Papers by Keyword: Error Analysis

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Authors: Ji Jiao, Fei Fan Chen
Abstract: Based on information pipeline technology, a clock soft synchronization method used in distributed measurement and control system is proposed. Using a separate information pipeline, the synchronization information is broadcasted to nodes in the distributed measurement and control system by synchronization node every message transaction cycle time, and all nodes automatically synchronize the local clock after receiving it. We analyze the theoretical synchronization error and verify this clock soft synchronization method in CAN bus. The theory analysis and experimental results indicate that the synchronization error mainly consists of propagation delay error, drift error and CAN loop delay error, and it increases linearly with the increasing of transmission distance.
Authors: Yu Fei Cai, Chun Ling Zhu, Su Qing Shi
Abstract: A ground test method of the heat exchanger in intake is proposed using simplified method. A theoretical analysis was carried out to investigate its influences on the performance of heat exchanger. The results show that the performance of heat exchanger keeps invariable with the density of gas if the temperature and mass flow rate remain the same. The error caused by substituting total pressure of free stream for inlet entrance was analyzed and the results show that for subsonic inlet the experimental error is relatively small and the experimental error increasing rapidly as flight Mach number exceed 1.2 and flight altitude has little impact on the experimental error while the error increasing slightly with flight altitude.
Authors: Li Min Zhu, Chun Guo Liu, Shao Hui Wang, Ming Zhe Li
Abstract: In reverse engineering, in order to analyze the accuracy of formed work-piece, the shape error between the formed work-piece and its CAD model need to be calculated. In this paper, a matching method on the basis of triangle mesh is proposed. This matching method includes three parts: pre-positioning, rough registration and fine registration. Firstly, the maximum projective plane of cloud data is designed to parallel to the xy plane through translation and rotation, and cloud data is translated by a vector which can be obtained with the point with the maximum z coordinate and the origin of coordinates. Secondly, cloud data is gradually rotated 360 degree around z axis confirm the angle making the error minimum. In this way, an initial value of ICP algorithm can be obtained, which can avoid the local convergence in the algorithm. Finally, ICP algorithm can be applied to calculate the surface error further. After matching, the error between work-piece and the CAD model can be calculated by interpolation based on triangle mesh. The results show that the matching method can obtain the higher matching accuracy.
Authors: Wen Yue Zhang, Yan Jun Ge, Jun Yue Yang
Abstract: Aiming at the problems of complex circuit and parameter adjustment in traditional current type power amplifier of Magnetic Bearing (MB), a new realization method of control system based on DSP (Digital Signal Processor) is proposed. The difference with traditional power amplifier is that the current control loop is realized through software in DSP, so some advanced control strategies will be adopted easily, and the control parameters could be modified freely. Besides, the models established in MATLAB using common control strategy and advanced strategy are simulated separately, and the simulation results show the better effect can be obtained with the latter. Finally, the rotor of a 1-DOF MB prototype can be suspended within 0.01mm in the experiment, and the control strategy and parameters can be modified freely by software in DSP.
Authors: Un Chung Cho
Abstract: V-grooved quartz substrates are manufactured by glass molding press and the pitch errors of the molded quartz fiber array blocks are statistically investigated. The V-grooved carbon molds of 8 and 16 channels and 250 μm in pitch are machined and then quartz substrates are molded on the V-grooved carbon molds by glass molding press. The pitch errors of X, Y and diagonal axis are measured and then statically analyzed. It is demonstrated that the V-grooved quartz fiber array blocks of 8 and 16 channels and 250 μm in pitch can be manufactured by glass molding technology without significant pitch errors.
Authors: Jun Xue Ren, Shan Shan Li, Jing Wen Zeng, Qian Lin
Abstract: Aiming at error evaluation of aero-engine blade airfoil in blade inspection. A new inspection method based on modeling matching is proposed, through the introduction of location weighting factor the mathematical model is built to accomplish precise matching between the CAD design model and measurement model. Besides, gradient descent particle swarm optimization (PSO) method is used to optimize the calculating process. Besides, thin blade error evaluation system is developed based on UG/OPEN API technology. Practical example proved that the present method can improve the accuracy of the error evaluation, and reduce the misjudgment of the thin blade.
Authors: En Ming Miao, Ya Yun Gong, Tian Ju Cheng, Peng Cheng Niu
Abstract: Eddy current sensor is widely used in engineering applications.When it was calibrated, generally used random error analysis method,but this will expand the range of measurement errors and limit its engineering applications.In this paper, we use a new error analysis method to analyze upper and lower limit of multiple batches measurement data. At the same time, catching up with a criterion for the measurement time. This can obtain the measurement accuracy more precise and have good practical value.
Authors: Tao Wang, Bing Li, Hong Xing Yang
Abstract: Traditional transmission line tower grounding resistance measurements have many shortcomings, in order to make up the defects the model of transmission line tower with good conductor wires and multiple grounding leads was builded, and then the algorithm of tower grounding resistance on-line measurement was proposed. On this condition, a system based on this algorithm was designed and further analysis of the error during data processing was conducted. At last, the MATLAB simulation indicates that the algorithm has a accuracy that meets the practical requirements.
Authors: Jing Li
Abstract: Interlanguage is an important issue in the field of second language acquisition for the past forty years. This study classifies the errors into three levels-lexicon, syntax and discourse, and then analyses the error examples to reflect the cause of interlanguage. The result may make some suggestions to the English teachers in English teaching.
Authors: Qi Zhang, Hong Lin Ma, Yong Ting Zhao, Jie Yang, Bin Zheng
Abstract: The parallelism between an industrial camera and a servo motion direction is corrected with the help of image measurement to shadowed geometric contours. Then a nearly orthogonal angle between XY servo motion directions is obtained according to an inherent geometry relationship in contours. The installation error of a PCB in platform is compensated based on automatic multi-spot imaging finally. An experimental prototype was built while the PCB alignment was implemented on a lot of samples according to the method introduced above. It proves that the developed immediate alignment method as well as its specific embodiment fulfills the requirement of positioning accuracy in the initial design.
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