0143-轉(zhuǎn)向臂零件數(shù)控加工工藝、加工仿真
0143-轉(zhuǎn)向臂零件數(shù)控加工工藝、加工仿真,轉(zhuǎn)向,零件,數(shù)控,加工,工藝,仿真
一、 選題的依據(jù)及意義：
本次設(shè)計(jì)是四年大學(xué)所學(xué)基礎(chǔ)課程的一次綜合設(shè)計(jì)，我們要全面綜合的運(yùn)用四年來我們所學(xué)習(xí)的機(jī)械專業(yè)方面的知識(shí)來進(jìn)行研究和設(shè)計(jì)。此次設(shè)計(jì)也是我們走向崗位的最后一次設(shè)計(jì)。
本次設(shè)計(jì)的主要目的：
（1） 運(yùn)用機(jī)械制造工藝學(xué)及有關(guān)課程（機(jī)械設(shè)計(jì)、互換性與測(cè)量技術(shù)、工程材料與熱處理、金屬切削與刀具等）的知識(shí)，結(jié)合生產(chǎn)實(shí)踐中學(xué)到的知識(shí)，獨(dú)立地分析和解決工藝問題，初步具備設(shè)計(jì)一個(gè)中等復(fù)雜程度零件的工藝規(guī)程的能力。
（2） 熟練正確的調(diào)查研究的方法，收集國(guó)內(nèi)外有關(guān)資料，掌握正確的設(shè)計(jì)思想，方法和手段。熟悉并能夠熟練地運(yùn)用相關(guān)工藝手冊(cè)、設(shè)計(jì)手冊(cè)、標(biāo)準(zhǔn)、圖標(biāo)等技術(shù)資料的能力。
（3） 進(jìn)一步的熟悉運(yùn)算，三維軟件，仿真軟件等的運(yùn)用。
二、 國(guó)內(nèi)外研究概況及發(fā)展趨勢(shì)（含文件綜述）
（一）、本課題背景知識(shí)
1．?dāng)?shù)控加工技術(shù)的發(fā)展歷程
1949年美國(guó)Parson公司與麻省理工學(xué)院開始合作，歷時(shí)三年研制出能進(jìn)行三軸控制的數(shù)控銑床樣機(jī)，取名“Numerical Control”。
1953年麻省理工學(xué)院開發(fā)出只需確定零件輪廓、指定切削路線，即可生成NC程序的自動(dòng)編程語(yǔ)言。
1959年美國(guó)Keaney&Trecker公司開發(fā)成功了帶刀庫(kù)，能自動(dòng)進(jìn)行刀具交換，一次裝夾中即能進(jìn)行銑、鉆、鏜、攻絲等多種加工功能的數(shù)控機(jī)床，這就是數(shù)控機(jī)床的新種類——加工中心。
1968年英國(guó)首次將多臺(tái)數(shù)控機(jī)床、無(wú)人化搬運(yùn)小車和自動(dòng)倉(cāng)庫(kù)在計(jì)算機(jī)控制下連接成自動(dòng)加工系統(tǒng)，這就是柔性制造系統(tǒng)FMS。
1974年微處理器開始用于機(jī)床的數(shù)控系統(tǒng)中，從此CNC(計(jì)算機(jī)數(shù)控系統(tǒng))軟線數(shù)控技術(shù)隨著計(jì)算機(jī)技術(shù)的發(fā)展得以快速發(fā)展。
1976年美國(guó)Lockhead公司開始使用圖像編程。利用CAD(計(jì)算機(jī)輔助設(shè)計(jì))繪出加工零件的模型，在顯示器上“指點(diǎn)”被加工的部位，輸入所需的工藝參數(shù)，即可由計(jì)算機(jī)自動(dòng)計(jì)算刀具路徑，模擬加工狀態(tài)，獲得NC程序。
DNC(直接數(shù)控)技術(shù)始于20世紀(jì)60年代末期。它是使用一臺(tái)通用計(jì)算機(jī)，直接控制和管理一群數(shù)控機(jī)床及數(shù)控加工中心，進(jìn)行多品種、多工序的自動(dòng)加工。DNC群控技術(shù)是
FMS柔性制造技術(shù)的基礎(chǔ)，現(xiàn)代數(shù)控機(jī)床上的DNC接口就是機(jī)床數(shù)控裝置與通用計(jì)算機(jī)之間進(jìn)行數(shù)據(jù)傳送及通訊控制用的，也是數(shù)控機(jī)床之間實(shí)現(xiàn)通訊用的接口。隨著DNC數(shù)控技術(shù)的發(fā)展，數(shù)控機(jī)床已成為無(wú)人控制工廠的基本組成單元。
20世紀(jì)90年代，出現(xiàn)了包括市場(chǎng)預(yù)測(cè)、生產(chǎn)決策、產(chǎn)品設(shè)計(jì)與制造和銷售等全過程均由計(jì)算機(jī)集成管理和控制的計(jì)算機(jī)集成制造系統(tǒng)CIMS。其中，數(shù)控是其基本控制單元。
20世紀(jì)90年代，基于PC-NC的智能數(shù)控系統(tǒng)開始得到發(fā)展，它打破了原數(shù)控廠家各自為政的封閉式專用系統(tǒng)結(jié)構(gòu)模式，提供開放式基礎(chǔ)，使升級(jí)換代變得非常容易。充分利用現(xiàn)有PC機(jī)的軟硬件資源，使遠(yuǎn)程控制、遠(yuǎn)程檢測(cè)診斷能夠得以實(shí)現(xiàn)。
我國(guó)雖然早在1958年就開始研制數(shù)控機(jī)床，但由于歷史原因，一直沒有取得實(shí)質(zhì)性成果。20世紀(jì)70年代初期，曾掀起研制數(shù)控機(jī)床的熱潮，但當(dāng)時(shí)是采用分立元件，性能不穩(wěn)定，可靠性差。1980年北京機(jī)床研究所引進(jìn)日本FANUC5、7、3、6數(shù)控系統(tǒng)，上海機(jī)床研究所引進(jìn)美國(guó)GE公司的MTC－1數(shù)控系統(tǒng)，遼寧精密儀器廠引進(jìn)美國(guó)Bendix公司的Dynapth LTD10數(shù)控系統(tǒng)。在引進(jìn)、消化、吸收國(guó)外先進(jìn)技術(shù)的基礎(chǔ)上，北京機(jī)床研究所又開發(fā)出BS03經(jīng)濟(jì)型數(shù)控和BS04全功能數(shù)控系統(tǒng)，航天部706所研制出MNC864數(shù)控系統(tǒng)?！鞍宋濉逼陂g國(guó)家又組織近百個(gè)單位進(jìn)行以發(fā)展自主版權(quán)為目標(biāo)的“數(shù)控技術(shù)攻關(guān)”，從而為數(shù)控技術(shù)產(chǎn)業(yè)化建立了基礎(chǔ)。20世紀(jì)90年代末，華中數(shù)控自主開發(fā)出基于PC-NC的HNC數(shù)控系統(tǒng)，達(dá)到了國(guó)際先進(jìn)水平，加大了我國(guó)數(shù)控機(jī)床在國(guó)際上的競(jìng)爭(zhēng)力度。
據(jù)1997年不完全統(tǒng)計(jì)，全國(guó)共擁有數(shù)控機(jī)床12萬(wàn)臺(tái)。目前，我國(guó)數(shù)控機(jī)床生產(chǎn)企業(yè)有100多家，年產(chǎn)量增加到1萬(wàn)多臺(tái)，品種滿足率達(dá)80%，并在有些企業(yè)實(shí)施了FMS和CIMS工程，數(shù)控機(jī)床及其加工技術(shù)進(jìn)入了實(shí)用階段。
2．?dāng)?shù)控加工技術(shù)的發(fā)展方向
現(xiàn)代數(shù)控加工正在向高速化、高精度化、高柔性化、高一體化、網(wǎng)絡(luò)化和智能化等方向發(fā)展。
1) 高速切削
受高生產(chǎn)率的驅(qū)使，高速化已是現(xiàn)代機(jī)床技術(shù)發(fā)展的重要方向之一。高速切削可通過高速運(yùn)算技術(shù)、快速插補(bǔ)運(yùn)算技術(shù)、超高速通信技術(shù)和高速主軸等技術(shù)來實(shí)現(xiàn)。
高主軸轉(zhuǎn)速可減少切削力，減小切削深度，有利于克服機(jī)床振動(dòng)，傳入零件中的熱量大大減低，排屑加快，熱變形減小，加工精度和表面質(zhì)量得到顯著改善。因此，經(jīng)高速加工的工件一般不需要精加工。
2) 高精度控制
高精度化一直是數(shù)控機(jī)床技術(shù)發(fā)展追求的目標(biāo)。它包括機(jī)床制造的幾何精度和機(jī)床使用的加工精度控制兩方面。
提高機(jī)床的加工精度，一般是通過減少數(shù)控系統(tǒng)誤差，提高數(shù)控機(jī)床基礎(chǔ)大件結(jié)構(gòu)特性和熱穩(wěn)定性，采用補(bǔ)償技術(shù)和輔助措施來達(dá)到的。目前精整加工精度已提高到0.1 μm，并進(jìn)入了亞微米級(jí)，不久超精度加工將進(jìn)入納米時(shí)代。(加工精度達(dá)0.01 μm)
3) 高柔性化
柔性是指機(jī)床適應(yīng)加工對(duì)象變化的能力。目前，在進(jìn)一步提高單機(jī)柔性自動(dòng)化加工的同時(shí)，正努力向單元柔性和系統(tǒng)柔性化發(fā)展。
數(shù)控系統(tǒng)在21世紀(jì)將具有最大限度的柔性，能實(shí)現(xiàn)多種用途。具體是指具有開放性體系結(jié)構(gòu)，通過重構(gòu)和編輯，視需要系統(tǒng)的組成可大可??；功能可專用也可通用，功能價(jià)格比可調(diào)；可以集成用戶的技術(shù)經(jīng)驗(yàn)，形成專家系統(tǒng)。
4) 高一體化
CNC系統(tǒng)與加工過程作為一個(gè)整體，實(shí)現(xiàn)機(jī)電光聲綜合控制，測(cè)量造型、加工一體化，加工、實(shí)時(shí)檢測(cè)與修正一體化，機(jī)床主機(jī)設(shè)計(jì)與數(shù)控系統(tǒng)設(shè)計(jì)一體化。
5) 網(wǎng)絡(luò)化
實(shí)現(xiàn)多種通訊協(xié)議，既滿足單機(jī)需要，又能滿足FMS(柔性制造系統(tǒng))、CIMS(計(jì)算機(jī)集成制造系統(tǒng))對(duì)基層設(shè)備的要求。配置網(wǎng)絡(luò)接口，通過Internet可實(shí)現(xiàn)遠(yuǎn)程監(jiān)視和控制加工，進(jìn)行遠(yuǎn)程檢測(cè)和診斷，使維修變得簡(jiǎn)單。建立分布式網(wǎng)絡(luò)化制造系統(tǒng)，可便于形成“全球制造”。
6) 智能化
21世紀(jì)的CNC系統(tǒng)將是一個(gè)高度智能化的系統(tǒng)。具體是指系統(tǒng)應(yīng)在局部或全部實(shí)現(xiàn)加工過程的自適應(yīng)、自診斷和自調(diào)整；多媒體人機(jī)接口使用戶操作簡(jiǎn)單，智能編程使編程更加直觀，可使用自然語(yǔ)言編程；加工數(shù)據(jù)的自生成及智能數(shù)據(jù)庫(kù)；智能監(jiān)控；采用專家系統(tǒng)以降低對(duì)操作者的要求等。
三、研究?jī)?nèi)容及實(shí)驗(yàn)方案：
本設(shè)計(jì)的研究重點(diǎn)是：
1根據(jù)零件實(shí)物或模型在CAD/CAM軟件中進(jìn)行數(shù)字化三維設(shè)計(jì)。
2編制零件的數(shù)控加工工藝。
3.生成零件的NC加工程序，進(jìn)行仿真加工。
4.研究零件的加工誤差檢測(cè)方法。
實(shí)驗(yàn)方案：
1.生產(chǎn)類型的確定
2.選擇毛坯、確定毛坯尺寸、確定毛坯圖
3.工藝路線擬定
4選擇加工設(shè)備及刀具、夾具、量具
5.確定切削用量及基本時(shí)間
四、目標(biāo)、主要特設(shè)及工作進(jìn)度
1 搜集資料寫開題報(bào)告，英文翻譯。 第1周～第2周
2 零件的三維建模。 第3周～第5周
3 加工工藝設(shè)計(jì)，加工程序編制 第6周～第8周
4.加工誤差檢測(cè)方法研究。 第9周～第14周5.撰寫畢業(yè)論文。 第15周～第16周
6.答辯準(zhǔn)備及畢業(yè)答辯 第17周
五、參考文獻(xiàn)
[1] 張冶，洪雪. Unigraphics NX三維工程設(shè)計(jì)與渲染教程.北京：清華大學(xué)出版社，2004.
[2] 曾向陽(yáng)，謝國(guó)明. UG NX基礎(chǔ)及應(yīng)用教程（建模、裝配、制圖）. 北京：電子工業(yè)出版社， 2003.
[3] 王紅兵.UG NX數(shù)控編程實(shí)用教程.北京：清華大學(xué)出版社，2004.
[4] 宋曉華等.基于UG參數(shù)化的產(chǎn)品優(yōu)化設(shè)計(jì)，CAD/CAM與制造業(yè)信息化，2003.4
[5] L.Qiang. A Distributive and Collaborative Concurrent Product Design System Through the. WWW/Internet. Advanced Manufacturing Technology(2001)17.
轉(zhuǎn)向臂零件數(shù)控加工工藝、加工仿真
摘要：本文介紹了轉(zhuǎn)向臂零件加工工藝的基本類型及工藝規(guī)程，并重點(diǎn)對(duì)工藝過程和數(shù)控仿真加工過程進(jìn)行了分析探討。本文主要利用三維軟件來設(shè)計(jì)仿真加工的全部過程。本文設(shè)計(jì)的轉(zhuǎn)向臂，在工農(nóng)業(yè)中的應(yīng)用非常廣泛。通過分析其在錘上模鍛的變形過程，應(yīng)用金屬塑性變形基本原理，制定了轉(zhuǎn)向臂的成形工藝。在設(shè)計(jì)過程中，根據(jù)轉(zhuǎn)向臂零件的各種參數(shù)，分析了其由坯料變?yōu)槌尚五懠淖冃芜^程，制定出了較為合理的工藝流程；由轉(zhuǎn)向臂鍛件的制坯過程，設(shè)計(jì)出了較為經(jīng)濟(jì)，使用方便，較為合理的加工過程。
關(guān)鍵詞：工藝設(shè)計(jì)? 模具設(shè)計(jì)
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Steering arms parts CNC processing technology, machining simulation
Abstract： This text introduced the basic type and the craft rules distance of the hot Forging craft, laying equal stress on to order to model principle and transform process to carry on an analytical study to the hammer mold Forging.This text design of change direction arm, very extensive in the application in the work agriculture.Pass analytical it the mold Forging transforms process on the hammer, applying the metals to transform basic principle, drawing up to change direction arm of take shape a craft, and complete to change direction arm of the Forging mold design.During the period of design, according to change direction various parameter of the arm spare parts, analyze it is anticipate by the metals to change in to take shape the Forging piece to transform process, draw up more reasonable craft process;From change direction the arm Forging piece system process, design more economic, use convenience, more reasonable molding tool.
Keyword: Craft design???? The molding tool design
Signature of supervisor:
Step Motor& Servo Motor Systems and Controls
Motion Architect? Software Does the Work for You... Configure ,Diagnose, Debug Compumotor’s Motion Architect is a Microsoft? Windows?-based software development tool for 6000Series products that allows you to automatically generate commented setup code, edit and execute motion control programs, and create a custom operator test panel. The heart of Motion Architect is the shell, which provides an integrated environment to access the following modules.
? System Configurator—This module prompts you to fill in all pertinent set-up information to initiate motion. Configurable to the specific 6000 Series product that is selected, the information is then used to generate actual 6000-language code that is the beginning of your program.
? Program Editor—This module allows you to edit code. It also has the commands available through “Help” menus. A user’s guide is provided on disk.
? Terminal Emulator—This module allows you to interact directly with the 6000 product. “Help” is again available with all commands and their definitions available for reference.
? Test Panel—You can simulate your programs, debug programs, and check for program flow using this module.
Motion Architect? has been designed for use with all 6000 Series products—for both servo and stepper technologies. The versatility of Windows and the 6000 Series language allow you to solve applications ranging from the very simple to the complex.
Motion Architect comes standard with each of the 6000 Series products and is a tool that makes using these controllers even more simple—shortening the project development time considerably. A value-added feature of Motion Architect, when used with the 6000 Servo Controllers, is its tuning aide. This additional module allows you to graphically display a variety of move parameters and see how these parameters change based on tuning values.
Using Motion Architect, you can open multiple windows at once. For example, both the Program Editor and Terminal Emulator windows can be opened to run the program, get information, and then make changes to the program.
On-line help is available throughout Motion Architect, including interactive access to the contents of the Compumotor 6000 Series Software Reference Guide.
SOLVING APPLICATIONS FROM SIMPLE TO COMPLEX
Servo Control is Yours with Servo Tuner Software
Compumotor combines the 6000 Series servo controllers with Servo Tuner software. The Servo Tuner is an add-on module that expands and enhances the capabilities of Motion Architect?.
Motion Architect and the Servo Tuner combine to provide graphical feedback of real-time motion information and provide an easy environment for setting tuning gains and related systemparameters as well as providing file operations to save and recall tuning sessions.
Draw Your Own Motion Control Solutions with Motion Toolbox Software
Motion Toolbox? is an extensive library of LabVIEW? virtual instruments (VIs) for icon-based programming of Compumotor’s 6000 Series motion controllers.
When using Motion Toolbox with LabVIEW, programming of the 6000 Series controller is accomplished by linking graphic icons, or VIs, together to form a block diagram.
Motion Toolbox’s has a library of more than 150 command,status, and example VIs. All command and status VIs include LabVIEW source diagrams so you can modify them, if necessary, to suit your particular needs. Motion Toolbox als user manual to help you gut up and running quickly.
comprehensiveM Software for Computer-Aided Motion Applications
CompuCAM is a Windows-based programming package that imports geometry from CAD programs, plotter files, or NC programs and generates 6000 code compatible with Compumotor’s 6000 Series motion controllers. Available for purchase from Compumotor, CompuCAM is an add-on module which is invoked as a utility from the menu bar of Motion Architect.
From CompuCAM, run your CAD software package. Once a drawing is created, save it as either a DXF file, HP-GL plot file or G-code NC program. This geometry is then imported into CompuCAM where the 6000 code is generated. After generating the program, you may use Motion Architect functions such as editing or downloading the code for execution.
Motion Builder Software for Easy Programming of the 6000 Series
Motion Builder revolutionizes motion control programming. This innovative software allows programmers to program in a way they are familiar with—a flowchart-style method. Motion Builder decreases the learning curve and makes motion control programming easy.
Motion Builder is a Microsoft Windows-based graphical development environment which allows expert and novice programmers to easily program the 6000 Series products without learning a new programming language. Simply drag and drop visual icons that represent the motion functions you want to perform.
Motion Builder is a complete application development environment. In addition to visually programming the 6000 Series products, users may configure, debug, download, and execute the motion program.
SERVO VERSUS STEPPER... WHAT YOU NEED TO KNOW
Motor Types and Their Applications
The following section will give you some idea of the applications that are particularly appropriate for each motor type, together with certain applications that are best avoided. It should be stressed that there is a wide range of applications which can be equally well met by more than one motor type, and the choice will tend to be dictated by customer preference, previous experience or compatibility with existing equipment.
A helpful tool for selecting the proper motor for your application is Compumotor’s Motor Sizing and Selection software package. Using this software, users can easily identify the appropriate motor size and type.
High torque, low speed
continuous duty applications are appropriate to the step motor. At low speeds it is very efficient in terms of torque output relative to both size and input power. Microstepping can be used to improve smoothness in lowspeed applications such as a metering pump drive for very accurate flow control.
High torque, high speed
continuous duty applications suit the servo motor, and in fact a step motor should be avoided in such applications because the high-speed losses can cause excessive motor heating.
Short, rapid, repetitive moves
are the natural domain of the stepper due to its high torque at low speeds, good torque-to-inertia ratio and lack of commutation problems. The brushes of the DC motor can limit its potential for frequent starts, stops and direction changes.
Low speed, high smoothness applications
are appropriate for microstepping or direct drive servos.
Applications in hazardous environments
or in a vacuum may not be able to use a brushed motor. Either a stepper or a brushless motor is called for, depending on the demands of the load. Bear in mind that heat dissipation may be a problem in a vacuum when the loads are excessive.
SELECTING THE MOTOR THAT SUITS YOUR APPLICATION
Introduction
Motion control, in its widest sense, could relate to anything from a welding robot to the hydraulic system in a mobile crane. In the field of Electronic Motion Control, we are primarily concerned with systems falling within a limited power range, typically up to about 10HP (7KW), and requiring precision in one or more aspects. This may involve accurate control of distance or speed, very often both, and sometimes other parameters such as torque or acceleration rate. In the case of the two examples given, the welding robot requires precise control of both speed and distance; the crane hydraulic system uses the driver as the feedback system so its accuracy varies with the skill of the operator. This wouldn’t be considered a motion control system in the strict sense of the term.Our standard motion control system consists of three basic elements:
Fig. 1 Elements of motion control system
The motor. This may be a stepper motor (either rotary or linear), a DC brush motor or a brushless servo motor. The motor needs to be fitted with some kind of feedback device unless it is a stepper motor.
Fig. 2 shows a system complete with feedback to control motor speed. Such a system is known as a closed-loop velocity servo system.
Fig. 2 Typical closed loop (velocity) servo system
The drive. This is an electronic power amplifier thatdelivers the power to operate the motor in response to low-level control signals. In general, the drive will be specifically designed to operate with a particular motor type – you can’t use a stepper drive to operate a DC brush motor, for instance.
Application Areas of Motor Types
Stepper Motors
Stepper Motor Benefits
Stepper motors have the following benefits:
? Low cost
? Ruggedness
? Simplicity in construction
? High reliability
? No maintenance
? Wide acceptance
? No tweaking to stabilize
? No feedback components are needed
? They work in just about any environment
? Inherently more failsafe than servo motors.
There is virtually no conceivable failure within the stepper drive module that could cause the motor to run away. Stepper motors are simple to drive and control in an open-loop configuration. They only require four leads. They provide excellent torque at low speeds, up to 5 times the continuous torque of a brush motor of the same frame size or double the torque of the equivalent brushless motor. This often eliminates the need for a gearbox. A stepper-driven-system is inherently stiff, with known limits to the dynamic position error.
Stepper Motor Disadvantages
Stepper motors have the following disadvantages:
? Resonance effects and relatively long settling
times
? Rough performance at low speed unless a
microstep drive is used
? Liability to undetected position loss as a result of
operating open-loop
? They consume current regardless of load
conditions and therefore tend to run hot
? Losses at speed are relatively high and can cause
excessive heating, and they are frequently noisy
(especially at high speeds).
? They can exhibit lag-lead oscillation, which is
difficult to damp. There is a limit to their available
size, and positioning accuracy relies on the
mechanics (e.g., ballscrew accuracy). Many of
these drawbacks can be overcome by the use of
a closed-loop control scheme.
Note: The Compumotor Zeta Series minimizes or
reduces many of these different stepper motor disadvantages.
There are three main stepper motor types:
? Permanent Magnet (P.M.) Motors
? Variable Reluctance (V.R.) Motors
? Hybrid Motors
When the motor is driven in its full-step mode, energizing two windings or “phases” at a time (see Fig. 1.8), the torque available on each step will be the same (subject to very small variations in the motor and drive characteristics). In the half-step mode, we are alternately energizing two phases and then only one as shown in Fig. 1.9. Assuming the drive delivers the same winding current in each case, this will cause greater torque to be produced when there are two windings energized. In other words, alternate steps will be strong and weak. This does not represent a major deterrent to motor performance—the available torque is obviously limited by the weaker step, but there will be a significant improvement in low-speed smoothness over the full-step mode.
Clearly, we would like to produce approximately equal torque on every step, and this torque should be at the level of the stronger step. We can achieve this by using a higher current level when there is only one winding energized. This does not over dissipate the motor because the manufacturer’s current rating assumes two phases to be energized the current rating is based on the allowable case temperature). With only one phase energized, the same total power will be dissipated if the current is increased by 40%. Using this higher current in the one-phase-on state produces approximately equal torque on alternate steps (see Fig. 1.10).
Fig. 1.8 Full step current, 2-phase on
Fig. 1.9 Half step current
Fig. 1.10 Half step current, profiled
We have seen that energizing both phases with equal currents produces an intermediate step position half-way between the one-phase-on positions. If the two phase currents are unequal, the rotor position will be shifted towards the stronger pole. This effect is utilized in the microstepping drive, which subdivides the basic motor step by proportioning the current in the two windings. In this way, the step size is reduced and the low-speed smoothness is dramatically improved. High-resolution microstep drives divide the full motor step into as many as 500 microsteps, giving 100,000 steps per revolution. In this situation, the current pattern in the windings closely resembles two sine waves with a 90° phase shift between them (see Fig. 1.11). The motor is now being driven very much as though it is a conventional AC synchronous motor. In fact, the stepper motor can be driven in this way from a 60 Hz-US (50Hz-Europe) sine wave source by including a capacitor in series with one phase. It will rotate at 72 rpm.
Fig. 1.11 Phase currents in microstep mode
Standard 200-Step Hybrid Motor
The standard stepper motor operates in the same way as our simple model, but has a greater number of teeth on the rotor and stator, giving a smaller basic step size. The rotor is in two sections as before, but has 50 teeth on each section. The half-tooth displacement between the two sections is retained. The stator has 8 poles each with 5 teeth, making a total of 40 teeth (see Fig. 1.12).
Fig. 1.12 200-step hybrid motor
If we imagine that a tooth is placed in each of the gaps between the stator poles, there would be a total of 48 teeth, two less than the number of rotor teeth. So if rotor and stator teeth are aligned at 12 o’clock, they will also be aligned at 6 o’clock. At 3 o’clock and 9 o’clock the teeth will be misaligned. However, due to the displacement between the sets of rotor teeth, alignment will occur at 3 o’clock and 9 o’clock at the other end of the rotor.
The windings are arranged in sets of four, and wound such that diametrically-opposite poles are the same. So referring to Fig. 1.12, the north poles at 12 and 6 o’clock attract the south-pole teeth at the front of the rotor; the south poles at 3 and 9 o’clock attract the north-pole teeth at the back. By switching current to the second set of coils, the stator field pattern rotates through 45°. However, to align with this new field, the rotor only has to turn through 1.8°. This is equivalent to one quarter of a tooth pitch on the rotor, giving 200 full steps per revolution.
Note that there are as many detent positions as there are full steps per rev, normally 200. The detent positions correspond with rotor teeth being fully aligned with stator teeth. When power is applied to a stepper drive, it is usual for it to energize in the “zero phase” state in which there is current in both sets of windings. The resulting rotor position does not correspond with a natural detent position, so an unloaded motor will always move by at least one half step at power-on. Of course, if the system was turned off other than in the zero phase state, or the motor is moved in the meantime, a greater movement may be seen at power-up.
Another point to remember is that for a given current pattern in the windings, there are as many stable positions as there are rotor teeth (50 for a 200-step motor). If a motor is de-synchronized, the resulting positional error will always be a whole number of rotor teeth or a multiple of 7.2°. A motor cannot “miss” individual steps – position errors of one or two steps must be due to noise, spurious step pulses or a controller fault.
Fig. 2.19 Digital servo drive
Digital Servo Drive Operation
Fig. 2.19 shows the components of a digital drive for a servo motor. All the main control functions are carried out by the microprocessor, which drives a D-to-A convertor to produce an analog torque demand signal. From this point on, the drive is very much like an analog servo amplifier.
Feedback information is derived from an encoder attached to the motor shaft. The encoder generates a pulse stream from which the processor can determine the distance travelled, and by calculating the pulse frequency it is possible to measure velocity.
The digital drive performs the same operations as its analog counterpart, but does so by solving a series of equations. The microprocessor is programmed with a mathematical model (or “algorithm”) of the equivalent analog system. This model predicts the behavior of the system. In response to a given input demand and output position. It also takes into account additional information like the output velocity, the rate of change of the input and the various tuning settings.
To solve all the equations takes a finite amount of time, even with a fast processor – this time is typically between 100ms and 2ms. During this time, the torque demand must remain constant at its previously-calculated value and there will be no response to a change at the input or output. This “update time” therefore becomes a critical factor in the performance of a digital servo and in a high-performance system it must be kept to a minimum.
The tuning of a digital servo is performed either by pushbuttons or by sending numerical data from a computer or terminal. No potentiometer adjustments are involved. The tuning data is used to set various coefficients in the servo algorithm and hence determines the behavior of the system. Even if the tuning is carried out using pushbuttons, the final values can be uploaded to a terminal to allow easy repetition.
In some applications, the load inertia varies between wide limits – think of an arm robot that starts off unloaded and later carries a heavy load at full extension. The change in inertia may well be a factor of 20 or more, and such a change requires that the drive is re-tuned to maintain stable performance. This is simply achieved by sending the new tuning values at the appropriate point in the operating cycle.
步進(jìn)電機(jī)和伺服電機(jī)的系統(tǒng)控制
運(yùn)動(dòng)的控制者---軟件：只要有了軟件，它可以幫助我們配置改裝、診斷故障、調(diào)試程序等。數(shù)控電動(dòng)機(jī)的設(shè)計(jì)者會(huì)是一個(gè)微軟窗口 ——基于構(gòu)件的軟件開發(fā)工具，可以為6000系列產(chǎn)品設(shè)置代碼，同時(shí)可以控制設(shè)計(jì)者與執(zhí)行者的運(yùn)動(dòng)節(jié)目，并創(chuàng)造一個(gè)定制運(yùn)營(yíng)商的測(cè)試小組。運(yùn)動(dòng)建筑師的心臟是一個(gè)空殼，它可以為進(jìn)入以下模塊提供一個(gè)綜合環(huán)境。
1. 系統(tǒng)配置——這個(gè)模塊提示您填寫所有相關(guān)初成立信息啟動(dòng)議案。配置向具體6000系列產(chǎn)品的選擇，然后這些信息將用于產(chǎn)生實(shí)際的6000 - 語(yǔ)言代碼，這是你的開始計(jì)劃。
2. 程序編輯器 ——允許你編輯代碼。它也有可行的“幫助”命令菜單。A用戶指南提供了相關(guān)的磁盤指南。
3. 終端模擬器——本模塊，可讓您直接與6000系列產(chǎn)品互動(dòng)。他所提供的“幫助”是再次參考所有命令和定義。
4. 測(cè)試小組——你可以使用本模塊，模擬程序，調(diào)試程序，并跟蹤檢測(cè)程序。
運(yùn)動(dòng)建筑師已經(jīng)將所有的6000系列產(chǎn)品都運(yùn)用在了步進(jìn)電機(jī)和伺服電機(jī)的技術(shù)上。由于豐富的對(duì)話窗口和6000系列語(yǔ)言，使得你能夠從簡(jiǎn)單到復(fù)雜的解決問題。
運(yùn)動(dòng)建筑師的6000系列產(chǎn)品的標(biāo)準(zhǔn)配置工具，能夠使得這些控制器更加簡(jiǎn)單，相當(dāng)大的縮短項(xiàng)目開發(fā)時(shí)間。它的另外一個(gè)增值特點(diǎn)是使用6000伺服控制器的調(diào)諧助手。基于調(diào)諧價(jià)值觀，這個(gè)額外的模塊可以以圖形化的方式為你展示各種參數(shù)。看看這些參數(shù)是如何讓變化的。用運(yùn)動(dòng)的建筑師，你可以一次性打開多個(gè)窗口。舉例來說，無(wú)論是程序編輯器和終端模擬器窗口，你都可以打開運(yùn)行程序， 得到信息，然后改變這一程序。運(yùn)動(dòng)建筑師可以利用在線幫助，在整個(gè)互動(dòng)接觸內(nèi)容中為數(shù)控電機(jī)6000系列軟件做參考指南。
從簡(jiǎn)單到復(fù)雜的解決應(yīng)用
伺服控制是你用伺服調(diào)諧器軟件控制。數(shù)控電機(jī)與6000系列伺服控制器相結(jié)合并應(yīng)用伺服調(diào)諧器軟件。伺服調(diào)諧器是一個(gè)新增功能模塊，它擴(kuò)展和提高運(yùn)動(dòng)建筑師的能力。議案建筑師與伺服調(diào)諧器結(jié)合起來，以提供圖形化的反饋方式，反饋實(shí)時(shí)運(yùn)動(dòng)信息并提供簡(jiǎn)便環(huán)境設(shè)置微調(diào)收益及相關(guān)制參數(shù)以及提供文件操作，以保存并記得微調(diào)會(huì)議。
請(qǐng)你用運(yùn)動(dòng)工具箱軟件解決自己的運(yùn)動(dòng)控制。運(yùn)動(dòng)工具箱實(shí)際上是一個(gè)為數(shù)控電機(jī)和6000系列運(yùn)動(dòng)控制器而設(shè)計(jì)的廣泛應(yīng)用的虛擬圖標(biāo)式編程儀器。
當(dāng)使用運(yùn)動(dòng)工具箱與虛擬編程儀時(shí)，編程6000系列控制器實(shí)質(zhì)上是完成連接圖形圖標(biāo)，或加上形成框圖使之可見。 運(yùn)動(dòng)工具箱中包含了1500多條命令，狀態(tài)欄，實(shí)例等。所有的命令、狀態(tài)欄、實(shí)例都包括可視的來源圖表，使您可以修改他們，如果有必要，可以滿足您的特殊的需要。運(yùn)動(dòng)工具箱同時(shí)還具有一個(gè)可視窗口，基于安裝程序和一個(gè)全面的用戶手冊(cè)，可以幫助您運(yùn)行得更好更快。
軟件電腦輔助運(yùn)動(dòng)應(yīng)用軟件compucam
compucam是基于微軟的編程包，它能從 CAD程序、示波器文檔、數(shù)控程序和產(chǎn)生6000系列數(shù)控電機(jī)密碼相兼容的運(yùn)動(dòng)控制器中輸入幾何圖形。購(gòu)買數(shù)控電機(jī)是可行的，因?yàn)閏ompucam是一個(gè)附加模塊，是運(yùn)動(dòng)建筑師的菜單欄，它是作為公用部分而被引用的。程序從compucam開始運(yùn)行CAD軟件包。一旦程序被起草創(chuàng)作，它就會(huì)被保存為DXF文件，或惠普-吉爾段文檔，或G代碼數(shù)控程序。這些幾何圖形然后輸入compucam中，產(chǎn)生6000系列代碼。在程序運(yùn)行之后，你可使用的運(yùn)動(dòng)建筑師功能塊，如編輯或下載代碼等執(zhí)行程序。
運(yùn)動(dòng)執(zhí)行者軟件可輕松編程6000系列
運(yùn)動(dòng)執(zhí)行者革命性控制運(yùn)動(dòng)編程。這一具有創(chuàng)新意義的軟件允許程序員以他們所熟悉的- 流程圖式的方法編程。 運(yùn)動(dòng)執(zhí)行者降低了學(xué)習(xí)曲線，并使運(yùn)動(dòng)控制編程變得相當(dāng)容易。運(yùn)動(dòng)執(zhí)行者是一套微軟軟件，基于圖形化窗口的發(fā)展，讓專家和新手程序員容易學(xué)習(xí)計(jì)劃6000系列產(chǎn)品新的編程語(yǔ)言。 簡(jiǎn)單地拖放代表議案職能的視覺圖標(biāo)，你可以隨時(shí)的進(jìn)行你所需要的操作。運(yùn)動(dòng)執(zhí)行者是一個(gè)完整的應(yīng)用開發(fā)環(huán)境的軟件。除了視覺編程6000 系列產(chǎn)品，用戶還可以配置，調(diào)試，下載， 策劃和執(zhí)行的議案計(jì)劃。
電機(jī)類型及其應(yīng)用
下一節(jié)將會(huì)給你介紹一些的適用特別場(chǎng)合的電機(jī)，而某些應(yīng)用是最好避免。應(yīng)當(dāng)強(qiáng)調(diào)說，在一個(gè)廣范的應(yīng)用范圍，電機(jī)是可同樣滿足一個(gè)以上的汽車類型， 而選擇往往是由客戶偏好、以往經(jīng)驗(yàn)或與現(xiàn)有的設(shè)備的兼容性決定的。一個(gè)非常有用的工具箱，可供你選擇適當(dāng)?shù)倪\(yùn)動(dòng)，為你選擇電機(jī)與選擇軟件包是compumotor軟件包。使用這個(gè)軟件，使用戶可以輕松找出適當(dāng)?shù)碾姍C(jī)大小和類型。
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