講講平面(mian)磨床的(de)(de)(de)(de)(de)(de)換(huan)(huan)向(xiang)(xiang)過程(cheng) 配合理(li)想(xiang)控(kong)(kong)制曲線，平面(mian)磨床采(cai)用電(dian)液(ye)比例閥的(de)(de)(de)(de)(de)(de)液(ye)壓傳動換(huan)(huan)向(xiang)(xiang)系(xi)統(tong)。實(shi)現了以主動減小流量來降低速度，最終(zhong)達到平穩(wen)無(wu)沖擊換(huan)(huan)向(xiang)(xiang)的(de)(de)(de)(de)(de)(de)目的(de)(de)(de)(de)(de)(de)----一種(zhong)智能(neng)(neng)控(kong)(kong)制型(xing)(xing) 換(huan)(huan)向(xiang)(xiang)系(xi)統(tong)，工況(kuang)改變的(de)(de)(de)(de)(de)(de)情況(kuang)下也能(neng)(neng)實(shi)現理(li)想(xiang)換(huan)(huan)向(xiang)(xiang)。這種(zhong)液(ye)壓傳動換(huan)(huan)向(xiang)(xiang)系(xi)統(tong)對(dui)輸出的(de)(de)(de)(de)(de)(de)位移或速度實(shi)現了很好的(de)(de)(de)(de)(de)(de)智能(neng)(neng)化控(kong)(kong)制，使得(de)換(huan)(huan)向(xiang)(xiang)過程(cheng)具有一定的(de)(de)(de)(de)(de)(de)可控(kong)(kong)制性，因(yin)而(er)有 非常廣泛(fan)的(de)(de)(de)(de)(de)(de)應(ying)用范圍分析了換(huan)(huan)向(xiang)(xiang)沖擊機理(li)，摘要:對(dui)平面(mian)磨床的(de)(de)(de)(de)(de)(de)換(huan)(huan)向(xiang)(xiang)過程(cheng)進行(xing)了簡單地討論。并比較(jiao)了幾種(zhong)常用換(huan)(huan)向(xiang)(xiang)方法的(de)(de)(de)(de)(de)(de)優缺點。最后(hou)，引出了智能(neng)(neng)控(kong)(kong)制型(xing)(xing)換(huan)(huan)向(xiang)(xiang)系(xi)統(tong)，提出理(li)想(xiang)控(kong)(kong)制曲線的(de)(de)(de)(de)(de)(de)概念。 

       關鍵詞:平面磨床 

       1、引言(yan) 　　

       其工(gong)(gong)作臺(tai)的(de)(de)運(yun)動(dong)是連續往(wang)復(fu)式運(yun)動(dong)，平面(mian)(mian)(mian)(mian)磨(mo)床(chuang)是一種(zhong)機(ji)械加工(gong)(gong)常用(yong)(yong)機(ji)床(chuang)。對運(yun)動(dong)平穩(wen)性(xing)、換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)精度、換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)頻率都有較高(gao)的(de)(de)要求。目前，平面(mian)(mian)(mian)(mian)磨(mo)床(chuang)正向(xiang)(xiang)(xiang)(xiang)大(da)型 化、高(gao)速(su)化發(fa)展，有些平面(mian)(mian)(mian)(mian)磨(mo)床(chuang)的(de)(de)工(gong)(gong)作臺(tai)往(wang)復(fu)速(su)度已(yi)經達到40耐而(er)n[〕。大(da)型高(gao)速(su)平面(mian)(mian)(mian)(mian)磨(mo)床(chuang)的(de)(de)運(yun)動(dong)慣性(xing)很大(da)，當(dang)其換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)時，就會導(dao)致背壓(ya)急劇升(sheng)高(gao)，從(cong)而(er)引起(qi)換(huan)(huan) 向(xiang)(xiang)(xiang)(xiang)沖(chong)擊，這會對機(ji)床(chuang)發(fa)生災(zai)難(nan)性(xing)的(de)(de)影響(xiang)，所以換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)平穩(wen)性(xing)問題(ti)已(yi)成為制約磨(mo)床(chuang)工(gong)(gong)作速(su)度和加工(gong)(gong)精度提(ti)高(gao)的(de)(de)重要因素。系統(tong)(tong)中的(de)(de)換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)方(fang)式和換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)控(kong)制參數對換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)沖(chong)擊有決定性(xing)的(de)(de)作用(yong)(yong)，平面(mian)(mian)(mian)(mian)磨(mo)床(chuang)采(cai)用(yong)(yong)液壓(ya)傳動(dong)。設計新(xin)的(de)(de)液壓(ya)換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)系統(tong)(tong)已(yi)迫在眉睫(jie)。下面(mian)(mian)(mian)(mian)從(cong)換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)方(fang)法和控(kong)制策略(lve)的(de)(de)角(jiao)度來討論磨(mo)床(chuang)的(de)(de)換(huan)(huan)向(xiang)(xiang)(xiang)(xiang)沖(chong)擊問題(ti)。 

       2、換向沖擊的機理 　　

       由于(yu)在(zai)其液壓系統(tong)中(zhong)，當液壓傳(chuan)動平面磨床(chuang)換(huan)向(xiang)(xiang)時。換(huan)向(xiang)(xiang)閥(fa)閥(fa)口(kou)瞬時關(guan)閉，油(you)路突(tu)然斷開，使得回油(you)腔的油(you)液無(wu)法排泄。m和v越大，可以看(kan)出。動能(neng)就越大，換(huan)向(xiang)(xiang)沖(chong)擊(ji)也就越大。對于(yu)大慣量(liang)高速(su)運行的平面磨床(chuang)來說，其換(huan)向(xiang)(xiang)沖(chong)擊(ji)是巨大的這不僅(jin)影響了(le)機(ji)床(chuang)的加(jia)工精度(du)，而且也妨礙了(le)正常運行與使用壽命。人們(men)都希望機(ji)床(chuang)實現理(li)(li)想(xiang)(xiang)換(huan)向(xiang)(xiang)。所謂理(li)(li)想(xiang)(xiang)換(huan)向(xiang)(xiang)是指，任何工況下(xia)，機(ji)床(chuang)速(su)度(du)都可以依照某一理(li)(li)想(xiang)(xiang)曲線無(wu)突(tu)變的光滑減小，閥(fa)門關(guan)閉瞬間，速(su)度(du)剛好減為零，即動能(neng)全部轉化(hua)為熱能(neng)被損耗。理(li)(li)想(xiang)(xiang)的換(huan)向(xiang)(xiang)過程是無(wu)沖(chong)擊(ji)的。

       3、常用液壓傳動換向方法(fa)分析 

       下面對它作一(yi)個(ge)簡(jian)單的(de)分(fen)析對比。當前(qian)應用(yong)于(yu)平(ping)面磨床的(de)液壓傳動換向方法很多。 

       3.1采用行程換向(xiang)閥的(de)換向(xiang)方法 　　

       換(huan)向(xiang)(xiang)(xiang)閥芯上(shang)聯出一拔桿，為采(cai)用(yong)行程(cheng)換(huan)向(xiang)(xiang)(xiang)閥換(huan)向(xiang)(xiang)(xiang)。利用(yong)工(gong)作臺上(shang)的行程(cheng)擋塊推動(dong)拔桿來實現(xian)(xian)自動(dong)換(huan)向(xiang)(xiang)(xiang)。工(gong)作臺慢速(su)運動(dong)時，當(dang)換(huan)向(xiang)(xiang)(xiang)閥到達(da)(da)中間位置(zhi)，不管 液(ye)壓(ya)(ya)缸(gang)左右兩腔或是都通(tong)壓(ya)(ya)力油、或是都通(tong)回(hui)油、或是都封閉，這時，液(ye)壓(ya)(ya)缸(gang)兩腔沒有液(ye)壓(ya)(ya)力推動(dong)，都會使工(gong)作臺運動(dong)停(ting)止，因而換(huan)向(xiang)(xiang)(xiang)閥不能到達(da)(da)另一端(duan)，也就出現(xian)(xian) 了(le)所謂“死點”;另外(wai)當(dang)工(gong)作臺高速(su)運動(dong)時，擋塊推動(dong)拔桿使換(huan)向(xiang)(xiang)(xiang)閥變換(huan)方向(xiang)(xiang)(xiang)非常快，液(ye)壓(ya)(ya)缸(gang)的一腔壓(ya)(ya)力突然(ran)由工(gong)作壓(ya)(ya)力p降低到0另一腔則由0突然(ran)上(shang)升(sheng)到p這就 出現(xian)(xian)了(le)極大的換(huan)向(xiang)(xiang)(xiang)沖(chong)擊。目(mu)前這種系統應用(yong)在小型磨床上(shang)的比較多。 

       3.2采用電磁(ci)換向閥的(de)換向方法(fa) 　

       由行(xing)程(cheng)擋(dang)塊推動行(xing)程(cheng)開(kai)關發出換(huan)(huan)(huan)(huan)向(xiang)信號，行(xing)程(cheng)換(huan)(huan)(huan)(huan)向(xiang)閥(fa)(fa)改為電磁換(huan)(huan)(huan)(huan)向(xiang)閥(fa)(fa)的換(huan)(huan)(huan)(huan)向(xiang)方法。使電磁鐵(tie)動作推動滑(hua)閥(fa)(fa)換(huan)(huan)(huan)(huan)向(xiang)，可以防止“死點”但它一種開(kai)關型(xing)液壓閥(fa)(fa)，根據指令瞬間開(kai)啟(qi)或閉合，即瞬時(shi)接(jie)通或切斷回(hui)油(you)通道，這樣的液壓換(huan)(huan)(huan)(huan)向(xiang)系統(tong)在換(huan)(huan)(huan)(huan)向(xiang)時(shi)會有(you)很大的沖擊發生。 

       3.3采用電液換(huan)(huan)向閥的換(huan)(huan)向方法 　

       再(zai)由控(kong)制(zhi)(zhi)油(you)(you)(you)推動(dong)主(zhu)(zhu)閥(fa)(fa)(fa)換(huan)(huan)(huan)(huan)向(xiang)(xiang)。先導閥(fa)(fa)(fa)沒(mei)有換(huan)(huan)(huan)(huan)向(xiang)(xiang)前(qian)，用電液換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)替換(huan)(huan)(huan)(huan)電磁(ci)換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)便構(gou)成了(le)一種新的(de)(de)(de)換(huan)(huan)(huan)(huan)向(xiang)(xiang)方(fang)法。電液換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)由先導閥(fa)(fa)(fa)電磁(ci)滑(hua)閥(fa)(fa)(fa)和主(zhu)(zhu)閥(fa)(fa)(fa)液動(dong)滑(hua)閥(fa)(fa)(fa)組成。此 系統是(shi)通過先導閥(fa)(fa)(fa)換(huan)(huan)(huan)(huan)向(xiang)(xiang)切(qie)換(huan)(huan)(huan)(huan)控(kong)制(zhi)(zhi)油(you)(you)(you)路(lu)。控(kong)制(zhi)(zhi)油(you)(you)(you)路(lu)的(de)(de)(de)油(you)(you)(you)流方(fang)向(xiang)(xiang)不改(gai)(gai)變(bian)(bian)，換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)總保持在(zai)原來(lai)的(de)(de)(de)一端，主(zhu)(zhu)油(you)(you)(you)路(lu)方(fang)向(xiang)(xiang)不改(gai)(gai)變(bian)(bian)，工(gong)(gong)(gong)作臺總是(shi)可(ke)以(yi)繼續前(qian)進。一旦控(kong)制(zhi)(zhi)油(you)(you)(you)路(lu)切(qie)換(huan)(huan)(huan)(huan) 了(le)方(fang)向(xiang)(xiang)，主(zhu)(zhu)閥(fa)(fa)(fa)閥(fa)(fa)(fa)芯(xin)就(jiu)依照事(shi)先調定(ding)的(de)(de)(de)速度移動(dong)到另一工(gong)(gong)(gong)作位(wei)置，主(zhu)(zhu)油(you)(you)(you)路(lu)方(fang)向(xiang)(xiang)改(gai)(gai)變(bian)(bian)，工(gong)(gong)(gong)作臺也就(jiu)換(huan)(huan)(huan)(huan)向(xiang)(xiang)運動(dong)，防止了(le)換(huan)(huan)(huan)(huan)向(xiang)(xiang)“死(si)點” 　這樣(yang)大(da)慣量(liang)工(gong)(gong)(gong)作臺的(de)(de)(de)動(dong)能(neng)(neng)(neng)就(jiu)可(ke)以(yi)通過節流作用轉化(hua)為(wei)熱能(neng)(neng)(neng)而被消耗，電液換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)(fa)主(zhu)(zhu)閥(fa)(fa)(fa)的(de)(de)(de)控(kong)制(zhi)(zhi)油(you)(you)(you)口(kou)大(da)小是(shi)可(ke)調的(de)(de)(de)即換(huan)(huan)(huan)(huan)向(xiang)(xiang)時間△t可(ke)以(yi)延(yan)長。能(neng)(neng)(neng)夠有效地(di)減小換(huan)(huan)(huan)(huan)向(xiang)(xiang)沖 擊，因(yin)此這種換(huan)(huan)(huan)(huan)向(xiang)(xiang)方(fang)法在(zai)很長時間內居(ju)于主(zhu)(zhu)導地(di)位(wei)。但其換(huan)(huan)(huan)(huan)向(xiang)(xiang)參(can)數只能(neng)(neng)(neng)事(shi)先調定(ding)，不能(neng)(neng)(neng)根據工(gong)(gong)(gong)況的(de)(de)(de)改(gai)(gai)變(bian)(bian)而改(gai)(gai)變(bian)(bian)，這對工(gong)(gong)(gong)況隨時改(gai)(gai)變(bian)(bian)的(de)(de)(de)系統來(lai)說，不可(ke)能(neng)(neng)(neng)實現(xian)理想的(de)(de)(de)換(huan)(huan)(huan)(huan) 向(xiang)(xiang)。 

       4、電液比例(li)換向系統 　

       工(gong)況改變的(de)(de)(de)(de)(de)(de)情況下，上述換(huan)(huan)(huan)(huan)(huan)向(xiang)方(fang)法都(dou)(dou)是(shi)主動控(kong)(kong)(kong)制(zhi)(zhi)型換(huan)(huan)(huan)(huan)(huan)向(xiang)。無(wu)法適應(ying)新工(gong)況對換(huan)(huan)(huan)(huan)(huan)向(xiang)的(de)(de)(de)(de)(de)(de)要(yao)(yao)求(qiu)，另外都(dou)(dou)會(hui)發生一定(ding)的(de)(de)(de)(de)(de)(de)換(huan)(huan)(huan)(huan)(huan)向(xiang)沖(chong)(chong)擊。于是(shi)采用(yong)(yong)電(dian)(dian)液(ye)(ye)(ye)伺(si)服閥(fa)(fa)(fa)(fa)(fa)并實(shi)行閉環控(kong)(kong)(kong)制(zhi)(zhi)的(de)(de)(de)(de)(de)(de)液(ye)(ye)(ye) 壓(ya)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)應(ying)運而(er)生。這(zhe)(zhe)種(zhong)(zhong)(zhong)系(xi)(xi)(xi)統(tong)(tong)(tong)是(shi)一種(zhong)(zhong)(zhong)智能(neng)控(kong)(kong)(kong)制(zhi)(zhi)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)，由(you)微(wei)(wei)型計算(suan)機(ji)(ji)實(shi)現(xian)(xian)(xian)對其換(huan)(huan)(huan)(huan)(huan)向(xiang)機(ji)(ji)構的(de)(de)(de)(de)(de)(de)自動化控(kong)(kong)(kong)制(zhi)(zhi)。該(gai)方(fang)案既充(chong)分(fen)利用(yong)(yong)了電(dian)(dian)液(ye)(ye)(ye)伺(si)服閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)(de)(de)(de)各種(zhong)(zhong)(zhong)優點，又(you)可將(jiang)多種(zhong)(zhong)(zhong) 成熟的(de)(de)(de)(de)(de)(de)微(wei)(wei)機(ji)(ji)控(kong)(kong)(kong)制(zhi)(zhi)技術應(ying)用(yong)(yong)到系(xi)(xi)(xi)統(tong)(tong)(tong)上。這(zhe)(zhe)種(zhong)(zhong)(zhong)液(ye)(ye)(ye)壓(ya)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)換(huan)(huan)(huan)(huan)(huan)向(xiang)精(jing)度(du)很高(gao)，而(er)且沖(chong)(chong)擊較小(xiao)，使得大(da)型高(gao)速(su)平面磨床的(de)(de)(de)(de)(de)(de)換(huan)(huan)(huan)(huan)(huan)向(xiang)平穩性(xing)得到極大(da)的(de)(de)(de)(de)(de)(de)提(ti)高(gao)。所(suo)以(yi)這(zhe)(zhe)種(zhong)(zhong)(zhong)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)一般只適用(yong)(yong)于較高(gao)精(jing)度(du)要(yao)(yao)求(qiu)的(de)(de)(de)(de)(de)(de)系(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)。但因電(dian)(dian)液(ye)(ye)(ye)伺(si)服閥(fa)(fa)(fa)(fa)(fa)結構復雜、造價(jia)高(gao)且抗污染能(neng)力(li)差。 研(yan)究將(jiang)電(dian)(dian)液(ye)(ye)(ye)比例(li)(li)閥(fa)(fa)(fa)(fa)(fa)引人大(da)型高(gao)速(su)平面磨床的(de)(de)(de)(de)(de)(de)液(ye)(ye)(ye)壓(ya)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)中(zhong)。電(dian)(dian)液(ye)(ye)(ye)比例(li)(li)閥(fa)(fa)(fa)(fa)(fa)是(shi)介于開(kai)關型的(de)(de)(de)(de)(de)(de)液(ye)(ye)(ye)壓(ya)閥(fa)(fa)(fa)(fa)(fa)與伺(si)服閥(fa)(fa)(fa)(fa)(fa)之間的(de)(de)(de)(de)(de)(de)一種(zhong)(zhong)(zhong)液(ye)(ye)(ye)壓(ya)元(yuan)件(jian)。除了控(kong)(kong)(kong)制(zhi)(zhi)精(jing)度(du)及(ji)響應(ying)快速(su)性(xing)方(fang)面還 不(bu)如(ru)伺(si)服閥(fa)(fa)(fa)(fa)(fa)外，因此(ci)(ci)。其它方(fang)面的(de)(de)(de)(de)(de)(de)性(xing)能(neng)和控(kong)(kong)(kong)制(zhi)(zhi)水平與伺(si)服閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)(de)(de)(de)相當(dang)，其動、靜態性(xing)能(neng)足以(yi)滿足大(da)多數工(gong)業應(ying)用(yong)(yong)的(de)(de)(de)(de)(de)(de)要(yao)(yao)求(qiu)，而(er)且其抗污染性(xing)強且造價(jia)低。與采用(yong)(yong)電(dian)(dian)液(ye)(ye)(ye)伺(si)服閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)(de)(de)(de)液(ye)(ye)(ye)壓(ya)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)工(gong)作原(yuan)理(li)類似，采用(yong)(yong)電(dian)(dian)液(ye)(ye)(ye)比例(li)(li)閥(fa)(fa)(fa)(fa)(fa)的(de)(de)(de)(de)(de)(de)液(ye)(ye)(ye)壓(ya)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)。通(tong)過(guo)(guo)微(wei)(wei)機(ji)(ji)輸(shu)入控(kong)(kong)(kong)制(zhi)(zhi)比例(li)(li)閥(fa)(fa)(fa)(fa)(fa)閥(fa)(fa)(fa)(fa)(fa)芯的(de)(de)(de)(de)(de)(de)開(kai)度(du)大(da)小(xiao)，來實(shi)現(xian)(xian)(xian)對平面磨床工(gong)作臺的(de)(de)(de)(de)(de)(de)運動位(wei) 移或(huo)速(su)度(du)的(de)(de)(de)(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)，而(er)進(jin)(jin)行換(huan)(huan)(huan)(huan)(huan)向(xiang)的(de)(de)(de)(de)(de)(de)這(zhe)(zhe)種(zhong)(zhong)(zhong)系(xi)(xi)(xi)統(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)閥(fa)(fa)(fa)(fa)(fa)芯位(wei)移是(shi)由(you)微(wei)(wei)機(ji)(ji)輸(shu)人的(de)(de)(de)(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)曲線來調(diao)節的(de)(de)(de)(de)(de)(de)所(suo)以(yi)能(neng)夠實(shi)現(xian)(xian)(xian)適時對比例(li)(li)閥(fa)(fa)(fa)(fa)(fa)閥(fa)(fa)(fa)(fa)(fa)芯開(kai)度(du)大(da)小(xiao)進(jin)(jin)行調(diao)節，能(neng)適應(ying)各種(zhong)(zhong)(zhong)不(bu)同(tong)的(de)(de)(de)(de)(de)(de)工(gong)作情 況。平面磨床采用(yong)(yong)該(gai)液(ye)(ye)(ye)壓(ya)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)進(jin)(jin)行換(huan)(huan)(huan)(huan)(huan)向(xiang)時，配(pei)合以(yi)理(li)想(xiang)控(kong)(kong)(kong)制(zhi)(zhi)曲線便能(neng)實(shi)現(xian)(xian)(xian)理(li)想(xiang)的(de)(de)(de)(de)(de)(de)平穩無(wu)沖(chong)(chong)擊換(huan)(huan)(huan)(huan)(huan)向(xiang)過(guo)(guo)程(cheng)。此(ci)(ci)過(guo)(guo)程(cheng)中(zhong)，工(gong)作臺的(de)(de)(de)(de)(de)(de)動能(neng)同(tong)樣是(shi)通(tong)過(guo)(guo)節流作用(yong)(yong)轉(zhuan)化為熱能(neng) 而(er)消(xiao)耗(hao)的(de)(de)(de)(de)(de)(de)對于大(da)型高(gao)速(su)平面磨床來說，該(gai)換(huan)(huan)(huan)(huan)(huan)向(xiang)系(xi)(xi)(xi)統(tong)(tong)(tong)具有很高(gao)的(de)(de)(de)(de)(de)(de)使用(yong)(yong)價(jia)值。

       5、控制戰略(lve)的(de)研究 　

       換(huan)向(xiang)(xiang)閥(fa)主閥(fa)芯(xin)的運(yun)(yun)動規律(lv)對于換(huan)向(xiang)(xiang)沖(chong)擊(ji)和(he)換(huan)向(xiang)(xiang)性(xing)能有(you)(you)決(jue)定性(xing)的作用，換(huan)向(xiang)(xiang)過(guo)程中。稱這種(zhong)(zhong)閥(fa)芯(xin)運(yun)(yun)動規律(lv)為控(kong)(kong)(kong)制(zhi)曲(qu)(qu)(qu)(qu)(qu)線(xian)。對于電(dian)液比例(li)換(huan)向(xiang)(xiang)系(xi)統的設計來說(shuo)，最(zui)重要(yao)的 就(jiu)是(shi)控(kong)(kong)(kong)制(zhi)曲(qu)(qu)(qu)(qu)(qu)線(xian)的選定。而(er)(er)控(kong)(kong)(kong)制(zhi)策略的研究，也就(jiu)是(shi)尋(xun)找(zhao)一條理想(xiang)控(kong)(kong)(kong)制(zhi)曲(qu)(qu)(qu)(qu)(qu)線(xian)，使得電(dian)液比例(li)換(huan)向(xiang)(xiang)系(xi)統實現(xian)平穩(wen)(wen)無沖(chong)擊(ji)換(huan)向(xiang)(xiang)。通常的適(shi)用條件下，理想(xiang)控(kong)(kong)(kong)制(zhi)曲(qu)(qu)(qu)(qu)(qu)線(xian)是(shi)一條光 滑的高(gao)(gao)次曲(qu)(qu)(qu)(qu)(qu)線(xian)，換(huan)向(xiang)(xiang)初始時(shi)(shi)刻加(jia)速(su)(su)(su)度(du)由0逐漸(jian)增加(jia)，消除了(le)激進等(deng)減速(su)(su)(su)曲(qu)(qu)(qu)(qu)(qu)線(xian)在(zai)開始時(shi)(shi)加(jia)速(su)(su)(su)度(du)突變(bian)而(er)(er)產生的沖(chong)擊(ji)。然(ran)后加(jia)速(su)(su)(su)度(du)取(qu)得最(zui)大值，實現(xian)快速(su)(su)(su)減速(su)(su)(su)，當速(su)(su)(su)度(du)快接(jie) 近0時(shi)(shi)候，加(jia)速(su)(su)(su)度(du)減小(xiao)，平穩(wen)(wen)過(guo)渡到0這種(zhong)(zhong)曲(qu)(qu)(qu)(qu)(qu)線(xian)很好地克服了(le)激進等(deng)減速(su)(su)(su)曲(qu)(qu)(qu)(qu)(qu)線(xian)的局限性(xing)，而(er)(er)且(qie)還(huan)解決(jue)了(le)提(ti)高(gao)(gao)工作速(su)(su)(su)度(du)與(yu)提(ti)高(gao)(gao)換(huan)向(xiang)(xiang)精度(du)之間的矛盾。無論換(huan)向(xiang)(xiang)時(shi)(shi)的初速(su)(su)(su) 度(du)有(you)(you)多大，只要(yao)控(kong)(kong)(kong)制(zhi)液壓缸依照理想(xiang)曲(qu)(qu)(qu)(qu)(qu)線(xian)運(yun)(yun)動，理論上就(jiu)能在(zai)換(huan)向(xiang)(xiang)終點(dian)實現(xian)零(ling)沖(chong)擊(ji)和(he)零(ling)誤差。