車床上料機械手設(shè)計(桂理工)
車床上料機械手設(shè)計(桂理工),車床上料機械手設(shè)計(桂理工),車床,機械手,設(shè)計,理工
桂林理工大學
本科學生畢業(yè)設(shè)計(論文)
任 務(wù) 書
學 院: 機械與控制工程學院
課題名稱: 車床上料機械手設(shè)計
專業(yè)(方向):機械設(shè)計制造及其自動化(機械裝備)
班 級:2011級2班
學生姓名:梁學念 學號: 3110644203
指導(dǎo)教師:孫金榮 職稱: 講師
下發(fā)日期:2015年1月12日
桂林理工大學教務(wù)處制
課題名稱
車床送料機械手的設(shè)計
主要內(nèi)容(包括設(shè)計參數(shù))與要求
1. 設(shè)計背景: 工業(yè)機械手是工業(yè)生產(chǎn)的必然產(chǎn)物,它是一種模仿人體上肢的部分功能,按照預(yù)定要求輸送工件或握持工具進行操作的自動化技術(shù)設(shè)備,對實現(xiàn)工業(yè)生產(chǎn)自動化,推動工業(yè)生產(chǎn)的進一步發(fā)展起著重要作用。因而具有強大的生命力受到人們的廣泛重視和歡迎。實踐證明,工業(yè)機械手可以代替人手的繁重勞動,顯著減輕工人的勞動強度,改善勞動條件,提高勞動生產(chǎn)率和自動化水平。工業(yè)生產(chǎn)中經(jīng)常出現(xiàn)的笨重工件的搬運和長期頻繁、單調(diào)的操作,采用機械手是有效的。
2. 設(shè)計思路 :通過應(yīng)用CAD繪圖軟件技術(shù)對機械手進行結(jié)構(gòu)設(shè)計和液壓傳動原理設(shè)計,它能實行自動上料運動;在安裝工件時,將工件送入卡盤中的夾緊運動等。上料機械手的運動速度是按著滿足生產(chǎn)率的要求來設(shè)定。
3.設(shè)計參數(shù):
(1)工件為10kg,長度小于800mm的小型回轉(zhuǎn)體棒料。
(2)自由度(四個自由度),臂轉(zhuǎn)動180o,臂上下運動500mm ;
(3)臂伸長(收縮)500mm,手部轉(zhuǎn)動±180o;
工 作 進 程 及 需 完 成 工 作 量
1. 開題論證階段(第1、2周)
2. 上網(wǎng)查閱資料,圖書資料查詢,獲取必備相關(guān)資料,做好前期工作。(第3周)
3. 抓取機構(gòu)的設(shè)計(包括手部、腕部、手臂的設(shè)計)(第3、4、5周)
4. 液壓系統(tǒng)的設(shè)計以及草圖繪畫(第6周)
5. 機身機座的結(jié)構(gòu)設(shè)計、機械手的定位以及平穩(wěn)性(第7、8周)
6. 機械手的控制、數(shù)據(jù)整理以及校核(第9周)
7.論文編寫和修改、零件圖和裝配圖繪畫(第3至9周)
8.論文完成日期5月20日
需要完成的工作量
1、10000字左右的畢業(yè)論文或設(shè)計報告一份,具體內(nèi)容、格式要求以畢業(yè)實習指導(dǎo)書為準。
2、相關(guān)技術(shù)文檔資料。包括原始資料、軟件工程相應(yīng)文檔資料、各階段總結(jié)等。
3、開題設(shè)計書一份。
4、10篇以上參考文獻內(nèi)容摘要或綜合讀書筆記。
5、一篇10000個以上印刷符號的外文譯文(附原文)。要求其內(nèi)容與畢業(yè)設(shè)計(論文)題目有關(guān)。
6、實習鑒定表、實習日志、實習總結(jié)等。
應(yīng) 遵 守 的 法 紀 法 規(guī)
在校期間,不得違反國家法律法規(guī),要嚴格遵守學校的各種規(guī)章制度,按時作息,及時完成畢業(yè)設(shè)計所需的工作量,聽從指導(dǎo)老師的意見和建議,畢業(yè)實習期間注意自身安全。
畢業(yè)設(shè)計(論文)完成日期: 2015 年 5 月 15 日
指導(dǎo)教師: (簽字)
教研室主任: (簽字)
本科畢業(yè)設(shè)計(論文)
開題報告(含論文綜述)
學 院:機械與控制工程學院
所屬教研室:機械教研室
課題名稱:車床上料機械手設(shè)計
專業(yè)(方向):機械設(shè)計制造及其自動化(機械裝備)
班 級:2011級2班 學號: 3110644203
學 生:梁學念
指導(dǎo)教師:孫金榮 職稱: 講師
開題日期:2015年3月21日
一、畢業(yè)設(shè)計(論文)選題的目的和意義。[ ⑴ 課題名稱;⑵ 有關(guān)的研究方向的歷史、現(xiàn)狀和發(fā)展情況分析;⑶ 前人在本選題研究領(lǐng)域中的工作成果簡述]
1.課題名稱:車床上料機械手設(shè)計
2.選題目的和意義:
目前,我國大多數(shù)工廠的生產(chǎn)線上機床裝卸工件仍由人工完成,其勞動強度大、生產(chǎn)效率低,而且具有一定的危險性,已經(jīng)滿足不了生產(chǎn)自動化的發(fā)展趨勢。為了提高工作效率,降低成本,并使生產(chǎn)線發(fā)展成為柔性制造系統(tǒng),適應(yīng)現(xiàn)代機械行業(yè)自動化生產(chǎn)的要求,針對具體生產(chǎn)工藝,結(jié)合機床的實際結(jié)構(gòu),利用機械手技術(shù),設(shè)計用一臺送料機械手代替人工工作,以提高勞動生產(chǎn)率。本機械手主要與數(shù)控機床組合最終形成生產(chǎn)線。
2.1國內(nèi)外研究現(xiàn)狀
目前,在國內(nèi)外各種機器人和機械手的研究成為科研的熱點,其研究的現(xiàn)狀和大體趨勢如下:
A.機械結(jié)構(gòu)向模塊化、可重構(gòu)化發(fā)展。例如關(guān)節(jié)模塊中的伺服電機、減速機、檢測系統(tǒng)三位一體化;由關(guān)節(jié)模塊、連桿模塊用重組方式構(gòu)造機器人整機。
B.工業(yè)機器人控制系統(tǒng)向基于PC機的開放型控制器方向發(fā)展,便于標準化、網(wǎng)絡(luò)化;器件集成度提高,控制柜日見小巧,且采用模塊化結(jié)構(gòu);大大提高了系統(tǒng)的可靠性、易操作性和可維修性。
C.機器人中的傳感器作用日益重要,除采用傳統(tǒng)的位置、速度、加速度等傳感器外,裝配、焊接機器人還應(yīng)用了視覺、力覺等傳感器,而遙控機器人則采用視覺、聲覺、力覺、觸覺等多傳感器的融合技術(shù)來進行決策控制;多傳感器融合配置技術(shù)成為智能化機器人的關(guān)鍵技術(shù)。
D.關(guān)節(jié)式、側(cè)噴式、頂噴式、龍門式噴涂機器人產(chǎn)品標準化、通用化、模塊化、系列化設(shè)計;柔性仿形噴涂機器人開發(fā),柔性仿形復(fù)合機構(gòu)開發(fā),仿形伺服軸軌跡規(guī)劃研究,控制系統(tǒng)開發(fā)。
E.焊接、搬運、裝配、切割等作業(yè)的工業(yè)機器人產(chǎn)品的標準化、通用化、模塊化、系列化研究;以及離線示教編程和系統(tǒng)動態(tài)仿真。
3.發(fā)展趨勢:
(一)擴大機械手在熱加工行業(yè)上的應(yīng)用
目前國內(nèi)機械手應(yīng)用在機械工業(yè)冷加工作業(yè)中的較多,而在鑄、鍛、焊、熱處理等熱加工以及裝配作業(yè)等方面的應(yīng)用較少。因熱加工作業(yè)的物件重、形狀復(fù)雜、環(huán)境溫度、高等,給機械手的設(shè)計、制造帶來不少困難,這就需要解決技術(shù)上的難點,使機械手更好地為熱加工作業(yè)服務(wù)。同時,在其它行業(yè)和工業(yè)部門,也將隨著工業(yè)技術(shù)水平的不斷提高,而逐步擴大機械手的使用。
(二)提高工業(yè)機械手的工作性能
機械手工作性能的優(yōu)劣,決定著它能否正常地應(yīng)用于生產(chǎn)中。機械手工作性能中的重復(fù)定位精度和工作速度兩個指標,是決定機械手能否保質(zhì)保量地完成操作任務(wù)的關(guān)鍵因素。因此要解決好機械手的工作平穩(wěn)性和快速性的要求,除了從解決緩沖定位措施入手外,還應(yīng)發(fā)展?jié)M足機械手性能要求價廉的電液伺服閥,將伺服控制系統(tǒng)應(yīng)用于機械手上。
(三)發(fā)展組合式機械手
從機械手本身的特點來說,可變程序的機械手更適應(yīng)產(chǎn)品改型、設(shè)備更新,多品種小批量的要求,但是它的成本高,專用機械手價廉,但適用范圍又受到限制.。因此,對一些特殊用途的場合,就需要專門設(shè)計、專門加工,這樣就提高了產(chǎn)品成本。為了適應(yīng)應(yīng)用領(lǐng)域分門別類的要求,可將機械手的結(jié)構(gòu)設(shè)計成可以組合的型式。組合式機械手是將一些通用部件(如手臂伸縮部件,升降部件、回轉(zhuǎn)部件和腕部回轉(zhuǎn)、俯仰部份配上與其業(yè)的要求S選擇必要的能完成預(yù)定機能的單元部件,以機座為基礎(chǔ)進行組合,配上與其相適應(yīng)的控制部分,即成為能完成特殊要求的機械手。它可以簡化結(jié)構(gòu),兼顧了使用上的專用性和設(shè)計上的通用性,便于標準化、系列化設(shè)計和組織專業(yè)化生產(chǎn),有利于提高機械手的質(zhì)量和降低造價,是一種有發(fā)展前途的機械手。
(四)研制具有“視覺’’和“觸覺"的所謂“智能機器人"
對于需用人工進行靈巧操作及需要進行判斷的工作場合,工業(yè)機械手很難代替人的勞動。如在工作過程中出現(xiàn)事故、障礙和情況變化等,機械手不能自動分辨糾正,而只能停機待人們排除意外事故后才能繼續(xù)工作。因此,人們對機械手提出了更高的要求,希望使其具有“視覺”、“觸覺”等功能,使之對物件進行判斷、選擇,能連續(xù)調(diào)節(jié)以適應(yīng)變化的條件,并能進行“手部"協(xié)調(diào)動作。這就需要一個能處理大量信息的計算機,要求人與機器“對話”進行信息交流。
二、設(shè)計或研究主要內(nèi)容和重點,預(yù)期達到的目標及擬解決的主要問題和技術(shù)關(guān)鍵。(此部分為重點闡述內(nèi)容)
研究內(nèi)容:
1.研究數(shù)據(jù)及資料
原始數(shù)據(jù):自由度(四個自由度),臂轉(zhuǎn)動180o,臂上下運動500mm,臂伸長(收縮)500mm,手部轉(zhuǎn)動±180o。
設(shè)計要求:
a、上料機械手結(jié)構(gòu)設(shè)計圖、裝配圖、各主要零件圖(一套)b、液壓原理圖(一張)c、設(shè)計計算說明書(一份)。
技術(shù)要求
主要參數(shù)的確定:
a、坐標形式:直角坐標系?b、臂的運動行程:伸縮運動500mm,回轉(zhuǎn)運動180o。c、運動速度:使生產(chǎn)率滿足生產(chǎn)綱領(lǐng)的要求即可。d、控制方式:起止設(shè)定位置。e、定位精度:±0.5mm?f、手指握力:392N?g、驅(qū)動方式:液壓驅(qū)動。
2.料槽形式及分析動作要求
料槽形式
由于工件為重量10kg,長度小于800mm的小型回轉(zhuǎn)體棒料,此種形狀的零件通常采用自重輸送的輸料槽。
3.動作要求分析
動作一:送料;動作二:預(yù)夾緊;動作三:手臂上升;動作四:手臂旋轉(zhuǎn);動作五:小臂伸長;動作六:手腕旋轉(zhuǎn)。
4.解決主要問題和技術(shù)關(guān)鍵
本設(shè)計主要圍繞設(shè)計出來的機械手能否完成預(yù)期的動作要求并且能自動給機床自動上料,設(shè)計需要解決的問題主要包括:
4.1對手部設(shè)計的要求:
1、有適當?shù)膴A緊力
手部在工作時,應(yīng)具有適當?shù)膴A緊力,以保證夾持穩(wěn)定可靠,變形小,且不損壞工件的已加工表面。對于剛性很差的工件夾緊力大小應(yīng)該設(shè)計得可以調(diào)節(jié),對于笨重的工件應(yīng)考慮采用自鎖安全裝置。
2、有足夠的開閉范圍
夾持類手部的手指都有張開和閉合裝置。工作時,一個手指開閉位置以最大變化量稱為開閉范圍。對于回轉(zhuǎn)型手部手指開閉范圍,可用開閉角和手指夾緊端長度表示。手指開閉范圍的要求與許多因素有關(guān),如工件的形狀和尺寸,手指的形狀和尺寸,一般來說,如工作環(huán)境許可,開閉范圍大一些較好。
4.2臂伸縮機構(gòu)設(shè)計要求:
手臂是機械手的主要執(zhí)行部件。它的作用是支撐腕部和手部,并帶動它們在空間運動。臂部運動的目的,一般是把手部送達空間運動范圍內(nèi)的任意點上,從臂部的受力情況看,它在工作中即直接承受著腕部、手部和工件的動、靜載荷,而且自身運動又較多,故受力較復(fù)雜機械手的精度最終集中在反映在手部的位置精度上。所以在選擇合適的導(dǎo)向裝置和定位方式就顯得尤其重要了。手臂的伸縮速度為200m/s行程L=500mm。
4.3機身機座的結(jié)構(gòu)設(shè)計要求:
機身的直接支承和傳動手臂的部件。一般實現(xiàn)臂部的升降、回轉(zhuǎn)或俯仰等運動的驅(qū)動裝置或傳動件都安裝在機身上,或者就直接構(gòu)成機身的軀干與底座相連。因此,臂部的運動愈多,機身的結(jié)構(gòu)和受力情況就愈復(fù)雜,機身選擇是固定式。
4.4技術(shù)關(guān)鍵
收集關(guān)于機械手的設(shè)計資料,結(jié)合自身所學的《機械工程CAD繪圖》、《液壓與氣壓傳動》、《機械工程控制基礎(chǔ)》、《材料力學》、《機械原理》等一些專業(yè)課程知識對現(xiàn)有的資料進行分析,并運用自身所學的繪圖軟件包括CAD、PRE等軟件描繪出草圖。
三、研究方案:[ ⑴ 技術(shù)方案(有關(guān)方法、技術(shù)路線、技術(shù)措施);⑵ 實施方案所需的條件(技術(shù)條件、試驗條件等)]
研究方法:采用同其它同等機械類設(shè)備的類比,方案比較等方法,根據(jù)工業(yè)機械手的實際應(yīng)用特征及現(xiàn)有的物質(zhì)、經(jīng)濟技術(shù)、人力等條件,以所學的理論知識為基礎(chǔ),按照工業(yè)機械手工作的一般過程、設(shè)計標準,借鑒以往相似設(shè)備的成功經(jīng)驗進行初步設(shè)計,然后對初步設(shè)計方案進行驗算,修正,直至達到安全、經(jīng)濟、實用的目的。其中對于機械手設(shè)計中的關(guān)鍵問題、難點問題進行重點分析解決,確保整個設(shè)計方案的可行性和最佳性。
技術(shù)路線和實施方案:本課題研究主要內(nèi)容及基本過程是在深入調(diào)查研究的基礎(chǔ)上,根據(jù)實際基于送料機械手的應(yīng)用及目前國內(nèi)外研究成果,進行理論分析,分析已有各類機械手模型及產(chǎn)品,研究機械手不同工作需要,進一步實現(xiàn)機械手的規(guī)定動作并實現(xiàn)回原點。利用所建立的模擬機械手典型實例進行分析,討論模型合理性。
本課題研究具體安排如下:?
1.查閱相關(guān)資料,進行資料的收集與整理工作。?
2.完成整體研究方案。與指導(dǎo)教師進行方案討論,完善研究方案。?
3.充分分析機械手按規(guī)定回原點的方式,研究機械手不同情況下回原點的效率模式。?
4.完成理論建模;進行典型實例分析;模擬指標分析智能系統(tǒng)的設(shè)計。??
5.本課題運用液壓傳動的技術(shù)上料搬運機械手來實施控制,進而分析它的運動過程,來完成最后的機械手設(shè)計。
四、主要參考文獻目錄
主要參考資料?
[1]孫桓,陳作模,葛文杰.機械原理(第七版)[M].北京:高等教育出版社,2006.
[2]盧秉恒.機械制造技術(shù)基礎(chǔ)(第三版)[M].北京:機械工業(yè)出版社,2007.
[3]宋冬梅,何劍英.畫法幾何及機械制圖(第六版) [M].北京:高等教育出版社,2008.
[4]徐灝.機械設(shè)計手冊(第四版) [M].北京:機械工業(yè)出版社,2001.
[5]徐灝.機械設(shè)計手冊(第五版) [M].北京:機械工業(yè)出版社,2006.
[6]周伯英.工業(yè)機器人[M].北京:機械工業(yè)出版社,1995.????
[7]王積偉,黃宜.液壓與氣壓傳動[M].北京:機械工業(yè)出版社,2005.
[8]王萬森.人工智能原理及其應(yīng)用(第三版) [M].北京:電子工業(yè)出版社,2012.
五、畢業(yè)設(shè)計(論文)工作進度計劃。(必須包含一定工作量的計算機知識綜合應(yīng)用環(huán)節(jié))
總時間為17周,自2015年3月9日開始,6月26日結(jié)束。
1. 開題報告和任務(wù)書編寫,從3月9日~3月15日。
2. 上網(wǎng)查閱資料,圖書資料查詢,獲取必備相關(guān)資料,做好前期工作。(第三周)
3. 抓取機構(gòu)的設(shè)計(包括手部,腕部的設(shè)計)(第四周)
4. 液壓系統(tǒng)的設(shè)計以及草圖繪畫(第五、六周)
5. 機身機座的結(jié)構(gòu)設(shè)計(第七周)
6. 機械手的定位以及平穩(wěn)性(第八周)
7. 機械手的控制(第九周)
8. 數(shù)據(jù)整理以及校核(第十周)
9.論文編寫和修改、零件圖與裝配圖繪制(第三至十周)
10.論文完成日期5月15日
六、指導(dǎo)教師審核意見
指導(dǎo)教師簽字:
年 月 日
七、開題答辯結(jié)論和審核意見
教研室主任簽字:
年 月 日
本科畢業(yè)設(shè)計(論文)
外文翻譯(附外文原文)
學 院: 機械與控制工程
課題名稱: 車床上料機械手設(shè)計
專業(yè)(方向): 機械設(shè)計制造及其自動化
班 級: 機械11級2班
學 生: 梁學念
指導(dǎo)教師: 孫金榮
日 期: 2015年3月12日
21
外文原文:
Mechanical and control system for Manipulators
Abstract: Recently, in the world with a clip or a hand robot system has been developed, a variety of methods is applied on the, quasi humanized and non-personification. Not only the mechanical structure of these systems is investigated, but also the necessary control system is also included.. As the staff, these robots can use their hands to grasp different objects, without changing the clip. These manipulators possess special athletic abilities (such as small mass and inertia), which enable the object to be more complex and more precise in the work of robot manipulators.. These complex operations are grasped around arbitrary angle and axis rotation.. This paper outlines the general design of this manipulator, and gives a sample of such manipulators, such as the Karlsruhe smart hand. At the end of this paper, some new ideas are introduced, such as the use of liquid actuators for humanoid robot design a brand new robot manipulator.
Keywords: multi robot manipulator; robot hand; finishing operation; mechanical system; control system
1 .Introduction
In June 2001 in Karlsruhe, Germany to carry out special study a humanoid robot, in order to develop in a normal environment (such as kitchen or the living room) and human cooperation and interaction of the robot system. The design of these robots is designed to help us capture objects of size, shape and weight in a non -professional, non - industrial condition, such as in many objects. At the same time, they must be able to manipulate the object very well. This flexibility can only be through a strong adaptability of robot hand grasping system to obtain, that is, the so-called multi refers to the robot or robot hand.
The research project mentioned above is to create a humanoid robot, which will equip this robot hand system.. This novice will be produced by two organizations, which are IPR (process control and Robotics Research Institute) and C (Computer Science Institute), University of Karlsruhe.. These two organizations have the experience of making such systems, but slightly different views.
IPR made Karlsruhe dexterous hand II (as shown in Figure 1), is a four finger gripper is independent of each other, we will be introduced in detail in this paper. The hand made by IAI (as shown in Figure 17) is used as prosthetic for the disabled.
Figure 1.IPR Karlsruhe smart hand Figure 2 fluid hand developed by IAI
2 .general structure of robot hand
A robot hand can be divided into two major subsystems: mechanical systems and control systems.
The mechanical system can be divided into the structure design, the drive system and the sensor system, we will further introduce in the third part. In the fourth part of the introduction of the control system at least by the control of hardware and software components.
We will be on the two system problems of a basic introduction, and then use the Karlsruhe dexterous hand II demonstration.
3 .Mechanical Systems
The mechanical system will describe how the hand looks and what components. It determines the structure design, the number of fingers and the use of materials. In addition, the position of the actuator (such as the motor) and the sensor (e.g. position encoder) is also determined.
3.1 structure design
The structure design will have the very important function to the manipulator's flexibility, namely it can grasp which kind of object and can carry on to the object to carry on what kind of operation. When designing a robot hand, three basic elements must be determined: the number of fingers, the number of fingers, the size and placement of the fingers..
In order to crawl and operate the object safely within the manipulator, at least three fingers. In order to operate the object being grasped for 6 degrees of freedom (3 translational and 3 rotational degrees of freedom), each finger must have 3 separate joints.. This method was used in the first generation of Karlsruhe's smart hand.. However, in order to catch an object without the need to release it first to pick up, at least 4 fingers.
Two methods: the human and the non - human are to determine the size and placement of the finger.. Then it will depend on the object and the type of operation to which the desired operation is selected. It is easy to transfer grasping intention from hand to robot hand.. However, the placement of different sizes and asymmetric positions of each finger will increase the processing cost, and it is the control system becoming more complicated, because each finger must be controlled separately. For the symmetrical arrangement of identical fingers, often using a non-anthropomorphic approach. Because only need to process and construct a single "finger module", it can reduce the processing cost, but also the control system is simplified.
3.2 drive system
The flexibility of the actuator is also greatly affected by the drive of the joints, because it determines the potential strength, precision and speed of the joint movement.. Two aspects of the mechanical movement need to be considered: the movement source and the movement direction. In this case, there are several different methods, such as the paper [3], which can be produced by hydraulic cylinders or pneumatic cylinders, or, as most of the case, the motor is used.. In most cases, motor drive, such as motor too big and not directly associated with the corresponding finger joint together. Therefore, the movement must by the driver (usually located on the machine arm last connection point) transferred. There are several ways to realize this movement, such as the use of keys, the drive belt and the active axis. Using the indirect drive method of finger joint, more or less reduces the strength and accuracy of the whole system, and at the same time, the control system is complicated, because of different joint of each finger is often mechanically even together, but in the software of the control system but are respectively independent control. Because of these shortcomings, the direct fusion of the small motor drive and the knuckle is quite necessary.
3.3 sensing system
The sensing system of the robot hand can transfer the feedback information from the hardware to the control software.. It is necessary to establish a closed loop control for finger or object.. 3 types of sensors were used in the machine.
1)Hand state sensors determine the position of fingertip and finger joint and finger force situation. Know the precise position of the fingertips will make precise control possible. In addition, knowing that the finger is the force that is grasped at the object, you can grab a fragile object without breaking it.
2)The grasping state sensor provides the contact information between the finger and the object. This kind of tactile information can be determined in the process of grasping the first contact with the object in time, and can also avoid incorrect grasping, such as the edge and tip of the object.. It can also detect whether the object has been caught, so as to avoid the object due to fall and damage.
3)The object or pose sensor is used to determine the shape, position and direction of the object in a finger. This sensor is very essential if it is not clear to the case of the object.. If this sensor can also act on the object that has been grasped, it can also control the pose (position and direction) of the object, thus monitoring whether or not.
Depending on the drive system, the geometrical information about the joint position can be measured at a motion drive or directly at the joint. For example, if there is a rigid shaft coupling between the motor and the knuckle, then the position of the joint can be measured by a motor shaft (before the gear or after the gear).. However, if this coupling stiffness is not enough or to get a high accuracy, it can not use this method.
3.4 the mechanical system of the robot hand in Karlsruhe
In order to obtain more complex operation such as heavy grasping, the Karlsruhe smart hand II (KDH II) is composed of 4 fingers, and each finger is composed of 3 independent joints.. The hand is designed for applications in industrial environments (Figure 3) and a control box, cylinder and screw nut and other objects. Therefore, we selected four identical fingers. They are symmetric, non-anthropomorphic configuration and each finger can rotate 90 DEG (Fig. 4).
View from the first generation of Karlsruhe dexterous hand design by experience, for example, the problem of mechanical caused by the drive belts and larger friction factor leading to the control problem of Karlsruhe dexterous hand II uses a number of different design decisions. The DC motor between the joint 2 and the joint of each finger is integrated into the anterior part of the finger (Figure 5).This arrangement can be used with hard ball gears to transmit motion to the joints of the fingers. In the motor shaft angle encoder (before the gear) can be used as a high precision position sensor.
Figure 3 KDH II on industrial robot Figure 4 KDH II top view
In order to perception of the role of finger force on the object, we invented a six axis force torque sensor (Figure 6). The sensor can be used as a fingertip for the end of a finger and is equipped with a spherical fingertip.. It can grab lighter objects, but also can grab 3-5kg similar heavier objects. This sensor can measure the force of the direction of X, Y and Z and the torque of the winding axis.. In addition, the laser triangulation sensor 3 collinear is placed in the hands of KDH II (Figure 5). Because there are 3 such sensors, therefore not only can measure the distance between 3 single points, if you know the shape of the object, but also can detect the distance between the object surface and direction. The working frequency of the object state sensor is 1kHz, which can detect and avoid the slide of the object
Figure 5 KDH II side view. Figure six a 6 degree of freedom torsion sensor with a strain gage sensor
4 control system
The robot's control system determines which potential dexterity skills can actually be used, and those skills are provided by mechanical systems.. As mentioned before, the control system can be divided into the control computer, namely, the hardware and the control algorithm is the software.
The control system must meet the following conditions:
1) Must have sufficient input and output ports. For example, a low level hand with 9 degrees of freedom, its drive needs at least 9 way to simulate the output port, and there are 9 paths from the angle encoder input port. Such as force sensor, tactile sensor and object sensor, then port number will be increased by several times.
2) The ability to have a quick and real-time response to external events. For example, when the detected object falls, the corresponding measures can be taken immediately.
3) With a higher computational power to address some of the different tasks. Such as path planning, coordinate conversion, and closed-loop control for multi - object and object - parallel execution.
4) The volume of the control system is small so that it can be integrated directly into the operating system..
5) In the control system and between the drive and sensor must be electrically short. Especially for the sensor, if there is no word, a lot of interference will interfere with the sensor signal.
4.1 control hardware
In order to meet the requirements of the system, the hardware is distributed in several special processors.. The controller can be easily integrated into the operating system, such as the low input output interface (motor and sensor), which is handled by a simple microcontroller.. However, the higher level of the control port requires a higher computing power, and a flexible real-time operating system is needed.. This can be easily resolved through the PC.
Therefore, the control hardware is often composed of a distributed computer system, which is a microcontroller, and the other is a powerful processor. Different computing units are connected by a communication system, such as bus system.
4.2 control software
Robot hand control software is quite complex. Must be real-time and parallel control of the fingers, but also plan the new trajectory of the fingers and objects. Therefore, in order to reduce the complexity of the problem, it is necessary to divide this problem into several sub problems to deal with..
On the other hand, software development.. Robot hand is a research project, its programming environment such as user interface, programming tools and debugging facilities must be very strong and flexible. These can only be met using a standard operating system. The hierarchical control system method is widely used in the robot after pruning, in order to meet the special requirements of the manipulator control.
4.3 control system of the robot hand in Karlsruhe
As said in Section 4.1, a distributed method (Figure 7) is adopted for the hardware of the control hardware of the smart hand of Karlsruhe.. A microcontroller controls a finger drive and sensor respectively, and a microcontroller is used to control the object state sensor (laser triangulation).. These microcontrollers (Figure 7 the left and right side of the box) are directly mounted on the hand, so the shorter electrical connection between the driver and the sensor can be guaranteed. These microcontrollers are connected with the master computer and the master computer.. This master computer (Figure 8, gray box in Figure 7) is a parallel computer composed of six industrial computers. These computers are arranged in a two-dimensional plane. Adjacent computer module (a computer with up to 8 adjacent modules) using the dual port RAM for rapid communication (Figure 7, the dark gray box). A computer used to control a finger. Another is used to control the position between the object sensor and the object.. The rest of the computer is safely around the computer as mentioned above.. These computers are used to coordinate the entire control system. The structure of the control software reflects the architecture of the control hardware.. As shown in Figure 9.
Figure 7 II KDH control hardware architecture Figure 8 parallel master computer for controlling II KDH
A three maximum levels of online planning regarding this hand control system are being planned. The ideal object displacement command can be obtained by the superior robot control system and can be used as the precise programming of the object path.. According to the target path, the feasible fetching behavior of the finger can be planned (the feasible grasping position of the object) is feasible.. Now that the object movement plan can be obtained by finger path planning, and the real-time capability of the system is transmitted to the system.. If an object is grasped, its movement path is passed to the object's state controller.. This controller controls the pose of an object, which is determined by the sensor of the finger and the object state, and is used to obtain the desired pose.. If a finger does not touch the object, its mobile path will pass directly to the hand controller.. This hand controller will be associated with the expected finger position to all fingers of the controller to coordinate motion of all fingers. These are driving finger drives with the help of finger sensors.
Figure 9 hand control system for KDH II5 experimental results
To verify the ability of the Karlsruhe smart hand, we chose two requirements for operation.. One problem is the control of the pose (position and direction) of the object under the influence of the Internet.. Another problem is that the object must be able to rotate around any angle, which can only be realized by heavy catch.. This can reflect the operation ability of the complex task of the robot hand in Karlsruhe..
5.1 object attitude control
The object of the attitude controller is to determine the position and direction of the object to fit the given trajectory.. This task must be obtained in real-time conditions, despite the presence of internal changes and external disturbances.. Internal changes such as the rolling of the ball fingers on the object when the object is moving. This situation is shown in Figure 10, figure 11. This will cause unwanted additional movement and tilt of the object. The pose of these errors is hard to estimate.. Therefore, the input of the object state sensor must modify these errors. For the Karlsruhe smart hand, the three laser triangulation sensor is used to correct this error.. Figure 12 shows the tilt of the object in Figure 9 without attitude control.. The chart shows the expected trajectory in the X direction over time, while the image shows the actual rotation of the object (tilt) results. Because the object is enabled, the object in Figure 13 is reduced greatly.. The rotation of the object above remains constant, as expected
Figure 10 additional displacement due to rolling Figure 12 No state controlled object tilt
Figure 11 an additional undesired tilt due Figure 13 object state control to reduce
to the rolling of a ball finger tip over an object the object Tilt
The object state controller is also necessary for the compensation of external interference.. For example, the robot (arm, hand or finger) or the collision between objects and the outside may cause the slide of the object. This is more likely to lead to the loss of the object, which is not the case. In order to avoid the loss of an object in this case, it is necessary to detect the slide of the object and act quickly to stabilize the object..
In order to validate the Karlsruhe dexterous hand II control system of this interference processing capability, we do the following experiments: object to be caught, the finger contact force constant is reduced until the object began to fall. After the laser triangulation sensor detects the slide, the object state controller takes measures to re regulate the object to the desired position.. Figure 15 shows an example of this experiment.. In particular, Figure 14, which shows that the object falls off the start of the quite sudden and fairly fast. But the object state controller can also quickly enough to detect and compensate for slip, the position of the object (here: especially in X direction is sliding direction and the object's direction to and the beginning of the expected soon more consistent results.
Figure 14: the actual object position of the X direction Figure 15 slide experiment: the actual object direction of the Z axis
5.2 catch
Although the Karlsruhe smart hand is very flexible, it can not get every ideal object manipulation in the first operation.. This stems from the fact that fingers are small relative to the normal industrial robot, so the working range is very limited.. If the object is caught by fingers, it can be manipulated for the first time in the remainder of all fingers.. The condition of the feasible operation is that all the contact points must be in the working range of the associated finger for a long time. This greatly limits the feasibility of the operation.. In order to overcome this limitation, a operation called heavy grasping must be executed. When a contact point reaches the restricted area of the associated finger, the finger must be detached from the object and moved to a new contact position.. It must be more than 3 fingers to make the operation reliable. The period
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