轉(zhuǎn)向臂零件數(shù)控加工工藝仿真
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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)控電動機(jī)的設(shè)計(jì)者會是一個(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)動節(jié)目，并創(chuàng)造一個(gè)定制運(yùn)營商的測試小組。運(yùn)動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。他所提供的“幫助”是再次參考所有命令和定義。
4. 測試小組——你可以使用本模塊，模擬程序，調(diào)試程序，并跟蹤檢測程序。
運(yùn)動建筑師已經(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。由于豐富的對話窗口和6000系列語言，使得你能夠從簡單到復(fù)雜的解決問題。
運(yùn)動建筑師的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?；谡{(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)動的建筑師，你可以一次性打開多個(gè)窗口。舉例來說，無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)動建筑師可以利用在線幫助，在整個(gè)互動接觸內(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)動信息并提供簡便環(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)會議。
請你用運(yùn)動工具箱軟件解決自己的運(yùn)動控制。運(yùn)動工具箱實(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，可以幫助您運(yùn)行得更好更快。
軟件電腦輔助運(yùn)動應(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)動控制器中輸入幾何圖形。購買數(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)動建筑師功能塊，如編輯或下載代碼等執(zhí)行程序。
運(yùn)動執(zhí)行者軟件可輕松編程6000系列
運(yùn)動執(zhí)行者革命性控制運(yùn)動編程。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)動執(zhí)行者降低了學(xué)習(xí)曲線，并使運(yùn)動控制編程變得相當(dāng)容易。運(yùn)動執(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)品新的編程語言。 簡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)將會給你介紹一些的適用特別場合的電機(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，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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