https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000097045.pdf
http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf
笔记
from http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf
手臂的设计约束： 20磅的最大力和30英寸磅的扭矩
每个手部组件总共具有14个自由度，并且由前臂，两个DOF腕部以及具有位置，速度和力传感器的十二个DOF手组成。
前臂的底部直径为4英寸，长约8英寸，容纳所有十四台电机，
手部配备了42个传感器（不包括触觉感测）。// 每个关节都配有嵌入式绝对位置传感器，// 每个电机都配有增量式编码器。// 每个导螺杆组件以及手腕球关节连杆均被装备为应力传感器以提供力反馈。
过去的手工设计[4,5]使用了使用复杂滑轮系统或护套的腱索驱动装置，这两种装置在EVA空间环境中使用时都会造成严重的磨损和可靠性问题。为了避免与肌腱有关的问题，手使用柔性轴将电力从前臂的电动机传输到手指。使用小型模块化导螺杆组件将柔性轴的旋转运动转换为手中的直线运动。结果是一个紧凑而坚固的传动系。
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.
译文
from http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM113.pdf
Robonaut的手把它与以前的太空操纵器系统区别开来。这些双手可以装入目前为宇航员的戴手套而设计的所有相同的地方。手的一个关键特征是它的手掌自由度，使得Robonaut可以用一个工具和长轴与前臂的自由度进行排列，从而允许工具在狭小的空间中以最小的手臂运动使用。
图3中所示的每个手部组件总共具有14个自由度，并且由前臂，两个DOF腕部以及具有位置，速度和力传感器的十二个DOF手组成。前臂的底部直径为4英寸，长约8英寸，容纳所有十四台电机，电机控制和电力电子设备，以及所有手持线路。图4给出了该组件的分解图。手腕节距和偏航的联合行程被设计为在加压手套中达到或超过人手。
图4：前臂装配与计划的空间站EVA乘员接口和工具交互的要求为Robonaut手的设计提供了起点[1]。操纵EVA乘员组工具需要力量和灵巧的抓握。某些工具需要单手或多手指动作，同时牢牢抓住。拆卸和安装EVA轨道可替换单元（ORU）需要20磅的最大力和30英寸磅的扭矩[2]。
手由两部分组成（图5）：一个用于操作的灵巧工作组，以及一个抓握组件，它允许手在操纵或启动给定物体时保持稳定的抓握。这是工具使用的基本特征[3]。灵巧套装由两个3 DOF手指（食指和中指）和一个3 DOF可对折手指组成。抓握组由两个单DOF手指（无名指和小指）和一个手掌自由度组成。所有的手指都被安装在手掌上。为了匹配宇航员戴着手套的手的大小，电机安装在手外，机械动力通过柔性传动系传递。
过去的手工设计[4,5]使用了使用复杂滑轮系统或护套的腱索驱动装置，这两种装置在EVA空间环境中使用时都会造成严重的磨损和可靠性问题。为了避免与肌腱有关的问题，手使用柔性轴将电力从前臂的电动机传输到手指。使用小型模块化导螺杆组件将柔性轴的旋转运动转换为手中的直线运动。结果是一个紧凑而坚固的传动系。
图5：手部解剖总的来说，手部配备了42个传感器（不包括触觉感测）。每个接头都配有嵌入式绝对位置传感器，每个电机都配有增量式编码器。每个导螺杆组件以及手腕球关节连杆均被装备为称重传感器以提供力反馈。除了提供标准阻抗控制之外，一旦达到期望的抓力，手力控制算法利用非反向驱动手指驱动系统来节约电机能耗要求。预先规划的轨迹形式的手原语可用于在执行重复任务时最大限度地减少操作员的工作量。
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 [email protected], [email protected] 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.
描述了用于空间操作的高度拟人化的人类尺度机器人手的设计。这五个手指手与其整合的手腕和前臂相结合，拥有十四个独立的自由度。
该装置在通过加压式太空服手套操作时可非常好地近似于宇航员的手的运动学和所需的强度。详细解释了用于满足这些要求的机制及其背后的设计理念。集成经验揭示了与获得所需大小内的所需功能相关的挑战。呈现初始手指控制策略以及可获得的抓握的例子。
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 [email protected] 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.
预计国际空间站（ISS）上的车外活动（EVA）要求相当可观。这些维护和建设活动是昂贵且危险的。宇航员必须在可能离开空间站的相对安全之前进行广泛的准备，包括预先呼吸太空服空气压力长达4小时。一旦在室外，机组人员必须非常谨慎，以防止损坏宇航服。美国国家航空航天局约翰逊航天中心的机器人系统技术处目前正在开发机器人系统，以减少空间站人员的EVA负担，并且服务于快速反应能力。一个这样的系统，Robonaut正在设计和建造，以便与只有人机界面的外部空间站系统接口。为此，Robonaut手[1]提供了高度的拟人灵巧性，以确保与许多这些接口的兼容性。在过去的二十年中，已经开发出许多破纪录的灵巧机器人手[2-7]。这些设备使得机器人操纵器能够抓住和操纵未被设计为机器人的物体兼容。虽然有几个夹具[8-12]设计用于空间使用，有些甚至在太空中进行了测试[8,9,11]，但没有灵巧的机器人手在EVA条件下飞行。 Robonaut手是空间EVA使用中正在开发的几只手之一[13,14]，它的尺寸和能力最接近适合宇航员的手。
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.
与计划的空间站EVA乘员接口和工具交互的要求为Robonaut手设计要求提供了起点[1]。
操纵EVA乘员工具需要力量（包络）和灵巧的抓握（指尖）。某些工具需要单手或多手指动作，同时牢牢抓住。 20磅的最大力量。并需要30英寸磅的扭矩来拆卸和安装EVA轨道可更换单元（ORU）[15]。
所有EVA工具和ORU必须在发生断电时保留。可以构建兼容机器人和EVA的接口，或者构建一系列机器人工具来与EVA机组接口和工具进行交互。然而，这两种方法都是非常昂贵的，并且当然会增加一套空间站工具和接口，这些工具和接口已经计划得相当广泛。 Robonaut设计将使机器人的手EVA兼容，从而使所有EVA机组人机界面和工具机器人兼容。通过尽可能地再现适合宇航员手和手腕的空间的尺寸，运动学和强度，将EVA兼容性设计在手中。手指和联合行程的数量重现了加压套装手套的工作空间。 Robonaut手掌再现了与EVA界面交互所需的许多必要手段。保持在这个尺寸范围内保证Robonaut手将能够适应所有需要的地方。手腕节距和偏航的联合行程被设计为在加压手套中达到或超过人手。手部和腕部的尺寸可以重现必要的强度，以满足最大的EVA机组人员的要求。
图1：Robonaut手控系统设计灵巧的机器人手操纵各种工具具有独特的问题。在[2,16]中总结的大多数文献都涉及到灵巧的操纵。这些文献集中于使用三个灵巧手指来获得力闭合并仅使用指尖接触来操纵物体。虽然有用，但这种类型的操作不适用于工具使用。大多数EVA工具最适合用于包围式抓握。除了灵巧的抓握之外，还必须使用工具用手来支撑两种包络抓握类型，工具和力量。虽然文献可用于包络抓握[17]，但它并不像灵巧手那样先进。主要的复杂性包括确定和控制涉及包络抓握的许多接触区域的力。虽然自动化包络抓握的工作仍在继续，但Robonaut手已采用远程操作控制策略。美国国家航空航天局DART / FITT系统证明了这种操作方法[18]。 DART / FITT系统使用由操作员佩戴的Cyberglove®虚拟现实手套来控制Stanford / YPL手以成功执行空间相关任务。
2.1空间兼容性EVA空间兼容性将Robonaut手与其他许多人分开。所有组件材料均满足除气限制，以防止可能干扰其他空间系统的污染。不同材料制成的零件在EVA条件下经受极端温度变化时具有可接受的性能。无刷电机用于确保真空中的长寿命。所有零件都设计为使用经过验证的空间润滑剂。
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设计
Robonaut手（图1）总共有十四个自由度。
它由装有电机和驱动电子装置的前臂，两个自由度的手腕和
一个五指，十二自由度的手组成。
前臂的底部直径为4英寸，长约8英寸，可容纳全部14个电机，12个独立电路板以及所有手部布线。
手部组件手部本身分为两部分。一个用于操作的灵巧工作组（食指和中指），以及一个抓握组（无名指和小指），它允许手在操作或启动给定时保持稳定的抓握目的。这是工具使用的基本特征[13]。
灵巧组由两个三自由度手指（食指和中指）和一个三度自由对立拇指组成。抓握组由两个，一个自由度指（无名指和小指）和一个掌心自由度组成。所有的手指都被安装在手掌上（图2）。
为了匹配宇航员戴着手套的手的大小，电机安装在手外，机械动力通过柔性传动系传递。过去的手工设计[2,3]使用了使用复杂滑轮系统或护套的腱索驱动装置，这两种装置在EVA空间环境中使用时都会造成严重的磨损和可靠性问题。为了避免与肌腱有关的问题，手使用柔性轴将电力从前臂的电动机传输到手指。柔性轴的旋转运动通过小型模块化导丝转换成手中的线性运动。结果是紧凑而坚固的传动系。
所有的手都配备了43个（不包括触觉）传感器。每个接头都配有嵌入式绝对位置传感器，每个电机都配有增量式编码器。每个导螺杆组件以及手腕关节连杆均被装备为称重传感器以提供力反馈。
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手指传动系统
图3：手指导螺杆组件
手指驱动器包括
一个配备编码器和
14：1行星齿轮头的无刷直流电机。
与电机耦合的是不锈钢高柔性软轴。
柔性轴保持较短以减少振动，
并通过由聚四氟乙烯覆盖的开口弹簧组成的护套进行保护。
在柔性轴的远端是一个小型模块化螺杆组件（图3）。该组件将柔性轴的旋转运动转换为直线运动。该组件包括：
一个丝杠，它具有一个柔性轴连接和切入其中的轴承座，
一个设计用作张力传感器的外壳，支撑轴承，
一个带有与外壳配合的导轨的螺母（为了消除轴负载）以及连接到螺母上的短丝缆长度。 张力传感器安装在图3所示的壳体的平面上。将丝杠组件的顶部夹紧在手掌中，以允许壳体在负载下伸展或压缩，从而直接读取作用于手指。
组件的较早型号还包含切入导螺杆的整体式反射编码器。这种配置运行良好，但后来从手中删除，以尽量减少手中的接线。
图4：灵巧的手指
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灵巧的手指
三个自由度的灵巧手指（图4）包括
手指支架，
轭，
两个近侧手指段半壳，
解耦连杆组件，
中指段，
远侧手指段，
两个连接连杆和弹簧以消除间隙（未在图中显示）。
图5手指底座凸轮
手指的底座接头具有两个自由度：偏航（+ / -
25度）和俯仰（I00度）。这些运动由两个以不同方式工作的导螺杆组件提供。从螺杆组件延伸的短丝缆连接到近端指状部分半壳中的凸轮槽中（图5）。使用丝缆消除了处理两个自由度底部接头所需的大量接头。凸轮槽用于控制连接丝缆从导螺杆组件的弯曲半径（保持较大以避免对丝缆施加压力并允许使用过大的丝缆）。凹槽还允许在整个手指运动范围内保持几乎恒定的杠杆臂。由于连接丝缆保持较短（大约1英寸）并且其弯曲半径受到控制（允许丝缆的直径相对较大（0.07英寸）），因此丝缆在工作方向上像硬棒一样起作用（靠近手掌）和像相反方向的弹簧一样。换句话说，丝缆长度与其直径的比例使得
丝缆足够坚硬以将手指推开，
但如果手指接触或撞击物体，则丝缆会弯曲，使手指塌陷。
图6：解耦链接
灵巧手指的第二和第三个关节直接相连，以便它们以相等的角度关闭。这些接头由一个独立的导螺杆组件通过一个分离联动装置驱动（图6）。丝杠组件上的短丝缆连接到去耦链路中的枢轴丝缆终端。丝缆中的弯曲允许致动穿过两个自由度的基部接头，而不需要复杂的机构。连杆的设计使得丝缆的弧长度几乎恒定，不管基座接头的位置如何（比较图6中的弧A与弧B）。这使得远端关节的运动大致独立于基部关节。图2具有近端和远端段，并且在设计上类似于灵巧指状物，但具有明显更多的偏航行程和超长的间距。拇指也以这样的角度安装在手掌上，使得运动范围的增加导致人类拇指运动的合理仿真。这种安装方式可以使手执行抓握，这与通常的将拇指直接放在手指对面的惯例相比是不可能的[2,3,14]。拇指基座关节具有70度偏航和110度俯仰。远端关节有80度的间距。连杆手指安装图7：抓住手指基座关节的动作与灵巧的手指相同，但增加了凸轮式制动器以保持丝缆的弯曲半径在极大偏航角度时较大。拇指的远侧部分以类似于操纵手指的方式被驱动通过分离联动装置。拇指基座的扩展偏航行程使完全远端机械解耦困难。相反，关节在软件中解耦。
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
抓握手指有三个俯仰关节，每个关节都有90度的行程。手指由一个导螺杆组件致动，并且在操作指状物的近端手指段半壳中使用相同的凸轮槽（图5）。 7-bar指形连杆与灵巧指形的指形连杆相似，不同之处在于去耦连杆被拆除并且连杆与手指支架连接（图7）。在这种配置中，手指的每个关节都以大致相等的角度关闭。当前正在评估的手指的替代配置用刚性有限行程弹簧代替远侧连杆，以允许手指在抓住物体时更好地顺应。
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
拇指是获得许多与EVA工具接口所需的抓手的关键。手掌机构（图8）中显示的拇指为两个抓手提供了一个支架，并提供了一个拔？？动作，增强了工具抓握的稳定性。这允许手以使工具的轴线与前臂摇摆轴线对齐的方式抓住物体。这对许多常用工具（如螺丝刀）的使用非常重要。该机构包括两个枢转掌骨，一个共同的轴和两个扭力弹簧。抓手指和他们的导螺杆组件安装到掌骨。掌骨连接在同一根轴上的手掌上。第一个扭力弹簧放置在两个掌骨之间，在两者之间提供枢转力。第二个扭力弹簧放置在第二掌骨和手掌之间，迫使两掌骨靠在手掌上。致动导螺杆组件安装在手掌中，短丝缆连接到第一掌骨上的丝缆终端。扭力弹簧的尺寸使得当导螺杆组件拉下第一掌骨时，第二掌骨以一半的角度折叠第一掌骨。通过这种方式，手掌能够以与人手相似的方式进行杯子的揉搓而不会发生手指碰撞。
图9手腕机构
普通轴手掌铸造手腕通过两个线性执行器以不同方式驱动（图9）。线性执行器由一个滑块和一个带有一个整体滚珠丝杠的定制空心轴无刷直流电机组成。执行器通过安装在预先加载的球座中的球节连杆连接到手掌。图8：手掌机制手指彼此以微小的角度安装在手掌上，这与将手指安装在彼此平行的一般做法相反。•这种安装使手指可以像人手一样靠近在一起。为了进一步提高手的可靠性和坚固性，所有手指都安装在减震垫上。这使他们能够在不引起损坏的情况下承受非常高的影响。
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
设计手腕（图9）提供了无限制的通过，以最大化手指柔性轴的弯曲半径，同时接近加压宇航员手套的手腕节距和偏航行程。总行程为+/- 70度的俯仰和+/- 30度的偏航。这两条轴线相互交叉，并与前臂滚动轴的中心线相交。当与Robonaut Arm [19]连接时，这三个轴线结合在手腕袖口的中心，产生高效的运动学解决方案。袖套通过减震器安装在前臂上，以增加安全性。
图10：前臂前臂配置为带六个盖板的肋状外壳。将所有需要的设备包装在EVA前臂尺寸体积中是一项具有挑战性的任务。六个盖板以各种角度倾斜，并且使用键控安装接片来使前臂表面面积最小化。腕部直线执行器安装在两个盖板上，对称地固定在前臂上以保持高效的运动。另外四个盖板为三个手指马达组提供支架（图10）。这里不需要对称，因为柔性轴容易弯曲以适应奇怪的角度。盖板也设计用作散热器。随着电机，定制混合电机驱动器芯片安装在盖板上。
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整合挑战
正如所料，在手工原型，装配和初始测试中出现了许多集成挑战。其中一些问题和当前的解决方案如下。手中的许多部件都使用极其复杂的几何形状，以尽量减少零件数量并缩小手的尺寸。这些部件的制造可以通过直接从立体光刻模型将它们铸造在铝中来实现。这个过程以最小的成本产生相对高精度的部件。其中最好的例子就是手掌，形状复杂，有50多个洞，其中很少有相互正交的。
手指关节控制是通过用于偏航关节的对抗丝缆对和用于俯仰关节的预加载弹簧实现的。最初，通过球形连杆连接到灵巧指状物的前部的单个压缩弹簧在全开位置向基部关节施加不足的力矩。连接到手指背部的双张力弹簧改善了更多关节范围的预加载。然而，在完全打开位置期望的预加载在关闭期间导致较高的力。正在进行建立最佳预加载和使预加载力在整个范围内线性化的工作。指状丝缆提出了机械安装和数学挑战。灵巧的手指使用单个安装螺丝将丝缆固定到位，同时避免丝缆夹紧。这种配置允许丝缆在手指运动期间弯曲并产生合理恒定的杠杆臂。但是，在评估不同的丝缆直径时，使用单个螺钉进行组装很困难。拇指使用更安全的锁，其中包括一块带有突出部分的平板，该平板可牢固地按压其通道中的丝缆。这两种技术之间的交易正在继续。类似的丝缆连接装置也在为其他手指关节演变。丝缆的灵活性使封闭式运动学变得困难。手指移动时安装点处的丝缆弯曲不易准确建模。任何封闭模型都需要简化关于丝缆弯曲和与手指凸轮接触的假设。捕获所有相关数据的更简单的解决方案采用凭经验在线离线获取的多维数据图。具有足够高的分辨率，这些地图提供精确的正向和反向运动学数据。
手腕设计（图9）从复杂的多杆机构演变为更简单的二维滑块曲柄吊钩接头。最初弯曲的球形连杆将滑块连接到手掌，并带有凸轮，以便在俯仰运动期间旋转连杆以避开腕带。在重新设计手腕袖口和手掌之后，实现了目前的直线球链接。手指导向螺杆不可逆向驱动（应该意味着没电时不能动，有电时可以双向动），并且在包络抓握中可确保在发生电源故障时实现正向捕捉。如果不能及时恢复动力，可能需要其他Robonaut手[19]或者EVA机组人员手动打开手。
早期的手部设计结合了一个简单的退出环，通过摩擦轮啮合每个手指传动系，并缓慢打开每个手指关节。虽然这种情况在发生电源故障时运行良好，但无芯无刷直流电机的实验揭示了当电机由于过热而发生故障时的问题。电机绕组绝缘加热，扩大并占用电机，防止反向驱动。正在研究一种新的应急技术，用于打开将容纳马达卡死和功率损失的手。
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初始手指控制设计和测试
在任何操作发生之前，必须开发Robonaut手关节的基本位置控制。根据关节的不同，手指关节可以由单个电机或对立的电机控制。每个电机都连接到图3所示的手指传动系组件上。一个简单的PD控制器用于执行电机位置控制测试。
当手指关节卸载时，电机驱动系统的位置控制很简单。
当手指装入时，两个机械效应会影响驱动系统的动力。
将电机连接到丝杠的柔性轴卷起并作为扭转弹簧。虽然增加了一个额外的系统动态，但高比率的丝杠足以掩盖由遥控操作的柔性轴状态引起的位置误差。
加载过程中的第二个影响是增加了丝杠的摩擦力。电机驱动系统的不可逆性质使电机与施加的力有效地分离。因此，在关节加载期间，电机会看到转动丝杠所需的增加的扭矩。电机能够在正常负载时提供转动丝杠所需的扭矩。但是，热限制会限制电机在高转矩时的耐久性。为了适应这一限制，控制器将安装在导螺杆壳体上的应变仪的力反馈结合起来。控制器利用电机驱动系统的无后驱动能力，并在达到所需的力后正确地降低电机输出扭矩。在抓取过程中，将会沿着一个方向移动的指令将被忽略，该方向会将力增加到超出所需的水平。如果强制断电或在一个可以释放力的方向发出一个命令，电机将恢复正常的位置控制操作。该控制策略成功地将电机加热降至可接受的水平并降低功耗。
为了执行联合控制，必须确定与电机输出联合输出有关的运动特性。如前所述，由于丝缆交互作用的不同，封闭形式的运动学算法不易处理。一旦基于手指关节霍尔效应的位置传感器使用解算器进行校准，则使用用于正向和反向运动学的半自动运动学校准程序来构建查找表。运行期间霍尔传感器输出与霍尔效应传感器输出之间的变化可见于预加载弹簧无效的区域。使用不同弹簧策略的设计不足以解决这个问题。为提高定位精度，采用霍尔效应传感器位置反馈的闭环手指关节位置控制器作为此运动学校准程序的一部分。能够成功操纵许多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
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