安全性，经常造成停梯，给乘用人员带来不便和惊忧。且电梯一旦发生冲顶或蹲底，不但会造成电梯机械部件损坏，还可能出现人身事故。可编程序控制器(PLC)最早是根据顺序逻辑控制的需要而发展起来的，是专门为工业环境应用而设计的数字运算操作的电子装置。鉴于其种种优点，目前，电梯的继电器控制方式己逐渐被PLC控制所代替。同时，由于电机交流变频调速技术的发展，电梯的拖动方式己由原来直流调速逐渐过渡到了交流变频调速。因此，PLC控制技术加变频调速技术己成为现代电梯行业的一个热点。1. PLC控制电梯的优点(1)在电梯控制中采用了PLC，用软件实现对电梯运行的自动控制，可靠性大大提高。 (2)去掉了选层器及大部分继电器，控制系统结构简单，外部线路简化。 (3)PLC可实现各种复杂的控制系统，方便地增加或改变控制功能。 (4) PLC可进行故障自动检测与报警显示，提高运行安全性，并便于检修。 (5)用于群控调配和管理，并提高电梯运行效率。(6)更改控制方案时不需改动硬件接线。2.电梯变频调速控制的特点随着电力电子技术、微电子技术和计算机控制技术的飞速发展，交流变频调速技术的发展也十分迅速。电动机交流变频调速技术是当今节电、改善工艺流程以提高产品质量和改善环境、推动技术进步的一种主要手段。变频调速以其优异的调速性能和起制动平稳性能、高效率、高功率因数和节电效果，广泛的适用范围及其它许多优点而被国内外公认为最有发展前途的调速方式交流变频调速电梯的特点 能源消耗低 电路负载低，所需紧急供电装置小在加速阶段，所需起动电流小于2.5倍的额定电流。且起动电流峰值时间短。由于起动电流大幅度减小，故功耗和供电缆线直径可减小很多。所需的紧急供电装置的尺寸也比较小。 可靠性高，使用寿命长。 舒适感好电梯运行是跟随最佳给定的速度曲线运行的。其特性可适应人体感受，并保证运行噪声小，制动平稳 平层精度高 运行平稳无噪声在轿厢内，机房内及邻近区域确保噪声小。因为其系统中采用了高时钟频率。始终产生一个不失真的正弦波供电电流。电动机不会出现转距脉动。因此，消除了振动和噪声。3.电梯控制技术所谓电梯控制技术是指电梯的传动系统及操纵系统的电气自动控制。作为我国20世纪70年代电梯的主要标志是交流双速电梯。其调速方法是采用改变电梯牵引电动机的极对数，两种或两种不同级对数的绕组，其中极数少的绕组称为高速绕组，极数多的绕组称为低速绕组。高速绕组用于电梯的起动及稳速运行，低速绕组用于制动及电梯的维修。80年代初，VVVF变频变压系统控制的电梯问世。它采用交流电动机驱动，却可以达到直流电动机的水平，目前控制速度已达6米/秒。它的体积小，重量轻，效率高，节省能源等几乎包括了以往电梯的所有优点。是目前最新的电梯拖动系统。电梯在垂直运行过程中，有起点站也有终点站。对于三层楼以上的建筑物的电梯，起点站和终点站之间还没有停靠站，起点站设在一楼，终点站设在最高楼。设在一楼的起点站称为基站，起点站和终点站称为两端站，两端站之间称为中间站。各站厅外设有召唤箱，箱上设置有供乘用人员召唤电梯用的召唤按钮或触钮，一般电梯在两端站的召唤箱上各设置一只按钮或触钮。中间层站的召唤箱各设置两只按钮或触钮。对于无司机控制的电梯，在各层站的召唤箱上均设置一只按钮或触钮。而电梯的轿厢内部设置有（杂物电梯除外）操纵箱。操纵箱上设置有手柄开关或与层站对应的按钮或触钮，操纵箱上的按钮或触钮城内指令按钮或触钮。外指令按钮或触钮发出的电信号称为外指令信号，内指令按钮或触钮发出的电信号成为内指令信号。20世纪80年代中期后，触钮已被微动按钮所取代。作为电梯基站的厅外召唤箱，除设置一只召唤按钮或触钮外，还设置一只钥匙开关，以便下班关电梯时。司机或管理人员把电梯开到基站后，可以通过专用钥匙扭动该钥匙开关。把电梯的厅门关闭妥当后，自动切断电梯控制电源或动力电源。4. PLC控制电梯的设计随着城市建设的不断发展，高层建筑不断增多，电梯在国民经济和生活中有着广泛的应用。电梯作为高层建筑中垂直运行的交通工具已与人们的日常生活密不可分。实际上电梯是根据外部呼叫信号以及自身控制规律等运行的，而呼叫是随机的，电梯实际上是一个人机交互式的控制系统，单纯用顺序控制或逻辑控制是不能满足控制要求的，因此，电梯控制系统采用随机逻辑方式控制。目前电梯的控制普遍采用了两种方式，一是采用微机作为信号控制单元，完成电梯信号的采集、运行状态和功能的设定，实现电梯的自动调度和集选运行功能，拖动控制则由变频器来完成；第二种控制方式用可编程控制器（PLC）取代微机实现信号集选控制。从控制方式和性能上来说，这两种方法并没有太大的区别。国内厂家大多选择第二种方式，其原因在于生产规模较小，自己设计和制造微机控制装置成本较高；而PLC可靠性高，程序设计方便灵活，抗干扰能力强、运行稳定可靠等特点，所以现在的电梯控制系统广泛采用可编程控制器来实现。5.电梯控制系统特性在电梯运行曲线中的启动段是关系到电梯运行舒适感指标的主要环节，而舒适感又与加速度直接相关，根据控制理论，要使某个量按预定规律变化必须对其进行直接控制，对于电梯控制系统来说，要使加速度按理想曲线变化就必须采用加速度反馈，根据电动机的力矩方程式:MMZ=M=J（dn/dt），可见加速度的变化率反映了系统动态转距的变化，控制加速度就控制系统的动态转距M=MMZ。故在此段采用加速度的时间控制原则，当启动上升段速度达到稳态值的90%时，将系统由加速度控制切换到速度控制，因为在稳速段，速度为恒值控制波动较小，加速度变化不大，且采用速度闭环控制可以使稳态速度保持一定的精度，为制动段的精确平层创造条件。在系统的速度上升段和稳速段虽都采用PI调节器控制，但两段的PI参数是不同的，以提高系统的动态响应指标。在系统的制动段，即要对减速度进行必要的控制，以保证舒适感，又要严格地按电梯运行的速度和距离的关系来控制，以保证平层的精度。在系统的转速降至120r/min之前，为了使两者得到兼顾，采取以加速度对时间控制为主，同时根据在每一制动距离上实际转速与理论转速的偏差来修正加速度给定曲线的方法。例如在距离平层点的某一距离L处，速度应降为Vm/s，而实际转速高为Vm/s，则说明所加的制动转距不够，因此计算出此处的给定减速度值-ag后，使其再加上一个负偏差，即使此处的减速度给定值修正为-（ag+）使给定减速度与实际速度负偏差加大，从而加大了制动转距，使速度很快降到标准值，当电动机的转速降到120r/min以后，此时轿厢距平层只有十几厘米，电梯的运行速度很低，为防止未到平层区就停车的现象出现，以使电梯能较快地进入平层区，在此段采用比例调节，并采用时间优化控制，以保证电梯准确及时地进入平层区，以达到准确可靠平层。