一、什么是隨動系統
隨動系統servo system，是(shi)一(yi)種反饋控(kong)(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)。在(zai)這種系(xi)(xi)(xi)(xi)(xi)統(tong)中，輸出(chu)量是(shi)機(ji)(ji)械位移、速度(du)(du)或者加速度(du)(du)。因此隨(sui)(sui)(sui)(sui)(sui)動(dong)系(xi)(xi)(xi)(xi)(xi)統(tong)這一(yi)術語，與位置或速度(du)(du)，或加速度(du)(du)控(kong)(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)是(shi)同義語。在(zai)隨(sui)(sui)(sui)(sui)(sui)動(dong)系(xi)(xi)(xi)(xi)(xi)統(tong)中，有一(yi)類，它的參(can)考輸入(ru)不(bu)是(shi)時(shi)間的解析函數，如何變(bian)化(hua)(hua)事(shi)先(xian)并(bing)不(bu)知(zhi)道（隨(sui)(sui)(sui)(sui)(sui)著(zhu)時(shi)間任(ren)意變(bian)化(hua)(hua)）。控(kong)(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)的任(ren)務是(shi)在(zai)各種情況下(xia)保證輸出(chu)以(yi)(yi)一(yi)定(ding)精度(du)(du)跟隨(sui)(sui)(sui)(sui)(sui)著(zhu)參(can)考輸入(ru)的變(bian)化(hua)(hua)而(er)變(bian)化(hua)(hua)。微機(ji)(ji)位置伺服(fu)系(xi)(xi)(xi)(xi)(xi)統(tong)概述在(zai)自(zi)動(dong)控(kong)(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)中，把輸出(chu)量能夠以(yi)(yi)一(yi)定(ding)準確度(du)(du)跟隨(sui)(sui)(sui)(sui)(sui)輸入(ru)量的變(bian)化(hua)(hua)而(er)變(bian)化(hua)(hua)的系(xi)(xi)(xi)(xi)(xi)統(tong)稱(cheng)(cheng)(cheng)為(wei)隨(sui)(sui)(sui)(sui)(sui)動(dong)系(xi)(xi)(xi)(xi)(xi)統(tong)，亦稱(cheng)(cheng)(cheng)伺服(fu)系(xi)(xi)(xi)(xi)(xi)統(tong)。在(zai)控(kong)(kong)制系(xi)(xi)(xi)(xi)(xi)統(tong)中若給定(ding)的輸入(ru)信號是(shi)預先(xian)未知(zhi)且隨(sui)(sui)(sui)(sui)(sui)時(shi)間變(bian)化(hua)(hua)的并(bing)且系(xi)(xi)(xi)(xi)(xi)統(tong)的輸出(chu)量隨(sui)(sui)(sui)(sui)(sui)輸入(ru)量的變(bian)化(hua)(hua)而(er)變(bian)化(hua)(hua)這種系(xi)(xi)(xi)(xi)(xi)統(tong)就稱(cheng)(cheng)(cheng)為(wei)隨(sui)(sui)(sui)(sui)(sui)動(dong)系(xi)(xi)(xi)(xi)(xi)統(tong)。快(kuai)速跟蹤和(he)準確定(ding)位是(shi)隨(sui)(sui)(sui)(sui)(sui)動(dong)系(xi)(xi)(xi)(xi)(xi)統(tong)的兩(liang)個重(zhong)要技術指(zhi)標。
二、隨動系統的特點
改變電(dian)動機(ji)電(dian)樞回路總電(dian)阻調(diao)(diao)速方(fang)(fang)(fang)法最早(zao)被采用。該調(diao)(diao)速系統的(de)特點(dian)是：設(she)計、安(an)裝、調(diao)(diao)試方(fang)(fang)(fang)便、設(she)備(bei)線(xian)路簡單，投資小；缺點(dian)是：電(dian)動機(ji)的(de)機(ji)械特性(xing)變軟，耗(hao)能(neng)多；調(diao)(diao)速范(fan)圍小，不平滑。減弱電(dian)動機(ji)勵磁磁通調(diao)(diao)速方(fang)(fang)(fang)法調(diao)(diao)速范(fan)圍不大(da)，電(dian)動機(ji)的(de)機(ji)械特性(xing)變軟，只要求在額(e)定轉速以上升速時采用。
改變(bian)電(dian)動(dong)機的端電(dian)壓的調(diao)速(su)(su)方法調(diao)速(su)(su)系(xi)統(tong)調(diao)速(su)(su)范圍大、平滑性好(hao)。常采用的調(diao)壓調(diao)速(su)(su)方法是：采用晶閘管(guan)可控(kong)整(zheng)流(liu)裝置供電(dian)給直流(liu)電(dian)動(dong)機的調(diao)速(su)(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(liu)電(dian)(dian)(dian)動機(ji)(ji)的(de)特性方程可知(zhi)，電(dian)(dian)(dian)動機(ji)(ji)轉(zhuan)(zhuan)速隨(sui)著負載(zai)增加而下(xia)(xia)降(jiang)(jiang)的(de)原因是由于電(dian)(dian)(dian)樞回(hui)路(lu)電(dian)(dian)(dian)壓(ya)降(jiang)(jiang)增大之故。如果能夠做到隨(sui)著負載(zai)增加轉(zhuan)(zhuan)速有所下(xia)(xia)降(jiang)(jiang)時及時調整(zheng)晶閘管的(de)控制角，提高整(zheng)流(liu)電(dian)(dian)(dian)源的(de)輸出電(dian)(dian)(dian)壓(ya)，電(dian)(dian)(dian)動機(ji)(ji)的(de)轉(zhuan)(zhuan)速就會有一定的(de)回(hui)升(sheng)。這就必須依靠轉(zhuan)(zhuan)速的(de)閉環控制。
2、調速系統的靜特性
分析系(xi)統穩態特性(xing)的(de)目的(de)，就是要找出減少靜(jing)態速(su)降，擴大(da)調速(su)范圍(wei)的(de)途(tu)徑(jing)，改善系(xi)統的(de)調速(su)性(xing)能。
