Dimensional Synthesis CAD System Of Linkage Mechanism Based On Numerical Atlas Method

The dimensional synthesis of spatial linkage mechanism and planar linkage is an important part of linkage design. The scholar and experts carried out a lot of exploration and research for the dimensional synthesis of mechanism, corresponding have been proposed a number of methods. Numerical atlas method is used widely as the new method of the dimensional in the past ten years that it contain a number of dimensional types, high efficiency retrieval, simple operation, fast speed of calculate high accuracy. This paper uses numerical atlas method for dimensional synthesis and development of CAD system. So two aspects as follows are mainly studied in this dissertation.Firstly, Numerical atlases method based on harmonic theory and Fast Fourier Transform(FFT) is investigated and further perfect. It seek to extend this approach to the synthesis of spherical four-bar linkages for motion generation. Through harmonic analysis,the output characteristics of a spherical four-bar mechanism is observed to be dependent on the rigid body rotation angle operator. Subsequently, a database that contains 221968 sets of basic rotation angle dimensional types for a spherical four-bar mechanism was constructed. The theoretical formulas to calculate the actual dimension and installation parameters of spherical four bar mechanism are deduced from the harmonic parameters for position output and the harmonic parameters for the rigid body rotation angle operator. On the basis of the theoretical formulas and the numerical atlas database, the motion generation problem for a spherical four-bar mechanism was solved. Finally, two examples are provided to demonstrate the validity of this method.Secondly, it established the basic dimensional type harmonic characteristic parameters of database use numerical atlas method based on Fourier and wavelet theory. Then it identify the groups meet the design requirement of the basic dimensional types from harmonic characteristic parameters of database, and calculate the actual size and installation size corresponding mechanism, and database programming technology,object-oriented technology and CAD construction technology are adopted. With the tool of LabVIEW, the dimensional synthesis of CAD system is achieved.A lot of jobs have been carried out rounding these two main respects. The rigid-body guidance synthesis of spherical linkage mechanism is studied by using numerical atlases method, and write the corresponding data calculation program that called directly by LabVIEW. Two standard numerical atlases database for dimensional synthesis of spherical and planner linkage mechanism contains function synthesis, path synthesis. Using mixed programming technique of Matlab and LabVIEW, realized automatic extraction ofcharacteristic and automatic created of the standard atlas database. It created the design guide of CAD system that makes it used easily.