产品简介:

3.1手指传动系统

  该产品采用精密行星滚柱丝杆传动技术,内置无刷伺服电机,适用于具有低、中、高级性能要求的运动控制系统。该产品将内置无刷伺服电机与滚柱丝杆传动结构融为一体,伺服电机转子的旋转运动直接通过滚柱丝杠机构转化为推杆的直线运动。该产品可根据客户的需求进行个性化定制服务。

4整合挑战

1、性能优异,寿命长,维护成本低; 2、负载大,刚性好;

Dexterous Fingers

基本型号

Model

行程

Range

导程

Extent

最大载荷

Load

重量

Weight

HB IES-130

0-200mm

3mm/5mm/7.5mm

70KN

19KG

HB IES-100

0-200mm

3mm/5mm

16KN

11KG

HB IES-80

0-200mm

3mm/5mm

9KN

6.5KG

主机总体性能参数 OVERALL TECHNICAL DATA

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.

产品特点:

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

 

         一个丝杠,它具有一个柔性轴连接和切入其中的轴承座,

5、安装灵活,易拆卸维修;

Finger Drive Train

  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.

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.

3、发热量小,速度控制精度高; 4、结构紧凑,外形美观,应用范围广;

3.5

 

         解耦连杆组件,

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

Abstract

当手指装入时,两个机械效应会影响驱动系统的动力。

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。

Palm

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。

 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.

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。

         一个配备编码器和

         但如果手指接触或撞击物体,则丝缆会弯曲,使手指塌陷。

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.


 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

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。

  1. 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,
    1. 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

         柔性轴保持较短以减少振动,

 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.


Figure 4: Dexterous finger

 图6:解耦链接

   
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。

3.5手掌

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。

Initial Finger Control Design and Test

手臂的设计约束:   20磅的最大力和30英寸磅的扭矩

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

手指驱动器包括

from 

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.

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]。

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。

 3.6 Wrist/Forearm

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。

3.3抓握手指

Robonaut手(图1)总共有十四个自由度。

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。

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:

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。

 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.

         两个近侧手指段半壳,


末尾部分需要先分词,再用机器翻译

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]。

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Cyber​​glove®虚拟现实手套来控制Stanford /
YPL手以成功执行空间相关任务。

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。

5

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.

         中指段,

         14:1行星齿轮头的无刷直流电机。

 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。

一个五指,十二自由度的手组成。

 3 Design

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.

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。

译文

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。

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