https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000097045.pdf

http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf

筆記

from?http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf

手臂的設計約束：? ?20磅的最大力和30英寸磅的扭矩

每個手部組件總共具有14個自由度，并且由前臂粥脚，兩個DOF腕部以及具有位置喧枷，速度和力傳感器的十二個DOF手組成随闺。

前臂的底部直徑為4英寸，長約8英寸，容納所有十四臺電機景埃，

手部配備了42個傳感器（不包括觸覺感測）跪帝。// 每個關(guān)節(jié)都配有嵌入式絕對位置傳感器，// 每個電機都配有增量式編碼器崎苗。// 每個導螺桿組件以及手腕球關(guān)節(jié)連桿均被裝備為應力傳感器以提供力反饋狐粱。

過去的手工設計[4,5]使用了使用復雜滑輪系統(tǒng)或護套的腱索驅(qū)動裝置，這兩種裝置在EVA空間環(huán)境中使用時都會造成嚴重的磨損和可靠性問題胆数。為了避免與肌腱有關(guān)的問題肌蜻，手使用柔性軸將電力從前臂的電動機傳輸?shù)绞种浮Ｊ褂眯⌒湍K化導螺桿組件將柔性軸的旋轉(zhuǎn)運動轉(zhuǎn)換為手中的直線運動必尼。結(jié)果是一個緊湊而堅固的傳動系蒋搜。

英文

from?http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf

Robonaut’s hands set it apart from any previous space manipulator system. These hands can fit into all the same places currently designed for an astronaut’s gloved hand. A key feature of the hand is its palm degree of freedom that allows Robonaut to cup a tool and line up its long axis with the roll degree of freedom of the forearm, thereby, permitting tool use in tight spaces with minimum arm motion. Each hand assembly shown in figure 3 has a total of 14 DOFs, and consists of a forearm, a two DOF wrist, and a twelve DOF hand complete with position, velocity, and force sensors. The forearm, which measures four inches in diameter at its base and is approximately eight inches long, houses all fourteen motors, the motor control and power electronics, and all of the wiring for the hand. An exploded view of this assembly is given in figure 4. Joint travel for the wrist pitch and yaw is designed to meet or exceed that of a human hand in a pressurized glove. Page 2 Figure 4: Forearm Assembly The requirements for interacting with planned space station EVA crew interfaces and tools provided the starting point for the Robonaut Hand design [1]. Both power and dexterous grasps are required for manipulating EVA crew tools. Certain tools require single or multiple finger actuation while being firmly grasped. A maximum force of 20 lbs and torque of 30 in-lbs are required to remove and install EVA orbital replaceable units (ORUs) [2]. The hand itself consists of two sections (figure 5) : a dexterous work set used for manipulation, and a grasping set which allows the hand to maintain a stable grasp while manipulating or actuating a given object. This is an essential feature for tool use [3]. The dexterous set consists of two 3 DOF fingers (index and middle) and a 3 DOF opposable thumb. The grasping set consists of two, single DOF fingers (ring and pinkie) and a palm DOF. All of the fingers are shock mounted into the palm. In order to match the size of an astronaut’s gloved hand, the motors are mounted outside the hand, and mechanical power is transmitted through a flexible drive train. Past hand designs [4,5] have used tendon drives which utilize complex pulley systems or sheathes, both of which pose serious wear and reliability problems when used in the EVA space environment. To avoid the problems associated with tendons, the hand uses flex shafts to transmit power from the motors in the forearm to the fingers. The rotary motion of the flex shafts is converted to linear motion in the hand using small modular leadscrew assemblies. The result is a compact yet rugged drive train. Figure 5: Hand Anatomy Overall the hand is equipped with forty-two sensors (not including tactile sensing). Each joint is equipped with embedded absolute position sensors and each motor is equipped with incremental encoders. Each of the leadscrew assemblies as well as the wrist ball joint links are instrumented as load cells to provide force feedback. In addition to providing standard impedance control, hand force control algorithms take advantage of the non-backdriveable finger drive train to minimize motor power requirements once a desired grasp force is achieved. Hand primitives in the form of pre-planned trajectories are available to minimize operator workload when performing repeated tasks.

譯文

from?http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf

Robonaut的手把它與以前的太空操縱器系統(tǒng)區(qū)別開來篡撵。這些雙手可以裝入目前為宇航員的戴手套而設計的所有相同的地方。手的一個關(guān)鍵特征是它的手掌自由度豆挽，使得Robonaut可以用一個工具和長軸與前臂的自由度進行排列育谬，從而允許工具在狹小的空間中以最小的手臂運動使用。

圖3中所示的每個手部組件總共具有14個自由度帮哈，并且由前臂膛檀，兩個DOF腕部以及具有位置，速度和力傳感器的十二個DOF手組成但汞。前臂的底部直徑為4英寸宿刮，長約8英寸，容納所有十四臺電機私蕾，電機控制和電力電子設備僵缺，以及所有手持線路。圖4給出了該組件的分解圖踩叭。手腕節(jié)距和偏航的聯(lián)合行程被設計為在加壓手套中達到或超過人手磕潮。

圖4：前臂裝配與計劃的空間站EVA乘員接口和工具交互的要求為Robonaut手的設計提供了起點[1]。操縱EVA乘員組工具需要力量和靈巧的抓握容贝。某些工具需要單手或多手指動作自脯，同時牢牢抓住。拆卸和安裝EVA軌道可替換單元（ORU）需要20磅的最大力和30英寸磅的扭矩[2]斤富。

手由兩部分組成（圖5）：一個用于操作的靈巧工作組膏潮，以及一個抓握組件，它允許手在操縱或啟動給定物體時保持穩(wěn)定的抓握满力。這是工具使用的基本特征[3]焕参。靈巧套裝由兩個3 DOF手指（食指和中指）和一個3 DOF可對折手指組成。抓握組由兩個單DOF手指（無名指和小指）和一個手掌自由度組成油额。所有的手指都被安裝在手掌上叠纷。為了匹配宇航員戴著手套的手的大小，電機安裝在手外潦嘶，機械動力通過柔性傳動系傳遞涩嚣。

過去的手工設計[4,5]使用了使用復雜滑輪系統(tǒng)或護套的腱索驅(qū)動裝置，這兩種裝置在EVA空間環(huán)境中使用時都會造成嚴重的磨損和可靠性問題掂僵。為了避免與肌腱有關(guān)的問題航厚，手使用柔性軸將電力從前臂的電動機傳輸?shù)绞种浮Ｊ褂眯⌒湍K化導螺桿組件將柔性軸的旋轉(zhuǎn)運動轉(zhuǎn)換為手中的直線運動锰蓬。結(jié)果是一個緊湊而堅固的傳動系幔睬。

圖5：手部解剖總的來說，手部配備了42個傳感器（不包括觸覺感測）互妓。每個接頭都配有嵌入式絕對位置傳感器溪窒，每個電機都配有增量式編碼器坤塞。每個導螺桿組件以及手腕球關(guān)節(jié)連桿均被裝備為稱重傳感器以提供力反饋。除了提供標準阻抗控制之外澈蚌，一旦達到期望的抓力摹芙，手力控制算法利用非反向驅(qū)動手指驅(qū)動系統(tǒng)來節(jié)約電機能耗要求。預先規(guī)劃的軌跡形式的手原語可用于在執(zhí)行重復任務時最大限度地減少操作員的工作量宛瞄。

Design of the NASA Robonaut Hand R1

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000097045.pdf

C. S. Lovchik, H. A. Aldridge RoboticsTechnology Branch NASA Johnson Space Center Houston, Texas 77058 Iovchik@jsc.nasa.gov, haldridg@ems.jsc.nasa.gov Fax: 281-244-5534

Abstract

The design of a highly anthropomorphichuman scale robot hand for space based operations is described. This fivefinger hand combined with its integrated wrist and forearm has fourteenindependent degrees of freedom. The device approximates very well thekinematics and required strength of an astronaut's hand when operating througha pressurized space suit glove. The mechanisms used to meet these requirementsare explained in detail along with the design philosophy behind them.Integration experiences reveal the challenges associated with obtaining therequired capabilities within the desired size. The initial finger controlstrategy is presented along with examples of obtainable grasps.

描述了用于空間操作的高度擬人化的人類尺度機器人手的設計浮禾。這五個手指手與其整合的手腕和前臂相結(jié)合，擁有十四個獨立的自由度份汗。

該裝置在通過加壓式太空服手套操作時可非常好地近似于宇航員的手的運動學和所需的強度盈电。詳細解釋了用于滿足這些要求的機制及其背后的設計理念。集成經(jīng)驗揭示了與獲得所需大小內(nèi)的所需功能相關(guān)的挑戰(zhàn)杯活。呈現(xiàn)初始手指控制策略以及可獲得的抓握的例子匆帚。

?1 Introduction

The requirements for extra-vehicularactivity (EVA) onboard the International Space Station (ISS) are expected to beconsiderable. These maintenance and construction activities are expensive andhazardous. Astronauts must prepare extensively before they may leave therelative safety of the space station, including pre-breathing at space suit airpressure for up to 4 hours. Once outside, the crew person must be extremelycautious to prevent damage to the suit. The Robotic Systems Technology Branchat the NASA Johnson Space Center is currently developing robot systems toreduce the EVA burden on space station crew and also to serve in a rapidresponse capacity. One such system, Robonaut is being designed and built tointerface with external space station systems that only have human interfaces.To this end, the Robonaut hand [1] provides a high degree of anthropomorphicdexterity ensuring a compatibility with many of these interfaces. Many groundbreaking dexterous robot hands [2-7] have been developed over the past twodecades. These devices make it possible for a robot manipulator to grasp andmanipulate objects that are not designed to be robotically M. A. DiftlerAutomation and Robotics Department Lockheed Martin Houston, Texas 77058 diftler@jsc.nasa.gov Fax: 281-244-5534 compatible. While several grippers [8-12] havebeen designed for space use and some even tested in space [8,9,11], nodexterous robotic hand has been flown in EVA conditions. The Robonaut Hand isone of several hands [13,14] under development for space EVA use and is closestin size and capability to a suited astronaut's hand.

預計國際空間站（ISS）上的車外活動（EVA）要求相當可觀。這些維護和建設活動是昂貴且危險的旁钧。宇航員必須在可能離開空間站的相對安全之前進行廣泛的準備吸重，包括預先呼吸太空服空氣壓力長達4小時。一旦在室外歪今，機組人員必須非常謹慎嚎幸，以防止損壞宇航服。美國國家航空航天局約翰遜航天中心的機器人系統(tǒng)技術(shù)處目前正在開發(fā)機器人系統(tǒng)寄猩，以減少空間站人員的EVA負擔嫉晶，并且服務于快速反應能力。一個這樣的系統(tǒng)田篇，Robonaut正在設計和建造替废，以便與只有人機界面的外部空間站系統(tǒng)接口。為此斯辰，Robonaut手[1]提供了高度的擬人靈巧性舶担，以確保與許多這些接口的兼容性坡疼。在過去的二十年中彬呻，已經(jīng)開發(fā)出許多破紀錄的靈巧機器人手[2-7]。這些設備使得機器人操縱器能夠抓住和操縱未被設計為機器人的物體兼容柄瑰。雖然有幾個夾具[8-12]設計用于空間使用闸氮，有些甚至在太空中進行了測試[8,9,11]，但沒有靈巧的機器人手在EVA條件下飛行教沾。 Robonaut手是空間EVA使用中正在開發(fā)的幾只手之一[13,14]蒲跨，它的尺寸和能力最接近適合宇航員的手。

?2 Design and Control Philosophy

The requirements for interacting withplanned space station EVA crew interfaces and tools provided the starting pointfor the Robonaut Hand design [1]. Both power (enveloping) and dexterous grasps(finger tip) are required for manipulating EVA crew tools. Certain toolsrequire single or multiple finger actuation while being firmly grasped. Amaximum force of 20 lbs. and torque of 30 in-lbs are required to remove andinstall EVA orbital replaceable units (ORUs) [15]. All EVA tools and ORUs mustbe retained in the event of a power loss. It is possible to either buildinterfaces that will be both robotically and EVA compatible or build a seriesof robot tools to interact with EVA crew interfaces and tools. However, bothapproaches are extremely costly and will of course add to a set of spacestation tools and interfaces that are already planned to be quite extensive.The Robonaut design will make all EVA crew interfaces and tools roboticallycompatible by making the robot's hand EVA compatible. EVA compatibility isdesigned into the hand by reproducing, as closely.as possible, the size,kinematics, and strength of the space suited astronaut hand and wrist. Thenumber of fingers and the joint travel reproduce the workspace for apressurized suit glove. The Robonaut Hand reproduces many of the necessarygrasps needed for interacting with EVA interfaces. Staying within this sizeenvelope guarantees that the Robonaut Hand will be able to fit into all therequired places. Joint travel for the wrist pitch and yaw is designed to meetor exceed the human hand in a pressurized glove. The hand and wrist parts are??sizedto reproduce the necessary strength to meet maximum EVA crew requirements.Figure1: Robonaut Hand Control system design for a dexterous robot handmanipulating a variety of tools has unique problems. The majority of theliterature available, summarized in [2,16], pertains to dexterous manipulation.This literature concentrates on using three dexterous fingers to obtain forceclosure and manipulate an object using only fingertip contact. While useful,this type of manipulation does not lend itself to tool use. Most EVA tools arebest used in an enveloping grasp. Two enveloping grasp types, tool and power,must be supported by the tool-using hand in addition to the dexterous grasp.Although literature is available on enveloping grasps [17], it is not asadvanced as the dexterous literature. The main complication involvesdetermining and controlling the forces at the many contact areas involved in anenveloping grasp. While work continues on automating enveloping grasps, a tele-operationcontrol strategy has been adopted for the Robonaut hand. This method ofoperation was proven with the NASA DART/FITT system [18]. The DART/FITT systemutilizes Cyber glove? virtual reality gloves, worn by the operator, to controlStanford/YPL hands to successfully perform space relevant tasks. 2.1 SpaceCompatibility EVA space compatibility separates the Robonaut Hand from manyothers. All component materials meetoutgassing restrictions to prevent contamination that couldinterfere with other space systems. Parts made of different materials aretoleranced to perform acceptably under the extreme temperature variationsexperienced in EVA conditions. Brushless motors are used to ensure long life ina vacuum. All parts are designed to use proven space lubricants.

與計劃的空間站EVA乘員接口和工具交互的要求為Robonaut手設計要求提供了起點[1]授翻。

操縱EVA乘員工具需要力量（包絡）和靈巧的抓握（指尖）或悲。某些工具需要單手或多手指動作孙咪，同時牢牢抓住。 20磅的最大力量巡语。并需要30英寸磅的扭矩來拆卸和安裝EVA軌道可更換單元（ORU）[15]翎蹈。

所有EVA工具和ORU必須在發(fā)生斷電時保留∧泄可以構(gòu)建兼容機器人和EVA的接口荤堪，或者構(gòu)建一系列機器人工具來與EVA機組接口和工具進行交互。然而枢赔，這兩種方法都是非常昂貴的澄阳，并且當然會增加一套空間站工具和接口，這些工具和接口已經(jīng)計劃得相當廣泛踏拜。 Robonaut設計將使機器人的手EVA兼容碎赢，從而使所有EVA機組人機界面和工具機器人兼容。通過盡可能地再現(xiàn)適合宇航員手和手腕的空間的尺寸速梗，運動學和強度揩抡，將EVA兼容性設計在手中。手指和聯(lián)合行程的數(shù)量重現(xiàn)了加壓套裝手套的工作空間镀琉。 Robonaut手掌再現(xiàn)了與EVA界面交互所需的許多必要手段峦嗤。保持在這個尺寸范圍內(nèi)保證Robonaut手將能夠適應所有需要的地方。手腕節(jié)距和偏航的聯(lián)合行程被設計為在加壓手套中達到或超過人手屋摔。手部和腕部的尺寸可以重現(xiàn)必要的強度烁设，以滿足最大的EVA機組人員的要求。

圖1：Robonaut手控系統(tǒng)設計靈巧的機器人手操縱各種工具具有獨特的問題钓试。在[2,16]中總結(jié)的大多數(shù)文獻都涉及到靈巧的操縱装黑。這些文獻集中于使用三個靈巧手指來獲得力閉合并僅使用指尖接觸來操縱物體。雖然有用弓熏，但這種類型的操作不適用于工具使用恋谭。大多數(shù)EVA工具最適合用于包圍式抓握。除了靈巧的抓握之外挽鞠，還必須使用工具用手來支撐兩種包絡抓握類型疚颊，工具和力量。雖然文獻可用于包絡抓握[17]信认，但它并不像靈巧手那樣先進材义。主要的復雜性包括確定和控制涉及包絡抓握的許多接觸區(qū)域的力。雖然自動化包絡抓握的工作仍在繼續(xù)嫁赏，但Robonaut手已采用遠程操作控制策略其掂。美國國家航空航天局DART / FITT系統(tǒng)證明了這種操作方法[18]。 DART / FITT系統(tǒng)使用由操作員佩戴的Cyber??glove?虛擬現(xiàn)實手套來控制Stanford / YPL手以成功執(zhí)行空間相關(guān)任務潦蝇。

?2.1空間兼容性EVA空間兼容性將Robonaut手與其他許多人分開款熬。所有組件材料均滿足除氣限制深寥，以防止可能干擾其他空間系統(tǒng)的污染。不同材料制成的零件在EVA條件下經(jīng)受極端溫度變化時具有可接受的性能贤牛。無刷電機用于確保真空中的長壽命翩迈。所有零件都設計為使用經(jīng)過驗證的空間潤滑劑。

?3 Design

The Robonaut Hand (figure 1) has a total offourteen degrees of freedom. It consists of a forearm which houses the motorsand drive electronics, a two degree of freedom wrist, and a five finger, twelvedegree of freedom hand. The forearm, which measures four inches in diameter atits base and is approximately eight inches long, houses all fourteen motors, 12separate circuit boards, and all of the wiring for the hand. Y= Figure 2: Handcomponents The hand itself is broken down into two sections (figure 2): adexterous work set which is used for manipulation, and a grasping set whichallows the hand to maintain a stable grasp while manipulating or actuating agiven object. This is an essential feature for tool use [13]. The dexterous setconsists of two three degree of freedom fingers (pointer and index) and a threedegree of freedom opposable thumb. The grasping set consists of two, one degreeof freedom fingers (ring and pinkie) and a palm degree of freedom. All of thefingers are shock mounted into the palm (figure 2). In order to match the sizeof an astronaut's gloved hand, the motors are mounted outside the hand, andmechanical power is transmitted through a flexible drive train. Past handdesigns [2,3] have used tendon drives which utilize complex pulley systems orsheathes, both of which pose serious wear and reliability problems when used inthe EVA space environment. To avoid the problems associated with tendons, thehand uses flex shafts to transmit power from the motors in?the forearm to the fingers. The rotary motionof the flex shafts is converted to linear motion in the hand using smallmodular leadscre was semblies. The result is acompact yet rugged drive train.Over all the hand is equipped with forty-three sensors not including tactilesensing. Each joint is equipped with embedded absolute position sensors andeach motor is? equipped with incrementalencoders. Each of the leadscrew assemblies as well as the wristball joint linksare instrumented as load cells to provide force feedback.

3設計

Robonaut手（圖1）總共有十四個自由度盔夜。

它由裝有電機和驅(qū)動電子裝置的前臂负饲，兩個自由度的手腕和

一個五指，十二自由度的手組成喂链。

前臂的底部直徑為4英寸返十，長約8英寸，可容納全部14個電機椭微，12個獨立電路板以及所有手部布線洞坑。

手部組件手部本身分為兩部分。一個用于操作的靈巧工作組（食指和中指）蝇率，以及一個抓握組（無名指和小指）迟杂，它允許手在操作或啟動給定時保持穩(wěn)定的抓握目的。這是工具使用的基本特征[13]本慕。

靈巧組由兩個三自由度手指（食指和中指）和一個三度自由對立拇指組成排拷。抓握組由兩個，一個自由度指（無名指和小指）和一個掌心自由度組成锅尘。所有的手指都被安裝在手掌上（圖2）监氢。

為了匹配宇航員戴著手套的手的大小，電機安裝在手外藤违，機械動力通過柔性傳動系傳遞浪腐。過去的手工設計[2,3]使用了使用復雜滑輪系統(tǒng)或護套的腱索驅(qū)動裝置，這兩種裝置在EVA空間環(huán)境中使用時都會造成嚴重的磨損和可靠性問題顿乒。為了避免與肌腱有關(guān)的問題议街，手使用柔性軸將電力從前臂的電動機傳輸?shù)绞种浮Ｈ嵝暂S的旋轉(zhuǎn)運動通過小型模塊化導絲轉(zhuǎn)換成手中的線性運動璧榄。結(jié)果是緊湊而堅固的傳動系特漩。

所有的手都配備了43個（不包括觸覺）傳感器。每個接頭都配有嵌入式絕對位置傳感器犹菱，每個電機都配有增量式編碼器拾稳。每個導螺桿組件以及手腕關(guān)節(jié)連桿均被裝備為稱重傳感器以提供力反饋吮炕。

3.1

Finger Drive Train

Figure 3: Finger leadscrew assembly Thefinger drive consists of a brushless DC motor equipped with an encoder and a 14to 1 planetary gear head. Coupled to the motors are stainless steel highflexibility flex shafts. The flex shafts are kept short in order to minimizevibration and protected by a sheath consisting of an open spring covered withTeflon. At the distal end of the flex shaft is a small modular leadscrewassembly (figure 3). This assembly converts the rotary motion of the flex shaftto linear motion. The assembly includes: a leadscrew which has a flex shaftconnection and bearing seats cut into it, a shell which is designed to act as aload cell, support bearings, a nut with rails that mate with the shell (inorder to eliminate off axis loads), and a short cable length which attaches tothe nut. The strain gages are mounted on the flats of the shell indicated infigure 3. The top of the leadscrew assemblies are clamped into the palm of thehand to allow the shell to stretch or compress under load, thereby giving adirect reading of force acting on the fingers. Earlier models _of the assemblycontained an integral reflective encoder cut into the leadscrew. This configurationworked well but was eliminated from the hand in order to minimize the wiring inthe hand.

Figure 4: Dexterous finger

3.1手指傳動系統(tǒng)

圖3：手指導螺桿組件

手指驅(qū)動器包括

???????? 一個配備編碼器和

???????? 14：1行星齒輪頭的無刷直流電機腊脱。

與電機耦合的是不銹鋼高柔性軟軸。

???????? 柔性軸保持較短以減少振動龙亲，

???????? 并通過由聚四氟乙烯覆蓋的開口彈簧組成的護套進行保護陕凹。

在柔性軸的遠端是一個小型模塊化螺桿組件（圖3）悍抑。該組件將柔性軸的旋轉(zhuǎn)運動轉(zhuǎn)換為直線運動。該組件包括：

???????? 一個絲杠杜耙，它具有一個柔性軸連接和切入其中的軸承座搜骡，

???????? 一個設計用作張力傳感器的外殼，支撐軸承佑女，

???????? 一個帶有與外殼配合的導軌的螺母（為了消除軸負載）以及連接到螺母上的短絲纜長度记靡。???? 張力傳感器安裝在圖3所示的殼體的平面上。將絲杠組件的頂部夾緊在手掌中团驱，以允許殼體在負載下伸展或壓縮摸吠，從而直接讀取作用于手指。

???????? 組件的較早型號還包含切入導螺桿的整體式反射編碼器嚎花。這種配置運行良好寸痢，但后來從手中刪除，以盡量減少手中的接線紊选。

圖4：靈巧的手指

3.2

Dexterous Fingers

?Thethree degree of freedom dexterous fingers (figure 4) include the finger mount,a yoke, two proximal finger segment half shells, a decoupling link assembly, amid finger segment, a distal finger segment, two connecting links, and springsto eliminate backlash (not shown in figure). Figure 5 Finger base cam The basejoint of the finger has two degrees of freedom: yaw (+ /- 25 degrees) and pitch(I00 degrees). These motions are provided by two leadscrew assemblies that workin a differential manner. The short cables that extend from the leadscrewassemblies attach into the cammed grooves in the proximal finger segments halfshells (figure 5). The use of cables eliminates a significant number of jointsthat would otherwise be needed to handle the two degree of freedom base joint.The cammed grooves control the bend radius of the connecting cables from theleadscrew assemblies (keeping it larger to avoid stressing the cables andallowing oversized cables to be used). The grooves also allow a nearly constantlever arm to be maintained throughout the full range of finger motion. Becausethe connecting cables are kept short (approximately I inch) and their bendradius is controlled (allowing the cables to be relatively large in diameter(.07 inches)), the cables act like stiff rods in the working direction (closingtoward the palm) and like springs in the opposite direction. In other words,the ratio of the cable length to its

diameter is such that the cables are stiff enough to push the finger openbut if?the finger contacts or impacts anobject the cables will buckle, allowing the finger to collapse out of the way.

?Figure 6: Decoupling link The second and thirdjoints of the dexterous fingers are directly linked so that they close withequal angles. These joints are driven by a separate leadscrew assembly througha decoupling linkage (figure 6). The short cable on the leadscrew assembly isattached to the pivoting cable termination in the decoupling link. The flex inthe cable allows the actuation to pass across the two degree of freedom basejoint, without the need for complex mechanisms. The linkage is designed so thatthe arc length of the cable is nearly constant regardless of the position ofthe base joint (compare arc A to arc B in figure 6). This makes the motion ofdistal joints approximately independent of the base joint. figure 2 has aproximal and distal segment and is similar in design to the dexterous fingersbut has significantly more yaw travel and a hyper extended pitch. The thumb isalso mounted to the palm at such an angle that the increase in range of motionresults in a reasonable emulation of human thumb motion. This type of mountingenables the hand to perform grasps that are not possible with the common practiceof mounting the thumb directly opposed to the fingers [2,3,14]. The thumb basejoint has 70 degrees of yaw and 110 degrees of pitch. The distal joint has 80degrees of pitch. Linkages Finger Mount Figure 7:Grasping Finger The actuationof the base joint is the same as the dexterous fingers with the exception thatcammed detents have been added to keep the bend radius of the cable large atthe extreme yaw angles. The distal segment of the thumb is driven through adecoupling linkage in a manner similar to that of the manipulating fingers. Theextended yaw travel of the thumb base makes complete distal mechanicaldecoupling difficult. Instead the joints are decoupled in software.

3.2靈巧的手指

?三個自由度的靈巧手指（圖4）包括

???????? 手指支架啼止，

???????? 軛，

???????? 兩個近側(cè)手指段半殼兵罢，

???????? 解耦連桿組件献烦，

???????? 中指段，

???????? 遠側(cè)手指段卖词，

???????? 兩個連接連桿和彈簧以消除間隙（未在圖中顯示）仿荆。

圖5手指底座凸輪

手指的底座接頭具有兩個自由度：偏航（+ / -

25度）和俯仰（I00度）。這些運動由兩個以不同方式工作的導螺桿組件提供坏平。從螺桿組件延伸的短絲纜連接到近端指狀部分半殼中的凸輪槽中（圖5）拢操。使用絲纜消除了處理兩個自由度底部接頭所需的大量接頭。凸輪槽用于控制連接絲纜從導螺桿組件的彎曲半徑（保持較大以避免對絲纜施加壓力并允許使用過大的絲纜）舶替。凹槽還允許在整個手指運動范圍內(nèi)保持幾乎恒定的杠桿臂令境。由于連接絲纜保持較短（大約1英寸）并且其彎曲半徑受到控制（允許絲纜的直徑相對較大（0.07英寸）），因此絲纜在工作方向上像硬棒一樣起作用（靠近手掌）和像相反方向的彈簧一樣顾瞪。換句話說舔庶，絲纜長度與其直徑的比例使得

???????? 絲纜足夠堅硬以將手指推開，

???????? 但如果手指接觸或撞擊物體陈醒，則絲纜會彎曲惕橙，使手指塌陷钉跷。

?圖6：解耦鏈接

靈巧手指的第二和第三個關(guān)節(jié)直接相連弥鹦，以便它們以相等的角度關(guān)閉。這些接頭由一個獨立的導螺桿組件通過一個分離聯(lián)動裝置驅(qū)動（圖6）朦促。絲杠組件上的短絲纜連接到去耦鏈路中的樞軸絲纜終端。絲纜中的彎曲允許致動穿過兩個自由度的基部接頭栓始，而不需要復雜的機構(gòu)务冕。連桿的設計使得絲纜的弧長度幾乎恒定幻赚，不管基座接頭的位置如何（比較圖6中的弧A與弧B）。這使得遠端關(guān)節(jié)的運動大致獨立于基部關(guān)節(jié)落恼。圖2具有近端和遠端段油湖，并且在設計上類似于靈巧指狀物，但具有明顯更多的偏航行程和超長的間距领跛。拇指也以這樣的角度安裝在手掌上乏德，使得運動范圍的增加導致人類拇指運動的合理仿真喊括。這種安裝方式可以使手執(zhí)行抓握，這與通常的將拇指直接放在手指對面的慣例相比是不可能的[2,3,14]郑什。拇指基座關(guān)節(jié)具有70度偏航和110度俯仰蒲肋。遠端關(guān)節(jié)有80度的間距。連桿手指安裝圖7：抓住手指基座關(guān)節(jié)的動作與靈巧的手指相同兜粘，但增加了凸輪式制動器以保持絲纜的彎曲半徑在極大偏航角度時較大。拇指的遠側(cè)部分以類似于操縱手指的方式被驅(qū)動通過分離聯(lián)動裝置剃法。拇指基座的擴展偏航行程使完全遠端機械解耦困難路鹰。相反，關(guān)節(jié)在軟件中解耦优构。

3.5

Palm

3.3

Grasping Fingers

The grasping fingers have three pitchjoints each with 90 degrees of travel. The fingers are actuated by oneleadscrew assembly and use the same cam groove (figure 5) in the proximalfinger segment half shell as with the manipulating fingers. The 7-bar fingerlinkage is similar to that of the dexterous fingers except that the decouplinglink is removed and the linkage ties to the finger mount (figure 7). In thisconfiguration each joint of the finger closes down with approximately equalangles. An alternative configuration of the finger that is currently beingevaluated replaces the distal link with a stiff limited travel spring to allowthe finger to better conform while grasping an object.

3.5手掌

3.3抓握手指

抓握手指有三個俯仰關(guān)節(jié)雁竞，每個關(guān)節(jié)都有90度的行程。手指由一個導螺桿組件致動，并且在操作指狀物的近端手指段半殼中使用相同的凸輪槽（圖5）势腮。 7-bar指形連桿與靈巧指形的指形連桿相似漫仆，不同之處在于去耦連桿被拆除并且連桿與手指支架連接（圖7）泪幌。在這種配置中，手指的每個關(guān)節(jié)都以大致相等的角度關(guān)閉吗浩。當前正在評估的手指的替代配置用剛性有限行程彈簧代替遠側(cè)連桿没隘，以允許手指在抓住物體時更好地順應。

?3.4 Thumb

The thumb is key to obtaining many of thegrasps required for interfacing with EVA tools. The thumb shown in The palmmechanism (figure 8) provides a mount for the two grasping fingers and acupping motion that enhances stability for tool grasps. This allows the hand tograsp an object in a manner that aligns the tool's axis with the forearm rollaxis. This is essential for the use of many common tools, like screwdrivers.The mechanism includes two pivoting metacarpals, a common shaft, and twotorsion springs. The grasping fingers and their leadscrew assemblies mount intothe metacarpals. The metacarpals are attached to the palm on a common shaft.The first torsion spring is placed between the two metacarpals providing a pivotingforce between the two. The second torsion spring is placed between the secondmetacarpal and the palm, forcing both of the metacarpals back against the palm.The actuating leadscrew assembly mounts into the palm and the short cableattaches to the cable termination on the first metacarpal. The torsion springsare sized such that as the leadscrew assembly pulls down the first metacarpal, thesecond metacarpal folows a troughly half the angle of the first. In this waythe palm is able to cup in a way similar to that of the human hand without thefingers colliding.

Figure 9 Wrist mechanism

?COMMON SHAFT PALM CASTING The wrist isactuated in a differential manner through two linear actuators (figure 9). Thelinear actuators consist of a slider riding in recirculating ball tracks and acustom, hollow shaft brushless DC motor with an integral ballscrew. Theactuators attach to the palm through ball joint links, which are mounted in thepre-loaded ball sockets. Figure 8: Palm mechanism The fingers are mounted tothe palm at slight angles to each other as opposed to the common practice ofmounting them parallel to each other? This mounting allows the fingers to closetogether similar to a human hand. To further improve the reliability andruggedness of the hand, all of the fingers are mounted on shock loaders. Thisallows them to take very high impacts without incurring damage.

3.4拇指

拇指是獲得許多與EVA工具接口所需的抓手的關(guān)鍵阀湿。手掌機構(gòu)（圖8）中顯示的拇指為兩個抓手提供了一個支架瑰妄，并提供了一個拔？间坐？動作，增強了工具抓握的穩(wěn)定性劳澄。這允許手以使工具的軸線與前臂搖擺軸線對齊的方式抓住物體蜈七。這對許多常用工具（如螺絲刀）的使用非常重要。該機構(gòu)包括兩個樞轉(zhuǎn)掌骨溯警，一個共同的軸和兩個扭力彈簧狡相。抓手指和他們的導螺桿組件安裝到掌骨。掌骨連接在同一根軸上的手掌上尽棕。第一個扭力彈簧放置在兩個掌骨之間，在兩者之間提供樞轉(zhuǎn)力伊诵。第二個扭力彈簧放置在第二掌骨和手掌之間，迫使兩掌骨靠在手掌上搂橙。致動導螺桿組件安裝在手掌中笛坦，短絲纜連接到第一掌骨上的絲纜終端。扭力彈簧的尺寸使得當導螺桿組件拉下第一掌骨時版扩，第二掌骨以一半的角度折疊第一掌骨。通過這種方式蜻韭，手掌能夠以與人手相似的方式進行杯子的揉搓而不會發(fā)生手指碰撞柿扣。

圖9手腕機構(gòu)

?普通軸手掌鑄造手腕通過兩個線性執(zhí)行器以不同方式驅(qū)動（圖9）。線性執(zhí)行器由一個滑塊和一個帶有一個整體滾珠絲杠的定制空心軸無刷直流電機組成窄刘。執(zhí)行器通過安裝在預先加載的球座中的球節(jié)連桿連接到手掌娩践。圖8：手掌機制手指彼此以微小的角度安裝在手掌上，這與將手指安裝在彼此平行的一般做法相反翻伺。?這種安裝使手指可以像人手一樣靠近在一起。為了進一步提高手的可靠性和堅固性拉宗，所有手指都安裝在減震墊上辣辫。這使他們能夠在不引起損壞的情況下承受非常高的影響。

?3.6 Wrist/Forearm

?Design The wrist (figure 9) provides anunconstrained pass through to maximize the bend radii for the finger flexshafts while approximating the wrist pitch and yaw travel of a pressurizedastronaut glove. Total travel is +/- 70 degrees of pitch and +/- 30 degrees ofyaw. The two axes intersect with each other and the centerline of the forearmroll axis. When connected with the Robonaut Arm [19], these three axes combineat the center of the wrist cuff yielding an efficient kinematic solution. Thecuff is mounted to the forearm through shock loaders for added safety. Figure10: Forearm The forearm is configured as a ribbed shell with six cover plates.Packaging all the required equipment in an EVA forearm size volume is achallenging task. The six cover plates are skewed at a variety of angles andkeyed mounting tabs are used to minimize forearm surface area. Mounted on twoof the cover plates are the wrist linear actuators, which fit into the forearmsymmetrically to maintain efficient kinematics. The other four cover plateprovides mounts for clusters of three finger motors (Figure 10). Symmetry isnot required here since the flex shafts easily bend to accommodate odd angles.The cover plates are also designed to act as heat sinks. Along with the motors,custom hybrid motor driver chips are mounted to the cover plates.

3.6腕/前臂

?設計手腕（圖9）提供了無限制的通過姐浮，以最大化手指柔性軸的彎曲半徑葬馋，同時接近加壓宇航員手套的手腕節(jié)距和偏航行程肾扰〉坝猓總行程為+/- 70度的俯仰和+/- 30度的偏航。這兩條軸線相互交叉偷拔，并與前臂滾動軸的中心線相交沉颂。當與Robonaut Arm [19]連接時悦污，這三個軸線結(jié)合在手腕袖口的中心，產(chǎn)生高效的運動學解決方案彻坛。袖套通過減震器安裝在前臂上踏枣，以增加安全性。

圖10：前臂前臂配置為帶六個蓋板的肋狀外殼茵瀑。將所有需要的設備包裝在EVA前臂尺寸體積中是一項具有挑戰(zhàn)性的任務。六個蓋板以各種角度傾斜竞帽，并且使用鍵控安裝接片來使前臂表面面積最小化鸿捧。腕部直線執(zhí)行器安裝在兩個蓋板上，對稱地固定在前臂上以保持高效的運動堆巧。另外四個蓋板為三個手指馬達組提供支架（圖10）泼菌。這里不需要對稱，因為柔性軸容易彎曲以適應奇怪的角度哗伯。蓋板也設計用作散熱器。隨著電機乳附，定制混合電機驅(qū)動器芯片安裝在蓋板上。

4

Integration Challenges

As might be expected, many integrationchallenges arose during hand prototyping, assembly and initial testing. Some ofthe issues and current resolutions follow. Many of the parts in the hand useextremely complex geometry to minimize the part count and reduce the size ofthe hand. Fabrication of these parts was made possible by casting them inaluminum directly from stereo lithography models. This process yieldsrelatively high accuracy parts at a minimal cost. The best example of this isthe palm, which has a complex shape, and over 50 holes in it, few of which areorthogonal to each other. Finger joint control is achieved through antagonisticcable pairs for the yaw joints and pre-load springs for the pitch joints.Initially, single compression springs connected through ball links to the frontof the dexterous fingers applied insufficient moment to the base joints at thefull open position. Double tension springs connected to the backs of thefingers improved pre-loading over more of the joint range. However, desiredpre-loading in the fully open position resulted in high forces during closing.Work on establishing the optimal pre-load and making the preload forces linearover the full range is under way. The finger cables have presented bothmechanical mounting and mathematical challenges. The dexterous fingers usesingle mounting screws to hold the cables in place while avoiding cable pinch.This configuration allows the cables to flex during finger motion and yields areasonably constant lever arm. However assembly with a single screw isdifficult especially when evaluating different cable diameters. The thumb usesa more secure lock that includes a plate with a protrusion that securely pressesdown on the cable in its channel. The trade between these two techniques iscontinuing. Similar cable attachment devices are also evolving for the otherfinger joints. The cable flexibility makes closed form kinematics difficult.The bend of the cable at the mounting points as the finger moves is not easy tomodel accurately. Any closed form model requires simplifying assumptionsregarding cable bending and moving contact with the finger cams. A simplersolution that captures all the relevant data employs multi-dimensional datamaps that are empirically obtained off-line. With a sufficiently highresolution these maps provide accurate forward and inverse kinematics data. Thewrist design (figure 9) evolved from a complex multibar mechanism to a simplertwo-dimensional slider crank hook joint. Initially curved ball links connectedthe sliders to the palm with cams that rotated the links to avoid the wristcuff during pitch motion. After wrist cuff and palm redesign, the presentstraight ball links were achieved. The finger leadscrews are non-back drivableand in an enveloping grasp ensure positive capture in the event of a powerfailure. If power can not be restored in a timely fashion, it may be necessaryfor the other Robonaut hand [19] or for an EVA crew person to manually open thehand. An early hand design incorporated a simple back out ring that throughfriction wheels engaged each finger drive train and slowly opened each fingerjoint. While this works well in the event of a power failure, experiments withthe coreless brushless DC motors revealed a problem when a motor fails due tooverheating. The motor winding insulation heats up, expands and seizes themotor, preventing back-driving. A new contingency technique for opening thehand that will accommodate both motor seizing and power loss is beinginvestigated.

4整合挑戰(zhàn)

正如所料，在手工原型举农，裝配和初始測試中出現(xiàn)了許多集成挑戰(zhàn)。其中一些問題和當前的解決方案如下航背。手中的許多部件都使用極其復雜的幾何形狀棱貌，以盡量減少零件數(shù)量并縮小手的尺寸。這些部件的制造可以通過直接從立體光刻模型將它們鑄造在鋁中來實現(xiàn)今魔。這個過程以最小的成本產(chǎn)生相對高精度的部件障贸。其中最好的例子就是手掌，形狀復雜篮洁，有50多個洞，其中很少有相互正交的瓦阐。

手指關(guān)節(jié)控制是通過用于偏航關(guān)節(jié)的對抗絲纜對和用于俯仰關(guān)節(jié)的預加載彈簧實現(xiàn)的锋叨。最初，通過球形連桿連接到靈巧指狀物的前部的單個壓縮彈簧在全開位置向基部關(guān)節(jié)施加不足的力矩薄湿。連接到手指背部的雙張力彈簧改善了更多關(guān)節(jié)范圍的預加載偷卧。然而，在完全打開位置期望的預加載在關(guān)閉期間導致較高的力听诸。正在進行建立最佳預加載和使預加載力在整個范圍內(nèi)線性化的工作晌梨。指狀絲纜提出了機械安裝和數(shù)學挑戰(zhàn)须妻。靈巧的手指使用單個安裝螺絲將絲纜固定到位泛领，同時避免絲纜夾緊。這種配置允許絲纜在手指運動期間彎曲并產(chǎn)生合理恒定的杠桿臂渊鞋。但是，在評估不同的絲纜直徑時儡湾，使用單個螺釘進行組裝很困難执俩。拇指使用更安全的鎖，其中包括一塊帶有突出部分的平板丹皱，該平板可牢固地按壓其通道中的絲纜宋税。這兩種技術(shù)之間的交易正在繼續(xù)讼油。類似的絲纜連接裝置也在為其他手指關(guān)節(jié)演變。絲纜的靈活性使封閉式運動學變得困難乏屯。手指移動時安裝點處的絲纜彎曲不易準確建模瘦赫。任何封閉模型都需要簡化關(guān)于絲纜彎曲和與手指凸輪接觸的假設。捕獲所有相關(guān)數(shù)據(jù)的更簡單的解決方案采用憑經(jīng)驗在線離線獲取的多維數(shù)據(jù)圖确虱。具有足夠高的分辨率，這些地圖提供精確的正向和反向運動學數(shù)據(jù)窘问。

手腕設計（圖9）從復雜的多桿機構(gòu)演變?yōu)楦唵蔚亩S滑塊曲柄吊鉤接頭宜咒。最初彎曲的球形連桿將滑塊連接到手掌，并帶有凸輪儿咱，以便在俯仰運動期間旋轉(zhuǎn)連桿以避開腕帶。在重新設計手腕袖口和手掌之后，實現(xiàn)了目前的直線球鏈接东羹。手指導向螺桿不可逆向驅(qū)動（應該意味著沒電時不能動凯旭，有電時可以雙向動）使套，并且在包絡抓握中可確保在發(fā)生電源故障時實現(xiàn)正向捕捉侦高。如果不能及時恢復動力，可能需要其他Robonaut手[19]或者EVA機組人員手動打開手奉呛。

早期的手部設計結(jié)合了一個簡單的退出環(huán)，通過摩擦輪嚙合每個手指傳動系登馒，并緩慢打開每個手指關(guān)節(jié)咆槽。雖然這種情況在發(fā)生電源故障時運行良好，但無芯無刷直流電機的實驗揭示了當電機由于過熱而發(fā)生故障時的問題麦射。電機繞組絕緣加熱灯谣，擴大并占用電機，防止反向驅(qū)動胎许。正在研究一種新的應急技術(shù)呐萨，用于打開將容納馬達卡死和功率損失的手。

5

Initial Finger Control Design and Test

Before any operation can occur, basicposition control of the Robonaut hand joints must be developed. Depending onthe joint, finger joints are controlled either by a single motor or anantagonistic pair of motors. Each of these motors is attached to the fingerdrive train assembly shown in figure 3. A simple PD controller is used toperform motor position control tests. When the finger joint is unloaded,position control of the motor drive system is simple. When the finger isloaded, two mechanical effects influence the drive system dynamics. The flexshaft, which connects the motor to the lead screw, winds up and acts as atorsional spring. Although adding an extra system dynamic, the high ratio ofthe lead screw sufficiently masks the position error caused by the state of theflex shaft for teleoperated control. The second effect during loading is theincreased frictional force in the lead screw. The non-backdrivable nature ofthe motor drive system effectively decouples the motor from the applied force.Therefore, during joint loading, the motor sees the increasing torque requiredto turn the lead screw. The motor is capable of supplying the torque requiredto turn the lead screw during normal loading. However, thermal constraintslimit the motor's endurance at high torque. To accommodate this constraint, thecontroller incorporates force feedback from the strain gauges installed on thelead screw shell. The controller utilizes the non-back drivability of the motordrive system and properly turns down motor output torque once a desired forceis attained. During a grasp, a command to move in a direction that willincrease the force beyond the desired level is ignored. If the forced rops offor a command in a direction that will relieve the force is issued, the motor revertsto normal position control operation. This control strategy successfully lowersmotor heating to acceptable levels and reduces power consumption. To perform jointcontrol, the kinematics, which relates motor output?joint output, must be determined. As statedearlier, due to varying cable interactions a closed form kinematics algorithm isnot tractable. Once the finger joint hall-effect based position sensors arecalibrated using are solver, a semi-autonomous kinematic calibration procedure forboth forward and inverse kinematics is used to build look-up tables. Variationsbetween kinematics and hall-effect sensor outputs during operation are seen inregions where the pre-loading springs are not effective. Designs using differentspring strategies are underdevelopment to resolve this problem. To enhance positioningaccuracy, a closed loop finger joint position controller employing hall-effect sensorposition feedback is used as part of this kinematic calibration procedure. ableto successfully manipulate many EVA tool.

5初始手指控制設計和測試

在任何操作發(fā)生之前切距，必須開發(fā)Robonaut手關(guān)節(jié)的基本位置控制谜悟。根據(jù)關(guān)節(jié)的不同，手指關(guān)節(jié)可以由單個電機或?qū)α⒌碾姍C控制葡幸。每個電機都連接到圖3所示的手指傳動系組件上。一個簡單的PD控制器用于執(zhí)行電機位置控制測試床蜘。

當手指關(guān)節(jié)卸載時蔑水，電機驅(qū)動系統(tǒng)的位置控制很簡單。

當手指裝入時搀别，兩個機械效應會影響驅(qū)動系統(tǒng)的動力歇父。

??? 將電機連接到絲杠的柔性軸卷起并作為扭轉(zhuǎn)彈簧。雖然增加了一個額外的系統(tǒng)動態(tài)榜苫，但高比率的絲杠足以掩蓋由遙控操作的柔性軸狀態(tài)引起的位置誤差。

加載過程中的第二個影響是增加了絲杠的摩擦力灸异。電機驅(qū)動系統(tǒng)的不可逆性質(zhì)使電機與施加的力有效地分離羔飞。因此檐春，在關(guān)節(jié)加載期間，電機會看到轉(zhuǎn)動絲杠所需的增加的扭矩卡儒。電機能夠在正常負載時提供轉(zhuǎn)動絲杠所需的扭矩俐巴。但是，熱限制會限制電機在高轉(zhuǎn)矩時的耐久性擎鸠。為了適應這一限制缘圈，控制器將安裝在導螺桿殼體上的應變儀的力反饋結(jié)合起來袜蚕【钗校控制器利用電機驅(qū)動系統(tǒng)的無后驅(qū)動能力，并在達到所需的力后正確地降低電機輸出扭矩凿傅。在抓取過程中数苫，將會沿著一個方向移動的指令將被忽略，該方向會將力增加到超出所需的水平过椎。如果強制斷電或在一個可以釋放力的方向發(fā)出一個命令戏仓，電機將恢復正常的位置控制操作。該控制策略成功地將電機加熱降至可接受的水平并降低功耗赏殃。

為了執(zhí)行聯(lián)合控制仁热，必須確定與電機輸出聯(lián)合輸出有關(guān)的運動特性。如前所述抗蠢，由于絲纜交互作用的不同，封閉形式的運動學算法不易處理妨猩。一旦基于手指關(guān)節(jié)霍爾效應的位置傳感器使用解算器進行校準秽褒，則使用用于正向和反向運動學的半自動運動學校準程序來構(gòu)建查找表。運行期間霍爾傳感器輸出與霍爾效應傳感器輸出之間的變化可見于預加載彈簧無效的區(qū)域庐椒。使用不同彈簧策略的設計不足以解決這個問題蚂踊。為提高定位精度，采用霍爾效應傳感器位置反饋的閉環(huán)手指關(guān)節(jié)位置控制器作為此運動學校準程序的一部分窗宇。能夠成功操縱許多EVA工具。

SeveralexampletoolmanipulationsusingtheRobonauthand underteleoperatedcontrolareshowninfigures11and12. Figure11:ExamplesoftheRobonaut Handusingenvelopingpowergraspstoholdtools An importantsafetyfeatureof thehand,itsabilityto passivelycloseinresponsetoacontactonthebackof thefingers,causesproblemsfor closedloopjoint controlduringnormaloperation.Furtherrefinementof the kinematiccalibrationandthestraingaugeforcesensorsirequiredtoreliablydeterminewhenthefingersarebeing uncontrollablycosed.Oncethisinformation, alongwithabettermodelforthedrivetraindynamicsisavailable,thejointcontrollercanbemodifiedtodistinguishteloaded fromthenormaloperatingmode.Althoughconsiderableworkstillneedstobedone,joint controlsatisfactoryforteleoperatedcontrolof thehand hasbeenattained. For initial tests,the handwascontrolledin joint modefrominputsderivedfromtheCyberglove?wornbytheoperator.TheCybergloveuses bendsensors,whichareinterpretedbytheCyberglove electronicstodeterminethepositionof 18actionsof theoperator'shand. Someof theseactionsareabsolute positionsoffingerjointswhileotherarerelativemotions betweenjoints.Thechallengeisdevelopingamapping betweenthe 18 absoluteandrelativejointpositions determinedby theCybergloveandthe12jointsof the Robonaut hand. Thismapping must result in the Robonaut hand tracking the operator's hand as well aspossible. While some joints are directly mapped, others required heuristic algorithmsto fuse data from several glove sensors to produce a hand joint position command.In conjunction with an auto mated glove calibration program, a satisfactory mappingis experimentally obtainable.

Figure12:ExamplesoftheRobonaut Hand

Using these custom mappings, operators are

using dexterousgraspsforfinetoolmaipulationTofacilitatetestingofthehandbaselevelpadsasshown infigures11,12werefabricatedfromDow Cornings Silastic?E. Thepadsprovideanonslipcompliant surfacenecessary forpositivelygraspinganobject.Thesepadswillserveasthefoundationfortactilesensorsandbe coveredwithaprotectiveglove.Futureplansincludethedevelopment of agraspcriteriameasureforthestabilityofthehandgrasp.Thesecriteriawillbeusedtoassisttheoperatorindeterminingif agrasp isacceptable.Sincethebaselineoperationplandoesnot involveforcefeedbacktotheoperator,visualfeedback onlymaybeinsufficient toproperlydetermineif agraspisstable.Usingsomeknowledgeof theobjectwhichisbeinggraspedinconjunctionwiththeexistingleadscrew forcesensorsandasmallsetofadditional tactilesensors installedonthefingersandpalm,thecontrolsystemwilldeterminetheacceptabilityof thegraspandindicatethat measuretotheoperator.Theoperatorcanthendecide howbestousethisdatainreconfiguringthegrasptoa morestableconfiguration.Thisgraspcriteriameasurecouldevolveintoanimportantpartof anautonomous graspingsystem. 6 Conclusions TheRobonaut Hand is presented. This highly anthropomorphic human scale hand builtat the NASA Johnson Space Center is designed to interface with EVA crewinterfaces thereby increasing the number of robotically compatible operationsavailable to the International Space Station. Several novel mechanisms aredescribed that allow the Robonaut hand to achieve capabilities approaching thatof an astronaut wearing a pressurized space suited glove. The initial jointbased control strategy is discussed and example tool manipulations areillustrated. References 1. Lovchik, C. S., Difiler, M. A., Compact DexterousRobotic Hand. Patent Pending. 2. Salisbury, J. K., & Mason, M. T., RobotHands and the Mechanics of Manipulation. MIT Press, Cambridge, MA, 1985. 3.Jacobsen, S., et al., Design of the Utah/M.I.T. Dextrous Hand. Proceedings ofthe IEEE International Conference on Robotics and Automation, San Francisco, CA,1520-1532, 1986. 4. Bekey, G., Tomovic, R., Zeljkovic, I., Control Architecturefor the Belgrade/USC Hand. Dexterous Robot Hands, 136-149, Springer-Verlag, NewYork, 1990. 5. Maeda, Y., Susumu, T., Fujikawa, A., Development of anAnthropomorphic Hand (Mark-l). Proceedings of the 20 th International Symposiumon Industrial Robots, Tokyo, Japan, 53-544, 1989. 6. Ali, M., Puffer, R.,Roman, H., Evaluation of a Multifingered Robot Hand for Nuclear Power PlantOperations and Maintenance Tasks. Proceedings of the 5 th World Conference onRobotics Research, Cambridge, MA, MS94-217, 1994. 7. Hartsfield, J., SmartHands: Flesh is Inspiration for Next Generation of Mechanical Appendages. SpaceNews Roundup, NASA Johnson Space Center, 27(35), page 3, Houston, TX, 1988. 8.Carter, E. Monford, G., Dexterous End Effector Flight Demonstration,Proceedings of the Seventh Annual Workshop on Space Operations Applications andResearch, Houston, TX, 95-102, 1993. 9. Nagatomo, M. et al, On the Results ofthe MFD Flight Operations, Press Release, National Space Development Agency ofJapan, August, 1997. 10. Stieber, M., Trudel, C., Hunter, D., Robotic systemsfor the International Space Station, Proceedings of the IEEE InternationalConference on Robotics and Automation, Albuquerque, New Mexico, 3068-3073,1997. 11. Hirzinger, G., Brunner, B., Dietrich, J., Heindl, J., Sensor BasedSpace Robotics - ROTEX and its Telerobotic Features, IEEE Transactions onRobotics and Automation, 9(5), 649-663, 1993. 12. Akin, D., Cohen, R., Developmentof an Interchangeable End Effector Mechanism for the Ranger TeleroboticVehicle., Proceedings of the 28 th Aerospace Mechanism Symposium, Cleveland OH,79-89, 1994 13. Jau, B., Dexterous Tele-manipulation with Four Fingered HandSystem. Proceedings of the IEEE International Conference on Robotics andAutomation,. Nagoya, Japan, 338-343, 1995. 14. Butterfass, J., Hirzinger, G.,Knoch, S. Liu, H., DLR's Multi-sensory Articulated Hand Part I: HardandSoftware Architecture. Proceedings of the IEEE International Conference onRobotics and Automation, Leuven Belgium, 2081-2086, 1998. 15. ExtravehicularActivity (EVA) Hardware Generic Design Requirements Document, JSC 26626,NASA/Johnson Space Center, Houston, Texas, July, 1994. 16. Shimoga, K.B., RobotGrasp Synthesis: A Survey, International Journal of Robotics Research, vol. 15,no. 3, pp. 230-266, 1996. 17. Mirza, K. and Orin, D., General Formulation forForce Distribution in Power Grasp, Proceedings of the IEEE InternationalConference on Robotics and Automation, p.880-887, 1994. 18. Li, L., Cox, B.,Diftler, M., Shelton, S. , Rogers, B., Development of a Telepresence ControlledAmbidextrous Robot for Space Applications. Proceedings of the IEEEInternational Conference on Robotics and Automation, Minneapolis, MN, 58-63,1996. 19. Li, L., Taylor, E., EWS Robonaut: Work in Progress, Proceedings ofthe International Symposium on Artificial Intelligence, Robotics and Automationin

末尾部分需要先分詞粪躬，再用機器翻譯

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