機床上下料機械手設計【關節(jié)型】【四自由度】【說明書+CAD+SOLIDWORKS+仿真】
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機器人和電腦一體機制造關于生成工業(yè)機器人機械手的運動K. Kaltsoukalas, S. Makris, G. Chryssolouris佩特雷大學實驗室制造系統(tǒng)和自動化,希臘論文信息文章歷史:關鍵詞:2013年10月17日收到初稿路徑規(guī)劃2014年9月19日收到修改稿工業(yè)機器人運動2014年10月8日通過審核網格搜索2014年10月29日網上資源共享摘要在這個研究中,提出了一個智能搜索算法定義所需的位置和工業(yè)機器人機械手的定位效應路徑的想法。這個算法通過選擇和評估機器人的配置逐步達到所需的配置。構造網格的機器人替代配置使用一組參數,減少了搜索空間并減少計算時間。對于可選擇性的評價,使用多個標準,用以滿足不同的要求。替代的配置重點是給機器人的關節(jié),主要影響末端執(zhí)行器的位置。網格的分辨率和尺寸參數的設置在期望輸出的基礎上,高分辨率通過對目標位置只提供一些中間點用于平滑的路徑和一個粗略的估計。規(guī)劃的路徑是一系列的機器人配置。這種方法為一個沒有經驗的程序員自動生成機器人路徑提供了方便,這能達到預期的標準而不必記錄中間點到目標位置。 2014Elsevier有限公司保留所有權利 介紹近年來,由于能適應不同的市場需求和產品結構的變化,對柔性制造系統(tǒng)的需求日益增加。動態(tài)生產環(huán)境要求越來越多的裝配制造資源重新配置。自動裝配系統(tǒng),如機器人。它們的靈活性通常被制約因為高的編程工作要求機器人軌跡調整去適應不同的裝配單元布局。經驗豐富的機器人程序員不得不花大量時間采用常規(guī)的編程方法優(yōu)化每一個具體的應用機器人的路徑。一種廣泛應用的方法是演示編程,通過順序移動機器人的每個位置并記錄中間點的位置來示教。通過機器人控制器的連接記錄點產生機器人的最后路徑,路徑考慮到機器人的動力學約束并通過所有的約束點。機器人的最終軌跡高度依賴記錄點和程序員各自的編程經驗。機器人自動路徑規(guī)劃提出了一個問題,在過去的幾十年里如何實現(xiàn)移動機器人從初始到最終的位置進行的研究,主要集中在路徑規(guī)劃避障。一種運動規(guī)劃技術是通過采樣配置空間來構建近似的模型。在過去的幾年里,已經有很多為基于采樣的運動規(guī)劃算法進行改善的工作在進行了。在不同的類別中分類所有的規(guī)劃者很難定義一個單一的標準。經典的分離是基于路線圖規(guī)劃者和邏輯樹規(guī)劃者之間。概率路線圖路徑規(guī)劃中引入一個計算機器人無碰撞路徑的新方法。這個方法分兩個階段進行:學習和查詢。在學習階段,一個概率圖是通過生成機器人的隨機免費配置和使用一個簡單的運動規(guī)劃連接它們建設,也被稱為當地的規(guī)劃師。不同的方法已被用來解決各種各樣的問題,為了可變形物體的運動規(guī)劃而提出了構建和查詢路線圖兩種不同的方法。還提出了另一個變形的技術可以應用到生成的路徑中。介紹了障礙物的概率圖法,在生成節(jié)點的幾種策略進行了闡述并且提出了復雜三維工作區(qū)多級連接策略。通過擴展規(guī)劃無碰撞運動觸點配置的空間概率圖范例 ,隨機規(guī)劃被描述為在任意兩個多面體固體之間的CF兼容的運動規(guī)劃。這種方法的關鍵是隨機產生CF兼容的配置的新的采樣策略 。引入了快速擴展隨機樹的概念,基本的想法是,初始樣品(起始組態(tài))是樹的根和新產生的樣本,然后連接到樹中已經存在的樣品。兩個快速擴展隨機樹(RRTS)扎根在開始和在目標配置中。樹的每一個探索周圍的空間,也提出了對彼此通過一個簡單的貪婪算法的使用。雖然它最初被計劃設計為人手臂的運動動作(建模為一個自由度的運動鏈),在無碰撞把握和操作任務的自動圖形動畫中,該算法已被應用于各種路徑規(guī)劃問題。邏輯樹規(guī)劃者們已證明是處理實時規(guī)劃和重新規(guī)劃問題的一個很好的框架。為了修復快速擴展隨機樹進行更改時配置空間,一個重新規(guī)劃算法被提了出來。不是放棄當前RRT,該算法有效地只消除了新無效部分并保持休息。在工業(yè)環(huán)境中移動機器人的動態(tài)避障已經開始研究調查。然而,工業(yè)機器人通常被編程以執(zhí)行預定義的路徑。機器人編程的方法主要有兩大類:在線編程和離線編程。為了用戶的互動轉化為簡單任務提出了一個在線路徑規(guī)劃支持系統(tǒng)產生可接受的軌跡,適用于工業(yè)機器人的編程的問題。建議得出了一種新的方法,即機器人編程使用增強現(xiàn)實環(huán)境。為現(xiàn)場的機器人編程方法所需提供靈活性和適應性以應對不同環(huán)境。路徑規(guī)劃方法包括生成路徑的束搜索算法。有相似的研究表明,用戶能夠執(zhí)行的操作,即通過點的選擇和修改,為了實現(xiàn)一個光滑的無碰撞路徑。一個機器人運動規(guī)劃的方法,是根據預先計算的全局配置空間(C-)的連通性提出的。運動規(guī)劃,包括離線階段和在線階段和無碰撞的路徑將通過一個多分辨率策略下使用A*算法在C-空間中搜索。在這個研究中,提出了一種智能搜索算法去定義工業(yè)機器人機械手端部執(zhí)行器所需的位置和方向的路徑??晒┻x擇的配置的最大數量被一步步選擇和評價,直到所需的配置是接近預定的誤差范圍內為止。替代的配置是一個聰明的方式產生,重視主要影響機器人的空間位置的關節(jié)角度。在配置空間上,有一個人工推導機器人的替代組態(tài)網格。一套巧妙的參數用于減少搜索空間,提高算法的性能。對于替代品的評價,使用多個標準,可以提高算法拓展的靈活性,這是為了滿足不同的要求,即滿足最短路徑的要求。封面樣式湖 南 科 技 大 學英文文獻翻譯學 生 姓 名: 學 院: 專業(yè)及班級: 學 號: 指 導 教 師: 2015 年 5 月 30 日2.3機械手手臂結構的設計按照抓取工件的要求,車床上料機械手的手臂有三個自由度,及手臂的伸縮、左右回轉和降(或俯仰)運動。手臂的回轉和升降運動是通過立柱來實現(xiàn)的,立柱的橫向移動即為手臂的橫移。手臂的各種運動有氣缸來實現(xiàn)。2.3.1機械手手臂設計要求機器人手臂的作用,是在一定的載荷和一定的速度下,實現(xiàn)在機器人所要求的工作空間內的運動。在進行機器人手臂設計時,要遵循下述原則;1.應盡可能使機器人手臂各關節(jié)軸相互平行;相互垂直的軸應盡可能相交于一點,這樣可以使機器人運動學正逆運算簡化,有利于機器人的控制。2.機器人手臂的結構尺寸應滿足機器人工作空間的要求。工作空間的形狀和大小與機器人手臂的長度,手臂關節(jié)的轉動范圍有密切的關系。但機器人手臂末端工作空間并沒有考慮機器人手腕的空間姿態(tài)要求,如果對機器人手腕的姿態(tài)提出具體的要求,則其手臂末端可實現(xiàn)的空間要小于上述沒有考慮手腕姿態(tài)的工作空間。3.為了提高機器人的運動速度與控制精度,應在保證機器人手臂有足夠強度和剛度的條件下,盡可能在結構上、材料上設法減輕手臂的重量。力求選用高強度的輕質材料,通常選用高強度鋁合金制造機器人手臂。目前,在國外,也在研究用碳纖維復合材料制造機器人手臂。碳纖維復合材料抗拉強度高,抗振性好,比重?。ㄆ浔戎叵喈斢阡摰?/4,相當于鋁合金的2/3),但是,其價格昂貴,且在性能穩(wěn)定性及制造復雜形狀工件的工藝上尚存在問題,故還未能在生產實際中推廣應用。目前比較有效的辦法是用有限元法進行機器人手臂結構的優(yōu)化設計。在保證所需強度與剛度的情況下,減輕機器人手臂的重量。4.機器人各關節(jié)的軸承間隙要盡可能小,以減小機械間隙所造成的運動誤差。因此,各關節(jié)都應有工作可靠、便于調整的軸承間隙調整機構。5.機器人的手臂相對其關節(jié)回轉軸應盡可能在重量上平衡,這對減小電機負載和提高機器人手臂運動的響應速度是非常有利的。在設計機器人的手臂時,應盡可能利用在機器人上安裝的機電元器件與裝置的重量來減小機器人手臂的不平衡重量,必要時還要設計平衡機構來平衡手臂殘余的不平衡重量。6.機器人手臂在結構上要考慮各關節(jié)的限位開關和具有一定緩沖能力的機械限位塊,以及驅動裝置,傳動機構及其它元件的安裝。2.3.2設計具體采用方案機械手的垂直手臂(大臂)升降和水平手臂(小臂)的伸縮運動都為直線運動。直線運動的實現(xiàn)一般是氣動傳動,液壓傳動以及電動機驅動滾珠絲杠來實現(xiàn)??紤]到搬運工件的重量較大,考慮加工工件的質量達30KG,屬中型重量,同時考慮到機械手的動態(tài)性能及運動的穩(wěn)定性,安全性,對手臂的剛度有較高的要求。綜合考慮,兩手臂的驅動均選擇液壓驅動方式,通過液壓缸的直接驅動,液壓缸既是驅動元件,又是執(zhí)行運動件,不用再設計另外的執(zhí)行件了;而且液壓缸實現(xiàn)直線運動,控制簡單,易于實現(xiàn)計算機的控制。因為液壓系統(tǒng)能提供很大的驅動力,因此在驅動力和結構的強度都是比較容易實現(xiàn)的,關鍵是機械手運動的穩(wěn)定性和剛度的滿足。因此手臂液壓缸的設計原則是缸的直徑取得大一點(在整體結構允許的情況下),再進行強度的較核。同時,因為控制和具體工作的要求,機械手的手臂的結構不能太大,若僅僅通過增大液壓缸的缸徑來增大剛度,是不能滿足系統(tǒng)剛度要求的。因此,在設計時另外增設了導桿機構,小臂增設了兩個導桿,與活塞桿一起構成等邊三角形的截面形式,盡量增加其剛度;大臂增設了四個導桿,成正四邊形布置,為減小質量,各個導桿均采用空心結構。通過增設導桿,能顯著提高機械手的運動剛度和穩(wěn)定性,比較好的解決了結構、穩(wěn)定性的問題。2.4機械手腕部的結構設計機器人的手臂運動(包括腰座的回轉運動),給出了機器人末端執(zhí)行器在其工作空間中的運動位置,而安裝在機器人手臂末端的手腕,則給出了機器人末端執(zhí)行器在其工作空間中的運動姿態(tài)。機器人手腕是機器人操作機的最末端,它與機器人手臂配合運動,實現(xiàn)安裝在手腕上的末端執(zhí)行器的空間運動軌跡與運動姿態(tài),完成所需要的作業(yè)動作。2.4.1機器人手腕結構的設計要求1.機器人手腕的自由度數,應根據作業(yè)需要來設計。機器人手腕自由度數目愈多,各關節(jié)的運動角度愈大,則機器人腕部的靈活性愈高,機器人對對作業(yè)的適應能力也愈強。但是,自由度的增加,也必然會使腕部結構更復雜,機器人的控制更困難,成本也會增加。因此,手腕的自由度數,應根據實際作業(yè)要求來確定。在滿足作業(yè)要求的前提下,應使自由度數盡可能的少。一般的機器人手腕的自由度數為2至3個,有的需要更多的自由度,而有的機器人手腕不需要自由度,僅憑受臂和腰部的運動就能實現(xiàn)作業(yè)要求的任務。因此,要具體問題具體分析,考慮機器人的多種布局,運動方案,選擇滿足要求的最簡單的方案。2.機器人腕部安裝在機器人手臂的末端,在設計機器人手腕時,應力求減少其重量和體積,結構力求緊湊。為了減輕機器人腕部的重量,腕部機構的驅動器采用分離傳動。腕部驅動器一般安裝在手臂上,而不采用直接驅動,并選用高強度的鋁合金制造。3.機器人手腕要與末端執(zhí)行器相聯(lián),因此,要有標準的聯(lián)接法蘭,結構上要便于裝卸末端執(zhí)行器。4.機器人的手腕機構要有足夠的強度和剛度,以保證力與運動的傳遞。5.要設有可靠的傳動間隙調整機構,以減小空回間隙,提高傳動精度。6.手腕各關節(jié)軸轉動要有限位開關,并設置硬限位,以防止超限造成機械損壞。2.4.2設計具體采用方案通過對數控機床上下料作業(yè)的具體分析,考慮數控機床加工的具體形式及對機械手上下料作業(yè)時的具體要求,在滿足系統(tǒng)工藝要求的前提下提高安全和可靠性,為使機械手的結構盡量簡單,降低控制的難度,本設計手腕不增加自由度,實踐證明這是完全能滿足作業(yè)要求的,3個自由度來實現(xiàn)機床的上下料完全足夠。具體的手腕(手臂手爪聯(lián)結梁)結構見圖8。圖8 車床上料機械手手指2.5機械手末端執(zhí)行器(手爪)的結構設計2.5.1機械手末端執(zhí)行器的設計要求機器人末端執(zhí)行器是安裝在機器人手腕上用來進行某種操作或作業(yè)的附加裝置。機器人末端執(zhí)行器的種類很多,以適應機器人的不同作業(yè)及操作要求。末端執(zhí)行器可分為搬運用、加工用和測量用等。搬運用末端執(zhí)行器是指各種夾持裝置,用來抓取或吸附被搬運的物體。加工用末端執(zhí)行器是帶有噴槍、焊槍、砂輪、銑刀等加工工具的機器人附加裝置,用來進行相應的加工作業(yè)。測量用末端執(zhí)行器是裝有測量頭或傳感器的附加裝置,用來進行測量及檢驗作業(yè)。在設計機器人末端執(zhí)行器時,應注意以下問題;1.機器人末端執(zhí)行器是根據機器人作業(yè)要求來設計的。一個新的末端執(zhí)行器的出現(xiàn),就可以增加一種機器人新的應用場所。因此,根據作業(yè)的需要和人們的想象力而創(chuàng)造的新的機器人末端執(zhí)行器,將不斷的擴大機器人的應用領域。2.機器人末端執(zhí)行器的重量、被抓取物體的重量及操作力的總和機器人容許的負荷力。因此,要求機器人末端執(zhí)行器體積小、重量輕、結構緊湊。3.機器人末端執(zhí)行器的萬能性與專用性是矛盾的。萬能末端執(zhí)行器在結構上很復雜,甚至很難實現(xiàn),例如,仿人的萬能機器人靈巧手,至今尚未實用化。目前,能用于生產的還是那些結構簡單、萬能性不強的機器人末端執(zhí)行器。從工業(yè)實際應用出發(fā),應著重開發(fā)各種專用的、高效率的機器人末端執(zhí)行器,加之以末端執(zhí)行器的快速更換裝置,以實現(xiàn)機器人多種作業(yè)功能,而不主張用一個萬能的末端執(zhí)行器去完成多種作業(yè)。因為這種萬能的執(zhí)行器的結構復雜且造價昂貴。4.通用性和萬能性是兩個概念,萬能性是指一機多能,而通用性是指有限的末端執(zhí)行器,可適用于不同的機器人,這就要求末端執(zhí)行器要有標準的機械接口(如法蘭),使末端執(zhí)行器實現(xiàn)標準化和積木化。5.機器人末端執(zhí)行器要便于安裝和維修,易于實現(xiàn)計算機控制。用計算機控制最方便的是電氣式執(zhí)行機構。因此,工業(yè)機器人執(zhí)行機構的主流是電氣式,其次是液壓式和氣壓式(在驅動接口中需要增加電-液或電-氣變換環(huán)節(jié))。2.5.2機器人夾持器的運動和驅動方式機器人夾持器及機器人手爪。一般工業(yè)機器人手爪,多為雙指手爪。按手指的運動方式,可分為回轉型和移動型,按夾持方式來分,有外夾式和內撐式兩種。機器人夾持器(手爪)的驅動方式主要有三種1.氣動驅動方式這種驅動系統(tǒng)是用電磁閥來控制手爪的運動方向,用氣流調節(jié)閥來調節(jié)其運動速度。由于氣動驅動系統(tǒng)價格較低,所以氣動夾持器在工業(yè)中應用較為普遍。另外,由于氣體的可壓縮性,使氣動手爪的抓取運動具有一定的柔順性,這一點是抓取動作十分需要的。2.電動驅動方式電動驅動手爪應用也較為廣泛。這種手爪,一般采用直流伺服電機或步進電機,并需要減速器以獲得足夠大的驅動力和力矩。電動驅動方式可實現(xiàn)手爪的力與位置控制。但是,這種驅動方式不能用于有防爆要求的條件下,因為電機有可能產生火花和發(fā)熱。3.液壓驅動方式液壓驅動系統(tǒng)傳動剛度大,可實現(xiàn)連續(xù)位置控制。2.5.3機器人夾持器的典型結構1.楔塊杠桿式手爪利用楔塊與杠桿來實現(xiàn)手爪的松、開,來實現(xiàn)抓取工件。2.滑槽式手爪當活塞向前運動時,滑槽通過銷子推動手爪合并,產生夾緊動作和夾緊力,當活塞向后運動時,手爪松開。這種手爪開合行程較大,適應抓取大小不同的物體。3.連桿杠桿式手爪這種手爪在活塞的推力下,連桿和杠桿使手爪產生夾緊(放松)運動,由于杠桿的力放大作用,這種手爪有可能產生較大的夾緊力。通常與彈簧聯(lián)合使用。4.齒輪齒條式手爪這種手爪通過活塞推動齒條,齒條帶動齒輪旋轉,產生手爪的夾緊與松開動作。5.平行杠桿式手爪采用平行四邊形機構,因此不需要導軌就可以保證手爪的兩手指保持平行運動,比帶有導軌的平行移動手爪的摩擦力要小很多。2.5.4設計具體采用方案結合具體的工作情況,本設計采用連桿杠桿式的手爪。驅動活塞往復移動,通過活塞桿端部齒條,中間齒條及扇形齒條使手指張開或閉合。手指的最小開度由加工工件的直徑來調定。本設計按照工件的直徑為80-130mm來設計。手爪的具體結構形式如圖9所示:圖9 手爪的具體結構2.6機械手的機械傳動機構的設計2.6.1工業(yè)機器人傳動機構設計應注意的問題機器人是由多級聯(lián)桿和關節(jié)組成的多自由度的空間運動機構。除直接驅動型機器人以外,機器人各聯(lián)桿及各關節(jié)的運動都是由驅動器經過各種機械傳動機構進行驅動的。機器人所采用的傳動機構與一般機械的傳動機構相類似。常用的機械傳動機構主要有螺旋傳動、齒輪傳動、同步帶傳動、高速帶傳動等。由于傳動部件直接影響著機器人的精度、穩(wěn)定性和快速響應能力,因此,應設計和選擇滿足傳動間隙小,精度高,低摩擦、體積小、重量輕、運動平穩(wěn)、響應速度快、傳遞轉矩大、諧振頻率高以及與伺服電動機等其它環(huán)節(jié)的動態(tài)性能相匹配等要求的傳動部件。在設計機器人的傳動機構時要注意以下問題:1.為了提高機器人的運動速度及控制精度,要求機器人各運動部件的重量要輕,慣量要小。因此,機器人的傳動機構要力求結構緊湊,重量輕,體積小。2.在傳動鏈及運動副中要采用間隙調整機構,以減小反向空回所造成的運動誤差。3.系統(tǒng)傳動部件的靜摩擦力應盡可能小,動摩擦力應是盡可能小的正斜率,若為負斜率則易產生爬行,精度降低,壽命減小。因此,要采用低摩擦阻力的傳動部件和導向支承部件,如滾珠絲杠副、滾動導向支承等。4.縮短傳動鏈,提高傳動與支承剛度,如用預緊的方法提高滾珠絲杠副和滾動導軌副的傳動和支承剛度;采用大扭矩、寬調速的直流或交流伺服電機直接與絲杠螺母副連接,以減小中間傳動機構;絲杠的支承設計采用兩端軸向預緊或預拉伸支承結構等。5.選用最佳傳動比,以達到提高系統(tǒng)分辨率、減少等效到執(zhí)行元件輸出軸上的等效轉動慣量,盡可能提高加速能力。6.縮小反向死區(qū)誤差,如采取消除傳動間隙、減少支承變形等措施。7.適當的阻尼比,機械零件產生共振時,系統(tǒng)的阻尼越大,最大振幅就越小,且衰減越快;但大阻尼也會使系統(tǒng)的失動量和反轉誤差增大,穩(wěn)態(tài)誤差增大,精度降低。故在設計時要使傳動機構的阻尼合適。2.6.2工業(yè)機器人常用的傳動機構形式1.齒輪傳動機構在機器人中常用的齒輪傳動機構有圓柱齒輪,圓錐齒輪,諧波齒輪,擺線針輪及蝸輪蝸桿傳動等。機器人系統(tǒng)中齒輪傳動設計的一些問題齒輪傳動形式及其傳動比的最佳匹配選擇。齒輪傳動部件是轉矩、轉速和轉向的變換器用于伺服系統(tǒng)的齒輪減速器是一個力矩變換器。齒輪傳動比應滿足驅動部件與負載之間的位移及轉矩、轉速的匹配要求,其輸入電動機為高轉速,低轉矩,而輸出則為低轉速,高轉矩。故齒輪傳動系統(tǒng)要有足夠的剛度,還要求其轉動慣量盡量小,以便在獲得同一加速度時所需的轉矩小,即在同一驅動功率時,其加速度響應最大。齒輪的嚙合間隙會造成傳動死區(qū)(失動量),若該死區(qū)是閉環(huán)系統(tǒng)中,則可能造成系統(tǒng)不穩(wěn)定,常使系統(tǒng)產生低頻振蕩,因此要盡量采用齒側間隙小,精度高的齒輪;為盡量降低制造成本,要采用調整齒側間隙的方法來消除或減小嚙合間隙,從而提高傳動精度和系統(tǒng)的穩(wěn)定性。2.3 manipulator arm structure designAccording to the requirement, lathe to grab workpiece material arm has three degrees of freedom of the manipulator arm, and adjustable, turning around and drop (or pitch) movement.Turn and lifting movement of the arm is realized by pillar, column the lateral movement known as the shifting arm. Different campaigns have cylinder arm to realize. 2.3.1 manipulator arm design requirementsThe robotic arm role, it is in a certain load and a certain speed, realize the work required in robot in space sport. When designing the robotic arm, follow the following principles;1. Should as far as possible make the robotic arm each joint axis parallel; Perpendicular axis should as far as possible fellowship in a bit, so can make the robot kinematics inverse robot control simplifies, helps.2. The robotic arm structure size should satisfy the requirements of robots work space. Working space shapes and sizes and robot arm length, arm joint rotation range have close relationship. But the robotic arm end work space does not consider the space robot wrist gesture requirements, if robot wrist gesture to specific request, it can realize space arms ends to less than the above did not consider the wrist gesture work space.3. In order to improve the robot movement speed and control accuracy, should keep the robotic arm have enough under the condition of the strength and stiffness, as far as possible on the structure, material manage to reduce the weight of his arm. Strive to choose high intensity of lightweight materials, usually choose high-strength aluminum alloy manufacture a robotic arm. At present, in a foreign country, is also studying with carbon fiber composite materials manufacturing robot arm. Carbon fiber composite materials tensile strength, high ant-vibration sex good, small proportion (its proportion of 1/4 quite to steel, equivalent to aluminum alloy 2/3), but it is expensive, and in the performance stability and manufacturing complex shape workpiece exist problems of technology, it is not in application in practical production. At present more effective method is to use the finite element method for the optimization design of the robotic arm structure. The intensity and stiffness in ensuring the required under the weight of his arm, reduce the robot.4. The robot of each joint bearing clearance as small as possible, in order to reduce to mechanical clearance error motion caused. Therefore, the joints should have reliable operation, easy adjustment bearing clearance adjustment institutions.5. The robot arm relative to rotate the joints should as far as possible under the weight of the balance, the mechanical load and enhance decreases the response speed of the robotic arm movement is very favorable. In the design of robot arm, should as far as possible use in the robot of mechanical and electronic components and devices installed the weight of robotic arm to reduce weight, the unbalanced balancing mechanism when necessary to balance design remnants of unbalanced weight arm.6. The robotic arm on the structure to consider all the joints with certain limit switches and buffering mechanical set blocks, and driving device, transmission mechanism and other components installed.2.3.2 Design specific using schemeManipulator arm (arm) vertical lifting and level of arm (forearm) for linear motion telescopic movement. Linear motion realization is generally pneumatic transmission, hydraulic transmission and motor drive the ball screw to achieve. Considering the weight of carrying workpieces larger, consider the machining quality reaches the 30KG, belong to medium weight of the manipulator, and considering the stability of the dynamic performance and movement of the arm, the stiffness of safety, have higher demand. Comprehensive consideration, two arms driver all choose hydraulic drive mode, through hydraulic cylinder of direct drive, hydraulic cylinder is drive component and executive moving parts, and not to design another executive pieces; And the hydraulic cylinder realizing linear motion control simple, easy to realize the computer control.For hydraulic system can provide great motivation, so in driving force and structural strength are relatively easy to implement, and the key is manipulator of stability and stiffness of the sports meet. Therefore the arm hydraulic cylinder of design principle is the diameter of the cylinder made great point (in overall structures permission), then a nuclear strength.manipulator arm cannot too big, if only by increasing the hydraulic cylinder of cylinder size to increase stiffness, cannot satisfy the system is the rigidity requirement. Therefore, in the design of the additional guide-bar mechanism, forearm add two guide bar, and piston rod together constitute an equilateral triangle section form, try to increase its stiffness; Big arms add four guide bar, a positive quadrilateral layout, to reduce the quality, each guide bar adopts hollow structure. By adding a guide bar, can significantly improve the stability and stiffness of the manipulator movement, good solve structure, reliability problems. 2.4 structure design of robot wristRobot arm movement (including the waist of the seat, and gives the rotary motion) robot end actuators in its working space position, which the movement in the end of the installation of robotic arm, then gives the wrist robot end actuators in the motion of its working space gesture. CaoZuoJi robot wrist is the end of the robot, and the robotic arm with exercise, realize the end of installation of wrist of actuators space with movement trajectory posture, finish the homework action needed.2.4.1 The robot wrist structure design requirements1. Freedom of robot wrist readings, should according to assignments need to design. The more robot wrist freedom, the number of each joint Angle, the robot wrist the greater flexibility of the robot is higher, the adaptability also rightness homework more strong. However, the increase of freedom, also will make the wrist structure more complex, robot control more difficult, costs will increase. Therefore, the wrist of freedom, should according to actual operation degree is required to determine. In meet operational requirements of the premise, should make free degree as less. General robot wrist freedom for 2 to 3 degree, some needs more freedom, and some robot wrist dont need freedom, with only the movement by the arm and waist can achieve operational requirements of the task. Therefore, to the concrete analysis of multiple layouts, consider robot, sports scheme, choose the simplest satisfy the requirements of the plan.2. Robot wrist installed in the end of robot arm robot wrist, in the design, should strive to reduce the weight and volume to compact structure. In order to reduce the weight of robot wrist, wrist institutions drive sperating transmission. Wrist drive general installation in the arm, and do not adopt direct drive, and choose high-strength aluminum alloy manufacture.3. Robot wrist to and end actuators connected, accordingly, want to have the standard connection to facilitate the flange, structure of loading and unloading end actuators.4. Robot wrist institutions should have enough strength and stiffness, strength and movement to ensure the relay.5. To have reliable transmission gap adjusting mechanism, to minimize returned empty clearance, improve the transmission precision.6. The wrist of each joint axis rotation to limited a switch, and set limit to prevent hard out-of-gauge cause mechanical damage.2.4.2 design specific adopts planThrough the nc machine tools for feeding and unloading operations, considering the concrete analysis of concrete form CNC machine processing and manipulator up-down material operations in the specific requirements, and technological requirements of meet the system under the premise of improving safety and reliability of the structure of the manipulator, to make as far as possible simple, reduce the difficulty of the design and control of freedom, not to increase his wrist proved it is fully meet operational requirements of the three degrees of freedom, to realize the up-down material completely enough machine. Specific wrist (arms PAWS coupling beam) structure see figure 8.Figure 8 . Lathe feeding manipulator finger2.5 manipulator actuators (PAWS) structure designing2.5.1 manipulator actuator design requirementsRobot end actuator is installed on the robot wrist used for an operation or additional device homework. Robot end, many different kinds of actuators, in order to adapt to the different assignments and operation robot requirements. End actuators can be divided into move use, processing with with and measurement etc.Move use end actuators refers to all clamping device used to grab or adsorption transported objects.Processing with end actuators with gun, welding torch is milling cutter, grinding wheel, such as the robot machining tool, used for additional device corresponding processing work.With end actuator is measured with the additional head or sensors measuring device used to measuring and test operations.In design robot end actuators, should pay attention to the following questions;1. The robot end actuator is designed according to the operation requirement robot. A new terminal actuators occurrence, can increase a robotic new application places. Accordingly, according to the needs of the homework with people and create a new robot imagination, will continue at actuators expansion of the application field of robot.2. The weight of the robot end actuators to grab objects and the sum of weight and operating force the load force. The robot allow Therefore, request the end-effector actuators small volume, light weight, compact structure.3. The end-effector actuators with specificity is universal sexual paradox. Universal end actuators on the structure is complex, and even harder to achieve, for example, the universal humanoid multisensory dexterous robot hand yet practional utilization. At present, can be used to produce or those simple structure, universal sex not strong robot end actuators. Starting from the industrial application, should focus on the development of special, efficient robot end actuators, plus end actuators, in order to achieve the fast changing device of function, the robot is not advocated homework with a universal end actuators to complete variety of homework. Because this kind of everything the implementation of the structure is complex and expensive.4. Versatility and universal sex are two concepts, universal sex machine, and refers to the multi-energy refers to the end of generality, limited actuators, suitable for different robots, which requires the end actuators have standard machine interface (such as flange), make end actuators realizes standardization and blocks digestion.5. The end-effector actuators to facilitate installation and maintenance, easy to realize the computer control. Use computer control the most convenient is electric type actuator. Therefore, the industrial robot actuators mainstream is electric type, followed by the hydraulic and pneumatic type (in driving interface to increase electricity - liquid or electricity - air transform link).2.5.2 robot grippers sports and drive modeRobot grippers and machine hand claw. General industrial machine hand for double refers to how claws, PAWS. According to finger movement way, can be divided into back transformation and mobile type, press clamping way to points, within the clip type and supporting type two kinds.Robot grippers (PAWS) drive mode basically has 3 kinds1. Pneumatic drive mode this drive system is by electromagnetic valve to control the movement direction of the PAWS, with air regulator to adjust its movement speed. The pneumatic drive system of lower prices, so pneumatic grippers are widely used in industry. In addition, because gas compressibility, contentious hands-on claw grab motion has certain compliant sex, it is very need to grab action.2. Electric drive mode of electric drive PAWS application also more widely. The PAWS, generally USES the dc servo motor or stepping motor, and need to get enough gear reducer driving force and torque. Electric drive mode can realize the force PAWS with position control. But this cannot be used for driving way under the condition of a explosion-proof requirements, because motor may produce sparks and fever.3. Hydraulic drive mode hydraulic drive system transmission can achieve great stiffness.wherever continuous position control.2.5.3 The typical structure robot grippers1. Leveraged wedge PAWSUsing wedge block and levers to realize the pine, open PAWS, come to grab workpiece.2. Slide groove PAWSWhen the pistons forward movement, sliding channel through the pin PAWS merger, pushing produce clamping action and clamping force, when the pistons backward motion, PAWS loosen. This trip is larger, PAWS switching to grab different sizes of the object.3. Connecting rod leveraged PAWSThe PAWS in Detroit, connecting rod and leverage thrust PAWS produce clamped to relax) movement, because (the force-magnifying function, leverage the PAWS might produce larger clamping force. Usually use a combination of and the spring.4. Rack-and pinion type PAWSThe PAWS through the pistons pushing rack, rack driving gear rotating, produce the clamping PAWS with loosen action.5. Parallel leveraged PAWSAdopt parallelogram frame, so there is no need to guide can guarantee to keep the two fingers PAWS with parallel movement, the parallel rails than PAWS friction move to smaller.2.5.4 design specific adopts planCombined with concrete works, this design USES the connecting rod of lever PAWS. Driven by piston, piston rod ends move, the middle rack and rack is fan rack makes the fingers open or closed. The minimum opening finger by machining diameter to the setting. This design according to the workpiece diameter of 80-130mm to design. The concrete structure form PAWS shown as shown in figure 9:Figure 9 The specific structure PAWS2.6 manipulator mechanical transmission design2.6.1 industrial robot transmission mechanism design problems should be paid attention toRobot is by multistage league stem and joint space composed of multi-degree-of-freedom sports organization. In addition to direct drive robot, robot outside each league rod and exercise is of each joint by drive through all kinds of mechanical transmission mechanism driven. Robot adopted the transmission mechanism
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