一、什么是隨動系統
隨動系統servo system，是一種(zhong)反饋控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)。在(zai)這種(zhong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)(zhong)，輸(shu)(shu)出(chu)(chu)量(liang)(liang)是機(ji)械位移、速(su)(su)度(du)(du)或(huo)者加(jia)速(su)(su)度(du)(du)。因(yin)此隨(sui)動系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)這一術語，與(yu)位置或(huo)速(su)(su)度(du)(du)，或(huo)加(jia)速(su)(su)度(du)(du)控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)是同義語。在(zai)隨(sui)動系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)(zhong)，有一類，它(ta)的(de)(de)(de)(de)參考輸(shu)(shu)入(ru)不(bu)是時間(jian)的(de)(de)(de)(de)解析函(han)數，如何(he)變(bian)(bian)(bian)(bian)化事先并不(bu)知(zhi)道(dao)（隨(sui)著時間(jian)任(ren)意變(bian)(bian)(bian)(bian)化）。控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)的(de)(de)(de)(de)任(ren)務是在(zai)各種(zhong)情況下(xia)保(bao)證輸(shu)(shu)出(chu)(chu)以一定(ding)精度(du)(du)跟隨(sui)著參考輸(shu)(shu)入(ru)的(de)(de)(de)(de)變(bian)(bian)(bian)(bian)化而(er)變(bian)(bian)(bian)(bian)化。微機(ji)位置伺服(fu)(fu)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)概(gai)述在(zai)自動控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)(zhong)，把輸(shu)(shu)出(chu)(chu)量(liang)(liang)能夠以一定(ding)準確度(du)(du)跟隨(sui)輸(shu)(shu)入(ru)量(liang)(liang)的(de)(de)(de)(de)變(bian)(bian)(bian)(bian)化而(er)變(bian)(bian)(bian)(bian)化的(de)(de)(de)(de)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)稱為隨(sui)動系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)，亦稱伺服(fu)(fu)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)。在(zai)控(kong)制系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)(zhong)(zhong)若給(gei)定(ding)的(de)(de)(de)(de)輸(shu)(shu)入(ru)信號是預先未知(zhi)且隨(sui)時間(jian)變(bian)(bian)(bian)(bian)化的(de)(de)(de)(de)并且系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)的(de)(de)(de)(de)輸(shu)(shu)出(chu)(chu)量(liang)(liang)隨(sui)輸(shu)(shu)入(ru)量(liang)(liang)的(de)(de)(de)(de)變(bian)(bian)(bian)(bian)化而(er)變(bian)(bian)(bian)(bian)化這種(zhong)系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)就稱為隨(sui)動系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)。快速(su)(su)跟蹤(zong)和(he)準確定(ding)位是隨(sui)動系(xi)(xi)(xi)(xi)統(tong)(tong)(tong)的(de)(de)(de)(de)兩個重(zhong)要技(ji)術指標。
二、隨動系統的特點
改變(bian)(bian)電(dian)動機(ji)(ji)電(dian)樞回路總電(dian)阻(zu)調(diao)速(su)方法最早被(bei)采用。該調(diao)速(su)系統的特點是(shi)(shi)：設(she)計(ji)、安裝、調(diao)試(shi)方便(bian)、設(she)備線(xian)路簡單，投資小(xiao)；缺點是(shi)(shi)：電(dian)動機(ji)(ji)的機(ji)(ji)械特性(xing)變(bian)(bian)軟，耗能多(duo)；調(diao)速(su)范(fan)圍小(xiao)，不平滑。減弱電(dian)動機(ji)(ji)勵磁磁通調(diao)速(su)方法調(diao)速(su)范(fan)圍不大，電(dian)動機(ji)(ji)的機(ji)(ji)械特性(xing)變(bian)(bian)軟，只要求(qiu)在額定(ding)轉速(su)以上升速(su)時(shi)采用。
改變(bian)電動機的端電壓的調(diao)(diao)(diao)速方法(fa)調(diao)(diao)(diao)速系(xi)統(tong)調(diao)(diao)(diao)速范圍大、平滑(hua)性(xing)好。常采用的調(diao)(diao)(diao)壓調(diao)(diao)(diao)速方法(fa)是：采用晶(jing)閘(zha)管可控(kong)整流(liu)裝(zhuang)置供(gong)電給直(zhi)流(liu)電動機的調(diao)(diao)(diao)速系(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
由直流電(dian)(dian)動(dong)(dong)機的特性方程可知，電(dian)(dian)動(dong)(dong)機轉(zhuan)速隨(sui)著負(fu)載增加(jia)(jia)而下降(jiang)的原因是由于電(dian)(dian)樞回路電(dian)(dian)壓降(jiang)增大之故。如果能夠做到隨(sui)著負(fu)載增加(jia)(jia)轉(zhuan)速有(you)所下降(jiang)時及時調整晶(jing)閘管的控制角，提高整流電(dian)(dian)源的輸出電(dian)(dian)壓，電(dian)(dian)動(dong)(dong)機的轉(zhuan)速就會有(you)一定的回升。這就必須(xu)依靠轉(zhuan)速的閉(bi)環控制。
2、調速系統的靜特性
分析系統(tong)穩(wen)態特性的(de)目(mu)的(de)，就(jiu)是(shi)要找出減少靜態速降，擴大調速范(fan)圍(wei)的(de)途徑，改善系統(tong)的(de)調速性能。
