【正文】 遼寧石油化工大學(xué)繼續(xù)教育學(xué)院論文 33 參考文獻(xiàn) [1] 郭天祥 51單片機(jī) C語言教程，電子工業(yè)出版社， 2021年 3月； [2]張毅剛，彭喜源，譚曉鈞，曲春波 .MCS－ 51 單片機(jī)應(yīng)用設(shè)計(jì) [M].哈爾濱工業(yè)大學(xué)出版社 . [3]宋慶環(huán)，才衛(wèi)國，高志， 89C51單片機(jī)在直流電動機(jī)調(diào)速系統(tǒng)中的應(yīng)用 [M]。其中 P0 口接數(shù)碼管段選， P2口高四位接數(shù)碼管位選， 接電動機(jī)的 PWM調(diào)速端， 讀取光電測速電路送給單片機(jī)的脈沖 ，進(jìn)行電動機(jī)轉(zhuǎn)速的測量， P1 口接按鍵。 } } } } } 占空比調(diào)節(jié)部分 if(!Inc) pwm = pwm 0 ? pwm 1 : 0。按照任務(wù)的定義，每個(gè)功能模塊都能完成某一明確的任務(wù)，實(shí)現(xiàn)具體的某個(gè)功能，如測量、計(jì)算、顯示、鍵盤掃描、輸出控制等。 由上面的分析可以得到限流電阻 R 的值 1LEDLEDUUR IN??? 若我們想讓這個(gè) 4 位數(shù)碼管的每段工作時(shí)的電流為 為正常工作時(shí)的電壓取 。多數(shù)負(fù)載無論是電感性負(fù)載還是電容性負(fù)載都需要的調(diào)制頻率高于 10Hz，通常調(diào)制頻率為 1kHz 到 200kHz 之間。如遼寧石油化工大學(xué)繼續(xù)教育學(xué)院論文 XVIII 圖所示，電動機(jī)驅(qū)動電路 H橋式通常包括 4個(gè)三極管和一個(gè)電動機(jī)。電樞繞組端電壓不能隨意變化，因?yàn)殡娫醇半姍C(jī)繞組絕緣耐壓的限制，電樞繞組端電壓一般不能 超過額定電樞電壓，所以直流電機(jī)調(diào)壓調(diào)速是，電樞繞組的電壓大小只能在額定電樞電壓及其以下范圍內(nèi)調(diào)節(jié)。 STC 89C52RC 具有以下標(biāo)準(zhǔn)功能： 8k字節(jié) Flash， 256 字節(jié) RAM 32 位 I/O 口線 看門狗定時(shí)器， 2個(gè)數(shù)據(jù)指針，三個(gè) 16 位 定時(shí)器 /計(jì)數(shù)器 一個(gè) 6向量 2級中斷結(jié)構(gòu)，全雙工串行口 片內(nèi)晶振及 時(shí)鐘電路 另外， STC 89C52RC 可降至 0Hz 靜態(tài)邏輯操作，支持 2種 軟件 可選擇節(jié)電模式。雙極型可逆 PWM 變換器電樞平均電壓為 [3]： 2( 1 )o n o n o nd s s st T t tU U U UT T T?? ? ? ? 若定義占空比為 /dsUU?? 和電壓系數(shù) ? 的定義與不可逆變換器中相同，則在雙極式控制的可逆變換器中 ? =2? 1 與不可逆變換器中的不同。 綜合上述三種方案，本設(shè)計(jì)采用方案三作為整個(gè)系統(tǒng)的設(shè)計(jì)思路。 c r cn RU TC C C???? 內(nèi)遼寧石油化工大學(xué)繼續(xù)教育學(xué)院論文 VII 圖 11 直流電機(jī)的工作原理圖 電樞控制是在勵(lì)磁電壓不變的情況下，把控制電壓信號加到電機(jī)的電樞上，以控制電機(jī)的轉(zhuǎn)速。 微處理器控制直流電機(jī)發(fā)展現(xiàn)狀 微處理器誕生于上個(gè)世紀(jì)七十年代，隨著集成電路大規(guī)模及超大規(guī)模集成電路制造工藝的迅速發(fā)展，微 處理器的性價(jià)比越來越高。數(shù)字化直流調(diào)速裝置作為目前最新控制水平的傳動方式顯示了強(qiáng)大優(yōu)勢。 關(guān)鍵詞 ： STC89C52； PWM； 光耦隔離 ； 光電編碼盤 遼寧石油化工大學(xué)繼續(xù)教育學(xué)院論文 II Design of DC speed control system based on STC single chip microputer Abstract With the development of science and technology, automatic control system has been widely used and development in all walks of life, which the application of the automatic speed control system plays a particularly important role. DC motor as AC motor as the structure is simple, cheap, easy to manufacture, easy to maintain, but it has a good start, braking performance, it is appropriate in a wide range of smooth speed, DC speed control system is still automatically speed control system in the main form. Motor control from simple to plex, and mature into the mainstream. With the development of power electronics technology, the switching speed is faster, easier to control the fullcontrolled power devices MOSFET and IGBT bee mainstream, pulse width modulation technology showed a greater superiority: the main circuit line is simple, need to use the power ponents 。使直流調(diào)速系統(tǒng)的性能指標(biāo)大幅提高，應(yīng)用范圍不斷擴(kuò)大。在先進(jìn)的數(shù)控機(jī)床等數(shù)控位置伺服系統(tǒng)，已經(jīng)采用了如 DSP 等的高速微處理器，其執(zhí)行速度可達(dá)數(shù)百萬兆以上每秒，且具有適合的矩陣運(yùn)算 [2]。這些芯片除了有 PWM信號發(fā)生功能外，還有“死區(qū)”調(diào)節(jié)功能、過流過壓保護(hù)功能等。在一個(gè)開關(guān)周期內(nèi)， 0 ontt?? 時(shí) b1U 和 b4U 為正，晶體管 1VT 和4VT 飽和導(dǎo)通；而 b2U 和 b3U 為負(fù)值， 2VT 和 3VT 截止。根據(jù) 6N137 的數(shù)據(jù)手冊要求 8 腳之間必修接 104 旁路電容使輸出均勻化，降低負(fù)載需求。另外，在復(fù)位期間，端口引腳處于隨機(jī)狀態(tài)，復(fù)位后，系統(tǒng)將端口置為全“ l”態(tài)。同時(shí) H型 PWM電路工作在晶體管的飽和狀態(tài)與截止?fàn)顟B(tài)，具有非常高的效率。通過單片機(jī)等微處理器定的時(shí)器以及計(jì)數(shù)器的使用，方波的占空比 D 被調(diào)制用來對一個(gè)具體模擬信號的電平進(jìn)行編碼， PWM 信號仍然是數(shù)字的，在給定的任何時(shí)刻，它都只表現(xiàn)出開和關(guān)兩種狀態(tài)，驅(qū)動電路要么完全導(dǎo)通，要么完全關(guān)閉。 所有數(shù)碼管的段選全部連接在一起，如何能顯示不同的內(nèi)容呢？動態(tài)顯示的原理是多位數(shù)碼管，交替來進(jìn)行顯示，利用人的視覺暫留效果使人看到好像有多個(gè)數(shù)碼管同時(shí)顯示。然后，在給輸出端口置低電平 M— 個(gè)單位時(shí)間，即 20t /tM?— 。 遼寧石油化工大學(xué)繼續(xù)教育學(xué)院論文 XXVI num1=num2/100。這樣分開供電，避免了電動機(jī)對單片機(jī)等數(shù)字芯片及器件的干擾。 P2口有兩個(gè)功能 (1)擴(kuò)展外部存儲器時(shí)，當(dāng)作地址總線使用 (2)做一般 I/O 口使用，其內(nèi)部有上拉電阻； P3口有兩個(gè)功能 除了作為 I/O 使用外（其內(nèi)部有上拉電阻），還有一些 特殊功能，由特殊寄存器來設(shè)置，具體功能請參考我們后面的引腳說明。t e naturally or easily to them, and so they are trying to follow a predetermined set of rules. Some individuals with autism have normal intelligence, and many have special talents in areas such as music or memory. However, individuals with autism may have other mental or emotional problems that coexist with their autism. Some of these other disorders may include impulse control disorders, obsessivepulsive disorder , mood and anxiety disorders, and mental retardation . PSYCHOLOGICAL AND FAMILY FACTORS. Although Henry Maudsley, in the late 1800s, was the first psychiatrist to focus on very young children with mental disorders, it was the psychiatrist Leo Kanner who coined the phrase early infantile autism in 1943. Kanner believed that the parents of children with autistic behaviors were emotionally cold and intellectually distant. He coined the term refrigerator parents to describe them. His belief that parental personality and behavior played a powerful role in the development of autistic behaviors left a devastating legacy of guilt and selfblame among parents of autistic children that continues to this day. Recent studies are unequivocal, however, in demonstrating that parents of autistic children are no different from parents of healthy children in their personalities or parenting 遼寧石油化工大學(xué)繼續(xù)教育學(xué)院論文 39 behaviors. In fact, many families with an autistic child also have one or more perfectly healthy children. Because autistic children can be extremely sensitive to change, any change within the family situation can be potentially traumatic to the autistic child. A move, divorce, birth of a sibling or other stressors that occur in the lives of most families may evoke a more extreme reaction from an autistic child. While there is no single neurological abnormality found in children with autistic disorders, some research using noninvasive brain imaging techniques such as magic resonance imaging (MRI) suggests that certain areas of the brain may be involved. Several of the brain areas being researched are known to control emotion and the expression of emotion. These areas include the temporal lobe (large lobe of each side of the brain that contains a sensory area associated with hearing), the limbic system, the cerebellum, the frontal lobe, the amygdala, and the brain stem, which regulates homeostasis (body temperature and heart rate). Recent research has focused particularly on the temporal lobe because of the finding that previously healthy people who sustain temporal lobe damage may develop autisticlike symptoms. In animal