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锤片式饲料粉碎机的设计,锤片式,饲料,粉碎机,设计
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基于摩擦车道的高分辨率和大行程微进给机构摘要根据摩擦传动原理，设计了一个有很长冲程距离和高分辨率行走的微型送料置，这个装置由压电陶瓷元件驱动，并与螺旋轴和空气静压导轨结合起来。通过灵活的四连杆设计了可调预压装置。进行了灵活的联动装置的静态特性分析与有限元分析。微进给装置的传输特点是彻底分析。关键词：摩擦驱动器，压电驱动器，柔性铰链，有限元1. 引言非球面光学系统已被广泛用于诸如航空，航天产业，国防等。然而，大型面的非球面光学制造面临很大的困难，诸如工作效率低，成本高，增加对工艺设备的要求等问题。为了达到高精度，微位移分辨率的超精密机器必须进一步推进，以补偿在生产线上生产时产生的错误。因此，设计微进给机构已成为关键技术之一。近年来，压电陶瓷是新的微进给机构的发展。它具有体积小，功率大，分辨率高的优点，以及高频率响应等现象，如不加热，不反弹和粘性，因此它被广泛应用于微进给微控制器机制。如今，摩擦传动装置正逐渐被收购和使用。2微进给机构的结构和工作原理该微进给机构是由三部分组成：摩擦传动装置，滚珠丝杆及静压空气轴承指向方式。微进给机构采用压电陶瓷摩擦传动块，扭转了套筒和驱动器滚珠丝杠，从而带动空气轴承导轨实现微进给运动。该结构显示如图1轴承支架 2摩擦传动装置 3摩擦传动套筒 4静压空气轴承及导轨 5 滚珠丝杠 6 压电陶瓷基地 7压电陶瓷进料装置图1：（a）送料机构的结构如图2所示，饲料机制的工作原理是：摩擦传动与滚珠丝杠，4块摩擦传动原件对称放置在套筒两侧。每块压电陶瓷材料的疲劳导致了相应的夹持装置的疲劳，夹具夹持装置的疲软影响生产的压电陶瓷材料。当送料机构工作时，压电陶瓷用于在同一侧的两个块摩擦传动装置的紧固。-电子邮箱：，电话：（0451）15904608295，地址：哈尔滨工业大学413邮箱，邮编：150001。针对先进光学夹具，测试技术，高级光学制造技术的第三届国际Symp，由李扬，陈尧隆，恩斯特，伯恩哈德克利，李龙斌编辑。图1：（b）送料机构图片图2：进给机制的运行原则3可调预紧机制的设计此外，在摩擦传动装置上需要可调整的预紧机制，它必须有足够的预紧力。典型的预紧方法是钢板弹簧预紧机制，螺旋预紧机制，气压预紧机制等。在本文中该预紧机的制设计是灵活的平行四杆机构。它由压电陶瓷提供预紧力。该预紧力可以改变压电陶瓷的输入电压。如图3所示，利用有限元软件进行静态特性分析。当压电陶瓷的驱动力是最大值500N时，灵活安排四杆机构的刚性，通过有限元分析软件，得到K =24.15N/m，以及弹性铰链的最大应力为= 32.7Mpa。如果没有灵活的四杆机构（即当摩擦传动装置紧密接触时），压电陶瓷输出力通过灵活的四杆机构将完全转化为预紧力。4传动机构的特性分析学习和掌握辐射源驱动机制的特点，以采取适当的措施，以改善整体性能和设计提供了控制系统设计提供了依据。4.1驱动力矩当系统启动时，有一个初步的转动惯量作为结果的部分存在质量问题。为了研究驱动力矩，选择摩擦传动套筒作为研究课题。根据动力学理论的能量守恒，齿轮加工前和改装后，套筒的每部分摩擦转化为旋转惯量。正因为如此，我们可以得到转换后的转动惯量是 （a） 预紧机构的结构（b） 运动节点图（c）应力分布图图3：静态特性试验计划预紧机制其中p是丝杠间距，m;r是摩擦套筒半径，m;MS是球螺杆质量，kg;MT是摩擦套管质量，kg。通过上述分析，我们得到摩擦套筒的等效转动惯量。现在，我们选择的摩擦套筒作为课题调查，讨论驱动力矩（驱动力）所需要的设备启动时，它的影响因素。下面的等式工程设备开始时： （2）其中j是等效转动惯量，kgm2;是摩擦套筒角加速度，rad/s2;r是摩擦套筒半径，m;M是驱动力矩，Nm;F是驱动力（突破块之间摩擦和摩擦套筒摩擦），N当系统启动时，为了使套筒可以有一定的角加速度，一个适宜的驱动器偏转配件应用在对摩擦袖子上。偏转配件是由压电驱动器产生的输出力陶瓷。从式2我们可以得到的等效转动惯量，半径套筒和驱动器的摩擦压电陶瓷的力（突破块之间摩擦和摩擦套筒）是影响摩擦机制启动的因素，所以我们认为应该考虑每个因素的影响，以确保机制的正常启动。存在同样的问题时，送料机构将停止移动。4.2驱动刚性驱动刚性是进给的重要推动机制特征之一。现在，我们将详细的分析进给机制的驱动刚性，每个部分的刚性连接的级联有计算公式如下： （3）其中K是进给机制总硬度;KY是压电陶瓷的刚性;KF是摩擦套筒和摩擦块之间的刚度;KS是丝杠的轴向刚度;KS是丝杠扭转刚度;KN是螺母的刚性;KB是轴承的轴向刚度;KH是支架，轴承座刚度;KD是连接螺母块轴向刚度;下面是部分的分析和刚度计算：4.2.1压电陶瓷刚性本文中压电陶瓷陶瓷微定位系统是由中国电子科技集团公司第26研究所生产的WTYD0808055型。它是通过实验测量的刚性15.15N/m，如图4所示。4.2.2摩擦套筒的硬度块之间接触表面的的摩擦两个物体互相接触将有一定的向外力。力和位移之间的比例关系实际上反映了刚性特征。相应的刚性现在是：其中k是常数; N是压力;r是球体的摩擦表面理想化的半径。很显然在方程中，在特殊的摩擦传动装置系统中，k是从实验得到，r是常数，接触刚度的唯一的影响因素是压力N。图4：压电陶瓷刚性曲线4.2.3丝杠扭转刚度转变为轴向刚度传动链层面的转变需要统一计算它的刚性。因此，扭转刚性必须转化为轴向刚度，公式如下：其中是螺旋上升的角度，（）;D是丝杠直径，mm;F是丝杠轴向力，N;M是丝杠输入扭矩，Nmm;是丝杠和螺母之间的摩擦角（）;KT是丝杠扭转刚度，Nmm/rad;是螺丝扭转变形，rad;P是丝杠长度，mm;G是螺杆材料弹性剪切模量，Mpa;Jp截面惯性， mm4L是点到两个推力轴承的距离，mm。通过有限元分析可获得连接螺母块的轴向刚度，。螺母支架和轴承块的刚度是非常大的，可以不予考虑。通过查找表和计算可以得到其他部分刚度。总之，通过公式推导的机制驱动刚度，我们已经找到了驱动特性对学习的影响因素，驱动刚度对进一步研究驱动特性提供了基础。5. 进给机构的实验研究5.1实验系统的基础如图5所示，该实验系统是由进给机构，计算机，压电陶瓷驱动程序，电源组成图5：实验系统本文采用以平均曲线模型为基础的控制方法，建立开环控制模型。总之，测量压电陶瓷控制电压和滑行运输距离关系的实验曲线。利用Matlab软件，以适应的三次多项式代数和安装的时错误，图6所示，从中我们得到了相应的控制电压和距离和关系表达式，因此，控制进给机构的距离。 拟合线 错误拟合线图6：三次代数多项式拟合控制电压和距离的关系表达如方程7所示：其中x是输出的距离，;u是控制电压，V5.2系统分辨率的实验研究如图7所示，压电陶瓷具有一定的伸长率。在这个时候，微工作台的距离0.15微米。然后在此基础上逐步延伸，并在每一个时刻保持1.5秒。取样时间为100毫秒。该决议曲线可以通过测量得到的微进给机构的做法距离使用的电感图7：进给机制的距离分辨率曲线6. 结论本文中高分辨率和长冲程的微进给机构，有如下结论：1 预紧机制的关键在于设计了基于分析压电陶瓷静态特性的有限元软件;2分析了微进给机构的起动转矩和转动惯量计算的等效;分析驾驶微进给机构的刚度特性，并发现其影响因素;3该微进给机构游行可达300毫米，分辨率为0.05m以下。参考文献1. Seugng-Bok Choi, Sang-Soo Han. Position Control System Using ER Clutch and Piezoactuator. Pro. of SPIE, 2003, 5056: 424431 2. Suzuki H, Kodera S, Mabkawa S, et al. Study on Precision Grinding of Micro a Spherical Surface. JSPE, 1998, 64(4):619623. 3. Arrasmith S. R, Kozhinova I A, Gregg L L et al. Details of The polishing Spot in Magnetorheological Finishing(MRF).Proceedings of SPIE-the International Society for Optical Engineering, 2001,Vol.3782:92100. 4. Atherton P D, Xu Y, McConnell M. New X-Y Stage for Precision Positioning and Scanning. SPIE, 1996, 2865:1520. 5. Liu Yung -Tien, Toshiro Higuchi, Fung Rong-Fong. A Novel Precision Positioning Table Utilizing Impact Force of Spring-Mounted Piezoelectric Actuator. Precision Engineering, 2003, 27:14221 6. Lobontiu N, Goldfarb M, Garcia E. A Piezoelectric Drive Inchworm Locomotion Device. Mechanism and Machine Theory, 2001, 36: 425443. 7. A. A. Elmustafa, Max G. Lagally. Flexural-hinge Guided Motion Nanopositioner Stage for Precision Machining: Finite Element Simulations. Precision Engineering, 2001, 25: 7781 8. Jaehwa Jeong, Young-Man Choi, Jun-Hee Lee. Design and Control of Dual Servo Actuator for Near Field Optical Recording System. Pro. of SPIE, 2005, 6048: 18 9. Kim Jeong-Du, Nam Soo-Ryong. Development of a Micro-depth Control System for an Ultra-precision Lathe Using a Piezoelectric Actuator. International Journal of Machine Tools and Manufacture. Volume:37,Issue:4, April, 1997, pp.495509 10. Li Sheng-yi, Luo Bing, Dai Yi-fan, Peng Li. Design and Experiment of The Ultra Precision Twist-roller Friction Drive. ICAMT99.1999. Micro-feed Mechanism with High-Resolution and Large-Stroke Based on Friction Drive Haitao Liu, Zesheng Lu School of Mechantronics Engineering, Harbin Institute of Technology ABSTRACT Based on friction driving principle, design a long stroke length and high resolution walking micro-feeding device driven by piezoelectric ceramic elements and combined with the screw shaft and aerostatic guide way. The design was made to the adjustable preload device by flexible four-bar linkage. The static properties of flexible linkage device are analyzed with FEM. The transmission characteristics of micro-feeding device are exhaustively analyzed. Keywords: Friction drive, Piezoelectric actuator, Flexure hinge,Finite element 1. INTRODUCTION Aspheric optics has been widely used in industries such as aviation, aerospace, national defense and so on. However, the manufacture of large aspheric optics faces many problems such as great difficulty, low efficiency, high cost, increased requirement on process equipment etc 1, 2. In order to arrive at high precision, the micro displacement resolution of ultra-precision machine must be further advanced, so as to compensating the processing error online. Therefore, the design of micro-feed mechanism has become one of the key technologies 3-7. PZT is the new micro-feed mechanism developed in recent years. It has the advantages such as small volume, large power, high resolution, and high frequency response and so on and phenomena such as no heating, no backlash and mucosity, so its widely used micro controller in micro-feed mechanism. Nowadays, friction gearing mechanism is gradually been acquired and used 8, 9. 2. STRUCTURE AND OPERATING PRINCIPLE OF MICRO-FEED MECHANISM The micro-feed mechanism is made up of three parts: friction gearing, ball screw and static-pressure air-bearing guide way. Micro-feed mechanism uses the piezoelectricity ceramic friction gearing block, which twist up the sleeve and drive the ball screw, so as to bring along the air-bearing guide way to realize the micro-feed movement. The structure is shown as Figure 1. Figure 1: (a) Structure of the feed mechanism As shown in Figure 2, the operating principle of the feed mechanism is that, friction gearing sleeve connects with ball screw, four friction gearing blocks are placed symmetrically at both sides of the sleeve. Each block is droved by the corresponding piezoelectricity ceramic used for feeding and is gripped by the corresponding gripping mechanism, which is droved by the piezoelectricity ceramic used for gripping to produce clamp force. When feeding mechanism works, the E-mail:, Phone: (0451)15904608295, Address: Mailbox 413, Harbin Institute of Technology, Post Code: 150001. 2 1 3 4 5 6 7 1-Bearing bracket 2-Friction gearing block 3 Friction gearing sleeve 4-Static-pressure air-bearing guide way 5- Ball screw 6- Piezoelectricity ceramic base 7-Piezoelectricity ceramic used for feeding 3rd International Symp. on Advanced Optical Manufac. and Testing Tech.: Advanced Optical Manufacturing Technologies, edited by Li Yang, Yaolong Chen, Ernst-Bernhard Kley, Rongbin Li, Proc. of SPIE Vol. 6722, 67222E, (2007) 0277-786X/07/$18 doi: 10.1117/12.783140Proc. of SPIE Vol. 6722 67222E-1 piezoelectricity ceramic used for gripping on the same side drive both the friction gearing blocks to work in certain orderliness, so as that the friction gearing sleeve turn continuously. Figure 1: (b) Picture of the feed mechanism Figure 2: Operating principle of the feeding mechanism 3. DESIGN OF THE ADJUSTABLE PRETIGHTENING MECHANISM An adjustable retightening mechanism is required in the friction gearing mechanism, which must has enough pretightening force. The typical pretightening methods are plate spring pretightening mechanism, helical pretightening mechanism, and air pressure pretightening mechanism and so on. The retightening mechanism designed in this paper is flexible parallel four bars mechanism. Its droved by piezoelectricity ceramic to supply pretightening force. The pretightening force can be changed by controlling the input voltage of piezoelectricity ceramic. As shown in Figure 3, use the finite element software to analysis the static characteristic. When the drive force of piezoelectricity ceramic is 500N in maximum, the rigidity of flexible four bars mechanism, analyzed by finite element software, is K=24.15N/m, and the maximum stress of flexible hinges is =32.7Mpa. If there is no distortion in flexible four bars mechanism (that is when the friction gearing blocks contact rigidly), the output force of piezoelectricity ceramic will completely translates to pretightening force through the flexible four bars mechanism. 4. DRIVE CHARACTERISTIC ANALYSIS OF THE MECHANISM Studying and mastering the drive characteristic of mechanism redounds to adopting the proper measures to improve the whole performance and provides the design basis for designing the control system. 4.1 Drive torque Friction gearing block Friction gearing block Gripping mechanism Gripping mechanism Proc. of SPIE Vol. 6722 67222E-2AN When system starts, there is a problem on initial inertia moment as a result of the existence of parts quality. To research the drive torque, choose the friction gearing sleeve as subject investigated. According to the theory that the kinetic energy of gearing train is same before and after conversion, the rotary inertia of each part is transformed to friction sleeve. Because of that, we can get the rotary inertia after conversion is Figure 3: The static characteristic assay plan of pretightening mechanism 2222TSLD1()()()2222pppJm rmmm=+ (1) Where p is pitch of lead screw, m; r is radius of the friction sleeve, m; mS is quality of the ball screw, kg; mT is quality of the friction sleeve, kg. Through the above analysis, we get the equivalent rotary inertia of friction sleeve. Now we choose the friction sleeve as subject investigated to discuss the drive torque（drive force）that is needed when device starts and its influencing factors. The following equation works when device starts: J MF r= (2) Where J is equivalent rotary inertia, kgm2; is angular acceleration of friction sleeve, rad/s2; r is radius of the friction sleeve, m; M is drive torque, Nm; (b) Node motion nephogram (c) Von-mise stress envelope (a) Structure of the pretightening mechanism Proc. of SPIE Vol. 6722 67222E-3 F is drive force（breakout friction between friction block and friction sleeve）, N. When system starts, a condign drive deflecting couple should be applied on the friction sleeve, in order that the sleeve can have certain angular acceleration. The drive deflecting couple is generated by the output force of piezoelectricity ceramic. From equation 2 we can get that the equivalent rotary inertia of system, radius of the friction sleeve and drive force of the piezoelectricity ceramic (breakout friction between friction block and friction sleeve) are the influencing factor of mechanism start, so we should think over the influence of each factor to ensure the normal start of mechanism. Same questions exist when feed mechanism stop moving. 4.2 Driving rigidity The driving rigidity is one of the important driving characteristics of feed mechanism. Now we will analyze the driving rigidity of feed mechanism in detail as following. The rigidity of the feed mechanism is the cascade connection of the each segment rigidity of the feed mechanism, which has the calculated equation as follows: YFSSNBHD111111111KKKKKKKKK=+ (3) Where K is the total rigidity of the feed mechanism; KY is the rigidity of piezoelectricity ceramic; KF is the touching rigidity of surface in contact between friction block and friction sleeve; KS is the axial rigidity of lead screw; KS is the axial rigidity changed from the torsional rigidity of lead screw; KN is the rigidity of nut; KB is the rigidity of axial bearing; KH is rigidity of nut bracket and bearing block; KD is the axial rigidity of nut link block; Here is the analysis and calculation of part rigidity. 4.2.1 Rigidity of the piezoelectricity ceramic The piezoelectricity ceramic in this paper is the ceramic micro positioner typed WTYD0808055 produced by China Electronics Technology Group Corporation No.26 Research Institute. Its rigidity measured through experiment is 15.15N/m, as shown in Figure 4. 4.2.2 Touching rigidity of surface in contact between friction block and friction sleeve Two objects contacting with each other will have certain tangential transition before relative slip in the action of tangential external force, which is called pre-displacement. The proportional relation between force and displacement reflects a rigidity characteristic in fact 10. The corresponding rigidity now is: 1 31 3FKkrN= (4) Where k is const; N is normal pressure; r is the radius of idealized sphere on friction surface. Its clear in the equation that, in special friction gearing system, k is got from experiment, r is const, the only influencing factor of touching rigidity is normal pressure N. Its evident that the larger N is, the larger the touching rigidity K is. Proc. of SPIE Vol. 6722 67222E-4 Figure 4: Rigidity curve of piezoelectricity ceramic 4.2.3 Axial rigidity changed from the torsional rigidity of lead screw The dimension of driving chain needs to be transformed uniformly when calculating its rigidity. Therefore, the torsional rigidity must be transformed into axial rigidity as the following equation: PTGJMKL= (5) ST4tan()KKpd=+ (6) Where is the rising angle of lead screw, (); d is the diameter of lead screw, mm; F is the axial force of lead screw, N; M is the input moment of lead screw, Nmm; is the friction angle between lead screw and nut, (); KT is the torsional rigidity of lead screw, Nmm/rad; is the torsional deformation of lead screw, rad; p is the lead of lead screw, mm; G is the shear modulus of elasticity of lead screw material, Mpa; JP is the inertia moment of cross section, mm4, JP=d4/32; L is the maximum distance from loading point to two thrust bearing, mm. The axial rigidity of nut link block can be gained by the finite element analysis. The rigidity of nut bracket and bearing block is very large, which can be dismissed. The rigidity of other parts can be got by looking up table and calculating. In a word, by deducing the equation of drive rigidity of feed mechanism, we have found the influencing factors of driving rigidity caused by each driving segment, which offers the basis for further study on the driving characteristic. 5. EXPERIMENTAL STUDY OF THE FEED MECHANISM 5.1 Foundation of the experiment system 01234567809.819. 629. 439. 24958. 868. 678. 4N SProc. of SPIE Vol. 6722 67222E-5- -l:0:-V_ As shown in Figure 5, the experiment system is made up of feed mechanism, computer, piezoelectricity ceramic driver and its power supply and the inductance amesdial. Figure 5: Foundation of experiment system This paper uses a control method based on average curve model to set up the open loop control model. Above all, measure the experimental curve of relation between piezoelectricity ceramic control voltage and slide carriage distance. Using the Matlab software to fit the line with cubic algebraic multinomial, and the fitted line and fitted error line are as shown in Figure 6, from which we get the corresponding relational expression of control voltage and distance and therefore control the distance of feed mechanism. Figure 6: Fit with cubic algebraic multinomial Relational expression of control voltage and distance is as shown in equation 7: 73521.8 105.3 100.00440.022xuuu= + (7) Where x is the output distance, m; u is the control voltage, V. 5.2 Experimental study of system resolution As shown in Figure 7, piezoelectricity ceramic has certain elongation. At this time, the distance of micro working table is 0.15m. Then step elongating gradually on this base and keep 1.5s in each moment. The sampling time is 100ms. The resolution curve can be gained by measuring the practice distance of micro feed mechanism using the inductance amesdial. a) Fitted line b) Fitted error line Proc. of SPIE Vol. 6722 67222E-60.5IIIa45 Figure 7: Distance resolution curve of feed mechanism 6. CONCLUSION A step micro feed mechanism with long march and high resolution was designed in this paper, and the following conclusions were concluded: 1. Designed the pretightening mechanism based on the piezoelectricity ceramic flexible iron hinges and analyzed its static characteristic using the finite element software; 2. Analyzed the starting torque of micro f
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