The product uses precision planetary roller screw drive technology,
built-in brushless servo motor,applicable to a low,medium and
high-level performance motion control system. The product will be built
integrated brushless servo motor and ball screw drive structure, servo
motor rotor rotary motion into linear motion directly by putting a ball
screw mechanism. The product can be customized according to customer
demand for personalized service.


1、质量优质,寿命长,维护花销低; 2、负载大,刚性好;


3、发热量小,速度调控精度高; 4、布局紧密,外形姣好,应用范围广;















HB IES-130





HB IES-100










手臂的宏图限定:   20磅的最努力和30英寸磅的扭矩




各类问题都配有嵌入式绝对地点传感器,// 每一种电机都配有增量式编码器。//




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.









Design of the NASA Robonaut Hand R1

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


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.



 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.

前瞻国际空间站(ISS)上的车外活动(EVA)须要极其可观。那么些保卫安全定谐和建设活动是高昂且危险的。宇宙航行员必须在大概离开空间站的周旋安全在此之前行行广泛的备选,满含预先呼吸太空服空气压力长达4钟头。生机勃勃旦在窗外,机组职员必得拾贰分谨慎,防止杀跌坏宇宙航行服。U.S.国家航空宇航局Johnson航鸣蜩央的机器人系统技巧处近期正在开辟机器人系统,以削减空间站人士的EVA肩负,並且服务于急忙反应技巧。三个如此的系统,罗布onaut正在设计和建筑,以便与独有人机分界面包车型客车外表空间站系统接口。为此,罗布onaut手[1]提供了冲天的比喻灵巧性,以管教与广大这么些接口的宽容性。在过去的三十年中,已经开辟精湛多破纪录的利落机器人手[2-7]。那一个设施使得机器人垄断(monopoly卡塔尔(英语:State of Qatar)器能够吸引和决定未被设计为机器人的实体包容。即便有多少个夹具[8-12]规划用来空间应用,有个别以致在满午月进行了测量检验[8,9,11],但从不灵巧的机械人手在EVA条件下飞行。

 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.




/ BoraT系统验证了这种操作方法[18]。 DART /
SANTANAT系统运用由操作员佩戴的Cyber​​glove®设想现实手套来调节Stanford /


 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.











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
















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











手指的底座接头具备四个自由度:偏航(+ / –









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.




 3.4 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.





 3.6 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.





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.







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








Figure11:ExamplesoftheRobonaut Handusingenvelopingpowergraspstoholdtools
An importantsafetyfeatureof thehand,itsabilityto
thefingers,causesproblemsfor closedloopjoint
controlduringnormaloperation.Furtherrefinementof the
controlsatisfactoryforteleoperatedcontrolof thehand hasbeenattained. For
initial tests,the handwascontrolledin joint
electronicstodeterminethepositionof 18actionsof theoperator’shand.
Someof theseactionsareabsolute
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

infigures11,12werefabricatedfromDow Cornings Silastic®E.
Thepadsprovideanonslipcompliant surfacenecessary
coveredwithaprotectiveglove.Futureplansincludethedevelopment of
agrasp isacceptable.Sincethebaselineoperationplandoesnot
involveforcefeedbacktotheoperator,visualfeedback onlymaybeinsufficient
toproperlydetermineif agraspisstable.Usingsomeknowledgeof
forcesensorsandasmallsetofadditional tactilesensors
thegraspandindicatethat measuretotheoperator.Theoperatorcanthendecide
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
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