An Ultrasensitive Flexible and Bending Sensor for Detecting Angle and Micro-force Yang Chen1,a, Shaofei Guo1,b,Yan Xiong1,c and Lina Hao1,d*

Size: px

Start display at page:

Download "An Ultrasensitive Flexible and Bending Sensor for Detecting Angle and Micro-force Yang Chen1,a, Shaofei Guo1,b,Yan Xiong1,c and Lina Hao1,d*"

Briana Harper
5 years ago
Views:

1 4th Iteratioal Coferece o Sesors, Measuremet ad Itelliget Materials (ICSMIM 205) A Ultrasesitive Flexible ad Bedig Sesor for Detectig Agle ad Micro-force Yag Che,a, Shaofei Guo,b,Ya Xiog,c ad Lia Hao,d* School of Mechaical Egieerig ad Automatio, Northeaster Uiversity, Sheyag, Chia a eucheyag@63.com, b @qq.com, c @qq.com, d haolia@me.eu.edu.c Keywords: Flexible ad bedig sesor, Agle displacemet sesor, Micro-force sesor Abstract. The dexterous robotic had is required to ivestigate the characteristic of ﬁger movemets with perceptio ability of various sesors. A good agle displacemet sesor ca well describe figer motio i robotic had maipulatio tasks. I this paper, a flexible ad bedig sesor which was suitable to be mouted o flexible joit of robotic had was preseted i applicatio of detectig agle displacemet. Desig of coditio circuit was coducted to aalyze the relatioship betwee output voltage ad bedig agle. Calibratio of the sesor results exhibited sigificat lier relatioship, ad the sesitivity of the sesor was 3.68 V/ fuctioed as agle displacemet sesor. I additio, a Load Cells Force/Torque micro-force sesor was employed to calibrate the sesor which could also be used as a micro-force sesor i applicatio of cell micro-maipulatio filed, ad the sesitivity of the sesor was 3.3 mv/mn fuctioed as micro-force sesor. Itroductio I order to make the robot more itelliget ad maipulatig tasks well like huma beigs, most researches had bee doe o the perceptio system of robot ad iteractio with huma beigs ad ustructured eviromet []-[3]. A dexterous prosthesis had is oe of the most vital compoets i robot, ad the perceptio ability of the ed maipulator is a key specificatio for the robot. A well desiged robotic had always has multi-degree of freedom (DOF) like huma had, so we should get the degrees of each figer joits i real time to well uderstad the behavior of maipulatig tasks, ad accordig to the obtaied data from joit sesors, the feedback sigal is geerated by cotrol procedure to form a closed loop. Nowadays a few researchers have paid close attetio to adaptive maipulatio had with flexible joit, so some perceptio sesors o joit degree ad torque have bee discussed deeply. The overview of literatures o this study is as follows. F. Lotti et al [4] proposed the piezoresistive bed sesors i measurig the 2-DOF articulatio of the upper ﬁgers. Because of existece of loss of sesor sesitivity, it could ot measure the lateral bedig ad compressio. A. Cavallo et al [5] measured the positio of flexible joits with optoelectroic sesors, so did Leif P. Jetoft et al [6]. The differece betwee [5] ad [6] is that the former had was sigle-dof ad the latter oe is multi-dof. However the disadvatages of optoelectroic sesors are sigal alteratio ad atteuatio due to bedig or misaligmet. Leif P. Jetoft ad Robert D. Howe [7] proposed a low-cost flexible joit measurig by a Hall-effect sesor for their low drift ad the ease with assemblig o the SDM process, while the sesors will work icorrectly by uexpected magetic field, so the robotic had caot work i a magetic field eviromet. Nazrul Hamizi Ada et al [8]-[9] employed a variable resistace output bed sesor i Data Glove system to acquire the motio iformatio of figer joit. The experimet results well verified the effectiveess of sesors. M. Hazwa Ali et al [0] used carbo resistivity elemet iside thi strip ﬂex sesor whose resistace varied from variatio of the joit degree. I this paper, we used the ultrasesitive hybrid carbo polymer-based piezoresistive (HCP) film which was the same as the sesor i referece [] as a flexible joit sesor. The HCP films performed as a sesitive ad durable 3D micro-force sesor i Luo s work []. However, we iovatively proposed that this sesitive flexible sesor could be mouted o a flexible joit to measure its positio, ad the flexibility of the sesor could make its shape compliace to joit pose cosistetly, ad it was i favor of data acquisitio ad processig i real time The authors - Published by Atlatis Press 32

This paper is orgaized as follows: The secod sectio gives a brief property itroductio of HCP film, desig of a half-bridge coditio circuit to get output voltage of flexible sesor.

2 This paper is orgaized as follows: The secod sectio gives a brief property itroductio of HCP film, desig of a half-bridge coditio circuit to get output voltage of flexible sesor. The third sectio presets the calibratio of flexible sesor which ca be used as both micro-force sesor ad agle displacemet sesor, ad regressio aalysis of data sigificat demostrates effectiveess of the sesor. The last sectio is the summary o the work of this paper. Sesitive Flexible Sesor HCP Film The piezoresistive sesig film presets a cotiuous variable resistace itesified with bedig process. It is ultrasesitive reactio to the perceptio area with legth of 4 mm, width of 2 mm, ad thickess of 0.4 mm because of the carbo polymer material iside etire thi strip with legth of 20 mm, width of 6 mm, ad thickess of 0.4 mm. This flexible sesor is also cost-effective, stailess, durable ad light weight, so it becomes a optimal positio sesor for flexible joit i applicatio of robotic had. I additio, the thermal drift of the flexible sesor is as low as.63% i the temperature rage betwee 22 C ad 75. C []. That is to say, the flexible sesor ca be applied without room temperature eviromet. The flexible sesor employed i our study is show i Fig.. Desig of Coditio Circuit The flexible sesor works as a two-variable-series resistace with bedig motio process. The two variable resistaces are measurable from pi to pi 2 ad from pi 3 to pi 2 respectively. The two variable resistaces should be same i iitial state i theory. However, the ultrasesitive ability of the flexible sesor leads to differece of the two resistaces, ad uecessary bedig also make the resistace values differet. Based o the basic iformatio of the flexible sesor, we have desiged a half-bridge coditio circuit show i Fig. 2 to measure voltage outputs of the flexible sesor. The ullig resistor is used i half-bridge coditio circuit to balace the differet resistaces i the flexible sesor, so that the output voltage is zero. The gai resistace R G of this circuit is a costat value KΩ, ad the the output voltage gai ca be calculated by equatio (). 49.4kΩ G = + () R G Fig. The flexible sesor Fig. 2 The half-bridge coditio circuit Experimets Calibratio of Flexible Sesor Before the flexible sesor ca be applied i a robotic had, deflectio-voltage ad micro-force-voltage calibratio were coducted by a Load Cells Force/Torque micro-force sesor (Measurig rage: 0~0g, resolutio: 5µN), NI-PCI622 DAQ (6 bits ADC, output voltage rage: ±0V) ad 5-DOF micro-positioig platform (X, Y ad Z orietatios: 0μm/step), PC, DC power 33

3 ad some other commo experimetal apparatus. The calibratio experimetal platform is represeted i Fig. 3. Fig. 3 The calibratio experimetal platform I the calibratio, the Load Cells Force/Torque micro-force sesor which was calibrated before with the measure 9.24mN/V is attached to 5-DOF micro-positioig platform, ad the flexible sesor is attached to magetic stad. The tip of flexible sesor perceptio area is perpedicular to the micro-force sesor cotact. The ullig resistor should be adjusted to make output voltage zero. The calibratio begis at above iitial positio, ad makig the micro-force sesor move 20 steps towards the flexible sesor bedig orietatio each time, ad recordig the output voltages of micro-force sesor ad flexible sesor. Regressio Aalysis of Data Regressio Aalysis ca be used to predict relatioship betwee micro-force ad voltage of flexible sesor fuctioed as a micro-force sesor ad betwee step distace ad voltage of flexible sesor fuctioed as a agle displacemet sesor. We utilize the experimet data above, ad it is easy to fid that liear polyomial is suitable to express relatioship betwee tip displacemet ad voltage of flexible sesor show i Fig. 4 ad relatioship betwee tip displacemet ad force of micro-force sesor show i Fig. 5. The curve-fitted equatios (2) ad (3) of Fig. 4 ad 5 are as follows. U = d (2) F = 2.385d (3) Simultaeous equatios (2) ad (3) ca obtai relatioship betwee force ad voltage of flexible sesor, whose expressio is show as equatio (4). F2 = U (4) where d (mm) represets step distace, U (V) represets output voltage of flexible sesor, F (mn) represets force of micro-force sesor ad F 2 (mn) represets force of flexible sesor. So we get sesitivity of this flexible sesor fuctioed as a micro-force sesor (sesitivity: 3.3 mv/mn). However, we wat to use this flexible sesor as a agle displacemet sesor. To make the problem simplificatio, i small deformatio of flexible sesor situatio which is show i Fig. 6, the bedig agle of flexible sesor ca be calculated by equatio (5). 80d θ = (5) π R where R (approximate 25 mm) represets approximate to legth of flexible sesor ad θ ( ) represets bedig agle of flexible sesor. Simultaeous equatios (2) ad (5) ca obtai relatioship betwee agle ad voltage of flexible sesor, whose expressio is show as equatio (6). 34

4 θ =3.57U (6) We ca also get the sesitivity 3.68 V/ of this flexible sesor fuctioed as a agle displacemet sesor. I order to verify the flexible sesor is good eough to fuctio as both micro-force sesor ad agle displacemet sesor, correlatio coefficiets of equatios (2) to (3) eed to be calculated. Correlatio coefficiet ca idicate liearity relatioship betwee idepedet variable ad depedet variable. We get the values of correlatio coefficiet from equatio (7). Where X i represets idepedet variable, Y i represets depedet variable, X represets mea of idepedet variable, Y represets mea of depedet variable ad r 2 represets correlatio coefficiet. r are ad which give a sigificat proof to lier relatioship. ( X X)( Y Y) i i 2 i= = 2 2 ( Xi X) ( Yi Y) i= i= r (7) Fig. 4 Relatioship betwee tip displacemet ad voltage of flexible sesor Fig. 5 Relatioship betwee tip displacemet ad force of micro-force sesor Summary Fig. 6 Schematic diagram of flexible sesor bedig A ultrasesitive flexible ad bedig sesor with the coditio circuit has bee aalysis i detectig agle ad micro-force, which ca well describe a compliat joit agle as a agle displacemet sesor ad detect micro-force i cell ijectio maipulatio. The sesitivity of the sesor fuctioed as detectig agle displacemet is 3.68 V/, ad the sesitivity of the sesor fuctioed as detectig agle displacemet was 3.3 mv/mn. Because of the ultrasesitive static characteristics, this piezoresistive sesig film ca be employed i may other fields. Ackowledgemets This work was particularly sposored by the Natioal High Techology Research ad Developmet Program of Chia (863 Program) uder Grat No. 205AA042302, the Equipmet Pre-Research Program of Chia uder Grat No , the Natioal Natural Sciece Foudatio of Chia uder Grat No ad the Uiversity Iovatio Team of Liaoig Provice (LT204006). 35

5 The authors also thak sicerely the reviewers ad editors for their very pertiet remarks that helped this article become clearer ad more precise. Refereces [] M. Beetz, F. Balit-Beczedi, N. Blodow, D. Nyga, T. Wiedemeyer ad Z. C. Marto. RoboSherlock: Ustructured Iformatio Processig for Robot Perceptio. I: IEEE Iteratioal Coferece o Robotics ad Automatio (ICRA), Seattle, Washigto, USA [2] K. Ramirez-Amaro, M. Beetz, G. Cheg. Uderstadig the itetio of huma activities through sematic perceptio: observatio, uderstadig ad executio o a humaoid robot. Advaced Robotics, 205, 29(5): [3] S. B. Schorr, F. Q. Zha, W. R. Provacher, A. M. Okamura. Eviromet Perceptio i the Presece of Kiesthetic or Tactile Guidace Virtual Fixtures, I: Proceedigs of the Teth Aual ACM/IEEE Iteratioal Coferece o Huma-Robot Iteractio. ACM New,York, NY, USA, 205, [4] F. Lotti, P. Tiezzi, G. Vassura, L. Biagiotti, G. Palli ad C. Melchiorri. Developmet of UB had 3: Early results, I: Proceedigs of the 2005 IEEE Iteratioal Coferece o Robotics ad Automatio, Barceloa, 2005, [5] A. Cavallo, G. De Maria, C. Natale, S. Pirozzi. Optoelectroic joit agle sesor for robotic figers. Sesors ad Actuators A: Physical, 2009, 52(2): [6] L. P. Jetoft, A. M. Dollar, C. R. Wager, R. D. Howe. Itrisic Embedded Sesors for Polymeric Mechatroics: Flexible ad Force Sesig. Sesors, 204, 4(3): [7] L. P. Jetoft, R. D. Howe. Compliat figers make simple sesors smart, Proceedigs of the 200 IFToMM/ASME Workshop o Uderactuated Graspig (UG200), Motreal, Caada. 200, 9. [8] N. H. Ada, K. Wa, A. B. Shahrima, S. K. Zaaba ad H. Desa. The Developmet of a Low Cost Data Glove by Usig Flexible Bed Sesor for Resistive Iterfaces, I: The 2d Iteratioal Malaysia-Irelad Joit Symposium o Egieerig, Sciece ad Busiess. 202, [9] N. H. Ada, K. Wa, A. B. Shahrima, et al. Measuremet of the flexible bedig force of the idex ad middle figers for virtual iteractio, Procedia Egieerig, 202, 4, [0] M. H. Ali, K. Wa, Y. C. Seah, N. H. Ada, J. A. Bakar. Aalysis of Figer Movemet for Robotic Had (MAPRoh-) by Usig Motio Capture ad Flexible Bed Sesor, The 8th Iteratioal Coferece o Robotic, Visio, Sigal Processig & Power Applicatios. Spriger Sigapore, 204, [] Y. Luo, Y. She, N. Moha, Durable ad cost-effective 3-D microforce sesor for musical tuig ehaced micro palpatio of biological etities, SENSORS, 203 IEEE. IEEE, 203,

Experimental Noise Analysis of Reed Switch Sensor Signal under Environmental Vibration

Experimental Noise Analysis of Reed Switch Sensor Signal under Environmental Vibration Computer Techology ad Applicatio 7 (16) 96-1 doi: 1.1765/1934-733/16..4 D DAVID PUBLISHING Experimetal Noise Aalysis of Reed Switch Sesor Sigal uder Evirometal Vibratio Odgerel Ayurzaa 1 ad Hiesik Kim