【溫馨提示】====【1】設(shè)計(jì)包含CAD圖紙 和 DOC文檔，均可以在線預(yù)覽，所見(jiàn)即所得，，dwg后綴的文件為CAD圖，超高清，可編輯，無(wú)任何水印，，充值下載得到【資源目錄】里展示的所有文件======【2】若題目上備注三維，則表示文件里包含三維源文件，由于三維組成零件數(shù)量較多，為保證預(yù)覽的簡(jiǎn)潔性，店家將三維文件夾進(jìn)行了打包。三維預(yù)覽圖，均為店主電腦打開軟件進(jìn)行截圖的，保證能夠打開，下載后解壓即可。======【3】特價(jià)促銷，，拼團(tuán)購(gòu)買，，均有不同程度的打折優(yōu)惠，，詳情可咨詢QQ：1304139763 或者 414951605======【4】 題目最后的備注【JS系列】為店主整理分類的代號(hào)，與課題內(nèi)容無(wú)關(guān)，請(qǐng)忽視
一、課題的來(lái)源、目的、意義，國(guó)內(nèi)外基本情況
●課題的來(lái)源：
本課題來(lái)源于企業(yè)需求。
●課題的目的、意義:
在工業(yè)生產(chǎn)線中，機(jī)械手具有很廣泛的用途。它是工作抓取和裝配系統(tǒng)中的一個(gè)重要組成部分。它的基本作用是從指定位置抓取工件運(yùn)送到另一個(gè)指定的位置進(jìn)行裝配。機(jī)械手臂代替了人工的繁雜勞動(dòng)，并且操作精度高，提高了產(chǎn)品質(zhì)量和生產(chǎn)效率。
● 國(guó)內(nèi)外研究狀況及發(fā)展趨勢(shì)：
近20年來(lái), 氣動(dòng)技術(shù)的應(yīng)用領(lǐng)域迅速拓寬, 尤其是在各種自動(dòng)化生產(chǎn)線上得到廣泛應(yīng)用。電氣可編程控制技術(shù)與氣動(dòng)技術(shù)相結(jié)合, 使整個(gè)系統(tǒng)自動(dòng)化程度更高, 控制方式更靈活, 性能更加可靠；氣動(dòng)機(jī)械手、柔性自動(dòng)生產(chǎn)線的迅速發(fā)展, 對(duì)氣動(dòng)技術(shù)提出了更多更高的要求；微電子技術(shù)的引入, 促進(jìn)了電氣比例伺服技術(shù)的發(fā)展, 現(xiàn)代控制理論的發(fā)展, 使氣動(dòng)技術(shù)從開關(guān)控制進(jìn)入閉環(huán)比例伺服控制, 控制精度不斷提高；由于氣動(dòng)脈寬調(diào)制技術(shù)具有結(jié)構(gòu)簡(jiǎn)單、抗污染能力強(qiáng)和成本低廉等特點(diǎn), 國(guó)內(nèi)外都在大力開發(fā)研究。
從各國(guó)的行業(yè)統(tǒng)計(jì)資料來(lái)看, 近30 多年來(lái), 氣動(dòng)行業(yè)發(fā)展很快。20世紀(jì)70年代, 液壓與氣動(dòng)元件的產(chǎn)值比約為9∶1, 而30 多年后的今天, 在工業(yè)技術(shù)發(fā)達(dá)的歐美、日本等國(guó)家, 該比例已達(dá)到6∶4, 甚至接近5 ∶5。我國(guó)的氣動(dòng)行業(yè)起步較晚, 但發(fā)展較快。從20世紀(jì)80年代中期開始, 氣動(dòng)元件產(chǎn)值的年遞增率達(dá)20%以上, 高于中國(guó)機(jī)械工業(yè)產(chǎn)值平均年遞增率。隨著微電子技術(shù)、PLC技術(shù)、計(jì)算機(jī)技術(shù)、傳感技術(shù)和現(xiàn)代控制技術(shù)的發(fā)展與應(yīng)用, 氣動(dòng)技術(shù)已成為實(shí)現(xiàn)現(xiàn)代傳動(dòng)與控制的關(guān)鍵技術(shù)之一。
Ⅰ.氣動(dòng)機(jī)械手的應(yīng)用現(xiàn)狀
由于氣壓傳動(dòng)系統(tǒng)使用安全、可靠, 可以在高溫、震動(dòng)、易燃、易爆、多塵埃、強(qiáng)磁、輻射等惡劣環(huán)境下工作。而氣動(dòng)機(jī)械手作為機(jī)械手的一種, 它具有結(jié)構(gòu)簡(jiǎn)單、重量輕、動(dòng)作迅速、平穩(wěn)、可靠、節(jié)能和不污染環(huán)境、容易實(shí)現(xiàn)無(wú)級(jí)調(diào)速、易實(shí)現(xiàn)過(guò)載保護(hù)、易實(shí)現(xiàn)復(fù)雜的動(dòng)作等優(yōu)點(diǎn)。所以, 氣動(dòng)機(jī)械手被廣泛應(yīng)用于汽車制造業(yè)、半導(dǎo)體及家電行業(yè)、化肥和化工, 食品和藥品的包裝、精密儀器和軍事上。
Ⅱ.發(fā)展前景及方向
a)重復(fù)高精度
精度是指機(jī)器人、機(jī)械手到達(dá)指定點(diǎn)的精確程度, 它與驅(qū)動(dòng)器的分辨率以及反饋裝置有關(guān)。重復(fù)精度是指如果動(dòng)作重復(fù)多次, 機(jī)械手到達(dá)同樣位置的精確程度。重復(fù)精度比精度更重要, 如果一個(gè)機(jī)器人定位不夠精確, 通常會(huì)顯示一個(gè)固定的誤差, 這個(gè)誤差是可以預(yù)測(cè)的, 因此可以通過(guò)編程予以校正。重復(fù)精度限定的是一個(gè)隨機(jī)誤差的范圍, 它通過(guò)一定次數(shù)地重復(fù)運(yùn)行機(jī)器人來(lái)測(cè)定。隨著微電子技術(shù)和現(xiàn)代控制技術(shù)的發(fā)展, 以及氣動(dòng)伺服技術(shù)走出實(shí)驗(yàn)室和氣動(dòng)伺服定位系統(tǒng)的成套化。氣動(dòng)機(jī)械手的重復(fù)精度將越來(lái)越高, 它的應(yīng)用領(lǐng)域也將更廣闊, 如核工業(yè)和軍事工業(yè)等。
b)模塊化
有的公司把帶有系列導(dǎo)向驅(qū)動(dòng)裝置的氣動(dòng)機(jī)械手稱為簡(jiǎn)單的傳輸技術(shù), 而把模塊化拼裝的氣動(dòng)機(jī)械手稱為現(xiàn)代傳輸技術(shù)。模塊化拼裝的氣動(dòng)機(jī)械手比組合導(dǎo)向驅(qū)動(dòng)裝置更具靈活的安裝體系。它集成電接口和帶電纜及氣管的導(dǎo)向系統(tǒng)裝置, 使機(jī)械手運(yùn)動(dòng)自如。由于模塊化氣動(dòng)機(jī)械手的驅(qū)動(dòng)部件采用了特殊設(shè)計(jì)的滾珠軸承, 使它具有高剛性、高強(qiáng)度及精確的導(dǎo)向精度。優(yōu)良的定位精度也是新一代氣動(dòng)機(jī)械手的一個(gè)重要特點(diǎn)。模塊化氣動(dòng)機(jī)械手使同一機(jī)械手可能由于應(yīng)用不同的模塊而具有不同的功能, 擴(kuò)大了機(jī)械手的應(yīng)用范圍, 是氣動(dòng)機(jī)械手的一個(gè)重要的發(fā)展方向。
c)無(wú)給油化
為了適應(yīng)食品、醫(yī)藥、生物工程、電子、紡織、精密儀器等行業(yè)的無(wú)污染要求, 不加潤(rùn)滑脂的不供油潤(rùn)滑元件已經(jīng)問(wèn)世。隨著材料技術(shù)的進(jìn)步, 新型材料(如燒結(jié)金屬石墨材料) 的出現(xiàn), 構(gòu)造特殊、用自潤(rùn)滑材料制造的無(wú)潤(rùn)滑元件, 不僅節(jié)省潤(rùn)滑油、不污染環(huán)境, 而且系統(tǒng)簡(jiǎn)單、摩擦性能穩(wěn)定、成本低、壽命長(zhǎng)。
d)機(jī)電氣一體化
由“可編程序控制器- 傳感器- 氣動(dòng)元件”組成的典型的控制系統(tǒng)仍然是自動(dòng)化技術(shù)的重要方面;發(fā)展與電子技術(shù)相結(jié)合的自適應(yīng)控制氣動(dòng)元件, 使氣動(dòng)技術(shù)從“開關(guān)控制”進(jìn)入到高精度的“反饋控制”; 省配線的復(fù)合集成系統(tǒng), 不僅減少配線、配管和元件, 而且拆裝簡(jiǎn)單, 大大提高了系統(tǒng)的可靠性。而今, 電磁閥的線圈功率越來(lái)越小, 而PLC的輸出功率在增大, 由PLC直接控制線圈變得越來(lái)越可能。氣動(dòng)機(jī)械手、氣動(dòng)控制越來(lái)越離不開PLC, 而閥技術(shù)的發(fā)展, 又使PLC在氣動(dòng)機(jī)械手、氣動(dòng)控制中變得更加得心應(yīng)手。
氣動(dòng)技術(shù)經(jīng)歷了一個(gè)漫長(zhǎng)的發(fā)展過(guò)程, 隨著氣動(dòng)伺服技術(shù)走出實(shí)驗(yàn)室, 氣動(dòng)技術(shù)及氣動(dòng)機(jī)械手迎來(lái)了嶄新的春天。目前在世界上形成了以日本、美國(guó)和歐盟氣動(dòng)技術(shù)、氣動(dòng)機(jī)械手三足鼎立的局面。我國(guó)對(duì)氣動(dòng)技術(shù)和氣動(dòng)機(jī)械手的研究與應(yīng)用都比較晚, 但隨著投入力度和研發(fā)力度的加大, 我國(guó)自主研制的許多氣動(dòng)機(jī)械手已經(jīng)在汽車等行業(yè)為國(guó)家的發(fā)展進(jìn)步發(fā)揮著重要作用。隨著微電子技術(shù)的迅速發(fā)展和機(jī)械加工工藝水平的提高及現(xiàn)代控制理論的應(yīng)用, 為研究高性能的氣動(dòng)機(jī)械手奠定了堅(jiān)實(shí)的物質(zhì)技術(shù)基礎(chǔ)。由于氣動(dòng)機(jī)械手有結(jié)構(gòu)簡(jiǎn)單、易實(shí)現(xiàn)無(wú)級(jí)調(diào)速、易實(shí)現(xiàn)過(guò)載保護(hù)、易實(shí)現(xiàn)復(fù)雜的動(dòng)作等諸多獨(dú)特的優(yōu)點(diǎn), 可以預(yù)見(jiàn), 在不久的將來(lái), 氣動(dòng)機(jī)械手將越來(lái)越廣泛地進(jìn)入工業(yè)、航空、醫(yī)療、生活等領(lǐng)域。
二、 預(yù)計(jì)達(dá)到的目標(biāo)、關(guān)鍵理論和技術(shù)、完成課題的方案和主要措施
1．預(yù)計(jì)達(dá)到的目標(biāo)：
采用氣動(dòng)裝置PLC控制機(jī)械手，它的基本作用是從指定位置抓取工件運(yùn)送到另一個(gè)指定的位置進(jìn)行裝配。主要完成的是氣動(dòng)式機(jī)械手臂的結(jié)構(gòu)方面設(shè)計(jì)，以及用PLC軟件進(jìn)行簡(jiǎn)單的控制編程設(shè)計(jì)。
機(jī)械手具有三個(gè)自由度：上下一個(gè)，旋轉(zhuǎn)一個(gè)，手指的開閉一個(gè)。上下是10cm，前后是25cm，旋轉(zhuǎn)是90度，手抓開合是60度。工件尺寸大約在1.5～2cm直徑。
2．關(guān)鍵理論和技術(shù)：
運(yùn)用機(jī)械手的工作原理：機(jī)械手主要由執(zhí)行機(jī)構(gòu)、驅(qū)動(dòng)系統(tǒng)、控制系統(tǒng)以及位置檢測(cè)裝置等所組成。在PLC程序控制的條件下，采用氣壓傳動(dòng)方式，來(lái)實(shí)現(xiàn)執(zhí)行機(jī)構(gòu)的相應(yīng)部位發(fā)生規(guī)定要求的，有順序，有運(yùn)動(dòng)軌跡，有一定速度和時(shí)間的動(dòng)作。同時(shí)按其控制系統(tǒng)的信息對(duì)執(zhí)行機(jī)構(gòu)發(fā)出指令，必要時(shí)可對(duì)機(jī)械手的動(dòng)作進(jìn)行監(jiān)視，當(dāng)動(dòng)作有錯(cuò)誤或發(fā)生故障時(shí)即發(fā)出報(bào)警信號(hào)。位置檢測(cè)裝置隨時(shí)將執(zhí)行機(jī)構(gòu)的實(shí)際位置反饋給控制系統(tǒng)，并與設(shè)定的位置進(jìn)行比較，然后通過(guò)控制系統(tǒng)進(jìn)行調(diào)整，從而使執(zhí)行機(jī)構(gòu)以一定的精度達(dá)到設(shè)定位置。（如下圖所示）
機(jī)械手的系統(tǒng)工作原理框圖
運(yùn)用到所學(xué)知識(shí)有機(jī)械設(shè)計(jì)理論，液壓傳動(dòng)技術(shù)，電液控制技術(shù)，PLC控制編程技術(shù)，電工電子技術(shù)，液壓系統(tǒng)設(shè)計(jì)原理等。
3．完成課題具體方案措施如下：
（1）、機(jī)械手各執(zhí)行機(jī)構(gòu)設(shè)計(jì)，包括：末端執(zhí)行器、手臂、手腕及基座的設(shè)計(jì)
設(shè)計(jì)參數(shù)：
機(jī)械手（重復(fù)）定位精度：±0.5mm
機(jī)械手最大抓重：0.5kg
工件尺寸：直徑約1.5～2cm
支座旋轉(zhuǎn)角度為：90度（最大速度：90度每秒）
物料盤（采用步進(jìn)電機(jī)控制）每工步旋轉(zhuǎn)角度：30度（最大轉(zhuǎn)度：30度每秒）
Y軸大臂上下移動(dòng)距離為：20cm（最大速度10cm/s）
Y軸小臂上下移動(dòng)距離為：10cm（最大速度10cm/s）
X軸小臂伸縮距離：10cm （最大速度10cm/s）
手指開合角度為：60度（最大速度60度每秒）
料槽小臂（推動(dòng)工件的推桿）伸縮距離為：15cm（最大速度10cm/s）
（2）、驅(qū)動(dòng)系統(tǒng)的設(shè)計(jì)
本課題上下、旋轉(zhuǎn)和手爪開合三個(gè)自由度選擇氣壓傳動(dòng)系統(tǒng)驅(qū)動(dòng)，包括氣動(dòng)元器件的選取，氣動(dòng)回路的設(shè)計(jì)，并繪出氣動(dòng)原理圖。
（3）、設(shè)計(jì)控制部分
本機(jī)械手采用可編程序控制器(PLC)對(duì)機(jī)械手進(jìn)行控制，本課題將要選取PLC型號(hào)（初定三菱的PLC裝置），根據(jù)機(jī)械手的工作流程編制出PLC程序，并畫出梯形圖。預(yù)定工作流程如圖所示。
（4）、圖紙繪制。
裝配圖、零件圖、電路原理圖的繪制。
三、課題進(jìn)展計(jì)劃
日期
工作內(nèi)容
08.10.1～08.10.30
完成開題報(bào)告及資料翻譯
08.11.1～08.12.30
確定結(jié)構(gòu)方案
09.1.1～09.2.30
電氣控制部分方案設(shè)計(jì)與編程
09.3.1～09.4.30
圖紙繪制
09.5.1～09.5.30
撰寫畢業(yè)論文
09.6.1～09.6.10
答辯準(zhǔn)備及答辯
四、主要參考文獻(xiàn)
【1】徐炳輝. 氣動(dòng)手冊(cè)[M ]. 上?？茖W(xué)技術(shù)出版社, 2005
【2】明仁雄, 等. 液壓與氣壓傳動(dòng)[M ]. 國(guó)防工業(yè)出版社, 2003
【3】SMC (中國(guó)) 有限公司. 現(xiàn)代實(shí)用技術(shù)[M ] 北京:機(jī)械工業(yè)出版社, 1998
【4】SMC (中國(guó)) 有限公司. 現(xiàn)代實(shí)用技術(shù)[M ] 二版.北京: 機(jī)械工業(yè)出版社, 2003
【5】陸鑫盛, 周洪. 氣動(dòng)自動(dòng)化系統(tǒng)的優(yōu)化設(shè)計(jì)[M ]. 上?？茖W(xué)技術(shù)文獻(xiàn)出版社, 1999
【6】馬振福. 液壓與氣壓傳動(dòng)[M ]. 機(jī)械工業(yè)出版社,2004
【7】陳新元, 張安龍. 裝配線機(jī)械手電氣混合控制[ J ].液壓與氣動(dòng), 2007 (3)
【8】姜繼海, 宋錦春, 高常識(shí). 液壓與氣壓傳動(dòng)[M ]. 高等教育出版社, 2002
【9】上海工業(yè)大學(xué)流控研究室. 氣動(dòng)技術(shù)基礎(chǔ)[M ]. 機(jī)械工業(yè)出版社, 1982
【10】杜來(lái)林, 等. 北京大學(xué)出版社, 2005
【11】鄭洪生. 氣壓傳動(dòng)[M ]. 機(jī)械工業(yè)出版社
【12】[德] Werner Deppert/Kurt Stoll1 氣動(dòng)技術(shù)——低成本綜合自動(dòng)化[M ]. 李寶仁, 譯. 機(jī)械工業(yè)出版社,1999
【13】(日)大熊繁編著.機(jī)器人控制[M].北京:科學(xué)出版社,2002
【14】遷三郎.機(jī)器人工程學(xué)及其應(yīng)用[M].王琪民,等譯.北京:國(guó)防工業(yè)出版社,1989
【15】白井良明.機(jī)器人工程[M].北京:科學(xué)出版社,2001
【16】王孝華, 趙中林, 等. 氣動(dòng)元件及系統(tǒng)的使用與維修[M ]. 機(jī)械工業(yè)出版社, 1996
【17】蔡自興. 機(jī)器人學(xué)[M ]. 北京: 清華大學(xué)出版社,2000
【18】袁子榮. 液氣壓傳動(dòng)與控制[M ]. 重慶大學(xué)出版社, 2002
【19】路甬祥. 液壓氣動(dòng)技術(shù)手冊(cè)[M ]. 機(jī)械工業(yè)出版社,2002
【20】[美] Saeed B. Niku. 機(jī)器人學(xué)導(dǎo)論——分析、系統(tǒng)及應(yīng)用[M ] 1 孫富春, 朱紀(jì)洪, 劉國(guó)棟, 等譯孫增圻, 審校. 電子工業(yè)出版社, 2004
【21】氣動(dòng)機(jī)械手的應(yīng)用現(xiàn)狀及發(fā)展前景http://www.kj008.com/paper/pp1189.html
指導(dǎo)教師評(píng)語(yǔ):
指導(dǎo)教師簽字
系負(fù)責(zé)人簽字
年 月 日
- 7 -
Robot
After more than 40 years of development, since its first appearance till now, the robot has already been widely applied in every industrial fields, and it has become the important standard of industry modernization.
Robotics is the comprehensive technologies that combine with mechanics, electronics, informatics and automatic control theory. The level of the robotic technology has already been regarded as the standard of weighing a national modern electronic-mechanical manufacturing technology.
Over the past two decades, the robot has been introduced into industry to perform many monotonous and often unsafe operations. Because robots can perform certain basic more quickly and accurately than humans, they are being increasingly used in various manufacturing industries.
With the maturation and broad application of net technology, the remote control technology of robot based on net becomes more and more popular in modern society. It employs the net resources in modern society which are already three to implement the operatio of robot over distance. It also creates many of new fields, such as remote experiment, remote surgery, and remote amusement. What's more, in industry, it can have a beneficial impact upon the conversion of manufacturing means.
The key words are reprogrammable and multipurpose because most single-purpose machines do not meet these two requirements. The term “reprogrammable” implies two things: The robot operates according to a written program, and this program can be rewritten to accommodate a variety of manufacturing tasks. The term “multipurpose” means that the robot can perform many different functions, depending on the program and tooling currently in use.
Developed from actuating mechanism, industrial robot can imitation some actions and functions of human being, which can be used to moving all kinds of material components tools and so on, executing mission by execuatable program multifunction manipulator. It is extensive used in industry and agriculture production, astronavigation and military engineering.
During the practical application of the industrial robot, the working efficiency and quality are important index of weighing the performance of the robot. It becomes key problems which need solving badly to raise the working efficiencies and reduce errors of industrial robot in operating actually. Time-optimal trajectory planning of robot is that optimize the path of robot according to performance guideline of minimum time of robot under all kinds of physical constraints, which can make the motion time of robot hand minimum between two points or along the special path. The purpose and practical meaning of this research lie enhance the work efficiency of robot.
Due to its important role in theory and application, the motion planning of industrial robot has been given enough attention by researchers in the world. Many researchers have been investigated on the path planning for various objectives such as minimum time, minimum energy, and obstacle avoidance.
The basic terminology of robotic systems is introduced in the following:
A robot is a reprogrammable, multifunctional manipulator designed to move parts, materials, tools, or special devices through variable programmed motions for the performance of a variety of different task. This basic definition leads to other definitions, presented in the following paragraphs that give a complete picture of a robotic system.
Preprogrammed locations are paths that the robot must follow to accomplish work. At some of these locations, the robot will stop and perform some operation, such as assembly of parts, spray painting, or welding. These preprogrammed locations are stored in the robot’s memory and are recalled later for continuous operation. Furthermore, these preprogrammed locations, as well as other programming feature, an industrial robot is very much like a computer, where data can be stored and later recalled and edited.
The manipulator is the arm of the robot. It allows the robot to bend, reach, and twist. This movement is provided by the manipulator’s axes, also called the degrees of freedom of the robot. A robot can have from 3 to 16 axes. The term degrees of freedom will always relate to the number of axes found on a robot.
The tooling and grippers are not part of the robotic system itself: rather, they are attachments that fit on the end of the robot’s arm. These attachments connected to the end of the robot’s arm allow the robot to lift parts, spot-weld, paint, arc-well, drill, deburr, and do a variety of tasks, depending on what is required of the robot.
The robotic system can also control the work cell of the operating robot. The work cell of the robot is the total environment in which the robot must perform its task. Included within this cell may be the controller, the robot manipulator, a work table, safety features, or a conveyor. All the equipment that is required in order for the robot to do its job is included in the work cell. In addition, signals from outside devices can communicate with the robot in order to tell the robot when it should assemble parts, pick up parts, or unload parts to a conveyor.
The robotic system has three basic components: the manipulator, the controller, and the power source.
Manipulator
The manipulator, which dose the physical work of the robotic system, consists of two sections: the mechanical section and the attached appendage. The manipulator also has a base to which the appendages are attached.
The base of the manipulator is usually fixed to the floor of the work area. Sometimes, though, the base may be movable. In this case, the base is attached to either a rail or a track, allowing the manipulator to be moved from one location to anther.
As mentioned previously, the appendage extends from the base of the robot. The appendage is the arm of the robot. It can be either a straight, movable arm or a jointed arm. The jointed arm is also known as an articulated arm.
The appendages of the robot manipulator give the manipulator its various axes of motion. These axes are attached to a fixed base, which, in turn, is secured to a mounting. This mounting ensures that the manipulator will remain in one location.
At the end of the arm, a wrist is connected. The wrist is made up of additional axes and a wrist flange. The wrist flange allows the robot user to connect different tooling to the wrist for different jobs.
The manipulator’s axes allow it to perform work within a certain area. This area is called the work cell of the robot, and its size corresponds to the size of the manipulator. As the robot’s physical size increases, the size of the work cell must also increase.
The movement of the manipulator is controlled by actuators, or drive system. The actuator, or drive system, allows the various axes to move within the work cell. The drive system can use electric, hydraulic, or pneumatic power. The energy developed by the drive system is converted to mechanical power by various mechanical drive systems. The drive systems are coupled through mechanical linkages. These linkages, in turn, drive the different axes of the robot. The mechanical linkages may be composed of chains, gears, and ball screws.
Controller
The controller in the robotic system is the heart of the operation. The controller stores preprogrammed information for later recall, controls peripheral devices, and communicates with computers within the plant for constant updates in production.
The controller is used to control the robot manipulator’s movements as well as to control peripheral components within the work cell. The user can program the movements of the manipulator into the controller through the use of a hand-held teach pendant. This information is stored in the memory of the controller for later recall. The controller stores all program data for the robotic system. It can store several different programs, and any of these programs can be edited.
The controller is also required to communicate with peripheral equipment within the work cell. For example, the controller has an input line that identifies when a machining operation is completed. When the machine cycle is completed, the input line turns on, telling the controller to position the manipulator so that it can pick up the finished part. Then, a new part is picked up by the manipulator and placed into the machine. Next, the controller signals the machine to start operation.
The controller can be made from mechanically operated drums that step through a sequence of events. This type of controller operates with a very simple robotic system. The controllers found on the majority of robotic systems are more complex devices and represent state-of-the-art electronics. This is, they are microprocessor-operated. These microprocessors are either 8-bit, 16-bit, or 32-bit processors. This power allows the controller to the very flexible in its operation.
The controller can send electric signals over communication lines that allow it to talk with the various axes of the manipulator. This two-way communication between the robot manipulator and the controller maintains a constant update of the location and the operation of the system. The controller also controls any tooling placed on the end of the robot’s wrist.
The controller also has the job of communicating with the different plant computers. The communication link establishes the robot as part of a computer-assisted manufacturing (CAM) system.
As the basic definition stated, the robot is a reprogrammable, multifunctional manipulator. Therefore, the controller must contain some type of memory storage. The microprocessor-based systems operate in conjunction with solid-state memory devices. These memory devices may be magnetic bubbles, random-access memory, floppy disks, or magnetic tape. Each memory storage device stores program information for later recall or for editing.
Power supply
The power supply is the unit that supplies power to the controller and the manipulator. Two types of power are delivered to the robotic system. One type of power is the AC power for operation of the controller. The other type of power is used for driving the various axes of the manipulator. For example, if the robot manipulator is controlled by hydraulic or pneumatic drives, control signals are sent to these devices, causing motion of the robot.
For each robotic system, power is required to operate the manipulator. This power can be developed from either a hydraulic power source, a pneumatic power source, or an electric power source. These power sources are part of the total components of the robotic work cell.
Classification of Robots
Industrial robots vary widely in size, shape, number of axes, degrees of freedom, and design configuration. Each factor influences the dimensions of the robot’s working envelope or the volume of space within which it can move and perform its designated task. A broader classification of robots can been described as blew.
Fixed and Variable-Sequence Robots. The fixed-sequence robot (also called a pick-and place robot) is programmed for a specific sequence of operations. Its movements are from point to point, and the cycle is repeated continuously. The variable-sequence robot can be programmed for a specific sequence of operations but can be reprogrammed to perform another sequence of operation.
Playback Robot. An operator leads or walks the playback robot and its end effector through the desired path. The robot memorizes and records the path and sequence of motions and can repeat them continually without any further action or guidance by the operator.
Numerically Controlled Robot. The numerically controlled robot is programmed and operated much like a numerically controlled machine. The robot is servo-controlled by digital data, and its sequence of movements can be changed with relative ease.
Intelligent Robot. The intellingent robot is capable of performing some of the functions and tasks carried out by human beings. It is equipped with a variety of sensors with visual and tactile capabilities.
Robot Applications
The robot is a very special type of production tool; as a result, the applications in which robots are used are quite broad. These applications can be grouped into three categories: material processing, material handling and assembly.
In material processing, robots use to process the raw material. For example, the robot tools could include a drill and the robot would be able to perform drilling operations on raw material.
Material handling consists of the loading, unloading, and transferring of workpieces in manufacturing facilities. These operations can be performed reliably and repeatedly with robots, thereby improving quality and reducing scrap losses.
Assembly is another large application area for using robotics. An automatic assembly system can incorporate automatic testing, robot automation and mechanical handling for reducing labor costs, increasing output and eliminating manual handling concerns.
Hydraulic System
There are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical type. However, fluid systems are restricted to shorter distances than are electrical systems.
Hydraulic power transmission systems are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:
1. Pumps which convert available power from the prime mover to hydraulic power at the actuator.
2. Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.
3. Actuators which convert hydraulic power to usable mechanical power output at the point required.
4. The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.
5. Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank(reservoir).
6. Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid..
Hydraulic systems are used in industrial applications such as stamping presses, steel mills, and general manufacturing, agricultural machines, mining industry, aviation, space technology, deep-sea exploration, transportation, marine technology, and offshore gas and petroleum exploration. In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.
The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.
Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.
1. Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power system can readily start, stop, speed up or slow down, and position forces which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch. Fig. shows a fluid power system which allows an aircraft pilot to raise and lower his landing gear. When the pilot moves a small control valve in one direction, oil under pressure flows to one end of the cylinder to lower the landing gear. To retract the landing gear, the pilot moves the valve lever in the opposite direction, allowing oil to flow into the other end of the cylinder.
2. Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.
3. Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.
4. Simplicity, safety, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the steering unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, etc. are eliminated. This provides a simple, compact system. In applications. This is important where limitations of control space require a small steering wheel and it becomes necessary to reduce operator fatigue.
Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely eliminate. Also, most hydraulic oils can cause fires if an oil leak occurs in an area of hot equipment.
Pneumatic System
Pneumatic system use pressurized gases to transmit and control power. As the name implies, pneumatic systems typically use air (rather than some other gas ) as the fluid medium because air is a safe, low-cost, and readily available fluid. It is particularly safe in environments where an electrical spark could ignite leaks from system components.
In pneumatic systems, compressors are used to compress and supply the necessary quantities of air. Compressors are typically of the piston, vane or screw type. Basically a compressor increases the pressure of a gas by reducing its volume as described by the perfect gas laws. Pneumatic systems normally use a large centralized air compressor which is considered to be an infinite air source similar to an electrical system where you merely plug into an electrical outlet for electricity. In this way, pressurized air can be piped from one source to various locations throughout an entire industrial plant. The compressed air is piped to each circuit through an air filter to remove contaminants which might harm the closely fitting parts of pneumatic components such as valve and cylinders. The air then flows through a pressure regulator which reduces the pressure to the desired level for the particular circuit application. Because air is not a good lubricant (contains about 20% oxygen), pneumatics systems required a lubricator to inject a very fine mist of oil into the air discharging fr