一、什么是隨動系統
隨動系統servo system，是(shi)(shi)一(yi)種(zhong)反(fan)饋控制(zhi)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。在這(zhe)(zhe)種(zhong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)，輸(shu)(shu)(shu)(shu)(shu)出(chu)量是(shi)(shi)機(ji)械位(wei)移(yi)、速(su)度(du)或者加(jia)速(su)度(du)。因此隨(sui)動(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)這(zhe)(zhe)一(yi)術語(yu)(yu)，與位(wei)置(zhi)或速(su)度(du)，或加(jia)速(su)度(du)控制(zhi)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)是(shi)(shi)同(tong)義語(yu)(yu)。在隨(sui)動(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)，有一(yi)類(lei)，它的(de)(de)參考(kao)輸(shu)(shu)(shu)(shu)(shu)入(ru)(ru)不(bu)是(shi)(shi)時間(jian)的(de)(de)解析函(han)數，如何變(bian)化(hua)(hua)(hua)事先(xian)(xian)并(bing)不(bu)知道（隨(sui)著時間(jian)任意變(bian)化(hua)(hua)(hua)）。控制(zhi)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)任務是(shi)(shi)在各(ge)種(zhong)情(qing)況下(xia)保證輸(shu)(shu)(shu)(shu)(shu)出(chu)以一(yi)定精度(du)跟隨(sui)著參考(kao)輸(shu)(shu)(shu)(shu)(shu)入(ru)(ru)的(de)(de)變(bian)化(hua)(hua)(hua)而變(bian)化(hua)(hua)(hua)。微機(ji)位(wei)置(zhi)伺服(fu)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)概(gai)述在自動(dong)控制(zhi)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)，把輸(shu)(shu)(shu)(shu)(shu)出(chu)量能夠以一(yi)定準確度(du)跟隨(sui)輸(shu)(shu)(shu)(shu)(shu)入(ru)(ru)量的(de)(de)變(bian)化(hua)(hua)(hua)而變(bian)化(hua)(hua)(hua)的(de)(de)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)稱為(wei)隨(sui)動(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)，亦稱伺服(fu)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。在控制(zhi)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)若給定的(de)(de)輸(shu)(shu)(shu)(shu)(shu)入(ru)(ru)信(xin)號(hao)是(shi)(shi)預(yu)先(xian)(xian)未知且隨(sui)時間(jian)變(bian)化(hua)(hua)(hua)的(de)(de)并(bing)且系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)輸(shu)(shu)(shu)(shu)(shu)出(chu)量隨(sui)輸(shu)(shu)(shu)(shu)(shu)入(ru)(ru)量的(de)(de)變(bian)化(hua)(hua)(hua)而變(bian)化(hua)(hua)(hua)這(zhe)(zhe)種(zhong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)就稱為(wei)隨(sui)動(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)。快速(su)跟蹤和準確定位(wei)是(shi)(shi)隨(sui)動(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)兩個重(zhong)要技(ji)術指標。
二、隨動系統的特點
改變(bian)電(dian)動(dong)(dong)機(ji)(ji)電(dian)樞回路總電(dian)阻調(diao)(diao)(diao)速方(fang)法最早(zao)被采用。該調(diao)(diao)(diao)速系(xi)統的(de)特(te)(te)點是：設計、安(an)裝(zhuang)、調(diao)(diao)(diao)試方(fang)便、設備線(xian)路簡單(dan)，投資小；缺點是：電(dian)動(dong)(dong)機(ji)(ji)的(de)機(ji)(ji)械(xie)特(te)(te)性變(bian)軟，耗能多；調(diao)(diao)(diao)速范(fan)圍(wei)小，不平滑(hua)。減弱電(dian)動(dong)(dong)機(ji)(ji)勵磁(ci)磁(ci)通調(diao)(diao)(diao)速方(fang)法調(diao)(diao)(diao)速范(fan)圍(wei)不大，電(dian)動(dong)(dong)機(ji)(ji)的(de)機(ji)(ji)械(xie)特(te)(te)性變(bian)軟，只要求(qiu)在額定轉速以上(shang)升速時采用。
改變電(dian)動機的(de)(de)端電(dian)壓的(de)(de)調(diao)速(su)方法調(diao)速(su)系(xi)統(tong)調(diao)速(su)范(fan)圍大、平滑性好(hao)。常采用的(de)(de)調(diao)壓調(diao)速(su)方法是：采用晶閘管可控整(zheng)流裝(zhuang)置供電(dian)給直(zhi)流電(dian)動機的(de)(de)調(diao)速(su)系(xi)統(tong)。
三、隨動系統的基本形式
1、轉速負反饋調速系統的組成、原理及其靜特性
由直(zhi)流電(dian)(dian)動(dong)機(ji)的(de)特性方(fang)程可知(zhi)，電(dian)(dian)動(dong)機(ji)轉(zhuan)速(su)(su)隨著(zhu)負(fu)載增加而(er)下(xia)降的(de)原因(yin)是由于電(dian)(dian)樞回(hui)路電(dian)(dian)壓降增大之故。如果能夠做到隨著(zhu)負(fu)載增加轉(zhuan)速(su)(su)有所下(xia)降時及時調整(zheng)晶閘管的(de)控制(zhi)(zhi)角，提(ti)高整(zheng)流電(dian)(dian)源的(de)輸出電(dian)(dian)壓，電(dian)(dian)動(dong)機(ji)的(de)轉(zhuan)速(su)(su)就(jiu)會有一定的(de)回(hui)升(sheng)。這就(jiu)必(bi)須依(yi)靠轉(zhuan)速(su)(su)的(de)閉(bi)環控制(zhi)(zhi)。
2、調速系統的靜特性
分析(xi)系統穩態特性的(de)目的(de)，就是要找出減(jian)少靜態速降，擴大(da)調(diao)速范圍的(de)途徑，改善系統的(de)調(diao)速性能。
