【文章內容簡介】 ） 步進電機的運行控制： １） 轉速控制。接通起動開關 X30。脈沖控制器產生周期為 0。 1 秒的脈沖，使移位寄存器移位產生八拍時序脈沖。通過四相八拍環(huán)行分配器使四個輸出繼電器 Y Y3 Y3 Y33 按照單雙八拍的通電方 式接通，其接通順序為： Y30—— Y Y31—— Y31——Y3 Y32——Y32——Y3 Y33——Y33——Y3Y30——Y30 其相應于四相步進電動機繞組的通電順序為： PLC 功率放大器 步進電動機 ＰＬＣ電氣和測控系統設計 20 A—— A、 B—— B—— B、 C—— C—— C、 D—— D—— D、 A—— A 調整 T200 的定時時間，步進電機的接通順序不變，但間隔時間變化了。即 脈沖的頻率改變了，這樣可以通過軟件的辦法改變 T200 的定時時間來改變步進電機的轉速，實現步進電機的可調。 ２） 步數控制。改變步數控制 C230 的數值，將使步進電動機的步距改變。即可實現工件的 步距改變，有利于實現生產線布局的調節(jié)。 ３） 總之，改變 PLC 的控制程序，可實現步進電動機靈活多變的運行方式，有利于實現設計的模塊化。 2)轉步條件圖。 在負載驅動圖上加上名步序的轉步條件，構成轉步條件圖，如圖所示。當按下自動起動按鈕，機械手一、二、三的起動有效時，機械手開始動作。按步序完成所有動作，當機械手一、二、三都又處于原位時完成一次工作過程，當起動信號再一次有效時步序又轉換為第一次工作狀態(tài)。以后，用類似的方法完成一系列工藝過程的轉換。 ３） 狀態(tài)轉換圖和步進梯形圖。它由負載驅動圖和轉步條 件圖組合而成。圖中每個工藝過程，都由標有編號的狀態(tài)器代替，編號可在 S500—S800 范圍內選用。但不一定要連續(xù)排列。根據機械操作的工藝過程的狀態(tài)轉換圖，進行編程，而不設計常規(guī)的繼電器順序。 (3)方式選擇等通用程序 1) 狀態(tài)的初始化。如圖所示。狀態(tài)初始化包括初始狀置位和中間狀態(tài)器復位。 1. 初始狀態(tài)置位。在選擇返回原位方式下， 按返回原位按鈕，則表示機器初始化條件的初始狀態(tài)器 S500、 S5 S550 置位，其作用是使自動順序工作從原位開始，依次逐步進行轉換當最后工序完成之后 S500、 S5S550 又分別置位。 而在依次工作期間，即使誤按了起動按鈕，也不可能作另一次的起動，因為此時工序已不在原位， S500、 S5 S550 已處于不工作狀態(tài)。 2．中間狀態(tài)器復位。因為狀態(tài)器 S500—S800 均由后備電源支持，在失電時有可能是接通的。為防止順序控制動作，通常需要在返回原位和手動操作時，ＰＬＣ電氣和測控系統設計 21 對處于蹭狀態(tài)的狀態(tài)器進行總復位。指令格式如圖。 F670K103 是總復位功能指令，包括 F671 的 K 編號到 F672 的 K 編號的所有器件。 2) 狀態(tài)器轉換禁止 如圖。當用步進梯形指令控制狀態(tài)器轉換時，激勵特殊功能繼電器 M574 動作 ，則狀態(tài)器的自動轉換就被禁止。 當按下自動按鈕時， M110 產生脈沖輸出，使 M574 斷開，狀態(tài)器轉換禁止立即復位，進行后工序處理。 1． 對自動連續(xù)操作方式，狀態(tài)轉換禁止不受起動 X42 的影響，若按下停止按鈕時， M574 得電自保持，操作停止在現行工序。按起動按鈕又可繼續(xù)下去。 2． 手動方式及 PC 起動時，都可使 M574 得電自保持，禁止狀態(tài)轉換，直到按下起動按鈕。 ３．６ 生產線控制總程序 按照圖完整順序控制結構安排，將通用程序塊、手動程序塊、自動程序塊用FX2N80MR PLC 的跳轉條件程序有機地連 接起來，即得到生產線步進指令實現控制的總程序。 附加外文翻譯 外文文獻 I , robot controller A sophisticated approach to kinematics is what differentiates robot controllers from more general purpose motion equipment. An interesting situation emerged recently when a manufacturer tried to put a vision system on an assembly line. The idea was to locate parts on a moving conveyor with a vision system ,then position a robotics arm to pick them up line at a time .Engineers there diligently worked out numerous displacement fudge factors to relate the locations of the conveyor end effectors and parts imaged by the camera . The fudge factors let the motion controller infer the physical location of a part from the vision system data , then direct the arm to the right place ＰＬＣ電氣和測控系統設計 22 to pick it up. Problem was , the relative position of the various ponents all changed every time the conveyor went back on line after servicing or maintenance . The factors so carefully puted became useless .This necessitated regular rounds of recalculating new displacements. At the root of these difficulties were some fundamental misunderstandings about how generalpurpose motion controllers differ from more specialized robot controllers. Hardwarewise, the two can look similar. Both frequently employ Pentiumbased processors or adopt a hybrid approach with a general CPU supervising one or more digital signal processors dedicated to servo loops. However, the software architecture of a robot controller differs dramatically from that of an ordinary motioncontroller software: It generally consists of a routine for closedloop position or v velocity control ,operator interface functions , and routine for supervisory tasks. An important point to note is at the supervisory level of control . Tasks there that relate to handling motion do not extend much past simply issuing position mands and individual axes. In other word ,the supervisory level is relatively simply. The supervisory level of robot controller is more sophisticated. For one thing , it is written with the idea that ,post robotic systems incorporate feedback from highlevel sensors that reside outside the positionencoderfeedback servo loops of individual axes. Typical examples include industrial vision system and force sensors. Most robotic work involves using information from these sensors to calculate the trajectory of a robot arm. To handle this calculation process, supervisory level software implements a trajectory planning algorithm. This algorithm relates the physical location of positioning elements, sensor feedback ,and the objects being positioned in terms of what’s called a world coordinate system. This is in contrast to generalpurpose motion equipment which tends to use a separate reference frame for each axis of motion . One benefit of a worldcoordinate system is that it can eliminate the need for fudge factors relating sensor data to the position of various ponents. The state of the art is such that straightforward setup routines can pute suck information automatically. Moreover, data gathered during setup goes into transformation calculations that determin