球面四杆曲柄滑块机构函数综合的变步长数据库法

Variable Step Size Database Method for Function Generation of Spherical Four Bar Crank Slider Mechanism

提出了用变步长数据库法进行球面四杆曲柄滑块机构函数综合。通过对球面四杆曲柄滑块机构输入输出函数的谐波成分分析,发现了机构输出函数与其相应的谐波特征参数之间的内在联系。据此将机构基本尺寸型和对应的谐波特征参数存储在一起,建立了包含42 185组基本尺寸型的球面四杆曲柄滑块机构函数输出谐波特征参数的变步长数据库。借助模糊识别理论可以快速的从数据库中识别出若干组满足设计要求的机构基本尺寸型,从而实现球面四杆曲柄滑块机构的函数综合。为了提高综合精度,借助遗传算法对得到的结果进行了优化。最后以塑料温室的通风开启关闭装置作为实例,来说明球面四杆曲柄滑块机构函数综合的过程及变步长数据库法在空间机构综合中的应用。

The variable step size database method for the function synthesis of spherical four bar crank slider mechanism was presented. Based on the analysis of input and output function of the spherical four bar crank slider mechanism, the immanent connection between output function and its corresponding harmonic characteristic parameters was discovered. Based on this discovery, a numerical atlas with variable step size database of output angle function, which contains 42 185 groups of basic dimensional types, could be created by the harmonic characteristic components and associated basic dimensional type of spherical four bar crank slider mechanism. The best suitable basic dimensional type of spherical four bar crank slider mechanism for prescribed function was decided by using fuzzy identification method and numerical atlas database. Thus the function synthesis of spherical four bar crank slider mechanism was made possible. In order to improve the precision, the result could be optimized by genetic algorithm. The ventilation device of the greenhouse was taken as an example to illustrate the analysis process and application of this method.