Miniature robust five-dimensional fingertip force/torque sensor with high performance
Identifieur interne : 003629 ( Istex/Corpus ); précédent : 003628; suivant : 003630Miniature robust five-dimensional fingertip force/torque sensor with high performance
Auteurs : Qiaokang Liang ; Dan Zhang ; Yunjian Ge ; Xiuxiang Huang ; Zhongyang LiSource :
- Measurement Science and Technology [ 0957-0233 ] ; 2011.
Abstract
This paper proposes an innovative design and investigation for a five-dimensional fingertip force/torque sensor with a dual annular diaphragm. This sensor can be applied to a robot hand to measure forces along the X-, Y- and Z-axes (Fx, Fy and Fz) and moments about the X- and Y-axes (Mx and My) simultaneously. Particularly, the details of the sensing principle, the structural design and the overload protection mechanism are presented. Afterward, based on the design of experiments approach provided by the software ANSYS, a finite element analysis and an optimization design are performed. These are performed with the objective of achieving both high sensitivity and stiffness of the sensor. Furthermore, static and dynamic calibrations based on the neural network method are carried out. Finally, an application of the developed sensor on a dexterous robot hand is demonstrated. The results of calibration experiments and the application show that the developed sensor possesses high performance and robustness.
Url:
DOI: 10.1088/0957-0233/22/3/035205
Links to Exploration step
ISTEX:1D562E80D4A48E06E4929293F5717A324B0772D4Le document en format XML
<record><TEI wicri:istexFullTextTei="biblStruct"><teiHeader><fileDesc><titleStmt><title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</title><author><name sortKey="Liang, Qiaokang" sort="Liang, Qiaokang" uniqKey="Liang Q" first="Qiaokang" last="Liang">Qiaokang Liang</name><affiliation><mods:affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail:qiaokangustc@gmail.com</mods:affiliation></affiliation></author><author><name sortKey="Zhang, Dan" sort="Zhang, Dan" uniqKey="Zhang D" first="Dan" last="Zhang">Dan Zhang</name><affiliation><mods:affiliation>Canada Research Chair Laboratory of Robotics and Automation, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4, Canada</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail:Dan.Zhang@uoit.ca</mods:affiliation></affiliation></author><author><name sortKey="Ge, Yunjian" sort="Ge, Yunjian" uniqKey="Ge Y" first="Yunjian" last="Ge">Yunjian Ge</name><affiliation><mods:affiliation>State Key Laboratories of Robot Sensing Systems, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China</mods:affiliation></affiliation></author><author><name sortKey="Huang, Xiuxiang" sort="Huang, Xiuxiang" uniqKey="Huang X" first="Xiuxiang" last="Huang">Xiuxiang Huang</name><affiliation><mods:affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</mods:affiliation></affiliation></author><author><name sortKey="Li, Zhongyang" sort="Li, Zhongyang" uniqKey="Li Z" first="Zhongyang" last="Li">Zhongyang Li</name><affiliation><mods:affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</mods:affiliation></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">ISTEX</idno><idno type="RBID">ISTEX:1D562E80D4A48E06E4929293F5717A324B0772D4</idno><date when="2011" year="2011">2011</date><idno type="doi">10.1088/0957-0233/22/3/035205</idno><idno type="url">https://api.istex.fr/document/1D562E80D4A48E06E4929293F5717A324B0772D4/fulltext/pdf</idno><idno type="wicri:Area/Istex/Corpus">003629</idno></publicationStmt><sourceDesc><biblStruct><analytic><title level="a">Miniature robust five-dimensional fingertip force/torque sensor with high performance</title><author><name sortKey="Liang, Qiaokang" sort="Liang, Qiaokang" uniqKey="Liang Q" first="Qiaokang" last="Liang">Qiaokang Liang</name><affiliation><mods:affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail:qiaokangustc@gmail.com</mods:affiliation></affiliation></author><author><name sortKey="Zhang, Dan" sort="Zhang, Dan" uniqKey="Zhang D" first="Dan" last="Zhang">Dan Zhang</name><affiliation><mods:affiliation>Canada Research Chair Laboratory of Robotics and Automation, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4, Canada</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail:Dan.Zhang@uoit.ca</mods:affiliation></affiliation></author><author><name sortKey="Ge, Yunjian" sort="Ge, Yunjian" uniqKey="Ge Y" first="Yunjian" last="Ge">Yunjian Ge</name><affiliation><mods:affiliation>State Key Laboratories of Robot Sensing Systems, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China</mods:affiliation></affiliation></author><author><name sortKey="Huang, Xiuxiang" sort="Huang, Xiuxiang" uniqKey="Huang X" first="Xiuxiang" last="Huang">Xiuxiang Huang</name><affiliation><mods:affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</mods:affiliation></affiliation></author><author><name sortKey="Li, Zhongyang" sort="Li, Zhongyang" uniqKey="Li Z" first="Zhongyang" last="Li">Zhongyang Li</name><affiliation><mods:affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</mods:affiliation></affiliation></author></analytic><monogr></monogr><series><title level="j">Measurement Science and Technology</title><title level="j" type="abbrev">Meas. Sci. Technol.</title><idno type="ISSN">0957-0233</idno><idno type="eISSN">1361-6501</idno><imprint><publisher>IOP Publishing</publisher><date type="published" when="2011">2011</date><biblScope unit="volume">22</biblScope><biblScope unit="issue">3</biblScope><biblScope unit="page" from="1">1</biblScope><biblScope unit="page" to="11">11</biblScope><biblScope unit="production">Printed in the UK & the USA</biblScope></imprint><idno type="ISSN">0957-0233</idno></series><idno type="istex">1D562E80D4A48E06E4929293F5717A324B0772D4</idno><idno type="DOI">10.1088/0957-0233/22/3/035205</idno><idno type="PII">S0957-0233(11)54138-9</idno><idno type="articleID">354138</idno><idno type="articleNumber">035205</idno></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0957-0233</idno></seriesStmt></fileDesc><profileDesc><textClass></textClass><langUsage><language ident="en">en</language></langUsage></profileDesc></teiHeader><front><div type="abstract">This paper proposes an innovative design and investigation for a five-dimensional fingertip force/torque sensor with a dual annular diaphragm. This sensor can be applied to a robot hand to measure forces along the X-, Y- and Z-axes (Fx, Fy and Fz) and moments about the X- and Y-axes (Mx and My) simultaneously. Particularly, the details of the sensing principle, the structural design and the overload protection mechanism are presented. Afterward, based on the design of experiments approach provided by the software ANSYS, a finite element analysis and an optimization design are performed. These are performed with the objective of achieving both high sensitivity and stiffness of the sensor. Furthermore, static and dynamic calibrations based on the neural network method are carried out. Finally, an application of the developed sensor on a dexterous robot hand is demonstrated. The results of calibration experiments and the application show that the developed sensor possesses high performance and robustness.</div></front></TEI><istex><corpusName>iop</corpusName><author><json:item><name>Qiaokang Liang</name><affiliations><json:string>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</json:string><json:string>E-mail:qiaokangustc@gmail.com</json:string></affiliations></json:item><json:item><name>Dan Zhang</name><affiliations><json:string>Canada Research Chair Laboratory of Robotics and Automation, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4, Canada</json:string><json:string>E-mail:Dan.Zhang@uoit.ca</json:string></affiliations></json:item><json:item><name>Yunjian Ge</name><affiliations><json:string>State Key Laboratories of Robot Sensing Systems, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China</json:string></affiliations></json:item><json:item><name>Xiuxiang Huang</name><affiliations><json:string>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</json:string></affiliations></json:item><json:item><name>Zhongyang Li</name><affiliations><json:string>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</json:string></affiliations></json:item></author><subject><json:item><lang><json:string>eng</json:string></lang><value>force/torque sensor</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>fingertip sensor</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>robot hand</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>overload protection</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>design of experiments</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>neural network method</value></json:item></subject><language><json:string>eng</json:string></language><abstract>This paper proposes an innovative design and investigation for a five-dimensional fingertip force/torque sensor with a dual annular diaphragm. This sensor can be applied to a robot hand to measure forces along the X-, Y- and Z-axes (Fx, Fy and Fz) and moments about the X- and Y-axes (Mx and My) simultaneously. Particularly, the details of the sensing principle, the structural design and the overload protection mechanism are presented. Afterward, based on the design of experiments approach provided by the software ANSYS, a finite element analysis and an optimization design are performed. These are performed with the objective of achieving both high sensitivity and stiffness of the sensor. Furthermore, static and dynamic calibrations based on the neural network method are carried out. Finally, an application of the developed sensor on a dexterous robot hand is demonstrated. The results of calibration experiments and the application show that the developed sensor possesses high performance and robustness.</abstract><qualityIndicators><score>7.335</score><pdfVersion>1.4</pdfVersion><pdfPageSize>595 x 842 pts (A4)</pdfPageSize><refBibsNative>true</refBibsNative><keywordCount>6</keywordCount><abstractCharCount>1017</abstractCharCount><pdfWordCount>4987</pdfWordCount><pdfCharCount>28884</pdfCharCount><pdfPageCount>11</pdfPageCount><abstractWordCount>154</abstractWordCount></qualityIndicators><title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</title><genre.original><json:string>paper</json:string></genre.original><pii><json:string>S0957-0233(11)54138-9</json:string></pii><genre><json:string>research-article</json:string></genre><host><volume>22</volume><publisherId><json:string>MST</json:string></publisherId><pages><total>11</total><last>11</last><first>1</first></pages><issn><json:string>0957-0233</json:string></issn><issue>3</issue><genre><json:string>journal</json:string></genre><language><json:string>unknown</json:string></language><eissn><json:string>1361-6501</json:string></eissn><title>Measurement Science and Technology</title></host><publicationDate>2011</publicationDate><copyrightDate>2011</copyrightDate><doi><json:string>10.1088/0957-0233/22/3/035205</json:string></doi><id>1D562E80D4A48E06E4929293F5717A324B0772D4</id><score>1</score><fulltext><json:item><original>true</original><mimetype>application/pdf</mimetype><extension>pdf</extension><uri>https://api.istex.fr/document/1D562E80D4A48E06E4929293F5717A324B0772D4/fulltext/pdf</uri></json:item><json:item><original>false</original><mimetype>application/zip</mimetype><extension>zip</extension><uri>https://api.istex.fr/document/1D562E80D4A48E06E4929293F5717A324B0772D4/fulltext/zip</uri></json:item><istex:fulltextTEI uri="https://api.istex.fr/document/1D562E80D4A48E06E4929293F5717A324B0772D4/fulltext/tei"><teiHeader><fileDesc><titleStmt><title level="a">Miniature robust five-dimensional fingertip force/torque sensor with high performance</title></titleStmt><publicationStmt><authority>ISTEX</authority><publisher>IOP Publishing</publisher><availability><p>IOP</p></availability><date>2011</date></publicationStmt><sourceDesc><biblStruct type="inbook"><analytic><title level="a">Miniature robust five-dimensional fingertip force/torque sensor with high performance</title><author><persName><forename type="first">Qiaokang</forename><surname>Liang</surname></persName><affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</affiliation><affiliation>E-mail:qiaokangustc@gmail.com</affiliation></author><author><persName><forename type="first">Dan</forename><surname>Zhang</surname></persName><affiliation>Canada Research Chair Laboratory of Robotics and Automation, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4, Canada</affiliation><affiliation>E-mail:Dan.Zhang@uoit.ca</affiliation></author><author><persName><forename type="first">Yunjian</forename><surname>Ge</surname></persName><affiliation>State Key Laboratories of Robot Sensing Systems, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China</affiliation></author><author><persName><forename type="first">Xiuxiang</forename><surname>Huang</surname></persName><affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</affiliation></author><author><persName><forename type="first">Zhongyang</forename><surname>Li</surname></persName><affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</affiliation></author></analytic><monogr><title level="j">Measurement Science and Technology</title><title level="j" type="abbrev">Meas. Sci. Technol.</title><idno type="pISSN">0957-0233</idno><idno type="eISSN">1361-6501</idno><imprint><publisher>IOP Publishing</publisher><date type="published" when="2011"></date><biblScope unit="volume">22</biblScope><biblScope unit="issue">3</biblScope><biblScope unit="page" from="1">1</biblScope><biblScope unit="page" to="11">11</biblScope><biblScope unit="production">Printed in the UK & the USA</biblScope></imprint></monogr><idno type="istex">1D562E80D4A48E06E4929293F5717A324B0772D4</idno><idno type="DOI">10.1088/0957-0233/22/3/035205</idno><idno type="PII">S0957-0233(11)54138-9</idno><idno type="articleID">354138</idno><idno type="articleNumber">035205</idno></biblStruct></sourceDesc></fileDesc><profileDesc><creation><date>2011</date></creation><langUsage><language ident="en">en</language></langUsage><abstract><p>This paper proposes an innovative design and investigation for a five-dimensional fingertip force/torque sensor with a dual annular diaphragm. This sensor can be applied to a robot hand to measure forces along the X-, Y- and Z-axes (Fx, Fy and Fz) and moments about the X- and Y-axes (Mx and My) simultaneously. Particularly, the details of the sensing principle, the structural design and the overload protection mechanism are presented. Afterward, based on the design of experiments approach provided by the software ANSYS, a finite element analysis and an optimization design are performed. These are performed with the objective of achieving both high sensitivity and stiffness of the sensor. Furthermore, static and dynamic calibrations based on the neural network method are carried out. Finally, an application of the developed sensor on a dexterous robot hand is demonstrated. The results of calibration experiments and the application show that the developed sensor possesses high performance and robustness.</p></abstract><textClass><keywords scheme="keyword"><list><head>keywords</head><item><term>force/torque sensor</term></item><item><term>fingertip sensor</term></item><item><term>robot hand</term></item><item><term>overload protection</term></item><item><term>design of experiments</term></item><item><term>neural network method</term></item></list></keywords></textClass></profileDesc><revisionDesc><change when="2011">Published</change></revisionDesc></teiHeader></istex:fulltextTEI><json:item><original>false</original><mimetype>text/plain</mimetype><extension>txt</extension><uri>https://api.istex.fr/document/1D562E80D4A48E06E4929293F5717A324B0772D4/fulltext/txt</uri></json:item></fulltext><metadata><istex:metadataXml wicri:clean="corpus iop not found" wicri:toSee="no header"><istex:xmlDeclaration>version="1.0" encoding="ISO-8859-1"</istex:xmlDeclaration><istex:docType SYSTEM="http://ej.iop.org/dtd/iopv1_5_2.dtd" name="istex:docType"></istex:docType><istex:document><article artid="mst354138"><article-metadata><jnl-data jnlid="mst"><jnl-fullname>Measurement Science and Technology</jnl-fullname><jnl-abbreviation>Meas. Sci. Technol.</jnl-abbreviation><jnl-shortname>MST</jnl-shortname><jnl-issn>0957-0233</jnl-issn><jnl-coden>MSTCEP</jnl-coden><jnl-imprint>IOP Publishing</jnl-imprint><jnl-web-address>stacks.iop.org/MST</jnl-web-address></jnl-data><volume-data><year-publication>2011</year-publication><volume-number>22</volume-number></volume-data><issue-data><issue-number>3</issue-number><coverdate>March 2011</coverdate></issue-data><article-data><article-type type="paper" sort="regular"></article-type><type-number type="paper" numbering="article" artnum="035205">035205</type-number><article-number>354138</article-number><first-page>1</first-page><last-page>11</last-page><length>11</length><pii>S0957-0233(11)54138-9</pii><doi>10.1088/0957-0233/22/3/035205</doi><copyright>2011 IOP Publishing Ltd</copyright><ccc>0957-0233/11/035205+11$33.00</ccc><printed>Printed in the UK & the USA</printed><features colour="global" mmedia="no" suppdata="no"></features></article-data></article-metadata><header><title-group><title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</title><short-title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</short-title><ej-title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</ej-title></title-group><author-group><author address="mst354138ad1" email="mst354138ea1"><first-names>Qiaokang</first-names><second-name>Liang</second-name></author><author address="mst354138ad2" email="mst354138ea2"><first-names>Dan</first-names><second-name>Zhang</second-name></author><author address="mst354138ad3"><first-names>Yunjian</first-names><second-name>Ge</second-name></author><author address="mst354138ad1"><first-names>Xiuxiang</first-names><second-name>Huang</second-name></author><author address="mst354138ad1"><first-names>Zhongyang</first-names><second-name>Li</second-name></author></author-group><address-group><address id="mst354138ad1"><orgname>College of Polytechnic, Hunan Normal University</orgname>, Changsha, Hunan 410081, <country>People's Republic of China</country></address><address id="mst354138ad2"><orgname>Canada Research Chair Laboratory of Robotics and Automation, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology</orgname>, Oshawa, Ontario L1H 7K4, <country>Canada</country></address><address id="mst354138ad3"><orgname>State Key Laboratories of Robot Sensing Systems, Institute of Intelligent Machines, Chinese Academy of Sciences</orgname>, Hefei, Anhui 230031, <country>People's Republic of China</country></address><e-address id="mst354138ea1"><email mailto="qiaokangustc@gmail.com">qiaokangustc@gmail.com</email></e-address><e-address id="mst354138ea2"><email mailto="Dan.Zhang@uoit.ca">Dan.Zhang@uoit.ca</email></e-address></address-group><history received="15 April 2010" finalform="17 January 2011" online="15 February 2011"></history><abstract-group><abstract><heading>Abstract</heading><p indent="no">This paper proposes an innovative design and investigation for a five-dimensional fingertip force/torque sensor with a dual annular diaphragm. This sensor can be applied to a robot hand to measure forces along the <italic>X</italic>-, <italic>Y</italic>- and <italic>Z</italic>-axes (<italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic> and <italic>F<sub>z</sub></italic>) and moments about the <italic>X</italic>- and <italic>Y</italic>-axes (<italic>M<sub>x</sub></italic> and <italic>M<sub>y</sub></italic>) simultaneously. Particularly, the details of the sensing principle, the structural design and the overload protection mechanism are presented. Afterward, based on the design of experiments approach provided by the software ANSYS®, a finite element analysis and an optimization design are performed. These are performed with the objective of achieving both high sensitivity and stiffness of the sensor. Furthermore, static and dynamic calibrations based on the neural network method are carried out. Finally, an application of the developed sensor on a dexterous robot hand is demonstrated. The results of calibration experiments and the application show that the developed sensor possesses high performance and robustness.</p></abstract></abstract-group><classifications><keywords print="yes"><keyword>force/torque sensor</keyword><keyword>fingertip sensor</keyword><keyword>robot hand</keyword><keyword>overload protection</keyword><keyword>design of experiments</keyword><keyword>neural network method</keyword></keywords></classifications></header><body numbering="bysection"><sec-level1 id="mst354138s1" label="1"><heading>Introduction</heading><p indent="no">With respect to dexterous manipulation in unstructured human environments, the sense of force/torque is critical. As a consequence, force/torque (F/T) sensors have received much attention recently, particularly for applications that require F/T information feedback such as controlling motions of robots and industrial machines [<cite linkend="mst354138bib01" range="mst354138bib01,mst354138bib02,mst354138bib03,mst354138bib04,mst354138bib05,mst354138bib06,mst354138bib07,mst354138bib08,mst354138bib09">1–9</cite>]. Among various types of F/T sensors, the six- and three-dimensional F/T sensors have attracted the most attention because the majority of applications need three forces along the axes and three torques about the axes or just the former. However, in some applications such as three-finger grasping, some components of the six dimensions are not completely necessary. Therefore, research and development of F/T sensors with five-dimensional components is important. Currently, almost all F/T sensors are based on the measurement of elastic strains that occur on the force-sensing element. Thus, the higher the sensitivity of the F/T sensor, the more fragile the sensor will be. Hence, developing a proper method for sustaining overload is crucial, especially if the applied load may consist of an impulse and/or is unpredictable. F/T sensors are also used to estimate the location of contacts between the manipulator and its environment through measurements of three forces and three torques [<cite linkend="mst354138bib10">10</cite>, <cite linkend="mst354138bib11">11</cite>]. Besides, all multi-dimensional F/T sensors have some degree of cross coupling, which will greatly decrease the performance. Each F/T sensor must be individually calibrated and decoupled with a decoupling matrix, also called the calibration matrix. The conventional decoupling method featured matrix calculations that were simple and could attain the decoupling matrix quickly with moderate performance.</p><p>In this paper, a novel miniature robust five-dimensional F/T sensor with a dual annular diaphragm structure based on measurement of elastic strain that occurs on the force-sensing element is developed. This sensor is designed to simultaneously measure the normal force, <italic>F<sub>z</sub></italic>, both tangential force terms, <italic>F<sub>x</sub></italic> and <italic>F<sub>y</sub></italic>, as well as the torques, <italic>M<sub>x</sub></italic> and <italic>M<sub>y</sub></italic>, about the tangential axes. Overload protection for <italic>F<sub>z</sub></italic> based on structure character is proposed. A calibration experiment based on neural networks (NN) validates that it contains positive characteristics, such as strong linearity, weak couplings and overload protection.</p></sec-level1><sec-level1 id="mst354138s2" label="2"><heading>The sensing principle</heading><p indent="no">The most common method for detecting the force and torque is an electric measurement technique using strain gauges, whose electrical resistance is proportional to their length. The basic structure of a generic F/T sensor is illustrated in figure <figref linkend="mst354138fig01">1</figref>. It can be observed that there are four main steps to convert the applied load to equivalent forces and torques. These are outlined as follows.
<figure id="mst354138fig01"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig01.eps" width="20.5pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig01.jpg"></graphic-file></graphic><caption id="mst354138fc01" label="Figure 1"><p indent="no">Basic structure of a generic F/T sensor.</p></caption></figure></p><p indent="no"><italic>Step 1</italic>. Load elastic strain: when exposed to a load, the force-sensing element of the F/T sensor will deform and elastic strain will occur. The quality of the occurred strain (ϵ) only relates to the applied force/torque (<bold>F</bold>) after the dimensions of the force-sensing element are decided:
<display-eqn id="mst354138eqn01" eqnnum="1" eqnalign="center"></display-eqn><italic>Step 2</italic>. Elastic strain to resistance change: strain gauges bonded on the force-sensing element will have the same deformation and elastic strain as the bonded spot on the force-sensing element. The elastic strain results in equivalent linear changes in the resistance of the strain gauges.</p><p>The gauge factor, denoted by <italic>G<sub>f</sub></italic>, is a fundamental parameter describing the sensitivity to strain and is defined mathematically as follows [<cite linkend="mst354138bib12">12</cite>]:
<display-eqn id="mst354138eqn02" eqnnum="2" eqnalign="center"></display-eqn>where <italic>R</italic> is the original resistance of the strain gauge, <italic>L</italic> is the original length and ϵ is the normal strain that the strain gauge experiences. The gauge factor for metallic strain gauges is typically around 2. Therefore, the resistance change Δ<italic>R</italic> in the resistance of the strain gauge is
<display-eqn id="mst354138eqn03" eqnnum="3" eqnalign="center"></display-eqn>In practice, taking both linearity and sensitivity into account, the quality of the strain gauge should be less than 1000 micro-strains (10 × 10<sup>−6</sup>), which means that the change in resistance is less than 0.2<italic>R</italic>%. Hence signal processing such as amplification is required.</p><p><italic>Step 3</italic>. Resistance change to voltage output: a bridge circuit is always used to measure such small changes in resistances. A full-bridge circuit, whose four arms are all active strain gauges, increases the sensitivity of the circuit further. Since all four elements of the bridge will either decrease or increase resistance by the same proportion in response to changes in temperature, the effects of temperature change (from −10 to 50 °C) remain cancelled. Its measurement sensitivity is given by
<display-eqn id="mst354138eqn04" eqnnum="4" eqnalign="center"></display-eqn>where <italic>V</italic><sub>0</sub> is the output of the circuit, and <italic>V<sub>E</sub></italic> is the voltage excitation source.</p><p><italic>Step 4</italic>. Voltage output to force/torque output: when load <bold>F</bold> = (<italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic>, <italic>F<sub>z</sub></italic>, <italic>M<sub>x</sub></italic>, <italic>M<sub>y</sub></italic>)<italic><sup>T</sup></italic> that contains the forces <italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic> and <italic>F<sub>z</sub></italic> in the <italic>x</italic>, <italic>y</italic> and <italic>z</italic> directions respectively and the moments <italic>M<sub>x</sub></italic>, <italic>M<sub>y</sub></italic> about the <italic>X</italic>- and <italic>Y</italic>-axes, respectively, and <italic>M<sub>x</sub></italic>, <italic>M<sub>y</sub></italic> are applied to the sensor, the outputs of strain gauges attached at various locations will be <bold>S</bold> = (<italic>S</italic><sub>1</sub>, <italic>S</italic><sub>2</sub>, <italic>S</italic><sub>3</sub>, <italic>S</italic><sub>4</sub>, <italic>S</italic><sub>5</sub>)<italic><sup>T</sup></italic>. This relationship can be expressed as follows using the detection matrix <bold>T</bold>:
<display-eqn id="mst354138eqn05" eqnnum="5" eqnalign="center"></display-eqn>Accordingly, from the sensor outputs and based on the decoupling method, the applied forces and moments can be determined and calculated:
<display-eqn id="mst354138eqn06" eqnnum="6" eqnalign="center"></display-eqn>When <bold>S</bold> contains more than six elements and a rank that is equal to 6, the Moore–Penrose inverse technique must be employed to determine <bold>F</bold> from equation (<eqnref linkend="mst354138eqn05">5</eqnref>) as
<display-eqn id="mst354138eqn07" eqnnum="7" eqnalign="center"></display-eqn>Finally, the fingertip sensor measures equivalent forces and moments acting on the fingertip with respect to the sensors’ coordinate frame. It is therefore necessary to transform these forces from the sensors’ frame, <inline-eqn></inline-eqn>, and the sensors’ moments, <inline-eqn></inline-eqn>, onto another frame, <inline-eqn></inline-eqn>, and moments, <inline-eqn></inline-eqn>. This transformation can be represented as
<display-eqn id="mst354138eqn08" eqnnum="8" eqnalign="center"></display-eqn>which requires knowledge of the position, <italic>r<sup>c</sup><sub valign="yes">cs</sub></italic>, of the origin of frame <bold>S</bold> with respect to frame <bold>C</bold> as well as knowledge of the orientation, <bold>R</bold><sup><italic>c</italic></sup><sub valign="yes"><italic>s</italic></sub>, of frame <bold>S</bold> with respect to frame <bold>C</bold>. Note that in equation (<eqnref linkend="mst354138eqn08">8</eqnref>), the calculated <italic>M<sub>zc</sub></italic> is not real.</p></sec-level1><sec-level1 id="mst354138s3" label="3"><heading>Sensor design</heading><p indent="no">The unique design of the five-dimensional F/T sensor is detailed in figure <figref linkend="mst354138fig02">2</figref>. In particular, the proposed sensor comprises an upper hemisphere used for transferring the applied load to the next component, a center portion having active sensing portions sensitive to applied forces or moments, which is also featured with lead screws at both ends that connect the upper hemisphere and base frame, and a base frame that connects the sensor to environment via bolts. After assembly, there is an empty cavity between the force-sensing element and the base frame, which is used for mounting the amplifier circuit.
<figure id="mst354138fig02"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig02.eps" width="15pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig02.jpg"></graphic-file></graphic><caption id="mst354138fc02" label="Figure 2"><p indent="no">An exploded view of the developed sensor.</p></caption></figure></p><p>The developed five-dimensional fingertip sensor is supposed to serve as a fingertip on the manipulator while simultaneously measuring the forces and moments when the manipulator performs a grasping action. The measurement ranges for this sensor are set as <italic>F<sub>x</sub></italic> = <italic>F<sub>y</sub></italic> = ±30 N, <italic>F<sub>z</sub></italic> = 50 N, <italic>M<sub>x</sub></italic> = <italic>M<sub>y</sub></italic> = ±600 N mm. Also, the whole sensor has a size of Φ 24 mm × 30 mm and all parts of the sensor are made of aluminum alloy.</p><sec-level2 id="mst354138s3-1" label="3.1"><heading>Structure of elastic force-sensing elements</heading><p indent="no">The elastic force-sensing element connects the force/torque and strain gauges in the form of a sense organ. This sense organ is the most failure-prone component as it has the foremost exposure to the applied force/torque, given its smaller dimensions. Therefore, its design should consider not only the static and dynamic performances but also the sensitivity, linearity and the coupling coefficient among the dimensions. As its performance mainly determines the performance of the sensor, it is vital to design a proper configuration of the force-sensing element to detect forces and moments precisely.</p><p>As shown in figure <figref linkend="mst354138fig03">3</figref>, a novel monolithic force-sensing element with two annular diaphragms has been designed in a rotationally symmetric structure. A cylinder, arranged axially between the two annular diaphragms, connects the diaphragms at its two ends. Its monolithic construction reduces hysteresis and nonlinearity that is associated with bolted or glued construction.
<figure id="mst354138fig03"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig03.eps" width="20.5pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig03.jpg"></graphic-file></graphic><caption id="mst354138fc03" label="Figure 3"><p indent="no">A partially cutaway perspective view of the force-sensing element and its dimensions (all dimensions are in mm).</p></caption></figure></p><p>In order to understand the nature of the proposed F/T sensor based on annular diaphragms, a mathematical model of the annular diaphragms has been established. Figure <figref linkend="mst354138fig04">4</figref> shows the schematic diagram of an annular diaphragm. When a load is applied, the deformation mainly occurs in the annular diaphragm as its stiffness is far less than the stiffness of the other parts of the sensor.
<figure id="mst354138fig04"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig04.eps" width="15pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig04.jpg"></graphic-file></graphic><caption id="mst354138fc04" label="Figure 4"><p indent="no">Schematic diagram of an annular diaphragm.</p></caption></figure></p><p>From plate theory, one can establish that the maximum deflection ω<sub>max</sub> occurs at the radius <italic>r</italic> = <italic>r</italic><sub>0</sub>:
<display-eqn id="mst354138eqn09" lines="multiline" eqnnum="9" eqnalign="left"></display-eqn>where <italic>r</italic><sub>0</sub> = <italic>D</italic><sub>2</sub>/2 is the radius of the inner loop, <italic>R</italic> = <italic>D</italic><sub>1</sub>/2 is the radius of the outer loop of the annular diaphragm, <italic>h</italic> is the thickness of the annular diaphragm, <italic>E</italic> is the elastic modulus of the material and μ is the Poisson ratio of the material.</p><p>The radial normal strain, ϵ<sub><italic>r</italic></sub>, that occurs at the radius <italic>r</italic> is
<display-eqn id="mst354138eqn10" eqnnum="10" eqnalign="center"></display-eqn>The minimum natural vibration frequency of the annular diaphragm is
<display-eqn id="mst354138eqn11" eqnnum="11" eqnalign="center"></display-eqn></p></sec-level2><sec-level2 id="mst354138s3-2" label="3.2"><heading>Overload protection</heading><p indent="no">A drawback of most existing force/torque sensors is that they do not provide protection against excessively large forces acting on them [<cite linkend="mst354138bib13">13</cite>, <cite linkend="mst354138bib15">15</cite>]. As a result, the sensors can suffer fatal damage due to unexpected external or excessively large forces/torques. Conventional methods such as increasing the thickness of the sensing element and using a stronger material always decrease the motion of the element, which means the sensitivity of the sensor will be decreased correspondingly. The objective of this overload mechanism is to provide an improved sensor with high sensitivity.</p><p>As mentioned above, the outside cylinder surfaces of both the ends of the force-sensing element are featured with lead screws, which are used to connect and fasten the upper hemisphere and base frame. Therefore after assembly, there will be a uniform predetermined distance between the basal surface of the upper hemisphere and the top surface of the base frame. Based on the maximum displacement determined via FEA that will be introduced later, this distance was found to be 0.05 to 0.08 mm. As a result, an axial gap is created between the upper hemisphere and the base frame, which allows the former to be depressed only up to a specified limit. If the force, <italic>F<sub>z</sub></italic>, is large enough to make the elastic force-sensing element stretch by more than 0.04 to 0.08 mm, then the basal surface of the upper case will rest against the top surface of the base frame. Consequently, the deflection will be limited to approximately the amount of the stretch. Also, the upper hemisphere is rigid enough to transmit the overload force/torque to the base frame without inducing bending.</p><p>By changing the thickness and diameters of the annular diaphragm, the sensor could be fit to different measurement ranges. To clamp a measurement range and control the overload factor, an optimization method was utilized to obtain the dimensions of the elastic body by the optimization module of the ANSYS® program.</p></sec-level2></sec-level1><sec-level1 id="mst354138s4" label="4"><heading>Finite element method analysis and optimization design</heading><p indent="no">In order to understand the static characteristics and dynamic behavior of the force-sensing element and to determine the appropriate dimensions of the elastic body as well as the positions to bond the strain gauges, a finite element analysis (FEA) and optimization design are performed. This is based on the design of experiments (DOE) approach provided by the software ANSYS®.</p><sec-level2 id="mst354138s4-1" label="4.1"><heading>Optimization design</heading><p indent="no">Under the optimization theory, a methodology via the software ANSYS® for designing the force-sensing element has been adopted. The mechanism design as a multi-objective optimization problem based on the DOE approach provided by the software has been proposed, which can capture the behavioral changes due to parameter variations and optimize a set of goals for quantities such as stress and deflection and determine the most optimal values of the parameters. The design variables are the geometric dimensions of the force-sensing element; the sensitivity, the maximum deformation and the maximum and minimum radial normal strains are used to evaluate the performance of the force sensor.</p><p>In this study, the design parameters were the thickness <italic>h</italic> and the outer and inner diameters <italic>D</italic><sub>1</sub> and <italic>D</italic><sub>2</sub> of the annular diaphragms, which are subject to the bounds</p><p indent="no">0.45 mm ⩽ <italic>h</italic> ⩽ 1 mm,</p><p indent="no">4 mm ⩽ <italic>D</italic><sub>2</sub> ⩽ 4.5 mm,</p><p indent="no">16 mm ⩽ <italic>D</italic><sub>1</sub> ⩽ 20 mm,</p><p indent="no">with the objectives</p><p indent="no">ϵ<sub>max</sub> ⩽ 1000 mm/mm,</p><p indent="no">ϵ<sub>min</sub> ⩽ −500 mm/mm,</p><p indent="no"><italic>d</italic><sub>max</sub> ⩽ 0.05 mm,</p><p indent="no">where ϵ<sub>max</sub> and ϵ<sub>min</sub> are the maximum and minimum elastic strains that occur on the elastic beams, and <italic>d</italic><sub>max</sub> is the maximum deformation that occurs on the elastic element. The possible sample points chosen by the software are shown in figure <figref linkend="mst354138fig05">5</figref>. The first and second objectives can make sure that the elastic element of the force sensor works within the elastic limit and that it has enough elastic strain to sense the applied forces and moments. The third objective is to make sure the sensor has good linearity and stability.
<figure id="mst354138fig05"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig05.eps" width="20.5pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig05.jpg"></graphic-file></graphic><caption id="mst354138fc05" label="Figure 5"><p indent="no">Sample points selected by the software.</p></caption></figure></p><p>Finally, as shown in figure <figref linkend="mst354138fig06">6</figref>, the software captures the three optimal values of the design parameters, which are shown in detail in table <tabref linkend="mst354138tab01">1</tabref>. Group 2 was used to fabricate the sensor. Figure <figref linkend="mst354138fig07">7</figref> shows the sensitivities of the three parameters. It is clear that the thickness of the diaphragm <italic>h</italic> is the most sensitive parameter for the three output parameters.
<figure id="mst354138fig06" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig06.eps" width="26pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig06.jpg"></graphic-file></graphic><caption id="mst354138fc06" label="Figure 6"><p indent="no">Sample chart with objectives.</p></caption></figure><figure id="mst354138fig07" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig07.eps" width="26pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig07.jpg"></graphic-file></graphic><caption id="mst354138fc07" label="Figure 7"><p indent="no">Sensitivities of parameters.</p></caption></figure><table id="mst354138tab01" frame="topbot" indent="no"><caption id="mst354138tc01" label="Table 1"><p indent="no">Results of the optimization design.</p></caption><tgroup cols="7"><colspec colnum="1" colname="col1" align="left"></colspec><colspec colnum="2" colname="col2" align="left"></colspec><colspec colnum="3" colname="col3" align="left"></colspec><colspec colnum="4" colname="col4" align="left"></colspec><colspec colnum="5" colname="col5" align="left"></colspec><colspec colnum="6" colname="col6" align="left"></colspec><colspec colnum="7" colname="col7" align="left"></colspec><thead><row><entry>Group</entry><entry><italic>h</italic> (mm)</entry><entry><italic>D</italic><sub>1</sub> (mm)</entry><entry><italic>D</italic><sub>2</sub> (mm)</entry><entry>ϵ<sub>max</sub></entry><entry>ϵ<sub>min</sub></entry><entry><italic>d</italic><sub>max</sub> (mm)</entry></row></thead><tbody><row><entry>1</entry><entry>0.9959</entry><entry>16.176</entry><entry>4.4025</entry><entry>5.3 × 10<sup>−4</sup></entry><entry>−5.32 × 10<sup>−4</sup></entry><entry>0.0014</entry></row><row><entry>2</entry><entry>0.982 38</entry><entry>17.395</entry><entry>4.1325</entry><entry>5.4 × 10<sup>−4</sup></entry><entry>−5.37 × 10<sup>−4</sup></entry><entry>0.001 85</entry></row><row><entry>3</entry><entry>0.9891</entry><entry>18.708</entry><entry>4.2675</entry><entry>5.3 × 10<sup>−4</sup></entry><entry>−5.28 × 10<sup>−4</sup></entry><entry>0.002 145</entry></row></tbody></tgroup></table></p></sec-level2><sec-level2 id="mst354138s4-2" label="4.2"><heading>Static characteristics analysis</heading><p indent="no">In order to understand the static characteristics such as the strain and deformation distribution in detail, FEA is performed.</p><sec-level3 id="mst354138s4-2-1" label="4.2.1"><heading>Under the applied tangential force <italic>F<sub>x</sub></italic> (similarly with <italic>F<sub>y</sub></italic>)</heading><p indent="no">As shown in figure <figref linkend="mst354138fig08">8</figref>, the elastic strain and deformation mainly occur on the annular diaphragms of the force-sensing element, and the lower annular diaphragm has an identical stress distribution in terms of pattern and magnitude. The distribution of the radial normal strain shows that the radial strain spreads along the <italic>X</italic>-axis by means of −, +, −, + and reaches the maximum and minimum (967 and −967 mm/mm, respectively) at a spot close to the inner and outer circumferences respectively. The applied force was <italic>F<sub>x</sub></italic> = 30 N in this case. In addition, the maximum deformation (0.089 56 mm) occurs at the left and right ends of the outer circumference along the <italic>X</italic>-axis.
<figure id="mst354138fig08" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig08.eps" width="36pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig08.jpg"></graphic-file></graphic><caption id="mst354138fc08" label="Figure 8"><p indent="no">The distribution of normal elastic strain and deformation of the force-sensing element under the applied force <italic>F<sub>x</sub></italic>.</p></caption></figure></p></sec-level3><sec-level3 id="mst354138s4-2-2" label="4.2.2"><heading>Under the applied normal force <italic>F<sub>z</sub></italic></heading><p indent="no">As shown in figure <figref linkend="mst354138fig09">9</figref>, the elastic strain and deformation mainly occur on the annular diaphragms of the force-sensing element, and the lower annular diaphragm has an identical stress distribution in terms of both pattern and magnitude. It is obvious that the radial strain spreads along the radial direction and reaches a maximum and minimum (943.7 and −889.7 mm/mm, respectively) at a location close to the inner and outer circumferences respectively when subject to the applied force <italic>F<sub>z</sub></italic> = 50 N. In addition, the maximum deformation (0.0611 mm) occurs at the outer circumference of the upper annular diaphragm.
<figure id="mst354138fig09" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig09.eps" width="36pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig09.jpg"></graphic-file></graphic><caption id="mst354138fc09" label="Figure 9"><p indent="no">The distribution of normal elastic strain and deformation of the force-sensing element under the applied force <italic>F<sub>z</sub></italic>.</p></caption></figure></p></sec-level3><sec-level3 id="mst354138s4-2-3" label="4.2.3"><heading>Under the applied moment <italic>M<sub>x</sub></italic> (similarly with <italic>M<sub>y</sub></italic>)</heading><p indent="no">Figure <figref linkend="mst354138fig10">10</figref> shows that the normal elastic strain is concentrated at the inner edge of the diaphragm. It reaches a maximum and minimum (853 and −848 µϵ, respectively) at the center of the upper annular diaphragm along the <italic>Y</italic>-axis when subject to the applied torque <italic>M<sub>x</sub></italic> = 600 N mm. The pattern of strain distributions is similar to the situation in which the sensor is under the applied force <italic>F<sub>y</sub></italic>. The same distributed strain map occurs on the lower annular diaphragm because of the same structure and boundary condition. In addition, the maximum deformation (0.0992 mm) occurs at the outer circumference of the upper annular diaphragm along the <italic>Y</italic>-axis.
<figure id="mst354138fig10" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig10.eps" width="36pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig10.jpg"></graphic-file></graphic><caption id="mst354138fc10" label="Figure 10"><p indent="no">The distribution of normal elastic strain and deformation of the force-sensing element under the applied moment <italic>M<sub>x</sub></italic>.</p></caption></figure></p></sec-level3></sec-level2><sec-level2 id="mst354138s4-3" label="4.3"><heading>Dynamic analysis</heading><p indent="no">When subjected to applied loads or displacements, the sensor behaves in a dynamic manner. Consequently, to study these effects a modal analysis via ANSYS® was conducted to confirm that the sensor behaves well dynamically. Performance characteristics such as vibration tendencies (natural frequencies and mode shapes) are important parameters in the design of a structure for dynamic loading conditions. These were obtained via modal analysis.</p><p>A fixed support to the lower surface of the base frame through which the sensor is connected with manipulators was the boundary condition applied to conduct modal analysis. Within ANSYS, the number of frequencies of interest was specified. These were the first eight natural frequencies (shown in table <tabref linkend="mst354138tab02">2</tabref>), and first eight mode shape illustrations (figure <figref linkend="mst354138fig11">11</figref>) that are helpful in understanding how the sensor vibrates. Based on the analysis mentioned above, the maximum service frequency of the proposed sensor is about <inline-eqn></inline-eqn><italic>f</italic><sub>1</sub> = 1054.1 Hz, which is higher than that for existing F/T sensors and equal to the result calculated from equation (<eqnref linkend="mst354138eqn11">11</eqnref>).
<figure id="mst354138fig11" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig11.eps" width="36pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig11.jpg"></graphic-file></graphic><caption id="mst354138fc11" label="Figure 11"><p indent="no">The first eight mode shapes of the sensor.</p></caption></figure><table id="mst354138tab02" frame="topbot" indent="no"><caption id="mst354138tc02" label="Table 2"><p indent="no">The first eight natural frequencies.</p></caption><tgroup cols="9"><colspec colnum="1" colname="col1" align="left"></colspec><colspec colnum="2" colname="col2" align="left"></colspec><colspec colnum="3" colname="col3" align="left"></colspec><colspec colnum="4" colname="col4" align="left"></colspec><colspec colnum="5" colname="col5" align="left"></colspec><colspec colnum="6" colname="col6" align="left"></colspec><colspec colnum="7" colname="col7" align="left"></colspec><colspec colnum="8" colname="col8" align="left"></colspec><colspec colnum="9" colname="col9" align="left"></colspec><thead><row><entry>Mode</entry><entry>1</entry><entry>2</entry><entry>3</entry><entry>4</entry><entry>5</entry><entry>6</entry><entry>7</entry><entry>8</entry></row></thead><tbody><row><entry>Natural frequency (Hz)</entry><entry>1581.8</entry><entry>1582</entry><entry>2723.3</entry><entry>5427.8</entry><entry>6682.2</entry><entry>6683</entry><entry>9809.2</entry><entry>11 073</entry></row></tbody></tgroup></table></p></sec-level2></sec-level1><sec-level1 id="mst354138s5" label="5"><heading>Sensor fabrication</heading><p indent="no">The sensor was fabricated using the design optimization procedure reported above. Figure <figref linkend="mst354138fig12">12</figref> shows the fabricated prototype of the five-dimensional fingertip force sensor. The whole sensor has a size of Φ 24 mm × 30 mm.
<figure id="mst354138fig12"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig12.eps" width="20.5pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig12.jpg"></graphic-file></graphic><caption id="mst354138fc12" label="Figure 12"><p indent="no">Digital image of the proposed sensor with the amplifying and the data processing circuits.</p></caption></figure></p><p>It is important to bond the strain gauges onto the proper place and with the proper orientation of the force-sensing element. This is always chosen to be the place having the maximum strains and the orientations along the maximum stress planes. This will ensure maximum sensitivity and repeatability. All of the gauges used in this study are <italic>Y</italic> series linear strain gauges (1-LY11-3/120) made by HBM Inc. The measuring grid foil of the gauges is made of constantan and the nominal resistance is 120 Ω.</p><p>Based on the strain and stress analysis mentioned above, the positions conducive for strain gauges to detect strain are the inner ring and the outer ring of the annular diaphragms. Therefore, the inner ring and the external ring are selected to arrange the strain gauges to detect axial strains imposed by loads. On the upper annular diaphragm (as shown in figure <figref linkend="mst354138fig13">13</figref>), the strain gauges <italic>R</italic><sub>11</sub>, <italic>R</italic><sub>12</sub>, <italic>R</italic><sub>13</sub>, <italic>R</italic><sub>14</sub> are arranged along the radial direction (<italic>Y</italic>-axis) as group <italic>X</italic><sub>1</sub> to detect the torque <italic>M<sub>x</sub></italic> about the <italic>X</italic>-axis; the strain gauges <italic>R</italic><sub>21</sub>, <italic>R</italic><sub>22</sub>, <italic>R</italic><sub>23</sub>, <italic>R</italic><sub>24</sub> are arranged along the radial direction (<italic>X</italic>-axis) perpendicular to group <italic>X</italic><sub>1</sub> as group <italic>Y</italic><sub>1</sub> to detect the torque <italic>M<sub>y</sub></italic> about the <italic>Y</italic>-axis. On the lower annular diaphragm (as shown in figure <figref linkend="mst354138fig13">13</figref>), the strain gauges <italic>R</italic><sub>31</sub>, <italic>R</italic><sub>32</sub>, <italic>R</italic><sub>33</sub>, <italic>R</italic><sub>34</sub> are arranged along the radial direction (<italic>X</italic>-axis) as group <italic>X</italic><sub>2</sub> to detect the force <italic>F<sub>x</sub></italic> along the <italic>X</italic>-axis; <italic>R</italic><sub>41</sub>, <italic>R</italic><sub>42</sub>, <italic>R</italic><sub>43</sub>, <italic>R</italic><sub>44</sub> are arranged along the radial direction (<italic>Y</italic>-axis) as group <italic>Y</italic><sub>2</sub> to detect the force <italic>F<sub>y</sub></italic> along the <italic>Y</italic>-axis; <italic>R</italic><sub>51</sub>, <italic>R</italic><sub>52</sub>, <italic>R</italic><sub>53</sub>, <italic>R</italic><sub>54</sub> are arranged along the radial direction (45° to the group <italic>X</italic><sub>2</sub>) as group <italic>Z</italic><sub>2</sub> to detect the normal force <italic>F<sub>z</sub></italic>.
<figure id="mst354138fig13"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig13.eps" width="20.5pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig13.jpg"></graphic-file></graphic><caption id="mst354138fc13" label="Figure 13"><p indent="no">Strain gauge arrangement on the upper (left) and lower (right) annular diaphragms.</p></caption></figure></p><p>In order to convert the change in resistance due to strain to a voltage that is proportional to the strain, the Wheatstone bridge is used since it has performances such as high sensitivity, wide measurement range, simple circuit and high precision. According to the arrangement scheme of strain gauges, the Wheatstone bridge connection mode of the sensor is determined as shown in figure <figref linkend="mst354138fig14">14</figref>. The four groups of strain gauges are all connected in a full-bridge circuit, in which every bridge arm is a strain gauge.
<figure id="mst354138fig14" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig14.eps" width="26pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig14.jpg"></graphic-file></graphic><caption id="mst354138fc14" label="Figure 14"><p indent="no">Wheatstone bridge connection mode.</p></caption></figure></p><p>When the sensor is subjected to a single force/torque <italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic>, <italic>F<sub>z</sub></italic>, <italic>M<sub>x</sub></italic> and <italic>M<sub>y</sub></italic> respectively, the corresponding output of each bridge is
<eqn-group id="mst354138eqngrp01"><display-eqn id="mst354138eqn12" lines="multiline" eqnnum="12" eqnalign="left"></display-eqn><display-eqn id="mst354138eqn13" lines="multiline" eqnnum="13" eqnalign="left"></display-eqn><display-eqn id="mst354138eqn14" lines="multiline" eqnnum="14" eqnalign="left"></display-eqn><display-eqn id="mst354138eqn15" lines="multiline" eqnnum="15" eqnalign="left"></display-eqn><display-eqn id="mst354138eqn16" lines="multiline" eqnnum="16" eqnalign="left"></display-eqn></eqn-group>where <italic>K</italic> is the sensitivity coefficient of the strain gauges, ϵ<sub><italic>i</italic></sub> is the elastic strain at the spot where <italic>R<sub>i</sub></italic> is bonded on the diaphragms, <italic>U</italic> is the excitation voltage and (Δ<italic>R<sub>i</sub></italic>/<italic>R<sub>i</sub></italic>)<sub>ϵ</sub> refers to the change in the resistance of the strain gauge <italic>R<sub>i</sub></italic> due to strain variation.</p></sec-level1><sec-level1 id="mst354138s6" label="6"><heading>Calibration and decoupling based on NN</heading><p indent="no">All multi-axis force/torque sensors have some degree of cross coupling between components such that a change in the output of the other axes was produced when a force/torque was applied on one axis. In this study, as the elastic body is machined from monolithic blocks of aluminum, there are some inherent cross couplings or cross talk between channels. However the deformation of the elastic body and the measuring circuits is almost linear, and the couplings could be eliminated by decoupling.</p><p>The calibration and decoupling procedure of the sensor was performed on the calibration platform (as shown in figure <figref linkend="mst354138fig15">15</figref>) as follows. The sensor was mounted on the calibration platform and a load cap was fixed on the top of the sensor. Five kinds of forces/torques can be applied to the sensor by weights acting through pulleys and tendons. One end of each tendon was hung with weights while the other end was connected to the load cap. A single component of five forces/torques was applied to the sensor with a series of values within measurement. In the meantime, the output voltages of the sensitive bridge circuits were recorded, where the relationships between the applied loads and the measured values were obtained (the output of the A/D convertor) by the static decoupling method based on NN. This is shown in figure <figref linkend="mst354138fig16">16</figref>. The input vector (<inline-eqn></inline-eqn>) is the output voltages of the sensitive bridge circuits, and the output vector (<inline-eqn></inline-eqn>) is the output forces/torques of the sensor after decoupling. The learning samples are a group of applied forces/torques and the corresponding output voltages of the sensitive bridge circuits in the calibration procedure. After the network training, the weight value (<bold>W</bold> = [<bold>w</bold><sub><italic>ij</italic></sub>] <italic>i</italic>, <italic>j</italic> = 1, 2, …, 5) is taken as a decoupling matrix:
<display-eqn id="mst354138eqn17" eqnnum="17" eqnalign="center"></display-eqn>Comparing formula (<eqnref linkend="mst354138eqn06">6</eqnref>) with formula (<eqnref linkend="mst354138eqn17">17</eqnref>),
<display-eqn id="mst354138eqn18" eqnnum="18" eqnalign="center"></display-eqn>so one can obtain the decoupling matrix by the neural network method (NNM):
<display-eqn id="mst354138eqn19" lines="multiline" eqnnum="19" eqnalign="left"></display-eqn>And the deviation value
<display-eqn id="mst354138eqn20" lines="multiline" eqnnum="20" eqnalign="left"></display-eqn>The experimental results and the output curves of the sensor are shown in figure <figref linkend="mst354138fig17">17</figref>. Here when one component of five forces/torques is calibrated, the others are set at zero.
<figure id="mst354138fig15" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig15.eps" width="31pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig15.jpg"></graphic-file></graphic><caption id="mst354138fc15" label="Figure 15"><p indent="no">Calibration platform (<italic>a</italic>) and its sketch map (<italic>b</italic>).</p></caption></figure><figure id="mst354138fig16"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig16.eps" width="15pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig16.jpg"></graphic-file></graphic><caption id="mst354138fc16" label="Figure 16"><p indent="no">NN model for calibration and decoupling.</p></caption></figure><figure id="mst354138fig17" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig17.eps" width="26pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig17.jpg"></graphic-file></graphic><caption id="mst354138fc17" label="Figure 17"><p indent="no">Static calibration results: (<italic>a</italic>) component <italic>F<sub>x</sub></italic>; (<italic>b</italic>) component <italic>F<sub>y</sub></italic>; (<italic>c</italic>) component <italic>F<sub>z</sub></italic>; (<italic>d</italic>) component <italic>M<sub>x</sub></italic> (similar to <italic>M<sub>y</sub></italic>).</p></caption></figure></p><p>The calibration results indicated that the nonlinearity errors of the <italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic>, <italic>F<sub>z</sub></italic>, <italic>M<sub>x</sub></italic> and <italic>M<sub>y</sub></italic> measurements are 0.1% F.S. 0.1% F.S., 0.11% F.S., 0.14% F.S. and 0.14% F.S., respectively. After zero adjustment, the maximum interference errors of the <italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic>, <italic>F<sub>z</sub></italic>, <italic>M<sub>x</sub></italic> and <italic>M<sub>y</sub></italic> measurements are 1.1% F.S., 1.1% F.S., 1.4% F.S., 1.5% F.S. and 1.5% F.S., respectively. Both the main channel and the coupling channel have good symmetry about the zero point and good linear relations between inputs and outputs. Hence it is confirmed that the developed force sensor is excellent in the maximum error criterion [<cite linkend="mst354138bib13" range="mst354138bib13,mst354138bib14,mst354138bib15,mst354138bib16,mst354138bib17">13–17</cite>].</p><p>As mentioned before, when subjected to applied loads or displacements, the sensor behaves dynamically. Therefore, the dynamic performances such as natural frequency and adjusting time are important criteria when judging the quality of a F/T sensor. In this study, in order to accurately test the dynamic performance of the developed F/T sensor, a dynamic calibration experiment based on the step-response method was performed as follows. At first, the weight was hung to apply a single load to the sensor and the pulley was held to keep the sensor unapplied. When the pulley was released quickly, the weight went into freefall and the load was applied to the sensor very suddenly. This generated a step force or torque. In the meantime, the output of the bridge was recorded by a real-time digital signal processing (DSP)-based data acquisition system. Figure <figref linkend="mst354138fig18">18</figref> shows the calibration results in different directions. The experimental results indicate that the step-response times are about 105 ms for the components <italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic>, <italic>M<sub>x</sub></italic> and <italic>M<sub>y</sub></italic> and 25 ms for the component <italic>F<sub>z</sub></italic>, respectively, which is acceptable for general applications.
<figure id="mst354138fig18" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig18.eps" width="36pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig18.jpg"></graphic-file></graphic><caption id="mst354138fc18" label="Figure 18"><p indent="no">Results of the dynamic calibration experiment: (<italic>a</italic>) component <italic>F<sub>x</sub></italic> (similar to <italic>F<sub>y</sub></italic>); (<italic>b</italic>) component <italic>M<sub>x</sub></italic> (similar to <italic>M<sub>y</sub></italic>); (<italic>c</italic>) component <italic>F<sub>z</sub></italic>.</p></caption></figure></p></sec-level1><sec-level1 id="mst354138s7" label="7"><heading>Dexterous hands based on designed fingertip sensors</heading><p indent="no">To evaluate the performance of the developed fingertip F/T sensor, a robot hand featured with the developed sensor has been designed. This is shown in figure <figref linkend="mst354138fig19" override="yes">19(<italic>a</italic>)</figref>. Three developed fingertip F/T sensors were mounted on the fingertips of the three-finger hand to detect contact and F/T information in real time. Through intelligent combination with other sensors such as vision and ultrasonic sensors, grasp refinement experiments could be conducted under specified control arithmetic. Figure <figref linkend="mst354138fig19" override="yes">19(<italic>b</italic>)</figref> shows the captured GUI when the robot hand performed the grasping of an egg.
<figure id="mst354138fig19" width="page"><graphic><graphic-file version="print" format="EPS" filename="images/mst354138fig19.eps" width="31pc"></graphic-file><graphic-file version="ej" format="JPEG" filename="images/mst354138fig19.jpg"></graphic-file></graphic><caption id="mst354138fc19" label="Figure 19"><p indent="no">A robot hand (<italic>a</italic>) featured with the developed fingertip sensor and its GUI (<italic>b</italic>).</p></caption></figure></p></sec-level1><sec-level1 id="mst354138s8" label="8"><heading>Conclusion</heading><p indent="no">This paper describes the development of a novel miniature robust five-dimensional F/T sensor with a dual annular diaphragm structure which may be used in robotics. The fingertip F/T sensor is designed to simultaneously measure the normal force <italic>F<sub>z</sub></italic>, both tangential force terms <italic>F<sub>x</sub></italic>, <italic>F<sub>y</sub></italic> and the torques <italic>M<sub>x</sub></italic>, <italic>M<sub>y</sub></italic> about the tangential axes. In order to eliminate the coupling among the components, the structure of elastic body for the five-dimensional F/T sensor is newly modeled, analyzed and manufactured. Overload protection based on structure character is proposed. With optimization design, optimal values of the geometric parameters of the elastic body are obtained. A calibration and decoupling experiment based on the NNM reveals that the maximum nonlinearity error and maximum interference error are 0.14% F.S. and 1.5% F.S., respectively. An application of the developed sensor shows that it contains positive characteristics such as high accuracy, strong linearity, weak couplings, and overload protection. To protect the robotic finger and/or the object being held, fingertip sensors should be equipped with synthetic skins, which is one of our future research works [<cite linkend="mst354138bib18" range="mst354138bib18,mst354138bib19,mst354138bib20">18–20</cite>].</p></sec-level1><acknowledgment><heading>Acknowledgments</heading><p indent="no">The authors would like to gratefully acknowledge the financial support from the National 863 Project under grant no 2006AA04Z244 and National Nature Science Foundation of China under grant nos NSFC60874097 and 60910005. The first author gratefully acknowledges the financial support from the China Scholarship Council, Ministry of Education of the PRC. The second author appreciates the financial support from the Canada Research Chairs program.</p></acknowledgment></body><back><references><heading>References</heading><reference-list type="numeric"><journal-ref id="mst354138bib01"><authors><au><second-name>Suwanratchatamanee</second-name><first-names>K</first-names></au><au><second-name>Matsumoto</second-name><first-names>M</first-names></au><au><second-name>Hashimoto</second-name><first-names>S</first-names></au></authors><year>2010</year><art-title>Robotic tactile sensor system and applications</art-title><jnl-title>IEEE Trans. Ind. Electron.</jnl-title><volume>57</volume><pages>1074–87</pages><crossref><cr_doi>http://dx.doi.org/10.1109/TIE.2009.2031195</cr_doi><cr_issn type="print">02780046</cr_issn><cr_issn type="electronic">15579948</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib02"><authors><au><second-name>Muller</second-name><first-names>I</first-names></au><au><second-name>Brito</second-name><first-names>R M</first-names></au><au><second-name>Pereira</second-name><first-names>C E</first-names></au><au><second-name>Brusamarello</second-name><first-names>V</first-names></au></authors><year>2010</year><art-title>Load cells in force sensing analysis—theory and a novel application</art-title><jnl-title>IEEE Instrum. Meas. Mag.</jnl-title><volume>13</volume><pages>15–9</pages><crossref><cr_doi>http://dx.doi.org/10.1109/MIM.2010.5399212</cr_doi><cr_issn type="print">10946969</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib03"><authors><au><second-name>Kaneko</second-name><first-names>M</first-names></au></authors><year>1996</year><art-title>Twin-head six-axis force sensors</art-title><jnl-title>IEEE Trans. Robot. Autom.</jnl-title><volume>12</volume><pages>146–54</pages><crossref><cr_doi>http://dx.doi.org/10.1109/70.481760</cr_doi><cr_issn type="print">1042296X</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib04"><authors><au><second-name>Stampfer</second-name><first-names>C</first-names></au><au><second-name>Jungen</second-name><first-names>A</first-names></au><au><second-name>Hierold</second-name><first-names>C</first-names></au></authors><year>2006</year><art-title>Fabrication of discrete nanoscaled force sensors based on single-walled carbon nanotubes</art-title><jnl-title>IEEE Sensors J.</jnl-title><volume>6</volume><pages>613–7</pages><crossref><cr_doi>http://dx.doi.org/10.1109/JSEN.2006.874490</cr_doi><cr_issn type="print">1530437X</cr_issn><cr_issn type="electronic">15581748</cr_issn></crossref></journal-ref><conf-ref id="mst354138bib05"><authors><au><second-name>Wang</second-name><first-names>J</first-names></au><au><second-name>Kondo</second-name><first-names>H</first-names></au><au><second-name>Guo</second-name><first-names>J</first-names></au><au><second-name>Guo</second-name><first-names>S</first-names></au><au><second-name>Tamiya</second-name><first-names>T</first-names></au></authors><year>2007</year><art-title>A force sensors-based catheter operating system</art-title><conf-title>Int. Conf. on Mechatronics and Automation 2007—ICMA 2007 (5–8 August 2007)</conf-title><pages>pp 1044–9</pages></conf-ref><conf-ref id="mst354138bib06"><authors><au><second-name>Bernstein</second-name><first-names>N L</first-names></au><au><second-name>Lawrence</second-name><first-names>D A</first-names></au><au><second-name>Pao</second-name><first-names>L Y</first-names></au></authors><year>2006</year><art-title>Sensor modeling in parallel force feedback haptic interfaces</art-title><conf-title>14th Symp. on Haptic Interfaces for Virtual Environment and Teleoperator Systems (25–26 March 2006)</conf-title><pages>pp 177–83</pages></conf-ref><journal-ref id="mst354138bib07"><authors><au><second-name>Bicchi</second-name><first-names>A</first-names></au><au><second-name>Salisbury</second-name><first-names>J K</first-names></au><au><second-name>Brock</second-name><first-names>D L</first-names></au></authors><year>1993</year><art-title>Contact sensing from force measurements</art-title><jnl-title>Int. J. Robot. Res.</jnl-title><volume>12</volume><pages>249–62</pages><crossref><cr_doi>http://dx.doi.org/10.1177/027836499301200304</cr_doi><cr_issn type="print">02783649</cr_issn><cr_issn type="electronic">00000000</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib08"><authors><au><second-name>Howe</second-name><first-names>R D</first-names></au></authors><year>1994</year><art-title>Tactile sensing and control of robotic manipulation</art-title><jnl-title>J. Adv. Robot.</jnl-title><volume>8</volume><pages>245–61</pages></journal-ref><conf-ref id="mst354138bib09"><authors><au><second-name>Maekawa</second-name><first-names>H</first-names></au><au><second-name>Tanie</second-name><first-names>K</first-names></au><au><second-name>Komoriya</second-name><first-names>K</first-names></au></authors><year>1995</year><art-title>Tactile sensor based manipulation of an unknown object by a multifingered hand with rolling contact</art-title><conf-title>Proc. IEEE Int. Conf. on Robotics and Automation</conf-title><conf-place>Nagoya, Aichi, Japan, May 1995</conf-place><pages>pp 743–50</pages></conf-ref><conf-ref id="mst354138bib10"><authors><au><second-name>Edin</second-name><first-names>B B</first-names></au><au><second-name>Ascari</second-name><first-names>L</first-names></au><au><second-name>Beccai</second-name><first-names>L</first-names></au><au><second-name>Roccella</second-name><first-names>S</first-names></au><au><second-name>Cabibihan</second-name><first-names>J-J</first-names></au><au><second-name>Carrozza</second-name><first-names>M C</first-names></au></authors><year>2006</year><art-title>Bio-inspired approach for the design and characterization of a tactile sensory system for a cybernetic prosthetic hand</art-title><conf-title>Proc. IEEE Int. Conf. on Robotics and Automation</conf-title><conf-place>Orlando, FL, USA, May 2006</conf-place><pages>pp 1354–8</pages></conf-ref><journal-ref id="mst354138bib11"><authors><au><second-name>Edin</second-name><first-names>B B</first-names></au><au><second-name>Ascari</second-name><first-names>L</first-names></au><au><second-name>Beccai</second-name><first-names>L</first-names></au><au><second-name>Roccella</second-name><first-names>S</first-names></au><au><second-name>Cabibihan</second-name><first-names>J-J</first-names></au><au><second-name>Carrozza</second-name><first-names>M C</first-names></au></authors><year>2008</year><art-title>Bio-inspired sensorization of a biomechatronic robot hand for the grasp-and-lift task</art-title><jnl-title>Brain Res. Bull.</jnl-title><volume>75</volume><pages>pp 785–95</pages><crossref><cr_doi>http://dx.doi.org/10.1016/j.brainresbull.2008.01.017</cr_doi><cr_issn type="print">03619230</cr_issn></crossref></journal-ref><book-ref id="mst354138bib12"><authors><au><second-name>Boyes</second-name><first-names>W</first-names></au></authors><year>2009</year><book-title>Instrumentation Reference Book</book-title><edition>3rd edn</edition><publication><place>Amsterdam</place><publisher>Elsevier</publisher></publication></book-ref><journal-ref id="mst354138bib13"><authors><au><second-name>Park</second-name><first-names>J-J</first-names></au><au><second-name>Kim</second-name><first-names>G-S</first-names></au></authors><year>2005</year><art-title>Development of the 6-axis force/moment sensor for an intelligent robot's gripper</art-title><jnl-title>Sensors Actuators</jnl-title><part>A</part><volume>118</volume><pages>127–34</pages><crossref><cr_doi>http://dx.doi.org/10.1016/S0924-4247(04)00538-2</cr_doi><cr_issn type="print">09244247</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib14"><authors><au><second-name>Liu</second-name><first-names>S A</first-names></au><au><second-name>Tzo</second-name><first-names>Hung L</first-names></au></authors><year>2002</year><art-title>A novel six-component force sensor of good measurement isotropy and sensitivities</art-title><jnl-title>Sensors Actuators</jnl-title><part>A</part><volume>100</volume><pages>223–30</pages><crossref><cr_doi>http://dx.doi.org/10.1016/S0924-4247(02)00135-8</cr_doi><cr_issn type="print">09244247</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib15"><authors><au><second-name>Kim</second-name><first-names>G-S</first-names></au></authors><year>2007</year><art-title>Development of a three-axis gripper force sensor and the intelligent gripper using it</art-title><jnl-title>Sensors Actuators</jnl-title><part>A</part><volume>137</volume><pages>213–22</pages></journal-ref><journal-ref id="mst354138bib16"><authors><au><second-name>Kim</second-name><first-names>G-S</first-names></au><au><second-name>Lee</second-name><first-names>H-D</first-names></au></authors><year>2003</year><art-title>Development of 6-axis force/moment sensor and its control system for an intelligent robot's gripper</art-title><jnl-title>Meas. Sci. Technol.</jnl-title><volume>14</volume><pages>1265–74</pages></journal-ref><journal-ref id="mst354138bib17"><authors><au><second-name>Kim</second-name><first-names>G-S</first-names></au></authors><year>2000</year><art-title>The development of a six-component force/moment sensor testing machine and evaluation of its uncertainty</art-title><jnl-title>Meas. Sci. Technol.</jnl-title><volume>11</volume><pages>1377–82</pages><crossref><cr_doi>http://dx.doi.org/10.1088/0957-0233/11/9/318</cr_doi><cr_issn type="print">09570233</cr_issn><cr_issn type="electronic">13616501</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib18"><authors><au><second-name>Shimoga</second-name><first-names>K B</first-names></au><au><second-name>Goldenberg</second-name><first-names>A A</first-names></au></authors><year>1996</year><art-title>Soft robotic fingertips: part 1. A comparison of construction materials</art-title><jnl-title>Int. J. Robot. Res.</jnl-title><volume>15</volume><pages>320–34</pages></journal-ref><journal-ref id="mst354138bib19"><authors><au><second-name>Cabibihan</second-name><first-names>J J</first-names></au><au><second-name>Pattofatto</second-name><first-names>S</first-names></au><au><second-name>Jomaa</second-name><first-names>M</first-names></au><au><second-name>Benallal</second-name><first-names>A</first-names></au><au><second-name>Carrozza</second-name><first-names>M C</first-names></au></authors><year>2009</year><art-title>Towards humanlike social touch for sociable robotics and prosthetics: comparisons on the compliance, conformance and hysteresis of synthetic and human fingertip skins</art-title><jnl-title>Int. J. Soc. Robot.</jnl-title><volume>1</volume><pages>29–40</pages><crossref><cr_doi>http://dx.doi.org/10.1007/s12369-008-0008-9</cr_doi><cr_issn type="print">18754791</cr_issn><cr_issn type="electronic">18754805</cr_issn></crossref></journal-ref><journal-ref id="mst354138bib20"><authors><au><second-name>Shimojo</second-name><first-names>M</first-names></au></authors><year>1997</year><art-title>Mechanical filtering effect of elastic cover for tactile sensor</art-title><jnl-title>IEEE Trans. Robot. Autom.</jnl-title><volume>13</volume><pages>128–32</pages><crossref><cr_doi>http://dx.doi.org/10.1109/70.554353</cr_doi><cr_issn type="print">1042296X</cr_issn></crossref></journal-ref></reference-list></references></back></article></istex:document></istex:metadataXml><mods version="3.6"><titleInfo><title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</title></titleInfo><titleInfo type="abbreviated"><title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</title></titleInfo><titleInfo type="alternative"><title>Miniature robust five-dimensional fingertip force/torque sensor with high performance</title></titleInfo><name type="personal"><namePart type="given">Qiaokang</namePart><namePart type="family">Liang</namePart><affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</affiliation><affiliation>E-mail:qiaokangustc@gmail.com</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Dan</namePart><namePart type="family">Zhang</namePart><affiliation>Canada Research Chair Laboratory of Robotics and Automation, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4, Canada</affiliation><affiliation>E-mail:Dan.Zhang@uoit.ca</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Yunjian</namePart><namePart type="family">Ge</namePart><affiliation>State Key Laboratories of Robot Sensing Systems, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Xiuxiang</namePart><namePart type="family">Huang</namePart><affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Zhongyang</namePart><namePart type="family">Li</namePart><affiliation>College of Polytechnic, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="research-article" displayLabel="paper"></genre><originInfo><publisher>IOP Publishing</publisher><dateIssued encoding="w3cdtf">2011</dateIssued><copyrightDate encoding="w3cdtf">2011</copyrightDate></originInfo><language><languageTerm type="code" authority="iso639-2b">eng</languageTerm><languageTerm type="code" authority="rfc3066">en</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType><note type="production">Printed in the UK & the USA</note></physicalDescription><abstract>This paper proposes an innovative design and investigation for a five-dimensional fingertip force/torque sensor with a dual annular diaphragm. This sensor can be applied to a robot hand to measure forces along the X-, Y- and Z-axes (Fx, Fy and Fz) and moments about the X- and Y-axes (Mx and My) simultaneously. Particularly, the details of the sensing principle, the structural design and the overload protection mechanism are presented. Afterward, based on the design of experiments approach provided by the software ANSYS, a finite element analysis and an optimization design are performed. These are performed with the objective of achieving both high sensitivity and stiffness of the sensor. Furthermore, static and dynamic calibrations based on the neural network method are carried out. Finally, an application of the developed sensor on a dexterous robot hand is demonstrated. The results of calibration experiments and the application show that the developed sensor possesses high performance and robustness.</abstract><subject><genre>keywords</genre><topic>force/torque sensor</topic><topic>fingertip sensor</topic><topic>robot hand</topic><topic>overload protection</topic><topic>design of experiments</topic><topic>neural network method</topic></subject><relatedItem type="host"><titleInfo><title>Measurement Science and Technology</title></titleInfo><titleInfo type="abbreviated"><title>Meas. Sci. Technol.</title></titleInfo><genre type="journal">journal</genre><identifier type="ISSN">0957-0233</identifier><identifier type="eISSN">1361-6501</identifier><identifier type="PublisherID">MST</identifier><identifier type="CODEN">MSTCEP</identifier><identifier type="URL">stacks.iop.org/MST</identifier><part><date>2011</date><detail type="volume"><caption>vol.</caption><number>22</number></detail><detail type="issue"><caption>no.</caption><number>3</number></detail><extent unit="pages"><start>1</start><end>11</end><total>11</total></extent></part></relatedItem><identifier type="istex">1D562E80D4A48E06E4929293F5717A324B0772D4</identifier><identifier type="DOI">10.1088/0957-0233/22/3/035205</identifier><identifier type="PII">S0957-0233(11)54138-9</identifier><identifier type="articleID">354138</identifier><identifier type="articleNumber">035205</identifier><accessCondition type="use and reproduction" contentType="copyright">2011 IOP Publishing Ltd</accessCondition><recordInfo><recordContentSource>IOP</recordContentSource><recordOrigin>2011 IOP Publishing Ltd</recordOrigin></recordInfo></mods></metadata><serie></serie></istex></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Ticri/CIDE/explor/HapticV1/Data/Istex/Corpus
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 003629 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Istex/Corpus/biblio.hfd -nk 003629 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Ticri/CIDE
|area= HapticV1
|flux= Istex
|étape= Corpus
|type= RBID
|clé= ISTEX:1D562E80D4A48E06E4929293F5717A324B0772D4
|texte= Miniature robust five-dimensional fingertip force/torque sensor with high performance
}}
| This area was generated with Dilib version V0.6.23. |  |