硅钢机组张力辊打滑现象的分析和解决措施

结合硅钢机组的实际运转情况,对张力辊的工况和受力进行理论分析,得出了张力辊产生打滑的几种可能原因,最后针对这些原因提出了相应的解决措施,并同时还在从控制的角度上对有效地防止张力辊打滑现象的出现进行了一定的探讨.     

冷轧连续退火机组中张力辊组主要参数的设计

以发电状态下两端带压辊和不带压辊的S辊组张力变化模型为基础,比较了不加压辊和加压辊以后张力辊平衡力矩的变化,推导了两张力辊偏移距、压辊直径的定量计算公式,讨论了防止打滑条件下张力辊组主要参数的设计过程.     

A study on the fault diagnosis of the 3-d roll shape in cold rolling

The metal processing system usually consists of various components such as motors, work rolls, backup rolls, idle rolls, sensors, etc. Even a simple fault in a single component in the system may cause a serious damage on the final product. It is, therefore, necessary to diagnose the faults of the components to detect and prevent a system failure. Especially, the defects in a work roll are critical to the quality of strip. In this study, a new 3-D diagnosis method was developed for roll shape defects in rolling processes. The new method was induced from analyzing the rolling mechanism by using a rolling force model, a tension model, the Hitchcock’ s equation, and measurement of the strip thickness, etc. Computer simulation shows that the proposed method is very useful in the diagnosis of the 3-D roll shape.     

Precision evaluation of surface form error of a large-scale roll workpiece on a drum roll lathe

This paper presents on-machine evaluation of surface form error components of a large-scale roll workpiece, including the out-of-roundness, the out-of-straightness, the taper angle and the diameter deviation, on a drum roll lathe. A pair of capacitive-type displacement probes is mounted on the carriage slide to target the two sides of the roll workpiece mounted on the spindle, which has a length of 2000 mm, a diameter of 320 mm and a mass of 350 kg. The outputs of the probes are employed to accurately evaluate the surface form error components through separating the influences of the motion errors of the spindle and the carriage slide of the lathe. It has been difficult to apply the reversal error-separation method for measurement of the out-of-roundness component of such a large workpiece because it is difficult to reverse the workpiece with respect to the spindle on the lathe due to its large size and heavy mass. An improved reversal operation technique, in which the spindle is rotated with respect to the stationary roll workpiece being held by a crane, is therefore proposed to solve this problem. Measurement uncertainty analysis is carried out to verify the reliability of the new technique for on-machine evaluation of the out-of-roundness component. The out-of-straightness component and the taper angle component of the roll workpiece are then evaluated by using a previously developed method. A simple and effective algorithm for evaluation of the diameter deviation component is also presented.     

Effect of taper tension profile on the telescoping in a winding process of high speed roll to roll printing systems

Winding is an integral operation in almost every roll to roll system. A center-wound roll is one of the suitable and general schemes in a winding mechanism. In general, the quality of wound roll is known to be related to the lateral displacement error and starring defect of a wound roll. Especially, a telescoping within a center-wound roll can cause damages such as misalignment between layers, folding, wrinkle, etc. Taper tension is known to be one of the major factors which affect the shape of a wound roll. It is therefore necessary to analyze the relationship between taper tension profile and telescoping within the center-wound roll to prevent winding failure and to sustain high quality of the printed materials. It is hard to compensate for undesirable winding roll shapes such as telescoping, because a winding is commonly a final process in roll to roll systems and has no feedback control mechanism to correct winding roll shape directly during winding operation. Therefore, an optimal taper tension profile and the accurate control of it in a winding section could be one way to shape the fail-safe of a wound roll. Through the correlation between taper tension profile and telescoping in a winding process, a mathematical model for the telescoping due to tension distribution in cross machine direction was developed, and verified by experimental study. A new logic to determine the proper taper tension profile was designed by combining and analyzing the winding mechanism which includes nip induced tension model, relationship between taper tension profile and telescoping, relationship between taper value and telescoping. Numerical simulations and experimental results show that the proposed method is very useful for determining the desirable taper tension profile during the winding process and preventing defects of winding roll shape such as telescoping.     

A study on the fault diagnosis of roller-shape using frequency analysis of tension signals and artificial neural networks based approach in a web transport system

Rollers in the continuous process systems are ones of key components that determine the quality of web products. The condition of rollers (e.g. eccentricity, runout) should be consistently monitored in order to maintain the process conditions (e.g. tension, edge position) within a required specification. In this paper, a new diagnosis algorithm is suggested to detect the defective rollers based on the frequency analysis of web tension signals. The kernel of this technique is to use the characteristic features (RMS, Peak value, Power spectral density) of tension signals which allow the identification of the faulty rollers and the diagnosis of the degree of fault in the rollers. The characteristic features could be used to train an artificial neural network which could classify roller conditions into three groups (normal, warning, and faulty conditions). The simulation and experimental results showed that the suggested diagnosis algorithm can be successfully used to identify the defective rollers as well as to diagnose the degree of the defect of those rollers.     

Machining accuracy improvement for a dual-spindle ultra-precision drum roll lathe based on geometric error analysis and calibration

This paper performs a comprehensive analysis and calibration on the geometric error of the ultra-precision drum roll lathe with dual-spindle symmetrical structure and cross slider layout. Firstly, the volumetric error model which contains all geometric errors of the dual-spindle ultra-precision drum roll lathe (DSUPDRL) is developed based on the combination of the homogenous transfer matrix (HTM) and multi-body system (MBS) theory. Secondly, sensitivity analysis for the volumetric error model is conducted to identify the sensitive geometric error components of the DSUPDRL using an improved Sobol method based on the quasi-Monte Carlo algorithm. The result of sensitivity analysis laid the foundation for the subsequent geometric error calibration. Then, some sensitive error components along the X and Z directions are calibrated using a laser interferometer and a pair of inductance displacement probes. Besides the volumetric error model, the concentricity error caused by dual-spindle symmetrical structure is proposed and calibrated by the on-machine measurement using a classic reversal method. Finally, a large-scale roller mold with a diameter of 250 mm and a length of 600 mm is machined using the DSUPDRL after calibration. The experimental result shows that 1.4 μm/600 mm generatrix accuracy is obtained, which validate the effectiveness of the geometric error analysis and calibration.     

A comparison of methods to estimate the roll torque in thin strip rolling

An energy balance method is used to calculate the roll torque associated with non-circular thin strip rolling and the results for the torque are compared with the moments of the forces exerted on the roll by the strip. An example is given in which the results of the two methods are quite different. This probably indicates that the axis of the roll is not at the point about which the moment is taken. The energy balance method is also used to estimate the torque associated with circular arc rolling. The results are compared with those calculated with Hill's formula in one example and, in another example, the comparison is made between the results from the energy method formulated in this paper and a commercial package which also uses both an energy method and Hill's formula.     

The comparison of joint kinematic error using the absolute and relative coordinate systems for human gait

Minimizing artifacts from skin movement is vital for acquiring more accurate kinematic data in human movement analysis. There are several stages that cause skin movement artifacts and these stages depend on the selection of the reference system, the error reduction method and the coordinate system in clinical gait analysis. Due to residual errors, which are applied to the Euler and Bryant angle methods in each stage, significant cumulative errors are generated in the motion analysis procedure. Thus, there is currently a great deal of research focusing on reducing kinematic errors through error reduction methods and kinematic error estimations in relation to the reference system. However, there have been no studies that have systematically examined the effects of the selected coordinate system on the estimation of kinematic errors, because most of these previous studies have been mainly concerned with the analysis of human movement using only the human models that are provided in the commercial 3D motion capture systems. Therefore, we have estimated the differences between the results of human movement analyses using an absolute coordinate system and a relative coordinate system during a gait, in order to establish which system provides a more accurate kinematic analysis at the ankle joint. Six normal adult subjects with no neurological or orthopedic conditions, lower extremity injuries, or recent history of lower extremity surgery were used in this study. The analysis was conducted at a walking speed of 1.35m/s. For the clinical estimation, we used a cardinal plane based on the segmental reference system and the differences were plotted on the planes. From this analysis, when a relative coordinate system was in the gait analysis, the average kinematic error occurring during the gait was determined to be 13.58mm, which was significantly higher than the error generated with an absolute coordinate system. Therefore, although the relative coordinate system can also be used to calculate the ankle joint center during the clinical gait analysis, the absolute coordinate system should be employed in order to obtain more accurate joint kinematic data. In addition, the results from this study can be used as a basis to select an appropriate coordinate system with regards to the diagnostic accuracy level required for various kinds of gait disorders. This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo Yong Hoon Rim received his B.S. and M.S degrees in Bio-Mechatronic engineering from Sungkyunkwan University in 2002 and 2004, respectively. Yong Hoon Rim is currently a Researcher at the Bio-Mechatronics center and also a candidate in the biomedical Ph.D. program at Sungkyunkwan University, Korea. His research interests are in the area of digital human modeling, workspace optimization and ergonomics in digital factory. Ahn Ryul Choi received his B.S. and M.S. degrees in Bio-Mechatronic engineering from Sungkyunkwan Univer-sity in 2005 and 2007, respectively. Ahn-Ryul Choi is curr-ently a Researcher at the Bio-Mechatronics center and also a candidate in the biomedical Ph.D. program at Sungkyunkwan University, Korea. His research interests are in the area of digital human modeling and simulation. Sang Sik Lee received his Ph.D. degree from Sungkyun-kwan Universi-ty in 2000. He is currently serving as a research professor at the Bio-Mechatronics center in Sungkyunkwan University. His research interests are in the area of digital human modeling and industrial ergonomics. Kyoung Kee Min received his Ph.D degree Sungkyunkwan University in 2008. Dr. Min is currently a researcher at the Bio-Mechatronics Center in Sungkyunkwan University. Dr. Min’s research interests are in the area of disease classification using artificial neural network, digital human modeling & control. Dong Hyuk Keum received his Ph.D. degree from Seoul National University in 1979. Dr. Keum is currently a Professor at the Department of Bio-Mechat- ronic engineering at Sungkyun-kwan University, Korea. He is currently serving as the chief of an evaluation committee of the Rural Development Administrator. Dr. Keum’s research interests are in the area of simulation of post-harvest systems, quality evaluation of food materials and the processing technology. Chang Hyun Choi received his Ph.D. degree from Iowa State University in 1988. Dr. Choi is currently a Professor at the Department of Bio-Mechatronic Engineering at Sungkyunkwan University, Korea. He is currently serving as an evaluation committee of the Rural Development Administration, Korea and Korea Industrial Technology Foundation. Dr. Choi’s research interests are in the area of nondestructive quality evaluation of foods, and automatic control of off-road machinery. Joung Hwan Mun received his Ph.D. degree majoring in mechanical engineering from the University of Iowa in 1998. Dr. Mun is currently a Professor at the Department of Bio-Mechat-ronic engineering at Sungkyun-kwan University in Suwon, Korea. He is currently serving as a director of the Bio-Mechatronics center with regard to an international IMS project. Dr. Mun’s research interests are in the area of digital human modeling, sports biomechanics, bio-electronics and digital factory for human oriented production system.     

软式操纵系统中张力调节器的设计研究

软式操纵系统是通过钢索张力来传递操纵力的,钢索张力的变化直接影响飞机的操纵性能。张力调节器就是使钢索在各种状态下保持张力恒定的一种调节装置。对张力调节器的原理、结构形式进行了综合论述,并结合设计实例来说明钢索张力调节器的设计过程及设计中各参数的选取原则。     

A study on analyzing the problem of the spherical form error

Many methods to evaluate the form error of a sphere have been studied over the years. Most of these, such as the optimum methods, employed the approximate local solution to obtain the desired results. In this paper, three mathematical models are constructed to evaluate the solutions of the minimum circumscribed sphere, the maximum inscribed sphere, and the minimum zone sphere by directly resolving the simultaneous linear algebraic equations. Examples are given to verify that the model is admissible and reliable. These simple mathematical methods are verified to be useful for determining the exact solution.     

A practical method to assess the performance of gravimetric flow test rigs by using the timing error

This paper proposes an improved method to assess the performance of a gravimetric flow test rig. It addresses the study of two of the most important measurement systems: the weighing scale and all mass-related corrections, and the time measurement system. By performing a regular diverter test according to ISO 4185:1980 several times and under different conditions, it was possible to determine not only the statistical variances of the diverter system, but also the variances of the meter under test and of the flow test facility separately. The proposed method allows also under special conditions the determination of systematic errors in the mass determination. The method has been successfully applied at the large water flow calibration facilities of PTB in Braunschweig and Berlin and is recommended as a routine to test the performance of gravimetric flow test facilities.     

Identification of thermal error in a feed system based on multi-class LS-SVM

Research of thermal characteristics has been a key issue in the development of high-speed feed system. The thermal positioning error of a ball-screw is one of the most important objects to consider for high-accuracy and high-speed machine tools. The research work undertaken herein ultimately aims at the development of a comprehensive thermal error identification model with high accuracy and robust. Using multi-class least squares support vector machines (LS-SVM), the thermal positioning error of the feed system is identified with the variance and mean square value of the temperatures of supporting bearings and screw-nut as feature vector. A series of experiments were carried out on a self-made quasi high-speed feed system experimental bench HUST-FS-001 to verify the identification capacity of the presented method. The results show that the recommended model can be used to predict the thermal error of a feed system with good accuracy, which is better than the ordinary BP and RBF neural network. The work described in this paper lays a solid foundation of thermal error prediction and compensation in a feed system.     

自适应模糊系统在车削工件直径误差预测中的应用研究

根据车削过程中工件直径误差的特点,提出了用自适应模糊系统预测由弹性变形等因素引起的工件直径误差的思路,通过梯度下降算法训练M amdan i型模糊系统,以确定合理的系统参数。根据工件直径误差与切削深度、进给量等的关系,进行车削实验,得到训练数据和测试数据,用训练数据训练模糊系统,进而用测试数据进行测试,得到结果合理,从而验证了利用自适应模糊系统进行工件直径误差预测的可行性。和回归分析的预测值进行比较,比较结果显示了自适应模糊系统在车削工件直径误差预测方面的应用具有优势。     

基于旋转毛玻璃片的全息系统去噪处理

针对噪声严重影响全息图采集时的质量和全息重建的效果,采取了电机带动毛玻璃片旋转的方法来去除全息系统的噪声。其理论依据为高速旋转的毛玻璃片能够降低激光的相干性,从而减小系统的本征噪声。利用旋转毛玻璃片的作用机理,将其应用于全息系统中,可有效去除系统中的噪声。实验表明,该方法能有效去除系统中的噪声,提高系统的信噪比,改善全息重建的效果。     

A numerical study on the effect of the flow control using bleeding systems in a bump-type inlet

In many supersonic inlets, several oblique shock waves are followed by a terminal normal shock wave. The normal shock-wave/turbulent boundary-layer interaction is critical with respect to its influence on the development of boundary layer throughout the subsonic diffuser and the total pressure recovery at the engine face. In the current study, the bump-type inlet was designed for two oblique shock waves and a normal shock wave. In addition, a porous surface was installed underneath the root of the normal shock wave. The effect of flow control on the interaction between the normal shock wave and turbulent boundary layer in supersonic inlets by using the bleeding system was investigated numerically and was evaluated with respect to the inlet performance parameters.

     

基于改进EMD的微机械陀螺随机误差建模方法

为了降低微机械(MEMS)陀螺仪的随机误差,提出一种将改进的经验模态分解法(EMD)与传统建模滤波方法相结合的新方法对随机误差进行处理。首先采用传统EMD算法将信号分解为有限个本征模态函数(IMF),并根据皮尔逊相关系数准则和噪声统计特性提出一种筛选机制,将IMF分为噪声IMFs、混叠IMFs和信号IMFs 3类;其次,对混叠IMFs进行时间序列建模,建模完成后进行卡尔曼滤波拟合;最后,将建模滤波后的混叠IMFs与信号IMFs进行重构,得到最终去噪信号。实验分析结果表明,本文方法在抑制随机误差的效果上有明显的优势,极大地改善了信号的质量,提高了惯导的解算精度。     

闭环运动控制系统中被控对象的模型辨识研究

分析采用运动控制器的典型运动控制系统的工作过程。利用闭环控制系统中的控制信息和反馈信息 ,在不增加任何硬件测试装置的条件下 ,从辨识所得到的闭环模型中得出被控对象系统的数学模型 ,实验证明该方法可行 ,可为系统参数优化和故障诊断等提供条件。     

利用偏心套消除大客车涂装吊具行走轮组安装位置误差

介绍利用偏心套消除大客车涂装吊具行走轮组安装位置误差,以保证吊具滚轮与工字钢轨道的接触均匀,转动灵活。该方法简单实用,成本低廉,值得在类似的大型滚动构件的加工制作中推广应用。     

机器人装配系统中精度对装配成功率的影响

利用《机器人装配系统的精度分析》一文中所得出的结果,并以ＳＲＸ－４型ＳＣＡＲＡ机器人对摩托车气门的装配为例,采用蒙特卡洛模拟法分析了装配系统精度对装配成功的影响,实验结果验证了所得结论的正确性。