應用PLC技術實現對(dui)機械手的控(kong)制，其任(ren)務是(shi)將工(gong)件從傳送(song)(song)帶A搬(ban)運(yun)到傳送(song)(song)帶B。采(cai)用移位指令設計順控(kong)程序。

機械(xie)(xie)手(shou)的動作示(shi)意圖如圖1所示(shi)，它是一個能夠產生(sheng)水平/垂直位(wei)移的機械(xie)(xie)設備，用來(lai)將工件由左工作臺搬(ban)運(yun)到右工作臺。

圖 1

1、工藝過程與(yu)控制要求

機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)的(de)(de)(de)全(quan)部動(dong)(dong)(dong)作由(you)(you)氣缸驅動(dong)(dong)(dong)，而氣缸又由(you)(you)相(xiang)應的(de)(de)(de)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)控制(zhi)。其中，上(shang)(shang)升(sheng)/下降和左(zuo)(zuo)(zuo)轉(zhuan)/右(you)轉(zhuan)分(fen)別由(you)(you)雙(shuang)線(xian)(xian)圈兩位(wei)(wei)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)控制(zhi)。例如(ru)：當(dang)(dang)(dang)下降電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)通(tong)電(dian)(dian)(dian)(dian)時，機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)下降；當(dang)(dang)(dang)下降電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)斷(duan)電(dian)(dian)(dian)(dian)時，機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)下降停止(zhi)。只有當(dang)(dang)(dang)上(shang)(shang)升(sheng)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)通(tong)電(dian)(dian)(dian)(dian)時，機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)才上(shang)(shang)升(sheng)；當(dang)(dang)(dang)上(shang)(shang)升(sheng)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)斷(duan)電(dian)(dian)(dian)(dian)時，機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)上(shang)(shang)升(sheng)停止(zhi)。同樣，左(zuo)(zuo)(zuo)轉(zhuan)/右(you)轉(zhuan)分(fen)別由(you)(you)左(zuo)(zuo)(zuo)轉(zhuan)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)和右(you)轉(zhuan)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)控制(zhi)。機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)的(de)(de)(de)放(fang)松(song)/夾緊由(you)(you)一個單線(xian)(xian)圈兩位(wei)(wei)電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa)(稱為夾緊電(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)(fa))來控制(zhi)氣缸的(de)(de)(de)運動(dong)(dong)(dong)。當(dang)(dang)(dang)該線(xian)(xian)圈通(tong)電(dian)(dian)(dian)(dian)時，機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)夾緊；當(dang)(dang)(dang)該線(xian)(xian)圈斷(duan)電(dian)(dian)(dian)(dian)時，機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)手(shou)放(fang)松(song)。

當機械手右移到位并準備下降時，為了確保安全，必須在右工作臺無工件時才允許機械手下降。也就是說，若上一次搬運到右工作臺上的工件尚未搬走時，機械手應自動停止下降，用光電開關I0.5進行無工件檢測。

機械(xie)(xie)手(shou)(shou)(shou)(shou)的動作過程如圖(tu)2所(suo)示。從原(yuan)點(dian)開(kai)(kai)(kai)(kai)始，按下(xia)(xia)(xia)啟(qi)動按鈕，下(xia)(xia)(xia)降(jiang)(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機械(xie)(xie)手(shou)(shou)(shou)(shou)下(xia)(xia)(xia)降(jiang)(jiang)(jiang)。下(xia)(xia)(xia)降(jiang)(jiang)(jiang)到(dao)(dao)(dao)(dao)(dao)(dao)(dao)底(di)時(shi)(shi)(shi)，碰到(dao)(dao)(dao)(dao)(dao)(dao)(dao)下(xia)(xia)(xia)限(xian)位(wei)(wei)(wei)(wei)開(kai)(kai)(kai)(kai)關(guan)(guan)，下(xia)(xia)(xia)降(jiang)(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，下(xia)(xia)(xia)降(jiang)(jiang)(jiang)停止(zhi)(zhi)；同(tong)時(shi)(shi)(shi)接(jie)通(tong)夾(jia)緊電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)，機械(xie)(xie)手(shou)(shou)(shou)(shou)夾(jia)緊。夾(jia)緊后(hou)，上升(sheng)(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機械(xie)(xie)手(shou)(shou)(shou)(shou)上升(sheng)(sheng)(sheng)。上升(sheng)(sheng)(sheng)到(dao)(dao)(dao)(dao)(dao)(dao)(dao)頂時(shi)(shi)(shi)，碰到(dao)(dao)(dao)(dao)(dao)(dao)(dao)上限(xian)位(wei)(wei)(wei)(wei)開(kai)(kai)(kai)(kai)關(guan)(guan)，上升(sheng)(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，上升(sheng)(sheng)(sheng)停止(zhi)(zhi)；同(tong)時(shi)(shi)(shi)接(jie)通(tong)右(you)移(yi)(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)，機械(xie)(xie)手(shou)(shou)(shou)(shou)右(you)移(yi)(yi)(yi)。右(you)移(yi)(yi)(yi)到(dao)(dao)(dao)(dao)(dao)(dao)(dao)位(wei)(wei)(wei)(wei)時(shi)(shi)(shi)，碰到(dao)(dao)(dao)(dao)(dao)(dao)(dao)右(you)限(xian)位(wei)(wei)(wei)(wei)開(kai)(kai)(kai)(kai)關(guan)(guan)，右(you)移(yi)(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，右(you)移(yi)(yi)(yi)停止(zhi)(zhi)。若此(ci)時(shi)(shi)(shi)右(you)工作臺上無工件，則光(guang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)(kai)(kai)(kai)關(guan)(guan)接(jie)通(tong)，下(xia)(xia)(xia)降(jiang)(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機械(xie)(xie)手(shou)(shou)(shou)(shou)下(xia)(xia)(xia)降(jiang)(jiang)(jiang)。下(xia)(xia)(xia)降(jiang)(jiang)(jiang)到(dao)(dao)(dao)(dao)(dao)(dao)(dao)底(di)時(shi)(shi)(shi)，碰到(dao)(dao)(dao)(dao)(dao)(dao)(dao)下(xia)(xia)(xia)限(xian)位(wei)(wei)(wei)(wei)開(kai)(kai)(kai)(kai)關(guan)(guan)，下(xia)(xia)(xia)降(jiang)(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，下(xia)(xia)(xia)降(jiang)(jiang)(jiang)停止(zhi)(zhi)； 同(tong)時(shi)(shi)(shi)夾(jia)緊電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機械(xie)(xie)手(shou)(shou)(shou)(shou)放松(song)。放松(song)后(hou)，上升(sheng)(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，機械(xie)(xie)手(shou)(shou)(shou)(shou)上升(sheng)(sheng)(sheng)。上升(sheng)(sheng)(sheng)到(dao)(dao)(dao)(dao)(dao)(dao)(dao)頂時(shi)(shi)(shi)， 碰到(dao)(dao)(dao)(dao)(dao)(dao)(dao)上限(xian)位(wei)(wei)(wei)(wei)開(kai)(kai)(kai)(kai)關(guan)(guan)，上升(sheng)(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，上升(sheng)(sheng)(sheng)停止(zhi)(zhi)；同(tong)時(shi)(shi)(shi)接(jie)通(tong)左(zuo)移(yi)(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)，機械(xie)(xie)手(shou)(shou)(shou)(shou)左(zuo)移(yi)(yi)(yi)。左(zuo)移(yi)(yi)(yi)到(dao)(dao)(dao)(dao)(dao)(dao)(dao)原(yuan)點(dian)時(shi)(shi)(shi)，碰到(dao)(dao)(dao)(dao)(dao)(dao)(dao)左(zuo)限(xian)位(wei)(wei)(wei)(wei)開(kai)(kai)(kai)(kai)關(guan)(guan)，左(zuo)移(yi)(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)閥(fa)(fa)斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，左(zuo)移(yi)(yi)(yi)停止(zhi)(zhi)。至此(ci)，機械(xie)(xie)手(shou)(shou)(shou)(shou)經(jing)過八步動作完成了一個周(zhou)期(qi)的動作。

圖 2

機(ji)械(xie)手的操作(zuo)方式分(fen)為手動操作(zuo)方式和自動操作(zuo)方式。自動操作(zuo)方式又分(fen)為步進(jin)、單周期和連續操作(zuo)三種方式。

（1）手(shou)動(dong)操(cao)作：就是用按(an)(an)(an)鈕(niu)(niu)操(cao)作對機(ji)械(xie)(xie)手(shou)的每步運(yun)動(dong)單(dan)獨進行(xing)控(kong)制。例如，當選(xuan)擇(ze)上(shang)/下(xia)(xia)運(yun)動(dong)時，按(an)(an)(an)下(xia)(xia)啟動(dong)按(an)(an)(an)鈕(niu)(niu)，機(ji)械(xie)(xie)手(shou)下(xia)(xia)降(jiang)；按(an)(an)(an)下(xia)(xia)停(ting)(ting)止(zhi)(zhi)按(an)(an)(an)鈕(niu)(niu)，機(ji)械(xie)(xie)手(shou)上(shang)升。當選(xuan)擇(ze)左/右運(yun)動(dong)時，按(an)(an)(an)下(xia)(xia)啟動(dong)按(an)(an)(an)鈕(niu)(niu)，機(ji)械(xie)(xie)手(shou)右移；按(an)(an)(an)下(xia)(xia)停(ting)(ting)止(zhi)(zhi)按(an)(an)(an)鈕(niu)(niu)，機(ji)械(xie)(xie)手(shou)左移。當選(xuan)擇(ze)夾(jia)緊/放松運(yun)動(dong)時，按(an)(an)(an)下(xia)(xia)啟動(dong)按(an)(an)(an)鈕(niu)(niu)，機(ji)械(xie)(xie)手(shou)夾(jia)緊；按(an)(an)(an)下(xia)(xia)停(ting)(ting)止(zhi)(zhi)按(an)(an)(an)鈕(niu)(niu)，機(ji)械(xie)(xie)手(shou)放松。

（2）步進操作：每按一次啟動(dong)按鈕(niu)，機械手(shou)完成一步動(dong)作后自動(dong)停止。

（3）單周(zhou)期操作：機械(xie)手(shou)從原點(dian)開始(shi)，按(an)一下啟動按(an)鈕，機械(xie)手(shou)自動完成一個(ge)周(zhou)期的動作后停止(zhi)。

（4）連(lian)續(xu)(xu)操(cao)作：機(ji)械(xie)手從原點開始(shi)，按(an)一下啟動按(an)鈕(niu)，機(ji)械(xie)手的動作將自動地(di)、連(lian)續(xu)(xu)不(bu)斷地(di)周(zhou)期(qi)性循環(huan)。在工(gong)作中(zhong)若按(an)下停(ting)(ting)止(zhi)按(an)鈕(niu)，則(ze)機(ji)械(xie)手將繼續(xu)(xu)完成一個(ge)周(zhou)期(qi)的動作后(hou)，回到(dao)原點自動停(ting)(ting)止(zhi)。

2、操作面板布(bu)置(zhi)

圖3位操作面(mian)板(ban)布置圖。

接通I0.7是單操作方式。按加載選擇開關的位置，用啟動/停止按鈕選擇加載操作，當加載選擇開關打到“左右”位置時，按下啟動按鈕，機械手右行;若按下停止按鈕，機械手左行。用上述操作可使機械手停在原點。

接通I1.0是步進方式。機械手在原點時，按下啟動按鈕，向前操作一步;每按啟動按鈕一次，操作一步。接通I1.1是單周期操作方式。機械手在原點時，按下啟動按鈕，自動操作一個周期。接通I1.2是連續操作方式。機械手在原點時，按下啟動按鈕，連續執行自動周期操作，當按下停止按鈕，機械手完成此周期動作后自動回到原點并不再動作。

圖 3

3、輸入(ru)/輸出端子(zi)地址(zhi)分配機械手控制系統所采用的PLC是德國西門子公司生產的S7-200CPU214，圖4是S7-200 CPU214輸入/輸出端子地址分配圖。該機械手控制系統共使用了14個輸入量，6個輸出量。

圖 4

4、整體(ti)程序結(jie)構

機械手的整體程序結構如圖5所示。若選擇單操作工作方式，I0.7斷開,接著執行單操作程序。(單操作程序可以獨立于自動操作程序，可另行設計)。

在(zai)單(dan)周期工作(zuo)(zuo)(zuo)方(fang)(fang)式(shi)和(he)連續操(cao)作(zuo)(zuo)(zuo)方(fang)(fang)式(shi)下，可執行(xing)自動(dong)操(cao)作(zuo)(zuo)(zuo)程序。在(zai)步(bu)(bu)進工作(zuo)(zuo)(zuo)方(fang)(fang)式(shi)，執行(xing)步(bu)(bu)進操(cao)作(zuo)(zuo)(zuo)程序，按一下啟動(dong)按鈕執行(xing)一個(ge)動(dong)作(zuo)(zuo)(zuo)，并(bing)按規定順序進行(xing)。

在需要自動操作方式時，中間繼電器M1.0接通。步進工作方式、單操作工作方式和自動操作方式，都用同樣的輸出繼電器。