【正文】 終點(diǎn)平衡位置的下一個(gè)平衡位置，并在該位置停下。 35BY48S03 型步進(jìn)電機(jī)主要參數(shù)如下： 步距角 ： 176。 畢業(yè)設(shè)計(jì)（論文） 5 最大空載起動(dòng)頻率 ： 電機(jī)在某種驅(qū)動(dòng)形式、電壓及額定電流下，在不加負(fù)載的情況下，能夠直接起動(dòng)的最大頻率。雙極性步進(jìn)電機(jī)驅(qū)動(dòng)電路的晶體管數(shù)目是單極性驅(qū)動(dòng)電路的兩倍，其中四顆下端晶體管通常是由微控制器直接驅(qū)動(dòng)，上端晶體管則需要成本較高的上端驅(qū)動(dòng)電路。您可以通過(guò)控制脈沖個(gè)數(shù)來(lái)控制角位移量，從而達(dá)到準(zhǔn)確定位的目的；同時(shí)您可以通過(guò)控制脈沖頻率來(lái)控制電機(jī)轉(zhuǎn)動(dòng)的速度和加速度，從而達(dá)到調(diào)速的目的。因此，用計(jì)算機(jī)控制步進(jìn)電機(jī)已經(jīng)成為了一 種必然的趨勢(shì)，也符合數(shù)字化的時(shí)代趨勢(shì)。 CPU 芯片 ........................................... 9 167。 大量實(shí)踐證明，對(duì)于不同功率的步進(jìn)電機(jī)，簡(jiǎn)單統(tǒng)一的直線升頻技術(shù)，不能夠讓電機(jī)工作在最佳效率狀態(tài)下，本設(shè)計(jì)采用程序控制的指數(shù)曲線升降頻，能夠方便地與不同電機(jī)的機(jī)械特性很好地適配，減少電機(jī)升降頻所用的時(shí)間，提高生產(chǎn)效率。 本次設(shè)計(jì)使用 AT89C51 單片機(jī)產(chǎn)生脈沖信號(hào)來(lái)控制 35BY48S03 型 步進(jìn)電機(jī)的運(yùn)行。 控制鍵電路 ....................................... 11 167。經(jīng)過(guò)不斷改良，今日步進(jìn)電機(jī)已廣泛運(yùn)用在需要高定位精度、高分解能、高響應(yīng)性、信賴性等靈活控制性高的機(jī)械系統(tǒng)中。 步進(jìn)電機(jī)實(shí)際上是一個(gè)數(shù)字 /角度轉(zhuǎn)換器，也是一個(gè)串行的數(shù) /模轉(zhuǎn)換器 .步進(jìn)電機(jī)的結(jié)構(gòu)與步進(jìn)電機(jī)所含的相數(shù)有關(guān) . 步進(jìn)電機(jī)是一種進(jìn)行精確步進(jìn)運(yùn)動(dòng)的機(jī)電執(zhí)行元件，它廣泛地用于工業(yè)機(jī)械的數(shù)字控制。雙極性驅(qū)動(dòng)電路的晶體管只需承受電機(jī)電壓，所以它不像單極性驅(qū)動(dòng)電路一樣需要箝位電路。 167。 相數(shù) ： 4 電壓 ： 12 V 電流 ： 電阻 ： 47Ω 最大靜轉(zhuǎn)距 ： 180N 實(shí)驗(yàn)表明，圖 13 所示的指數(shù)曲線是步進(jìn)電機(jī)最合理的升頻曲線，最符合電機(jī)和負(fù)載的慣性規(guī)律。 由于將多功能 8 位CPU 和閃爍存儲(chǔ)器組合在單個(gè)芯片中， 所以 ATMEL 的 AT89C51 是一種高效微控制器， 因其 高性能、高速度、體積小、價(jià)格低廉、穩(wěn)定可靠而得到廣泛應(yīng) 畢業(yè)設(shè)計(jì)（論文） 10 用 ， 成為 在工業(yè)生產(chǎn)中必不可少的器件， 而且 在日常生活中發(fā)揮的作用也越來(lái)越大 ， 為很多嵌入式控制系統(tǒng)提供了一種靈活性高且價(jià)廉的方案。 EA/VPP:當(dāng) EA 保持低電平時(shí)， 選用 外部程序存儲(chǔ)（ 0000HFFFFH），當(dāng) EA端保持高 電平時(shí)， 用 內(nèi)部程序存儲(chǔ)器。 由于按鈕是機(jī)械觸點(diǎn)，當(dāng)機(jī)械觸點(diǎn)斷開(kāi)、閉合時(shí)，會(huì)有抖動(dòng) ， 這種抖動(dòng)對(duì)于人來(lái)說(shuō)是感覺(jué)不到的，但對(duì)計(jì)算機(jī)來(lái)說(shuō)，則是完全能感應(yīng)到的， 因?yàn)橛?jì)算機(jī)處理的速度是在微秒級(jí)，而機(jī)械抖動(dòng)的時(shí)間至 少是毫秒級(jí) ， 對(duì)計(jì)算機(jī)而言，這已是一個(gè) “ 漫長(zhǎng) ” 的時(shí)間了。 降頻流程圖 圖 32 降頻流程圖 本文以 35BY48S03 步進(jìn)電機(jī)為例，首先根據(jù)步進(jìn)電機(jī)的特性設(shè)計(jì)一個(gè)數(shù)據(jù)區(qū)，再編寫(xiě)程序?qū)Υ藬?shù)據(jù)的的數(shù)據(jù)進(jìn)行調(diào)試。 如圖 34 所示，我們?cè)O(shè)頻率最高升至 1000HZ，用時(shí)為 5S，依此確定縱坐標(biāo)每一小格所對(duì)應(yīng)的頻率，橫坐標(biāo)每一小格對(duì)應(yīng)的時(shí)間。 t=65536temp。 T1_delay(t)。 AP=0。 AN=0。j) MotRun(F)。而且隨著系統(tǒng)使用時(shí)間越來(lái)越長(zhǎng)，元器件會(huì)發(fā)生變值。 畢業(yè)設(shè)計(jì)（論文） 27 附 錄 1 硬件電路原理圖 畢業(yè)設(shè)計(jì)（論文） 28 附 錄 2 主流程圖 畢業(yè)設(shè)計(jì)（論文） 29 外 文 材 料 譯 文 Quick Start for Beginners to Drive a Stepper Motor Introduction This application note is for novices who want a general quickstart guide showing how to control a stepper motor. Because stepper motors can be used in a variety of ways and are driven by a variety of devices, there is a great deal of information available about how these motors work and how to use them. To reduce confusion, the focus of this application note is on stepper motors that can be driven by microcontrollers. This document includes basic information needed to get started quickly, and includes a practical example that is simple and easy to implement. What is a Stepper Motor? A stepper motor is an electrically powered motor that creates rotation from electrical current driven into the motor. Physically, stepper motors can be large but are often small enough to be driven by current on the order of milliampere. Current pulses are applied to the motor, and this generates discrete rotation of the motor shaft. This is unlike a DC motor that exhibits continuous rotation. Although it is possible to drive a stepper motor in a manner where it has near continuous rotation, doing so requires more finesse of the input waveform that drives the stepper motor. Figure 1 illustrates some basic differences in stepper and DC motor rotation. 畢業(yè)設(shè)計(jì)（論文） 30 Types of Stepper Motors There are a variety of stepper motors available, but most of them can be separated into two groups: ? Permanentmag (PM) stepper motor — This kind of motor creates rotation by using the forces between a permanent mag and an electromag created by electrical current. An interesting characteristic of this motor is that even when it is not powered, the motor exhibits some magic resistance to turning. ? Variablereluctance (VR) stepper motor — Unlike the PM stepper motor, the VR stepper motor does not have a permanentmag and creates rotation entirely with electromagic forces. This motor does not exhibit magic resistance to turning when the motor is not powered. What is Inside? 畢業(yè)設(shè)計(jì)（論文） 31 Generally, a stepper motor consists of a stator, a rotor with a shaft, and coil windings. The stator is a surrounding casing that remains stationary and is part of the motor housing, while the rotor is a central shaft within the motor that actually spins during use. The characteristics of these ponents and how they are arranged determines whether the stepper motor is a PM or VR stepper motor. Figure 2 and Figure 3 show an example of these internal ponents. Figure 2. Permanent Mag (PM) Stepper Motor Taking a closer look, the rotor in PM stepper motors is actually a permanentmag. In some cases, the permanent mag is in the shape of a disk surrounding the rotor shaft. One arrangement is a magic disk which consists of north and south magic poles interlaced together. The number of poles on the magic disk varies from motor to motor. Some simple PM stepper motors such as the one in Figure 2 only have two poles on the disk, while others may have many poles. The stator usually has two or more coil windings, with each winding around a soft metallic core. 畢業(yè)設(shè)計(jì)（論文） 32 When electrical current flows through the coil windings, a magic field is generated within the coil. The metallic core is placed within the coil windings to help channel the electromagic field perpendicular to the outer perimeter of the magic disk. What is Inside? Depending upon the polarity of the electromagic field generated in the coil (north pole, out of the coil, or south pole, into the coil) and the closest permanent magic field on the disk, an attraction or repulsion force will exist. This causes the rotor to spin in a direction that allows an opposite pole on the perimeter of the magic disk to align itself with the electromagic field generated by the coil. When the nearest opposite pole on the disk aligns itself with the electromagic field generated by the coil, the rotor will e to a stop and remain fixed in this alignment as long as the electromagic field from the coil is not changed. VR stepper motors work in