一、什么是隨動系統
隨動系統servo system，是(shi)一(yi)種反饋控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)。在這種系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)，輸(shu)出量(liang)是(shi)機(ji)械位移、速(su)度(du)或(huo)者加(jia)速(su)度(du)。因此隨(sui)動(dong)(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)這一(yi)術(shu)語，與(yu)位置(zhi)或(huo)速(su)度(du)，或(huo)加(jia)速(su)度(du)控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)是(shi)同義語。在隨(sui)動(dong)(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)，有(you)一(yi)類，它的參考輸(shu)入不是(shi)時(shi)間(jian)的解析函數(shu)，如何變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)事先并不知道（隨(sui)著時(shi)間(jian)任意變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)）。控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)的任務是(shi)在各種情況下保(bao)證(zheng)輸(shu)出以一(yi)定(ding)精(jing)度(du)跟(gen)隨(sui)著參考輸(shu)入的變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)而變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)。微機(ji)位置(zhi)伺服(fu)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)概述在自動(dong)(dong)控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)，把輸(shu)出量(liang)能夠以一(yi)定(ding)準確度(du)跟(gen)隨(sui)輸(shu)入量(liang)的變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)而變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)的系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)稱為隨(sui)動(dong)(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)，亦稱伺服(fu)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)。在控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)若(ruo)給定(ding)的輸(shu)入信號是(shi)預(yu)先未(wei)知且隨(sui)時(shi)間(jian)變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)的并且系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)的輸(shu)出量(liang)隨(sui)輸(shu)入量(liang)的變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)而變(bian)(bian)(bian)化(hua)(hua)(hua)(hua)這種系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)就稱為隨(sui)動(dong)(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)。快速(su)跟(gen)蹤和(he)準確定(ding)位是(shi)隨(sui)動(dong)(dong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)的兩(liang)個重要技術(shu)指標。
二、隨動系統的特點
改變(bian)電(dian)動(dong)機(ji)(ji)電(dian)樞回路總(zong)電(dian)阻調速(su)方(fang)(fang)法(fa)最早(zao)被采用。該調速(su)系統的(de)特點是：設計、安裝、調試方(fang)(fang)便、設備線路簡單，投資(zi)小；缺點是：電(dian)動(dong)機(ji)(ji)的(de)機(ji)(ji)械特性(xing)變(bian)軟(ruan)，耗(hao)能多；調速(su)范(fan)圍小，不平(ping)滑(hua)。減弱(ruo)電(dian)動(dong)機(ji)(ji)勵磁磁通調速(su)方(fang)(fang)法(fa)調速(su)范(fan)圍不大，電(dian)動(dong)機(ji)(ji)的(de)機(ji)(ji)械特性(xing)變(bian)軟(ruan)，只要求在額定轉速(su)以(yi)上(shang)升速(su)時采用。
改變(bian)電動機(ji)的端電壓的調(diao)速(su)方法調(diao)速(su)系統調(diao)速(su)范圍大、平滑性好(hao)。常采用的調(diao)壓調(diao)速(su)方法是：采用晶閘管(guan)可控整流裝置供電給直流電動機(ji)的調(diao)速(su)系統。
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
由直流電(dian)動機(ji)的(de)(de)(de)特性方程可知(zhi)，電(dian)動機(ji)轉速(su)隨著負載(zai)增加(jia)而下降(jiang)(jiang)的(de)(de)(de)原(yuan)因是由于(yu)電(dian)樞回路電(dian)壓(ya)降(jiang)(jiang)增大之故。如果能夠做(zuo)到隨著負載(zai)增加(jia)轉速(su)有(you)所下降(jiang)(jiang)時及時調(diao)整晶(jing)閘管的(de)(de)(de)控(kong)制角，提高整流電(dian)源(yuan)的(de)(de)(de)輸(shu)出電(dian)壓(ya)，電(dian)動機(ji)的(de)(de)(de)轉速(su)就會有(you)一(yi)定的(de)(de)(de)回升(sheng)。這就必須依靠轉速(su)的(de)(de)(de)閉環(huan)控(kong)制。
2、調速系統的靜特性
分(fen)析(xi)系(xi)統穩態(tai)特性的(de)目的(de)，就是要找出減(jian)少靜態(tai)速(su)降，擴大調(diao)速(su)范(fan)圍(wei)的(de)途徑，改善系(xi)統的(de)調(diao)速(su)性能(neng)。
