GW40型钢筋弯曲机的结构设计与运动分析【16张CAD图纸+PDF图】
收藏
资源目录
压缩包内文档预览：
编号：118713491
类型：共享资源
大小：6.79MB
格式：ZIP
上传时间：2021-03-24
上传人：好资料QQ****51605
认证信息
个人认证
孙**（实名认证）
江苏
IP属地：江苏
45
积分
- 关 键 词：
-
GW40
型钢
弯曲
结构设计
运动
分析
16
CAD
图纸
PDF
- 资源描述：
-
喜欢这套资料就充值下载吧。。。资源目录里展示的都可在线预览哦。。。下载后都有，，请放心下载，，文件全都包含在内，，【有疑问咨询QQ:414951605 或 1304139763】
- 内容简介：
-
Study of ultra-miniature giant magneto resistance sensor systembased on 3D static magnetic analysis techniqueT. Lana, Y.W. Liua, M.H. Jina, S.W. Fana, Z.P. Chena, H. Liua,b,*aState Key Laboratory of Robotics and System (HIT), Harbin, PR ChinabInstitute of Robotics and System Dynamics, German Aerospace Center, Germanya r t i c l ei n f oArticle history:Received 27 November 2008Accepted 3 March 2009Available online 12 March 2009Keywords:Magnetic sensorFinite element techniques3D static magnetic analysisGMR sensorMEMSa b s t r a c tIn this study, a method for the modeling of ferromagnetic component of an ultra-miniaturegiant magneto resistance (GMR) sensor system is presented. The goal of the modeling is todesign appropriate angular sensor system for the highly integrated DLR/HIT II 5-finger dex-terous robot hand. A 3D static magnetic analysis modeling is used to avoid sensor damageby the excessive magnetic intensity and disorientation when other magnetic fields disturbthe primary field. Using the finite element results, appropriate shape and size of ferromag-netic component is compared and optimized. A simplified signal processing circuit is alsogiven for the ultra-miniature GMR sensor system. Finally experimental results show anangular accuracy of less than ?1?with only the residual offset compensation of ultra-min-iature GMR sensor system is obtained. Integration experiences reveal the challenges asso-ciated with obtaining the required capabilities within the desired size.? 2009 Elsevier Ltd. All rights reserved.1. IntroductionIn general, further system miniaturization will certainlycreate demands for a continuous down-scaling of sensorfunctions in a variety of different application fields 1.When developing sensors for measuring angular signal inminiature systems, it becomes obvious that the basic sen-sor has many limitations and imperfections (e.g. size,working distance, accuracy and offset) which prevent thedesigner from achieving the required specifications. To im-prove the basic sensor performance, one option is to tryand refine the sensor itself using better materials, produc-tion methods, etc. This choice is generally an expensiveone. Another option is to incorporate the sensor into a sys-tem which has the unique objective of improving the basicsensor performance. And one important trend in sensor re-search has been into the area of sensor systems 2.Accordingly, further scaling of sensor systems, is manda-tory for all applications where ultra-miniature size enablesthe integration of MEMS and other highly integratedsystems.As a magnetic field sensor, GMR sensor offers severalkey advantages (e.g. high sensitivity, miniature size, con-tactless install and wear-free work) over other kinds ofsensors 3,4. However, magnetic field sensor systems fordemanding applications inevitably contain ferromagneticparts 5. These ferromagnetic components are currentlyused as a part of the sensor itself, like in GMR sensor.The structure of such sensor systems is rather complex,rendering difficult their integration: in the case of GMRsensors, the issues include the mounting of the ferromag-netic component in limited assembly space, and the work-ing distance between ferromagnetic component and GMRsensor chip surface, which is usually 1.5 mm or more 68. Note that if the working distance is smaller, the mag-netic intensity generated by the ferromagnetic componentis usually so strong that it can upset its pinned layer, thuspermanently damaging the sensor element. Furthermore,the GMR sensor bridge in fact converts any field directionto two component signals, independent of their source0263-2241/$ - see front matter ? 2009 Elsevier Ltd. All rights reserved.doi:10.1016/j.measurement.2009.03.002* Corresponding author. Address: State Key Laboratory of Robotics andSystem (HIT), Harbin, PR China. Tel.: +86 451 864 120 42; fax: +86 451864 183 06.E-mail addresses: (T. Lan), Hong.liudlr.de (H.Liu).Measurement 42 (2009) 10111016Contents lists available at ScienceDirectMeasurementjournal homepage: /locate/measurement9. When a second magnetic field is add to the primaryfield, the resulting field is a superposed sum of both fieldsand it may lead to severe disorientation of the angularmeasurement. These two constraints obstruct the applica-tion of GMR sensor in highly integrated field.In this study, the ultra-miniature GMR sensor systemwith only 0.5 mm working distance is developed, and thedisorientation by other magnetic field is avoided and com-pensated also based on 3D static magnetic analysis tech-nique. This paper firstly introduces the concept of GMRsensor and finite element modeling. Secondly, the shapeand size of ferromagnetic component are compared andoptimized by using the 3D static magnetic analysis results.Then a simplified signal processing circuit is also given. Fi-nally the experimental results obtained with the developedmethod are compared with theoretical results.2. GMR sensor conceptGiant magneto resistance means the very large changein resistance in ultra-thin magnetic multilayer films. Thebasic GMR material construction includes a pinned layerand a free layer; the free layer can be influenced by anexternal magnetic field. An applied magnetic field of ade-quate magnitude, in the range greater than the saturationfield for the free layer and smaller than the standoff fieldfor the pinned layer, will force the free layer magnetizationto follow the field when it rotates. With a fixed referencelayer magnetization, and an in-step following of the freelayer magnetization, magneto resistance is a simple cosinefunction of the angle of the rotor relative to the stationarysensor. And the resistance R of a spin valve is related to theangle h between the free and the pinned layer magnetiza-tions in the following equationR=Rp 1 1=2GMR1 ? cosh1where the Rp is the lowest resistance when the two mag-netizations are parallel, and the GMR is the maximum per-centage magneto resistance.The angle sensor is used in combination with a planarpermanent magnet attached to a live shaft (rotor), asshown in Fig. 1. The permanent magnet is magnetized in-plan thus creating a field that is in the plane of the sensorchip and rotating with the shaft. This field forces the freelayer magnetization to rotate in phase with it and the ro-tor. Therefore the output signal is a sinusoidal function ofthe angle. With the permanent magnet, sensor design,and their axial configuration the same, the distance be-tween the magnet and the sensor, or working distance,determines the magnitude and distribution of the mag-netic field acting on the free layer of the SV resistors. Thebasic requirement for the working distance is that the low-est field acting on the free layer is large enough to saturateit, and the highest field does not distort the reference layer7.3. Finite element modeling (FEM)The method of finite element modeling is based on adiscretization of the solution domain into small regions.The program uses Maxwells equations as the basis forelectromagnetic field analysis. In magneto static problems,the unknown quantity (degree of freedom) is usually themagnetic vector potential, and is approximated by meansof polynomial shape functions. Other magnetic field quan-tities such as magnetic field flux density, magnetic inten-sity, current density, energy, forces, loss, inductance, andcapacitance are derived from the degree of freedom 10.The size of elements must be small enough to provide suf-ficient accuracy 11. In this way, the differential equationsof the continuous problem can be transformed into a sys-tem of algebraic equations for the discrete problem. Thepractical problems necessitate usually several thousandsof unknowns. However, appropriate numerical techniqueshave been developed, enabling to obtain the solution ofsuch systems within reasonable time, even when personalcomputers are used.As a highly integrated electromechanical system, robothand needs to complete complex tasks, like fine manipula-tion, it is often necessary to get enough accurate angularsignals to implement some control strategy 12. Thereforeangular sensor plays as a very important role in the sensorsystem and its signal accuracy affects control effect di-rectly. With high sensitivity and miniature size, GMR sen-sor is very appropriate for highly integrated system, likeDLR/HIT II 5-finger dexterous robot hand.As above stated, in spite of the benefits which GMR sen-sor has, there are still some imperfections in highly inte-grated application. Because in highly integrated system, itdoes not have enough space to install the sensor and per-manent magnet, then the sensor system should be de-signed to make the best use of the limited space. Forexample, in the DLR/HIT II dexterous robot hand, the dis-tance between shaft end and GMR sensor chip surface isonly 0.5 mm (as shown in Fig. 2). By the limitation of ma-chine structure, there are two types of permanent magnetcan be embedded into the shaft end. One is cylinder, theother is cube. In order to ensure enough strength and avoidinterference, the diameter of the cylinder permanent mag-net should be less than or equal to 2.5 mm, the length ofthe cube permanent magnet should be less than or equalto 6 mm, and both the thickness should be less than orequal to 1 mm. Face the problems of the limited spaceFig. 1. Schematic of an angle sensor-permanent magnet rotor 7.1012T. Lan et al./Measurement 42 (2009) 10111016and the demand of precise angular signals, and considercost and time of sensor development, it is unaccepted thatfirst manufacture permanent magnet and then measure itby measuring apparatus. Therefore, we present a validmethod that uses 3D static magnetic analysis techniquefor designing the type of the permanent magnet to guaran-tee appropriate direction and magnitude of the magneticfield.In order to reject disturbance of magnetic field, the liveshaft is made of non-magnetic stainless steel material.Then the model can be simplified and only the permanentmagnet is analyzed, so the burden of analysis calculation islightened greatly. The permanent magnets analyzed in thispaper are made of NdFeB35 material and have remanenceequal to 1.2340 T and coercive force equal to 11339 A/m.The 3D finite element analysis model of a cylinder perma-nent magnet and a cube permanent magnet are builtrespectively, and their spatial magnetization vector distri-butions are also shown. Fig. 3(a) shows a spatial magneti-zationvectordistributionsgeneratedbyacylinderpermanent magnet U2:5 ? 1 mm, and Fig. 3(b) repre-sents a spatial magnetization vector distributions gener-ated by a cube permanent magnet 6 ? 2 ? 1 mm. Fromthe figure, it can be seen that the magnetization vectorsgenerated by the cube permanent magnet are more planarthan those of the cylinder permanent magnet. It is becausethe length of the cube permanent magnet is bigger thanthe cylinder permanent magnet. Whereas GMR sensor chipis only sensitive in the parallel plane of the chip, ratherthan orthogonally to the chip, so the cube permanent mag-net is better than the cylinder permanent magnet for appli-cation of GMR sensor in this paper.However, GMR materials not only require the directionof magnetization vector, but also need the magnitude ofmagnetic intensity in its working range to avoid the sensorelement damage and signal distortion. Therefore the distri-bution of the magnetic intensity in the limited space ismust be achieved. Fortunately, 3D static magnetic analysistechnology can make these problems easy to be solved.With the help of 3D FEM software, we acquire 3D magneticfield distribution of different permanent magnet type (Figs.4 and 5). From the date sheet of GMR sensor chip, we knowthe working range absolute values are from 2388 A/m to15,920 A/m, namely B and C in Figs. 4 and 5. It means thatthe GMR sensor chip must be in domain between B and C.Fig. 4 shows a spatial distribution of magnetic intensitymagnitude (capped plane along X = 0 mm and Z = 1 mm)generated by a cube permanent magnet which size isFig. 2. Application of the GMR sensor in 5-finger dexterous robot hand.Fig. 3. A spatial magnetization vector distributions generated by (a) cylinder permanent magnet U2:5 ? 1 mm, (b) cube permanent magnet6 ? 2 ? 1 mm.T. Lan et al./Measurement 42 (2009) 1011101610136 ? 2 ? 1 mm. From the figure, it can be seen that most ofthe GMR sensor chip are in domain between A and B thatexceed the working range. Therefore the GMR sensor chipis unable to work normally, and we must find a way tomake the GMR sensor chip in its working range, i.e. inthe domain between B and C.It is well known that the magnitude of magnetic inten-sity can be diminished by dwindling the width and thick-ness of permanent magnet. Based on the 3D staticmagnetic analysis technique, the size can be dwindled stepby step to achieve the adequate magnitude of magneticintensity rather than first manufacture different sizes ofpermanent magnets and then measure them. Finally, theright size of the permanent magnet is acquired (as shownin Fig. 5). From the figure, it can be seen that the wholebody of the GMR sensor chip is in domain between B andC. Therefore the size (6 ? 1 ? 0:5 mm is the right one thatcan generate adequate magnitude of magnetic intensity.Additionally, the simulation results can be used to putother permanent magnet outside the working domain toavoid disorientation. And it also can be used to compensatedeviation in the succeeding digital processing.4. Signal detection and processingThe best way to get a high signal-gain for sensing theGMR resistance change is to build up a Wheatstone bridgeand sensing the differential voltage. In this case two oppo-site reference layer magnetizations are necessary to get thehighest resistance change (Fig. 6). One bridge can measurea 180? angle-range, so it is necessary to build up twoorthogonal bridges to detect angles of 0?360?. In this case,we need four different reference magnetization directionsin total, which define the measurement angle-orientationand turning direction regarding to the chip package.The percent change of resistance available with thisGMR material is about 5%. It means that the amplitude ofoutput signal is too small to content with the demands ofhigh accuracy angle detection. So a pair of analog multipli-ers and four low pass filters of the signal detection circuitare used to extract the amplitude of the signal and itsphase. The advantages of this configuration are simplicity,low component count, low cost, and ultra-miniature size.Take sine signal for example, the first low pass filter hasa capacitor in parallel with the feedback resistor, so the cir-cuit has a 6 dB per octave roll-off after a closed-loop 3 dBpoint defined by Fc 1=2 ?p? R2 ? C1. And output voltagebelow this corner frequency is defined by Eq. (2). The cir-cuit may be considered as an AC integrator at frequencieswell above Fc. However, the time domain response is thatof a single RC rather than an integral. Parallel combinationof R3 and R4 should be chosen equal to parallel combina-tion of the R1 and R2 to minimize errors due to bias cur-rent. The amplifier should be compensated for unity-gainor an internally compensated amplifier can be used.Vsin outR1 R2R3 R4?R4R1? 3:3 ?R2R1? Vsin in2The second filter is a low pass filter formed by R5 and C2,which pretends minimizing the bandwidth of noise andlimiting the valid spectrum in the system. Therefore theFig. 4. A spatial distribution of magnetic intensity magnitude generatedby a cube permanent magnet which size is 6 ? 2 ? 1 mm. (a) Cappedplane along X = 0 mm, (b) capped plane along Z = 1 mm.Fig. 5. A spatial distribution of magnetic intensity magnitude generatedby a cube permanent magnet which size is 6 ? 1 ? 0:5 mm. (a) Cappedplane along X = 0 mm, (b) capped plane along Z = 1 mm.1014T. Lan et al./Measurement 42 (2009) 10111016cut-off frequency for this filter is determined by the poleFrc 1=2 ?p? R5 ? C2.5. Experimental resultsThe ultra-miniature GMR sensor system has beendeveloped using the above explained method, which ful-fills the requirements of angular measurement and inte-grated level for DLR/HIT II 5-finger dexterous robot hand(as shown in Fig. 7).Experiments have been carried out to verify the validityof the model. When a constant voltage is applied to thebridge (as shown in Fig. 6), the output voltage Vsin_inis asine function, and Vcos_inis a cosine function of the anglebetween GMR sensor chip and the live shaft, with a com-mon direct current offset half of the supply voltage+3.3 V. The output signals are captured by a microcontrol-ler and plotted with a 0.5 mm working distance, along withthe theoretical sine and theoretical cosine curves (asshown in Fig. 8). The errors between measured valuesand theoretical values are also shown in Fig. 9. The curvewith circles represents sine error and the curve withsquares is cosine error.The angle is extracted from the measured sine and mea-sured cosine function, with the four quadrant inverse tan-gent function of these two values. The angle is obtainedwithout discontinuity or dead angle over full 360? (asshown in Fig. 10).Absolute non-linearity is defined as the deviation fromthe best linear fit with a unitary slope. ANL is often chosenbecause of the 360? periodicity. The measurement resultfor a 360? rotation magnetic field showed that the ANL er-ror is ?6?without any residual offset compensation. Asshown in Fig. 10, an ANL of second harmonic is observed(dashed curve), and the sources of this type of ANL are gainmismatch and non-orthogonality of the sensor axes. It canbe seen that the ANL repeat periodically. Therefore one cy-cle of the offset errors can be use to compensate the mea-sured signals. After offset compensation, the angular error(solid curve) is less than ?1?, which fulfills the require-ments of angular measurement in DLR/HIT II 5-finger dex-terous robot hand and many other applications.6. ConclusionsBased on 3D static magnetic analysis technique, theultra-miniature GMR sensor system with only 0.5 mmFig. 6. Schematic diagram of the GMR sensors signal detection and processing.Fig. 7. GMR sensor system of DLR/HIT II 5-finger dexterous robot hand.Fig. 8. Output signals of the GMR sensor compared with theoretical sineand cosine curves.T. Lan et al./Measurement 42 (2009) 101110161015working distance is newly developed for highly integratedDLR/HIT II 5-finger dexterous robot hand. Through theexperiment results mentioned above, the output charac-teristics of the GMR sensor system have been obtainedsuch as the measurement range, accuracy, working dis-tance and the repeatability. It also has the qualities of ul-tra-miniature size, simple structure and high reliability,all of which makes up for the shortcomings of traditionalmeasurement sensors, such as bulk, complexity, high cost,strict demand to working environment and assembly diffi-culty. This work also has established a good base for fur-ther study of magnetic sensor for micro sensor systemsof MEMS and highly integrated systems.AcknowledgementsThis project is supported by the National High Technol-ogy Research and Development Program of China (863 Pro-gram) (No. 2006AA04Z255) and Self-Planned Task (NO.SKLR200801A01) of State Key Laboratory of Robotics andSystem (HIT).References1 C. Hierold, C. Stampfer, T. Helbling, et al.
- 温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。
川公网安备: 51019002004831号