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河北建筑工程學(xué)院
畢業(yè)實習(xí)報告
系 別 機(jī)械工程系
專 業(yè) 機(jī)械設(shè)計制造及其自動化
班 級 機(jī)091班
姓 名 周文斌
學(xué) 號 2009307107
指導(dǎo)教師 李常勝
實習(xí)成績
畢業(yè)實習(xí)報告
1、實習(xí)目的
畢業(yè)實習(xí)是大學(xué)生完成四年的全部課程之后的最重要的實踐環(huán)節(jié)。也是在進(jìn)行畢業(yè)設(shè)計或畢業(yè)論文時必不可少的實踐性教學(xué)環(huán)節(jié)。它對于培養(yǎng)我們的動手能力有很大的意義，而且可以使我們了解傳統(tǒng)的機(jī)械制造工藝和現(xiàn)代機(jī)械制造技術(shù)。畢業(yè)實習(xí)為大學(xué)生提供了培養(yǎng)和造就實踐能力和創(chuàng)新能力的必要物質(zhì)基礎(chǔ)和良好的環(huán)境，這次畢業(yè)實習(xí)對我們畢業(yè)生來說意義非常的重大，因此每位同學(xué)都必須珍惜這一難得的機(jī)會，有效地利用寶貴的畢業(yè)實習(xí)時間，把培養(yǎng)實踐能力和打造創(chuàng)新能力作為畢業(yè)實習(xí)和畢業(yè)設(shè)計的指導(dǎo)思想。
2、 實習(xí)內(nèi)容
老師為了我們更加感性的認(rèn)識塔式起重機(jī)，安排我們?nèi)ラL春機(jī)械展銷會參觀實習(xí)。因為對塔式起重機(jī)比較陌生，所以我們對這次的實習(xí)抱很大希望，首先要對塔式起重機(jī)有個全面的了解，其次對于自己要設(shè)計的起升機(jī)構(gòu)更要弄明白。我們3月19日出發(fā)，經(jīng)過一天的坐火車我們來到東北老工業(yè)基地長春。第二天在老師的帶領(lǐng)下我們觀看了塔式起重機(jī)以及大型挖掘機(jī)等重要機(jī)械，讓我們著實的開了眼界。各個生產(chǎn)商都擺放著他們的代表性產(chǎn)品。我們詳細(xì)的看了每個部件，塔身、臂架、標(biāo)準(zhǔn)節(jié)、等等很多部件。當(dāng)然我仔細(xì)看了起升機(jī)構(gòu)的結(jié)構(gòu)并照下了很多照片以便下來自己再細(xì)細(xì)研究。在老師的介紹下我們對塔式起重機(jī)有了初步的認(rèn)識。
塔式起重機(jī)是一種塔身豎立起重臂會轉(zhuǎn)到起重機(jī)械。在工業(yè)與民用建筑施工中塔式起重機(jī)是完成預(yù)制構(gòu)件與其他建筑材料與工具等吊裝工作的主要設(shè)備。在高層建筑施工中，它的幅度利用率比其他類型起重機(jī)高。塔式起重機(jī)在高層工業(yè)和民用建筑施工的使用中一直處于領(lǐng)先地位。應(yīng)用塔式起重機(jī)對于加快施工進(jìn)度、縮短工期、降低工程造價起著重要的作用。由于塔式起重機(jī)性能參數(shù)不斷完善，使建筑工藝也有可能進(jìn)行許多重大改革，比如采用大型砌塊、大板結(jié)構(gòu)設(shè)置箱形結(jié)構(gòu)后，建筑物結(jié)構(gòu)件的預(yù)制裝備化、工廠化達(dá)到了很高的水平。
塔式起重機(jī)是在第二次世界大戰(zhàn)后才真正獲得發(fā)展的。在中國塔式起重機(jī)的生產(chǎn)與應(yīng)用已有40多年的歷史，經(jīng)歷了一個從側(cè)回到自行設(shè)計制造的過程。經(jīng)過多年的發(fā)展，中國塔式起重機(jī)行業(yè)隨著全國范圍建筑任務(wù)的增加而進(jìn)入了一個新的興盛時期，至此，無論從生產(chǎn)規(guī)模、應(yīng)用范圍和塔式起重機(jī)總量等角度來衡量，中國均堪稱塔式起重機(jī)大國。根據(jù)國內(nèi)外一些技術(shù)資料介紹，塔式起重機(jī)的發(fā)展趨勢可具體歸納為吊臂長度加長、工作速度提高且能調(diào)速、改善操縱條件、更多的采用組裝式結(jié)構(gòu)四個方面。
塔式起重機(jī)一般有四大工作機(jī)構(gòu)，它們是起升機(jī)構(gòu)、變幅機(jī)構(gòu)、回轉(zhuǎn)機(jī)構(gòu)、行走機(jī)構(gòu)。起升機(jī)構(gòu)用來實現(xiàn)載荷的升降，它是塔式起重機(jī)中最重要也是最基本的機(jī)構(gòu)，起升機(jī)構(gòu)的性能將直接影響到整臺塔式起重機(jī)的工作性能。變幅機(jī)構(gòu)是塔式起重機(jī)改變工作幅度的機(jī)構(gòu)，用以擴(kuò)大塔式起重機(jī)的工作范圍，提高工作效率。通過變幅機(jī)構(gòu)能將所運(yùn)輸?shù)奈锪线\(yùn)送到工作面上?；剞D(zhuǎn)機(jī)構(gòu)是塔式起重機(jī)的主要工作機(jī)構(gòu)之一，它能將起升在空間的物料繞塔式起重機(jī)垂直軸線作圓周運(yùn)動，擴(kuò)大塔式起重機(jī)的工作面。行走機(jī)構(gòu)的作用是驅(qū)動塔式起重機(jī)沿著軌道行駛、配合其他機(jī)構(gòu)完成水平運(yùn)輸及垂直運(yùn)輸工作。塔式起重機(jī)的自重和載荷重量通過行走機(jī)構(gòu)的行走輪傳給軌道。
塔式起重機(jī)的起升機(jī)構(gòu)通常由電機(jī)、制動器、減速器、卷筒、鋼絲繩、滑輪組及吊鉤等零部件組成。電機(jī)通過聯(lián)軸器與減速器相連。減速器的輸出軸上裝有卷筒，它通過鋼絲繩和安裝在塔身或塔頂上導(dǎo)向滑輪及滑輪組與吊鉤相連。電機(jī)工作時，卷筒將鋼絲繩卷進(jìn)或放出，通過滑輪組使吊鉤上的物品起升或下降。當(dāng)電機(jī)停止工作時，制動器通過彈簧力將制動輪剎住。
塔式起重機(jī)的變幅機(jī)構(gòu)按工作性質(zhì)可分為非工作性變幅機(jī)構(gòu)和工作性變幅機(jī)構(gòu)。非工作性變幅機(jī)構(gòu)指只在空載時改變幅度，調(diào)整取物裝置的作業(yè)位置，而在重物裝卸英東過程中幅度不再改變。這種變幅機(jī)構(gòu)變幅次數(shù)少，變幅時間對起重機(jī)的生產(chǎn)效率影響小，一般采用較低的變幅速度，其優(yōu)點是構(gòu)造簡單、自重輕。工作性變幅機(jī)構(gòu)是指能在帶載條件下變幅的機(jī)構(gòu)。變幅過程是起重機(jī)工作循環(huán)主要環(huán)節(jié)，變幅時間對起重機(jī)的生產(chǎn)效率有直接影響，一般采用較高的變幅速度。其優(yōu)點是生產(chǎn)率高，能更好地滿足裝卸工作地需要。工作性變幅機(jī)構(gòu)驅(qū)動功率較大，而且要求安裝限速和防止超載的安全裝置，與非工作性變幅機(jī)構(gòu)相比，構(gòu)造復(fù)雜，自重也較大。
塔式起重機(jī)的變幅機(jī)構(gòu)按機(jī)構(gòu)運(yùn)動形式分為臂架擺動式變幅機(jī)構(gòu)和運(yùn)行小車式變幅機(jī)構(gòu)。動臂式變幅機(jī)構(gòu)式通過吊臂俯仰擺動實現(xiàn)變幅。小車變幅塔式起重機(jī)是指通過起重小車沿起重臂運(yùn)行進(jìn)行變幅的塔式起重機(jī)。綜合變幅塔式起重機(jī)是指根據(jù)作業(yè)的需要臂架可以彎折的塔式起重機(jī)。
塔式起重機(jī)的回轉(zhuǎn)機(jī)構(gòu)能使塔機(jī)的起重臂架作360度回轉(zhuǎn)，這樣就擴(kuò)大了塔式起重機(jī)的工作面。塔式起重機(jī)回轉(zhuǎn)機(jī)構(gòu)包括回轉(zhuǎn)支撐裝置和驅(qū)動機(jī)構(gòu)兩部分。回轉(zhuǎn)支撐裝置為塔機(jī)的回轉(zhuǎn)部分提供穩(wěn)定、牢固的支撐，并將回轉(zhuǎn)部分的載荷傳遞給塔身部分；驅(qū)動機(jī)構(gòu)驅(qū)動塔機(jī)的回轉(zhuǎn)部分，使其相對塔機(jī)的固定部分實現(xiàn)回轉(zhuǎn)。塔式起重機(jī)的回轉(zhuǎn)支撐裝置一般有柱式回轉(zhuǎn)支撐裝置和滾動軸承式回轉(zhuǎn)支撐裝置。塔式起重機(jī)上一般采用電動回轉(zhuǎn)驅(qū)動裝置?；剞D(zhuǎn)驅(qū)動裝置通常安裝在塔機(jī)的回轉(zhuǎn)部分上，電動機(jī)經(jīng)減速器帶動最后一級小齒輪，小齒輪與裝在塔機(jī)固定部分上的大齒圈相嚙合，以實現(xiàn)回轉(zhuǎn)運(yùn)動。
行走機(jī)構(gòu)用以支撐起重機(jī)本身的重量和起重載荷，并使起重機(jī)水平運(yùn)行。起重機(jī)的行走方式分為有軌行走機(jī)構(gòu)和無軌行走機(jī)構(gòu)兩類。有軌行走是指車輪在專門鋪設(shè)的軌道上行走；無軌行走則采用輪胎或履帶，可以在普通的道路上行駛，機(jī)動性強(qiáng)。
通過老師的講解使我們更深入的了解的塔式起重機(jī)的構(gòu)造和功用。為我們的畢業(yè)設(shè)計做了很好的鋪墊。
3、實習(xí)結(jié)果
實習(xí)結(jié)束了,該次實習(xí)使我們不僅掌握了有關(guān)起升機(jī)構(gòu)的知識還了解了關(guān)于塔式起重機(jī)的其他部件。以前在課本上不能理解的問題都有了更深刻的認(rèn)識。這次實習(xí)以及前一段時間查閱的大量資料為我的畢業(yè)設(shè)計提供了良好的基礎(chǔ)，使我深深地體會到要想搞好設(shè)計，就必須耐心仔細(xì)地查找與設(shè)計相關(guān)的資料和信息（包括設(shè)計產(chǎn)品的基本功能、主要結(jié)構(gòu)、應(yīng)用特點及其發(fā)展前途，市場效益等）。我國目前制造業(yè)的發(fā)展?fàn)顩r也粗步了解了機(jī)械制造的發(fā)展趨勢。在新的世紀(jì)里,科學(xué)技術(shù)必將以更快的速度發(fā)展，更快更緊密得融合到各個領(lǐng)域中,而這一切都將大大拓寬機(jī)械制造業(yè)的發(fā)展方向。
將來的機(jī)械制造將會向“四個化”發(fā)展，即柔性化、靈捷化、智能化、信息化。即使工藝裝備與工藝路線能適用于生產(chǎn)各種產(chǎn)品的需要，能適用于迅速更換工藝、更換產(chǎn)品的需要,使其與環(huán)境協(xié)調(diào)的柔性,使生產(chǎn)推向市場的時間最短且使得企業(yè)生產(chǎn)制造靈活多變的靈捷化,還有使制造過程物耗,人耗大大降低,高自動化生產(chǎn),追求人的智能與機(jī)器智能高度結(jié)合的智能化，以及借助于物質(zhì)和能量的力量生產(chǎn)出價值的信息化。
4、實習(xí)總結(jié)或體會
畢業(yè)實習(xí)是我們從學(xué)校到社會的一座橋梁，是從理論到實際的一條紐帶。加強(qiáng)我們綜合能力的培養(yǎng)，使得我們既要掌握專業(yè)的基本理論和基本知識，又具有對于所學(xué)知識的運(yùn)用能力以及獨立工作的能力，為我們在畢業(yè)設(shè)計中、甚至為畢業(yè)后的實際工作打下了良好的基礎(chǔ)。通過此次畢業(yè)實習(xí)我們了解到目前機(jī)械制造的發(fā)展趨勢，也使我們清晰地定位我們所處的位置，對我們以后走上工作崗位起到一個良好的模范作用。紙上得來終覺淺，絕知此事要躬行。我深深地感覺到自己所學(xué)知識的膚淺和在實際運(yùn)用中的專業(yè)知識的匱乏，一旦接觸到實際，才發(fā)現(xiàn)自己知道的是多么少，這時才真正領(lǐng)悟到“學(xué)無止境”的含義。
河 北 建 筑 工 程 學(xué) 院
本科畢業(yè)設(shè)計（論文）
題
目
QTZ40塔式起重機(jī)——變幅系統(tǒng)的設(shè)計
學(xué) 科 專 業(yè) 機(jī)械設(shè)計制造及其自動化
班 級 機(jī)091班
姓 名 周文斌
指 導(dǎo) 教 師 李常勝
輔 導(dǎo) 教 師
河北建筑工程學(xué)院
畢業(yè)設(shè)計（論文）開題報告
課題
名稱
QTZ40塔式起重機(jī)——變幅系統(tǒng)的設(shè)計
系 別： 機(jī)械工程系
專 業(yè)： 機(jī)械設(shè)計制造及其自動化
班 級： 機(jī)091
學(xué)生姓名： 周文斌
學(xué) 號： 2009307107
指導(dǎo)教師： 李常勝
課題來源
導(dǎo)師課題
課題類別
工程設(shè)計
一、論文資料的準(zhǔn)備
1.塔式起重機(jī)概述
塔式起重機(jī)是一種塔身樹立起重臂回轉(zhuǎn)的起重機(jī)械，簡稱塔機(jī)，也叫塔吊，起源于西歐。具有工作效率高、使用范圍廣、回轉(zhuǎn)半徑大、起升高度大、操作方便以及安裝與拆卸比較簡便等特點。主要完成在高層建筑施工中預(yù)制構(gòu)件及其他建筑材料與工具等吊裝工作。塔式起重機(jī)應(yīng)具備下列特點：
（1）起升高度和工作幅度較大、起重力矩大；
（2）工作速度高，具有安裝微動性能及良好的調(diào)速性能；
（3）要求拆裝運(yùn)輸方便迅速，以適應(yīng)頻繁轉(zhuǎn)移工地的需要。
2.我國塔式起重機(jī)的發(fā)展現(xiàn)狀
塔式起重機(jī)在我國的生產(chǎn)與應(yīng)用已經(jīng)有50余年的歷史，經(jīng)歷了以個從測繪仿制到自行設(shè)計制造的過程，特別是進(jìn)入20世紀(jì)90年代以后，我國塔式起重機(jī)行業(yè)隨著全國范圍建筑任務(wù)的增加而進(jìn)入了一個興盛時期，年產(chǎn)量連年猛增，而且有部分產(chǎn)品出口到國外。
現(xiàn)在我國的建筑用塔式起重機(jī)已越來越普遍，從普通的多層民用建筑、房地產(chǎn)工程、高層建筑到大型的鐵路工程、橋梁工程、電力工程、水利工程等，到處都有塔機(jī)的應(yīng)用。近20年來，市場的需求，有力的促進(jìn)了技術(shù)的進(jìn)步，通過研究開發(fā)、技術(shù)創(chuàng)新、引進(jìn)消化，我們的設(shè)計手段和配套件生產(chǎn)能力也有了很大的進(jìn)步，計算機(jī)輔助設(shè)計、微電子技術(shù)、程控語言控制技術(shù)都在塔機(jī)上得到了應(yīng)用。當(dāng)然也不可否認(rèn)，我國的塔機(jī)產(chǎn)品的技術(shù)性能、制作質(zhì)量和品種型號規(guī)格，與發(fā)達(dá)國家產(chǎn)品相比，仍然存在較大的差距，特別是基礎(chǔ)零部件的可靠性、電氣元件、液壓元件、工藝安裝、生產(chǎn)設(shè)備和檢測手段等，差距更大。這就影響了我們整機(jī)產(chǎn)品的質(zhì)量和可靠性，增加了事故隱患。對此我們絕不可以掉以輕心，要加倍努力、敢于創(chuàng)新、嚴(yán)格把關(guān)、趕超國際水平。
3.我國塔式起重機(jī)的發(fā)展趨勢
我國大規(guī)模經(jīng)濟(jì)建設(shè)已有二十來年的歷史，這二十來年里，大量建筑物的涌現(xiàn)和大型工程的興建，鐵路、公路橋梁的建設(shè)，給塔式起重機(jī)提供了良好的市場。我國的塔式起重機(jī)發(fā)展趨勢可以分以下幾個方面：
我國塔機(jī)產(chǎn)品的品種、型號、規(guī)格應(yīng)向多樣化發(fā)展，以適應(yīng)不同工程、不同用戶的需求。就目前現(xiàn)實而言，我國塔式起重機(jī)幾乎是上回轉(zhuǎn)一統(tǒng)天下，下回轉(zhuǎn)塔機(jī)很少。
4. 國外發(fā)展概況
塔式起重機(jī)是在第二次世界大戰(zhàn)后才真正獲得發(fā)展的。戰(zhàn)后各國面臨著重建家園的艱巨任務(wù)，浩大的建筑工程量迫切需要大量性能良好的塔式起重機(jī)。自塔式起重機(jī)在建筑施工中顯露身手并逐漸成為工程機(jī)械一個重要分支以來，已經(jīng)有50余年歷史，其間利經(jīng)了曲折復(fù)雜的發(fā)展階段。70年代末，由于種種原因，國外塔式起重機(jī)制造業(yè)陷入了低谷，不少中小工廠紛紛停業(yè)或轉(zhuǎn)產(chǎn)，僅少數(shù)大廠得以維持。直至80年代末才呈現(xiàn)逐漸復(fù)蘇態(tài)勢，1994年為復(fù)蘇年頭，復(fù)蘇勢頭最好的國家為德國。據(jù)有關(guān)資料介紹，在塔機(jī)制造業(yè)鼎盛的70年代，西德?lián)碛懈魇剿C(jī)48500臺，80年代總量減至1/3，而近幾年，東西德合并，基建規(guī)模擴(kuò)大，塔機(jī)產(chǎn)量上升，現(xiàn)有塔機(jī)近40000臺，其中半數(shù)機(jī)齡不足5年 www.51lunwen.com 。如今世界塔機(jī)市場最為紅火的地區(qū)為東歐和亞太（特別是東南亞）。活躍在塔機(jī)市場上的著名產(chǎn)商是；德國的 Liebherr 、Peiner、 Wolff ，法國的 Potain 、BPR,意大利的 Potain-Simma、Comedil 、 Nauva 、 EDILMAC ，西班牙的Comensa ，芬蘭的 Betrox ，丹麥的KRφLL 澳大利亞的Favco。這些大廠為了在國際塔機(jī)市場上占有更多份額，莫不注重總結(jié)經(jīng)驗，認(rèn)真分析市場動態(tài)，下大力氣進(jìn)行產(chǎn)品的更新和開發(fā)。近年來，國外塔機(jī)在新產(chǎn)品開發(fā)上大致有下列一些特點：
(1)更多的廠家注重開發(fā)經(jīng)濟(jì)型城市塔機(jī)并擴(kuò)展成系列。
(2)國外塔機(jī)新產(chǎn)品中，有一些新穎的輕、中型折疊式快速安裝塔機(jī)頗引人注目。
(3) 根據(jù)一些國家城建當(dāng)局的有關(guān)規(guī)定，為防止塔機(jī)臂架在狹窄的空間運(yùn)行發(fā)生矛盾，避免吊臂相互碰撞以及碰到鄰近的建筑物，在城市高層建筑密集地區(qū)施工必須采用動臂式自升塔式起重機(jī)。
(4)在經(jīng)過較長時間研制之后，履帶式水平臂架塔機(jī)作為一種新產(chǎn)品正式問世。
(5) 變頻調(diào)速系統(tǒng)在國外塔機(jī)新產(chǎn)品上得到推廣應(yīng)用。
(6)高新技術(shù)開始在塔機(jī)上應(yīng)用。
(7)無論上回轉(zhuǎn)或下回轉(zhuǎn)式塔機(jī)，都十分重視駕駛室的平面設(shè)計和空間處理。
5.QTZ40型塔式起重機(jī)的簡單介紹及其市場前景
QTZ40自升式塔吊為上回轉(zhuǎn)、水平臂架、小車變幅、液壓自升式多用途塔吊。起重力矩400KN.m，最大起重量4t，獨立架設(shè)時最大起升高度可達(dá)30米，加附著最大起升可達(dá)100米，最大幅度分40米。該機(jī)參數(shù)先進(jìn)，性能優(yōu)良可靠，造型美觀，質(zhì)量精良，結(jié)構(gòu)簡單實用，設(shè)有先進(jìn)的安全裝置，維修方便，使用安全，價格合理，是廣大中小建筑企業(yè)理想的建筑施工機(jī)械。同時該機(jī)適用性好，廣泛用于中高層以下的各類工業(yè)與民用建筑和滑模施工的吊裝，還常用于港口、貨場的裝卸。
二、本課題的目的（重點及擬解決的關(guān)鍵問題）
本畢業(yè)設(shè)計是對機(jī)械專業(yè)學(xué)生在畢業(yè)前的一次全面訓(xùn)練，目的在于鞏固和擴(kuò)大學(xué)生在校期間所學(xué)的基礎(chǔ)知識和專業(yè)知識，訓(xùn)練學(xué)生綜合運(yùn)用所學(xué)知識分析和解決問題的能力。是培養(yǎng)、鍛煉學(xué)生獨立工作能力和創(chuàng)新精神之最佳手段。畢業(yè)設(shè)計要求每個學(xué)生在工作過程中，要獨立思考，刻苦鉆研，有所創(chuàng)造的分析、解決技術(shù)問題。通過畢業(yè)設(shè)計，使學(xué)生掌握裝載機(jī)的總體設(shè)計、工作裝置設(shè)計、牽引計算等技術(shù)工作的實現(xiàn)方法，為今后步入工作崗位打下良好的基礎(chǔ)。
重點及擬解決的問題是：
1、變幅機(jī)構(gòu)和變幅小車的形式，卷筒尺寸計算
2、小車的強(qiáng)度計算
3、整機(jī)傾翻穩(wěn)定性的計算
三、主要內(nèi)容、研究方法、研究思路
1.主要內(nèi)容
塔式起重機(jī)的總體設(shè)計、變幅機(jī)構(gòu)的設(shè)計、變幅小車的設(shè)計和計算等內(nèi)容。
2. 研究方法
本設(shè)計的題目是QTZ40變幅機(jī)構(gòu)的設(shè)計，主要設(shè)計理念是通過參照同類塔式起重機(jī)進(jìn)行設(shè)計。QTZ40塔式起重機(jī)有多種形式，此次設(shè)計的形式為上回轉(zhuǎn)液壓頂升自動加節(jié)，固定式高度，工作幅度等設(shè)計。本機(jī)性能先進(jìn)，結(jié)構(gòu)合理，操作使用安全可靠．其主要特點是起重力矩大、起升高度高、工作幅度大、作業(yè)空間廣、使用效率高。
3.研究思路
本設(shè)計書主要包括三部分：
第一部分是QTZ40塔式起重機(jī)總體方案的選擇及總體設(shè)計計算過程；
第二部分是變幅機(jī)構(gòu)的設(shè)計與計算：包括變幅機(jī)構(gòu)的形式、確定卷筒尺寸、選擇電動機(jī)、減速器、制動器、聯(lián)軸器；驗算實際變幅速度 驗算起、制動時間；電動機(jī)發(fā)熱驗算；卷筒強(qiáng)度的計算。
第三部分是變幅小車的設(shè)計：包括變幅小車的形式、變幅小車的強(qiáng)度計算。最后，還需要對不同截面的穩(wěn)定性、剛度及強(qiáng)度進(jìn)行驗算以及校核。
四、總體安排和進(jìn)度（包括階段性工作內(nèi)容及完成日期）
2013.3.25-2013.3.28 熟悉整理資料
2013.3.29-2013.4.13 方案選擇及總體設(shè)計
2013.4.14-2013.4.20 繪制總圖
2013.4.21-2013.5.15 變幅機(jī)構(gòu)、變幅小車的設(shè)計
2013.5.16-2013.6.5 繪制變幅機(jī)構(gòu)、變幅小車裝配圖
2013.6.6-2013.6.19 繪制零件圖紙
2013.6.19-2013.6.21 準(zhǔn)備論文及答辯
五、主要參考文獻(xiàn)
【1】 董剛 李建功 潘風(fēng)章主編 《機(jī)械設(shè)計》（第3版） 北京：機(jī)械工業(yè)出版社 1998
【2】 張質(zhì)文，虞和謙等.起重機(jī)設(shè)計手冊.北京：中國鐵道出版社.1997.
【3】 《機(jī)械設(shè)計手冊》（第1卷）（新版）機(jī)械設(shè)計手冊編委會編著
北京：機(jī)械工業(yè)出版社 2004.8
【4】 《機(jī)械設(shè)計手冊》（第2卷）（新版）機(jī)械設(shè)計手冊編委會編著
北京：機(jī)械工業(yè)出版社 2004.8
【5】 成大先主編《機(jī)械設(shè)計手冊》（第4版）北京：化學(xué)工業(yè)出版社 2002
【6】 顧迪民主編《工程起重機(jī)》（第2版）北京：中國建筑工業(yè)出版社 1988
【7】 劉品主編《互換性與測量技術(shù)基礎(chǔ)》（第2版）哈爾濱：哈爾濱工業(yè)大學(xué)出版社 2001
【8】 徐灝主編《機(jī)械設(shè)計手冊》（第2版） 北京：機(jī)械工業(yè)出版社 2000
【9】 曹雙寅主編《工程結(jié)構(gòu)設(shè)計原理》 南京：東南大學(xué)出版社 2002
【10】劉鴻文主編《材料力學(xué)》（第4版） 高等教育出版社
【11】《QTZ400塔式起重機(jī)使用說明書》
【12】張青 張瑞軍 編著《工程起重機(jī)結(jié)構(gòu)與設(shè)計》北京：化學(xué)工業(yè)出版社，2008.7
【13】中華人民共和國國家標(biāo)準(zhǔn)GB/T 13752-92 《塔式起重機(jī)設(shè)計規(guī)范》 北京：中國標(biāo)準(zhǔn)出版社 1993
【14】范俊祥主編《塔式起重機(jī)》 中國建材工業(yè)出版社
【15】許鎮(zhèn)宇、邱宣懷主編：《機(jī)械零件》 人民教育出版社
【16】劉佩衡主編《塔式起重機(jī)使用手冊》 北京：機(jī)械工業(yè)出版社，2002
【17】中國建設(shè)部《鋼結(jié)構(gòu)設(shè)計規(guī)范》 2003.12
【18】黃靖遠(yuǎn) 龔劍霞 賈延林 《機(jī)械設(shè)計學(xué)》北京工業(yè)出版社，2002
【19】safety on construction sites 著者American Society of civil Engineers.Task Committee on Crane Safety on Constructions Sites 中圖分類號：TH21-36
指導(dǎo)教師意見：
指導(dǎo)教師簽名： 日期：
教研室意見：
教研室主任簽名： 日期：
系意見：
系領(lǐng)導(dǎo)簽名： 日期：
系蓋章
課題來源：導(dǎo)師課題、社會實踐、自選、其他
課題類別：工程設(shè)計、施工技術(shù)、新品開發(fā)、軟件開發(fā)、科學(xué)實驗、畢業(yè)論文。
摘要
塔式起重機(jī)作為建筑施工的主要設(shè)備，在建筑等行業(yè)發(fā)揮著極其重要的作用。塔式起重機(jī)屬于臂架型起重機(jī)，由于其臂架鉸接在較高的塔身上，且可回轉(zhuǎn)，臂架長度較大，結(jié)構(gòu)輕巧、安裝拆卸運(yùn)輸方便，適于露天作業(yè)，因此大多數(shù)用于工業(yè)與民用建筑施工。
塔式起重機(jī)是為了滿足高層建筑施工、設(shè)備安裝而設(shè)計的新型起重運(yùn)輸機(jī)械，QTZ40塔式起重機(jī)是由建設(shè)部長沙建設(shè)機(jī)械研究院設(shè)計的新型建筑用塔式起重機(jī)，該機(jī)為水平臂架，小車變幅，上回轉(zhuǎn)自升式多用途塔機(jī)。
本設(shè)計的題目是固定式QTZ40塔式起重機(jī)起升系統(tǒng)的設(shè)計。QTZ40塔式起重機(jī)有多種形式，此次設(shè)計的形式為上回轉(zhuǎn)液壓頂升自動加節(jié)，可隨著建筑物的升高而升高，固定式高度為30米，在附著狀態(tài)下可達(dá)到100米，其工作幅度為40米。
本設(shè)計書主要包括三部分：第一部分是QTZ40塔式起重機(jī)總體方案的選擇及總體設(shè)計計算過程；第二部分是變幅機(jī)構(gòu)的設(shè)計與計算：包括變幅機(jī)構(gòu)的形式、確定卷筒尺寸、選擇電動機(jī)、減速器、制動器、聯(lián)軸器；驗算實際變幅速度 驗算起、制動時間；電動機(jī)發(fā)熱驗算；卷筒強(qiáng)度的計算；第三部分是變幅小車的設(shè)計：包括變幅小車的形式、變幅小車的強(qiáng)度計算。
關(guān)鍵詞：QTZ40塔式起重機(jī) 總體設(shè)計：變幅系統(tǒng)
ABSTRACT
As an important facility, the tower crane plays an important role in construction industry. The tower crane belongs to the arm rack type crane. Its arm is hinged on the high tower body, and it may rotate. It has longer arm, dexterous structure. What’s more, it is easy to be assembled, disassembled and transported. It is suitable for the open-air work and mainly used for industry and civil construction
Tower cranes are to meet high-rise construction building, equipment installation and design as a new type machinery of lifting transport. The QTZ40 tower cranes are new tower cranes designed by Changsha Institute of the Ministry of Construction Machinery used in construction building. The aircraft is horizontal boom, trolley luffing, on the back or decanted from the tower-type multi-purpose machines .
The design topic is the stationary QTZ40 tower crane system and the design of lifting structure. There are many kinds of QTZ40 tower crane. The form of this design is as below. With an upper rotating hydraulic pressure propping system, the machine could add height automatically and thus rise with the building ascension. The stationary type is 30meter high; it could reach the height of 100meters when it is being adhered. Its work scope is 40 meters.
This design book mainly includes three parts. The first part summarizes the present situation and the development tendency of the tower crane in both our country and abroad, as well as the characteristic and application occasion..The second part is the QTZ40 tower crane overall concept choice and the system design computation process; the third part is the organization design and the computation of lifting mechanism and the last is the design of the hook group.
Keywords: QTZ500 tower crane The total design：luffing system
目錄
第1章 前言·················································································1
1.1塔式起重機(jī)概述········································································1
1.2塔式起重機(jī)的發(fā)展趨勢································································1
第2章 總體設(shè)計···········································································2
2.1 概述····················································································2
2.2確定總體設(shè)計方案···································································2
2.2.1 選擇確定總體參數(shù)······························································· 2
2.2.2工作機(jī)構(gòu)··········································································20
2.2.3安全保護(hù)裝置··································································· 28
2.3 總體設(shè)計設(shè)計總則···································································30
2.3.1 整體工作級別···································································30
2.3.2 機(jī)構(gòu)工作級別···································································30
2.3.3 主要技術(shù)性能參數(shù)······························································31
2.4 平衡重的計算·········································································31
2.5 起重特性曲線·········································································33
2.6 塔機(jī)風(fēng)力計算······································································· 35
2.6.1工作工況Ⅰ···································································· 35
2.6.2工作工況Ⅱ···································································· 39
2.6.3非工作工況Ⅲ··································································41
2.7 整機(jī)的抗傾覆穩(wěn)定性計算···························································44
2.7.1工作工況Ⅰ···································································· 45
2.7.2工作工況Ⅱ···································································· 46
2.7.3非工作工況Ⅲ··································································47
2.7.3非工作工況Ⅳ··································································48
2.8 固定基礎(chǔ)穩(wěn)定性計算································································49
第3章 變幅機(jī)構(gòu)的設(shè)計和計算······················································ 51
3.1變幅機(jī)構(gòu)的形式······································································ 51
3.2 確定卷筒的尺寸······································································51
3.2.1 卷筒的名義直徑·······························································51
3.2.2 多層繞卷筒相關(guān)參數(shù)計算·····················································52
3.3. 選擇電動機(jī)、減速器、制動器、聯(lián)軸器·········································· 53
3.3.1選擇電動機(jī)···································································· 53
3.3.2 選擇減速器···································································· 54
3.3.3 變幅機(jī)構(gòu)制動器的選擇·······················································54
3.3.4變幅機(jī)構(gòu)聯(lián)軸器的選擇······················································· 55
3.4. 驗算變幅速度·······································································57
3.5驗算起、制動時間驗算······························································ 57
3.6電動機(jī)發(fā)熱校驗······································································ 59
3.7 校驗卷筒強(qiáng)度·········································································60
第4章 變幅小車的設(shè)計·······························································61
4.1 變幅小車的形式······································································61
4.2 變幅小車的設(shè)計······································································61
4.2.1繩索牽引式小車構(gòu)造及其驅(qū)動方式··········································61
4.2.2 運(yùn)行小車牽引力計算··························································63
4.2.3牽引繩最大張力································································66
4.2.4 選擇牽引繩····································································67
4.2.5 牽引卷筒計算··································································67
畢業(yè)設(shè)計小結(jié)··············································································70
參考文獻(xiàn)···················································································· 72
Manuscript received September 9, 2005. This work was supported by Siemens Automation and Drivers, who provided all of the equipment necessary in implementing the crane control. Furthermore, they provided financial support for graduate students to install and program the controller. K. A. Hekman was with the American University in Cairo, Cairo 11511 Egypt. He is now with the Engineering Department, Calvin College, Grand Rapids, MI 49546 USA. (phone 616-526-7095, fax: 616-526-6501, e-mail hekmancalvin.edu) W. E. Singhose is with the George W. Woodruff school of Mechanical Engineering, The Georgia Institute of Technology, Atlanta GA 30332 USA (e-mail:William.Singhoseme.gatech.edu) Abstract When cranes move objects in a workspace, the payload frequently swings with large amplitude motion. Open loop methods have addressed this problem, but are not effective for disturbances. Closed loop methods have also been used, but require variable speed driving motors. This paper develops a feedback based method for controlling single speed motors to cancel the measured payload oscillations by intelligently timing the ensuing on and off motor commands. The oscillation suppression scheme is experimentally verified on a bridge crane. I. INTRODUCTION Cranes are frequently used to transport objects in a cluttered workspace. One inherent problem with cranes is that the payload can swing freely. These oscillations pose safety hazards and can damage the payload or other objects in the workplace. Traditionally, an experienced crane operator has been required to keep the oscillations under control. More recently, various control approaches have been applied to augment the operators skill. These approaches fall into open and closed loop categories. One open loop approach used is input shaping, which has proven effective on cranes for reducing sway during and after the move 1,2,3, including during hosting 4. Shapers can be designed with increased robustness to modeling inaccuracies 5 (i.e. cable length changing the frequency). Another open loop approach is optimal control, which calculates a motion trajectory off line based on the mathematical model of the system 6,7. However, if the model is inaccurate, the performance will suffer. This is also the case with input shaping, but to a lesser degree. In addition, optimal control has not been used with current crane operator interfaces, as the path is not known beforehand. System model uncertainties and external disturbances provide the motivation for feedback control. Controllers have used the position and velocity of the trolley and the cable swing angle 8,9,10,11 or the spreader inclination 12 to generate trolley commands that reduce payload oscillations. Wave absorption control adjusts the trolley velocity to absorb any waves that are being returned by the payload, thereby canceling the oscillation 13. Feeding a delayed angle measurement back to the desired position has also been shown effective in reducing payload oscillations 14. Sorenson et al. 15 developed a control system that combined input shaping and PD feedback control. The feedback control used measurements from an overhead camera and compared the crane response to the modeled shaped response. In another method to reduce the effect of a disturbance, Park and Chang 16 proposed a “commandless” input shaping method for a telescopic handler. To compensate for the vibrations from unloading the handler, they introduce a pulse that induces vibration equal in magnitude but opposite in direction of the vibration from unloading. They show the methods potential by using it to reduce vibration by about 75%. However, issues of properly timing the impulse and ease of calibration remain. All of the feedback methods require the velocity or acceleration of the trolley to be precisely controlled. The research here is based on using measurement of payload swing to generate commands for simple on-off motors to cancel the payload swing, making it applicable to a broader range of cranes. II. VECTOR BASED INPUT SHAPER CALCULATION Booker 17 provides a framework for analyzing oscillations with vectors. Singhose et al. 18 provide insight into how vibration cancellation can be achieved in a vector-based analysis of input shapers. An impulse of magnitude A 1 applied to an undamped second-order system of unit mass will induce a response of () tAtx sin 1 = . (1) This has a magnitude A 1 and phase angle of zero. Similarly, if a second impulse of magnitude A 2 was applied at time T 2 , then it would result in an output of () ( ) ( ) 2222 sinsin TtATtAtx = , tT 2 . (2) This has a magnitude A 2 and phase angle =T 2 . The magnitudes and angles can be transformed into vector notation as seen in Fig. 1. Summing these vectors gives the total vibration response, as seen in Fig. 2. The corresponding time response of these impulses is seen in Fig. 3. After the second impulse, the total response matches the amplitude and phase of A R . If the system has damping, then this method needs to be modified. First, the angle changes to T 2 1= . (3) Feedback Control for Suppression of Crane Payload Oscillation Using On-Off Commands Keith A. Hekman, and William E. Singhose Proceedings of the 2006 American Control Conference Minneapolis, Minnesota, USA, June 14-16, 2006 WeC11.4 1-4244-0210-7/06/$20.00 2006 IEEE 1784 Second, damping causes the amplitude to decay over time. To account for the decay, calculations use the effective amplitude at t=0 that results in the required amplitude at T 2 of 2 1 22 = eAA eff . (4) A shaper can be designed such that the sum of all the effective impulses results in zero vibration, as seen in Fig. 4. To do this, the A 3eff is chosen to be the negative of A R from Fig. 2. To get the magnitude of this canceling impulse, it must be converted to the time it will occur using (3) and 2 1 33 = eAA eff . (5) In reality, systems are not moved with impulses. To create a practical command, the impulse sequence is convolved with the desired command. For example, Fig. 5 shows a step command convolved with two impulses produces a stair step command. The resulting command will not produce any residual vibrations. III. PAYLOAD OSCILLATION CANCELLATION. The goal of this research is not to create commands that result in no residual oscillation for point-to-point motion. Rather, the measured payload swing is used to create commands for simple on-off motors that cancel any oscillation once it occurs. When creating such commands, the magnitude of the actuator force vector cannot be arbitrarily chosen, as the motor can only be turned on and off. However, turning the motor on or off will cause payload oscillations, which can be represented as vectors. Unlike a pure impulse, these vectors will not have zero phase angles, as the motor does not instantly stop or accelerate to full speed. Therefore, by the time the command is completed, the payload will have some displacement and some velocity, giving a vector representation similar to Fig. 6. The vector for turning the motor off should have a similar magnitude, but in the opposite direction, assuming that the acceleration and deceleration dynamics are similar. If not, it can be represented by its own unique amplitude and phase. The controller developed here will use two command switches (on-off) to eliminate the position and velocity components of the vibration. The controller needs to calculate the appropriate times for these commands in real time. To make this calculation, a vector triangle is used, as seen in Fig. 7. The three sides of the triangle are the current vibration level (A vib ), and the vibration amplitudes of “on” and “off” commands. If the triangle can be created, then the oscillations can be forced back to zero (the origin of the vector diagram.) Assuming that the operator wants the crane to be moving, then the command sequence would be “off”, wait, then “on” again. Certain components of the triangle are known: the magnitude of the current vibration and the effect of turning the crane on (A on ) and off (A off ). The A 2eff A 1 A 3eff Fig. 4. Summing three vectors to get zero vibration * Shaped CommandInput ShaperInitial Command 0 0 0 Time Time Fig. 5. Creating a stair step command by convolution A on on / . Fig. 6. Vector representation for turning the motor on. A on eff on =T A vib A off vib A on eff on =T A vib A off vib (a) (b) off off Fig. 7. Vector diagram for calculating time to turn motor off. A 1 A 2 Time A m pl itu d e T 2 A 2 A 1 Impulse Sequence Vector Diagram 2 =T 1 =0 Fig. 1. Impulse sequence and corresponding vector diagram A 2 A 1 A R R Fig. 2. Summing two vectors to get the total response time response to A 1 response to A 2 time total response response to A R A 1 A 2 A 1 A R A 2 Fig. 3. Time response of impulses (adapted from 18) 1785 unknowns are the time until the crane is turned back “on” again (T), and at what existing vibration phase angle the crane should be turned “off” ( vib ). Since it is a triangle, there are two possible solutions as shown in Fig. 7. The time response of these solutions is given in Fig. 8. The solution in Fig. 7a is preferable as it has a smaller angle on =T, so the time until the vibration is canceled is shorter. Also, the swing angle is less. To find vib , the intermediate angles seen in Fig. 9 are used. From the law of cosines, cos2 222 viboffviboffeffon AAAAA += (6) oneffonoffeffonoffvib AAAAA cos2 222 += . (7) From (7) + = effonoff vibeffonoff on AA AAA 2 cos 222 1 (8) If there is no damping, then the solution can be solved directly since A on eff =A on . Note that most cranes have near zero damping, but if the damping is significant, then the same equation can be used to solve for on , but it must be solved iteratively, with 2 1 = on eAA oneffon . (9) Equation (8) is initially calculated using =0. After on is found, from Fig. 9 can be calculated using + = viboff effonviboff AA AAA 2 cos 222 1 (10) Once is known, vib can be calculated using += offvb (11) Once the controller has turned off the crane, it then waits until the angle of the vibration is opposite in direction to on . At this point, the controller turns the motor back on. If the calibration is perfect, oscillations will be eliminated. If the operator desires the crane to be stopped, then vibrations can be canceled by moving the overhead support either forward or backward. This results in two different phase angles of vibration that can be used for the controller, as seen in Fig. 10. In part (a), the reverse direction, the diagram is basically the same as Fig. 7a, except the on and the off are exchanged. Based on this, += + = + = ronvb vibon eff offvibon eff offon vib eff offon off AA AAA AA AAA 1 222 1 222 1 2 cos 2 cos (12) For Fig. 10b, the vector diagram has the same geometry for as (a), only rotated by radians. Therefore += fonvb 2 . (13) The controller compares the existing vibration phase angle to (12) and (13) and uses whichever angle occurs first. Once the crane is stopped, then the controller waits until the oscillation phase angle is opposite to that of the “on” command. Then, the motor is turned back on. The maximum oscillation magnitude that can be canceled using an on-off command is approximately twice the oscillation induced by an “on” command. If the current oscillation magnitude is larger than this, then the controller calculations are based on the maximum cancellation level. As a precaution, this maximum level can be reduced to limit the distance moved in canceling the oscillations, thus limiting the angle on and T. A limitation of this oscillation cancellation method is that it assumes that superposition can be applied for the vector representations of induced vibration. This is only true if the motor has time to reach its steady state velocity between the vectors, so small payload oscillations cannot be eliminated. Therefore, an oscillation magnitude threshold is used. IV. CONTROLLER IMPLEMENTATION The proposed controller using the oscillation cancellation techniques from Section III was implemented on a large bridge crane. The crane has a camera mounted on the trolley to measure the payload swing in the horizontal plane. The camera can also measure the height of the payload. All of the control actions were based on a single payload height. A off r eff off =T A vib A on r vib 1 A vib vib 2 (a, reverse) (b, forward) on f on r off A off f eff A on f Fig. 10. Vector diagram for when to turn on motor. off on m o t o r i npu t 0 time p a y lo a d s w in g from (a) from (b) Fig. 8. Time Response from vector diagram of Fig. 7. A on eff on =T A vib A off Fig. 9. Angles used to calculate command initiation time. (b ) Pa yloa d Sw in g (a) Mot o r In put 1786 The system could be calibrated at different heights and the timings would be based on the camera measured height. A. System Calibration The controller calculations (8)-(13) require the magnitude and phase angle of the oscillations caused by turning the motor “on” and “off”. These can be calculated by plotting the crane input and response on the same graph, as seen in Fig. 11. Fig. 11a shows the motor being turned off at about 5.5 seconds while the crane is moving forward. The motor takes about a second to come to rest after the command is issued. Fig. 11b shows the payload swing angle and the oscillation level m given by () 2 2 & +=m (14) where is the natural frequency of the system. The times of the zero crossing of the swing angle before (t b ) and after (t a ) the input change (t i ) were recorded. The phase angles of the oscillation before ( b ) and after ( a ) the input can be calculated using ( ) ( ) pipaapipbb tttttttt =+= 22 (15) where t p is the time of one oscillation period. The complex vector of the input transition is given by f off ba i f off i b i a eAememA = . (16) where m b and m a are the amplitudes of the oscillation before and after the input the subscript f denotes forward motion. A similar procedure can be done for the remaining vectors. Graphically, the s can be plotted for starting and stopping, for both forward and reverse, as seen in Fig. 12. On average the oscillation had an amplitude of a=0.052 radians at an angle of =1.11(+) radians (63.6 (+180). B. Controller Response for User Motion Fig. 13 shows the response of the crane to a user request to move backward. In Fig. 13a, the user input is shown using a line with circles. The resulting trolley speed is seen with a dashed line. As shown in Fig. 13b, the crane motion excites oscillations in the payload. Fig. 13c shows the phase angle of the oscillations given by = & 1 tan . (17) It also shows the switch angle calculated from (11)-(13). At the initial crossing (at about 2 seconds), the oscillation level is not large enough (1.7) to trigger a control action. It is one period later (at about 6 seconds) that the oscillation canceling control action takes place. At this point, the controller briefly turns off the crane motor, as seen in Fig. 13a by the solid line. At this point the switch angle jumps to the angle to turn back on the motor. At 7 seconds, this angle occurs, and the crane motor is turned back on. When the crane reaches full speed (at about 8 seconds), the oscillation level is quite small (about a half degree). The operator stops pressing the reverse button at about 11 seconds, as seen by the sold line in Fig. 13a. When the crane stops, oscillations are again induced. When the desired command is at rest, there are two switch angles -0.04 -0.02 0 0.02 0.04 -0.04 -0.02 0 0.02 0.04 / back start back stop forward start forward stop . Fig. 12. Oscillation vectors for different commands 0 1 us e r i nput ( % f u l l s peed) t i control motor speed 0 2 4 6 8 10 -5 0 5 t b t a m b m a s w i ng ang l e ( o ) time (s) payload angle vibration level Fig. 11. Measured bridge crane response to an “off” command (a) U s e r I nput ( % f u ll s p e e d ) (b ) s w ing a n gle ( ) -1 -0.5 0 0.5 1 u s e r i n p u t ( % fu l l s p e e d ) user input control scaled motor speed -4 -2 0 2 4 pay l o ad s w i n g ( o ) payload ang. oscillation amp. 0 2 4 6 8 10 12 14 16 -90 0 90 180 270 time (s) ph as e an gl e ( o ) oscillation ang. switch ang. Fig. 13. Response to an operator input of reverse (a) us er i nput (% f u l l s p eed) (b) payl oad s w i ng ( ) (c) phas e angl e ( ) 1787 -1 -0.5 0 0.5 1 u s e r i n p u t ( % fu l l s p e e d ) user input control sc. motor speed -5 0 5 pay l o ad s w i n g ( o ) payload ang. oscillation amp. 0 1 2 3 4 5 6 7 8 9 10 11 12 -90 0 90 180 270 time (s) ph as e an gl e ( o ) oscillation ang. switch ang. Fig. 15. Response to a large disturbance (a) us er i nput (% f u l l s p eed) (b) payl oad s w i ng ( ) (c) phas e angl e ( ) given by (12) and (13), as the crane can cancel the oscillation by going both forwards and backwards. The first angle occurs at a little after 13 seconds, and the crane moves forward slightly to cancel the oscillations. Once the crane is back at rest very little oscillations remain. C. Controller Response for Disturbance Rejection Fig. 14 shows the response of the crane to a disturbance when the bridge is at rest. At a little after 1 second, the payload was disturbed. At about 3 seconds, the oscillation phase angle matched the switch angle condition, and the controller commanded the trolley to move forward. At a little past 4 seconds, the phase angle matched again, and the trolley was commanded to stop. When the trolley came to rest at about 5.5 seconds, the payload swing was small. Fig. 15 shows the response to a very large disturbance. At about 1 second, the payload was pushed with a disturbance that is larger than a single on-off command can suppress. In this case, the first on-off control action suppressed the maximum amount, and then the second control action canceled the remaining oscillations by going in the opposite direction. This resulted in little oscillation after the crane had completed the second command at 6 seconds. The controller can also eliminate disturbances while the crane is moving, as seen in Fig. 16. While the crane was moving forward with little oscillation, the payload was disturbed at about 1 second. The controller initially gives a stop command at about 1.5 seconds, which ceases shortly afterward (before the oscillation phase angle matched the switch angle, not eliminated. The controller then waited until the appropriate phase angle, and then stopped the trolley at a time of about 6 seconds. At the appropriate time (7.5 seconds), the crane began accelerating but based on the time safety factor from off .) However, the payload was still being disturbed so the oscillations were, resulting in little oscillation when the crane had returned to full speed. V. CONCLUSION A control strategy has been developed for on-off motors to eliminate bridge crane payload oscillations. The control -1 -0.5 0 0.5 1 u s e r i n p u t ( % fu l l s p e e d ) user input control scaled motor speed -5 0 5 pay l o ad s w i n g ( o ) payload ang. oscillation amp. 0 1 2 3 4 5 6 7 8 9 10 -90 0 90 180 270 time (s) ph as e an gl e ( o ) oscillation ang. switch ang. Fig.14. Response to a disturbance while crane is at rest (a) us er i nput (% f u l l s p eed) (b) payl oad s w i ng ( ) (c) phas e angl e ( ) -1 -0.5 0 0.5 1 u s e r i n p u t ( % fu l l s p e e d ) user input control scaled motor speed -5 0 5 pay l o ad s w i n g ( o ) payload ang. oscillation level 0 1 2 3 4 5 6 7 8 9 10 -90 0 90 180 270 time (s) ph as e an gl e ( o ) oscillation ang. switch ang. Fig. 16. Response to a disturbance when moving (a) us er i nput (% f u l l s p eed) (b) payl oad s w i ng ( ) (c) phas e angl e ( ) 1788 uses the swing angle of the payload, and its derivative, to decide when to turn the crane on and off. The method can reduce the oscillations when the crane is moving or at rest. The strategy was implemented on a large bridge crane. Numerous experiments demonstrated the control systems effectiveness. VI. REFERENCES 1 Starr, G. P., “Swin