Full-Text Search:
Home|Journal Papers|About CNKI|User Service|FAQ|Contact Us|中文
《Transactions of the Chinese Society of Agricultural Engineering》 2016-08
Add to Favorite Get Latest Update

Adaptive numerical atlas method of spherical four-bar mechanism and its applications for harvester

Sun Jianwei;Chen Lu;Chu Jinkui;Liu Xianping;School of Mechatronic Engineering, Changchun University of Technology;Key Laboratory for Precision and Nontraditional Machining Technology of Ministry of Education, Dalian University of Technology;  
The dimensional synthesis of spherical four-bar linkages mechanism, which contains function generation, path synthesis and rigid-body guidance synthesis, is an important part of linkage design. For integral period dimensional synthesis of spherical four-bar linkages mechanism by using Fourier series theory, firstly the mathematical model of spherical four-bar linkages mechanism is established and the Fourier transform's function expression is given. The relationship between output function and the basic dimensional type is found out. Then the spherical four-bar linkages mechanism's harmonic characteristic parameters database is created. Secondly, by using the fuzzy identification theory, the best suitable basic dimensional type of spherical four-bar linkages mechanism for prescribed output function is obtained. Thus, it achieves the purpose of spherical four-bar linkages mechanism function generation. For non-integral period dimensional synthesis of linkage mechanism, the Fourier series theory can not be analyzed and integrated. In many applications, the design requirement is non-integer periodic function. Therefore, the purpose of this study was to propose a new numerical atlas method to apply to the non-integer periodic function generation problem of spherical four-bar mechanism. The wavelet function has a good analysis ability in both time and frequency, which is its unique advantage for non-integral period dimensional synthesis of linkage mechanism. By taking advantage of the multi-resolution characteristic of the wavelet function, this paper presents the Haar wavelet feature parameter method for the non-periodic function generation of spherical four-bar linkages mechanism. Based on the analysis by wavelet theory of non-integral period output function of the spherical four-bar mechanism, the connection between the wavelet feature parameters of output function by translation or scaling and the wavelet feature parameters of primitive function could be discovered. Then a self-adaptive database of basic dimensional type of spherical four-bar linkages mechanism could be created, which contained 148 995 groups of basic dimensional types. Based on the created database and fuzzy recognition theory, a method of matching recognition was proposed by using the relationship between the wavelet feature parameters of basic dimensional type and the wavelet feature parameters of the given non-periodic function. And the given design interval of the spherical four-bar mechanism non-periodic function generation was realized. Based on the recognized result and the immanent connection between output function and wavelet feature parameters, the optimization object function could be created by using genetic algorithm. Then the result was optimized. This paper took the pendulum disc type cutting mechanism of combine as an example to illustrate the effectiveness and practicality of this method. To optimize the spherical four-bar mechanism function output result, the genetic algorithm was adopted, the population size was set as 200, the crossover probability was 0.08, the mutation parameter was 0.06 and the crossover operator was used. The percent error of the first set mechanism was 1.92%, and that of the second set mechanism was 2.31%, which indicated that the pendulum disc type cutting mechanism of combine met the requirement of actual testing, which was 3%. The study for the function generation and the pendulum disc type cutting mechanism of combine provides a very important theoretical basic and reference for the design, analysis and further study on path synthesis and rigid-body guidance synthesis.
【Fund】: 国家自然基金(51105044 51175056)
【CateGory Index】: S225
Download(CAJ format) Download(PDF format)
CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.
【Co-citations】
Chinese Journal Full-text Database 2 Hits
1 YU Hongying;ZHAO Yanwei;XU Dongming;School of Mechatronics Engineering,Harbin Institute of Technology;;A path synthesis method of planar hinge four-bar linkage[J];Journal of Harbin Institute of Technology;2015-01
2 CANG Peng;LIU Wenrui;SUN Jianwei;School of Mechatronic Engineering,Changchun University of Technology;;Wavelet analysis for an open coupler curves of planar four bar linkages[J];Journal of Changchun University of Technology;2015-04
Similar Journals
©2006 Tsinghua Tongfang Knowledge Network Technology Co., Ltd.(Beijing)(TTKN) All rights reserved