伺服電機是指在伺服系統中控制機械元件運轉的發動機，是一種補助馬達間接變速裝置；伺服電機可使控制速度，位置精度十分準確，還可以將電壓信號轉化為轉矩和轉速以驅動控制對象，閉環控制。

　　直線電機(ji)是一種(zhong)將電能(neng)同時轉換成(cheng)(cheng)直線運動機(ji)械能(neng)，而無需其他之間(jian)(jian)轉換機(ji)構(gou)的(de)(de)傳動裝(zhuang)置；它(ta)還可(ke)(ke)以(yi)看作是一臺旋(xuan)轉電機(ji)按徑向剖(pou)開，并展成(cheng)(cheng)平面而成(cheng)(cheng)，由定子演(yan)變(bian)而來的(de)(de)一側(ce)稱(cheng)為初(chu)級(ji)(ji)，由轉子演(yan)變(bian)而來的(de)(de)一側(ce)稱(cheng)為次(ci)級(ji)(ji)；在實際上選用(yong)時，將初(chu)級(ji)(ji)和次(ci)級(ji)(ji)制造(zao)成(cheng)(cheng)不一樣(yang)的(de)(de)的(de)(de)長度，以(yi)做(zuo)到(dao)在所需行(xing)程(cheng)區域(yu)內初(chu)級(ji)(ji)與次(ci)級(ji)(ji)之間(jian)(jian)的(de)(de)耦合保(bao)持不變(bian)；直線電機(ji)還可(ke)(ke)以(yi)是短初(chu)級(ji)(ji)長次(ci)級(ji)(ji)，也能(neng)是長初(chu)級(ji)(ji)短次(ci)級(ji)(ji)，充分(fen)考慮到(dao)制造(zao)成(cheng)(cheng)本、運轉費(fei)用(yong)，當前平常(chang)均選用(yong)短初(chu)級(ji)(ji)長次(ci)級(ji)(ji)。

　　直線電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)結構(gou)緊湊、功率(lv)(lv)(lv)損(sun)耗(hao)小、快移(yi)速(su)度(du)高(gao)、加速(su)度(du)高(gao)、高(gao)速(su)度(du)（直線電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)經過同(tong)時(shi)(shi)(shi)驅(qu)(qu)動(dong)(dong)負載的(de)(de)(de)(de)方式，還可以完成(cheng)從高(gao)速(su)到低速(su)等不一樣(yang)的(de)(de)(de)(de)區域的(de)(de)(de)(de)高(gao)精度(du)位(wei)置定位(wei)控制(zhi)(zhi)；選(xuan)用(yong)(yong)(yong)(yong)于(yu)地鐵(tie)的(de)(de)(de)(de)自動(dong)(dong)門伺服(fu)(fu)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)在(zai)(zai)低速(su)的(de)(de)(de)(de)時(shi)(shi)(shi)候容(rong)易發生低頻(pin)振動(dong)(dong)現(xian)象，振動(dong)(dong)頻(pin)率(lv)(lv)(lv)與(yu)負載現(xian)象和(he)驅(qu)(qu)動(dong)(dong)器(qi)使用(yong)(yong)(yong)(yong)性能有關系；平常以為(wei)振動(dong)(dong)頻(pin)率(lv)(lv)(lv)為(wei)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)空載起(qi)跳頻(pin)率(lv)(lv)(lv)的(de)(de)(de)(de)一半。這些(xie)由伺服(fu)(fu)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)工作(zuo)原理所取(qu)決(jue)于(yu)的(de)(de)(de)(de)低頻(pin)振動(dong)(dong)現(xian)象相對于(yu)機(ji)(ji)(ji)(ji)(ji)器(qi)的(de)(de)(de)(de)正(zheng)常運(yun)轉(zhuan)十分(fen)不便。當(dang)伺服(fu)(fu)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)工作(zuo)在(zai)(zai)低速(su)時(shi)(shi)(shi)，平常應選(xuan)用(yong)(yong)(yong)(yong)阻尼技術來(lai)解(jie)決(jue)低頻(pin)振動(dong)(dong)現(xian)象，比(bi)如說在(zai)(zai)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)上加阻尼器(qi)，或驅(qu)(qu)動(dong)(dong)器(qi)上選(xuan)用(yong)(yong)(yong)(yong)細分(fen)化(hua)技術等。當(dang)前用(yong)(yong)(yong)(yong)作(zuo)電(dian)(dian)腦繡花機(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)伺服(fu)(fu)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)多數為(wei)五(wu)相混(hun)合式伺服(fu)(fu)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)，作(zuo)用(yong)(yong)(yong)(yong)是(shi)經過選(xuan)用(yong)(yong)(yong)(yong)高(gao)相數的(de)(de)(de)(de)步(bu)進電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)來(lai)減小步(bu)矩(ju)角和(he)提(ti)升控制(zhi)(zhi)精度(du)；不過選(xuan)用(yong)(yong)(yong)(yong)這種方式獲(huo)得的(de)(de)(de)(de)使用(yong)(yong)(yong)(yong)性能上的(de)(de)(de)(de)提(ti)升是(shi)有限的(de)(de)(de)(de)，同(tong)時(shi)(shi)(shi)投入也相應較高(gao)，選(xuan)用(yong)(yong)(yong)(yong)細分(fen)化(hua)驅(qu)(qu)動(dong)(dong)技術還可以盡(jin)可能改變伺服(fu)(fu)電(dian)(dian)機(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)運(yun)轉(zhuan)質量，減小轉(zhuan)矩(ju)波(bo)動(dong)(dong)，抑制(zhi)(zhi)振蕩(dang)，降低噪音，提(ti)升步(bu)矩(ju)分(fen)辨率(lv)(lv)(lv)。

　　事實上(shang)直(zhi)線(xian)電(dian)(dian)(dian)機也是(shi)伺(si)服(fu)(fu)電(dian)(dian)(dian)機的(de)一種。理論上(shang)，只需要有反饋的(de)系統（直(zhi)線(xian)電(dian)(dian)(dian)機通常以(yi)Hall或(huo)者直(zhi)線(xian)光柵反饋）都(dou)應(ying)該是(shi)伺(si)服(fu)(fu)系統。故(gu)此伺(si)服(fu)(fu)電(dian)(dian)(dian)機理應(ying)在廣義上(shang)被可分兩類：旋(xuan)轉伺(si)服(fu)(fu)電(dian)(dian)(dian)機和直(zhi)線(xian)伺(si)服(fu)(fu)電(dian)(dian)(dian)機，直(zhi)線(xian)電(dian)(dian)(dian)機的(de)特點(dian)：高動態特性(xing)、高剛性(xing)，相應(ying)于傳(chuan)統的(de)直(zhi)線(xian)傳(chuan)遞結構（如絲杠，電(dian)(dian)(dian)動缸），免維護保養(yang)，但投入較(jiao)高。