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grasped, and picked up by the system. The algorithms we have developed that relate sensing to actuation are quite general and applicable to a variety of plex robotic tasks that require visual feedback for arm and hand control. I. INTRODUCTION The focus of our work is to achieve a high level of interaction between realtime vision systems capable of tracking moving objects in 3D and a robot arm equipped with a dexterous hand that can be used to intercept, grasp, and pick up a moving object. We are interested in exploring the interplay of handeye coordination for dynamic grasping tasks such as grasping of parts on a moving conveyor system, 安徽建筑工業(yè)學院 畢業(yè)設計(論文) 33 assembly of articulated parts, or for grasping from a mobile robotic system. Coordination between an anism39。 and a separate arm control system puter that performs inverse kinematic transformations and jointlevel servicing. Each of these systems has its own sampling rate, noise characteristics, and processing delays, which need to be integrated to achieve smooth and stable realtime performance. In our case, this involves overing visual processing noise and delays with a predictive filter based upon a probabilistic analysis of the system noise characteristics. In addition, realtime arm control needs to be able to operate at fast servo rates regardless of whether new 安徽建筑工業(yè)學院 畢業(yè)設計(論文) 34 predictions of object position are available. The system consists of two fixed cameras that can image a scene containing a moving object (Fig. 1). A PUMA560 with a parallel jaw gripper attached is used to track and pick up the object as it moves (Fig. 2). The system operates as follows: 1) The imaging system performs a stereoscopic opticflow calculation at each pixel in the image. From these opticflow fields, a motion energy profile is obtained that forms the basis for a triangulation that can recover the 3D position of a moving object at video rates. 2) The 3D position of the moving object puted by step 1 is initially smoothed to remove sensor noise, and a nonlinear filter is used to recover the correct trajectory parameters which can be used for forward prediction, and the updated position is sent to the trajectoryplanner/armcontrol system. 3) The trajectory planner updates the jointlevel servos of the arm via kinematic transform equations. An additional fixedgain filter is used to provide servolevel control in case of missed or delayed munication from the vision and filtering system. 4) Once tracking is stable, the system mands the arm to intercept the moving object and the hand is used to grasp the object stably and pick it up. The following sections of the paper describe each of these subsystems in detail along with experimental results. П . PREVIOUS WORK Previous efforts in the areas of motion tracking and realtime control are too numerous to exhaustively list here. We instead list some notable efforts that have inspired us to use similar approaches. Burt et al. [9] have focused on highspeed feature detection and hierarchical scaling of images in order to meet the realtime demands of surveillance and other robotic applications. Related work has been reported by. Lee and Wohn [29] and Wiklund and Granlund [43] who use。 integration of systems with different sampling and processing rates. Most plex robotic systems are actually amalgams of different processing devices, connected by a variety of methods. For example, our system consists of three separate putation systems: a parallel image processing puter。 最后感謝 機械與電氣工程學 院和我的母校 —安徽建筑工業(yè)學院 四年來對我的大力栽培。 如果 我 們之間的相互幫助 ,此次設計的完成將變得非常困難。 黃 老師平日里工作繁多,但在我做畢業(yè)設計的每個階段,從查閱資料,設計草案的確定和修改,中期檢查 答辯 ,后期詳細設計,裝配草圖等整個過程中都給予了我悉心的指導。 隨著科技和社會的進步,智能機器人在人們生活的各個領域發(fā)揮著越來越大的作用。 3) 通過對各個典型機構(gòu)的設計,充分的理解和掌握了機械設計方面的知識,并且也對專業(yè)上的智能控制和誤差控制方面有了更加深刻的認識。 安徽建筑工業(yè)學院 畢業(yè)設計(論文) 29 5 總結(jié)與展望 歷經(jīng)一個學期的 努力, 六自由度機械手 終于 設計成功。i =30 1i = ? 帶輪的主動論轉(zhuǎn)速為 1n =3r/min 由式 1160dnV ?? V 一般在 5—— 25m/s 取 V=20m/s ?1 60 20 4 3d ???? 查表得:選帶輪為 Y 型帶 1d =20 又 2i =1 2 20d?? ? ? ? ?1 2 0 1 20 . 7 2d d a d d? ? ? ? ? 取 ? ?0 1 21 .5 6 0a d d? ? ? ? V 帶基準長度 ? ? ? ? 2210 0 1 202 1 8 2 .824 ddL a d d a? ?? ? ? ? ? 查表得: 取 dL =200 ? 00 ?? ? ? [8] 手腕擺動電機處蝸輪蝸桿、帶傳動比的確定 由手腕擺動處選用電機為 36BF003 型可得,運行頻率為 f=27000HZ ? mn =又 sn =5r/min ? 總傳動比 i= msnn = 又 大手臂擺動電機確定的一級帶輪傳動比為 1i = 小手臂擺動電機確定的二級帶輪傳動比為 2i =1 取三級傳動比為 3i =1 ? 蝸輪蝸桿的傳動比為 39。 小手臂電機處蝸輪蝸桿、帶傳動比的確定 由小手臂擺動選用電機為 45BF003 型可得,運行頻率為 f=27000HZ ? mn =又 sn =3r/min ? 總傳動比 i= msnn = 由大手臂擺動電機確定的一級帶輪傳動比為 1i = 取二級帶輪傳動比為 2i =1 ? 小手臂擺動電機蝸輪蝸桿的傳動比為 39。 安徽建筑工業(yè)學院 畢業(yè)設計(論文) 20 小手臂擺動電機的選擇 初步估計小手臂重量為 3Kg,設擺動速度為 3r/min 則小手臂折算到中軸上的轉(zhuǎn)動慣量為 2 22. 3 .2lJ m K g m??? ? ? ????? ? 小手臂折算到中軸上的轉(zhuǎn)動慣量為: 2 2 3 .1 40 .0 9 7 2 0 .0 3 .20T J W J N mT? ?? ? ? ? ? ? 小手臂擺動電機的最大靜轉(zhuǎn)矩為 m a x . 2 . 5 0 . 0 3 0 . 1 0 7 .0 . 7j KTT N m? ?? ? ? ? 選用常州寶馬集團前楊電機電器有限公司的 45BF003 型電機 其最大靜轉(zhuǎn)矩為 maxjT = ,能夠滿足機構(gòu)的要求 [7]。 手指對工件的夾緊力可按公式計算: 1 2 3NF K K K G? 式中 1K —— 安全系數(shù),通常 ; 2k —— 工作情況系數(shù),主要考慮慣性力的影響。夾緊裝置選擇常開式夾緊裝置,它在電機的驅(qū)動力的作用下機械手手抓實現(xiàn)張開和閉和 [5] 。本設計機械手采用夾持式手指 , 夾持式機械手按運動形式可分為回轉(zhuǎn)型和平移型。 ( 2) 移動型 移動型即兩手指相對支座作往復運動。 ( 了書寫方便,將 sin ,cosnn??改寫為 ,nnSC ) 本課題要研究的六自由度機械手 模型如圖 圖 DH模型 安徽建筑工業(yè)學院 畢業(yè)設計(論文) 14 有以上的坐標系推導法 ,可得出本課題六自由度機械手的運動參數(shù),如下: 表 關節(jié) i i? ( 186。 機器人的運動學方程 本文研究的機械手是具有 6個自由度的空間開鏈機構(gòu),它由一系列連桿通過轉(zhuǎn)動關節(jié)串聯(lián)而成,關節(jié)的相對轉(zhuǎn)動導致連桿的運動。坐標變換包括平移變換、旋轉(zhuǎn)變換與復合變換。 3 機械手的數(shù)學模型 機器人的數(shù)學基礎 為了描述機器人本身各連桿之間、機器人和環(huán)境之間的運動關系,通常將它們當成剛體, 進而 研究各剛體之間的運動關系。因此,機械手的驅(qū)動方案選擇電動驅(qū)動。 4) 機身,采用一個步進電機和一對蝸輪蝸桿機構(gòu)來實現(xiàn)底座的回轉(zhuǎn)運動。 安徽建筑工業(yè)學院 畢業(yè)設計(論文) 11 圖 整體 示意圖 機械手的主要部件及運動 在多關節(jié)式機械手的基本方案選定后,根據(jù)設計任務 ,為了滿足設計要求,本設計關于機械手具