Computer-Aided Innovative Design Of Planar Linkage Mechanism Based On Group Combination

Combination is also a kind of innovation,and combinative innovation is an usual creative design methods of machinery system.According to the composition principle of mechanism,it all can scheme out new mechanism by connecting some Assur groups into the driving link and the fixed link in turns, or joining different class group based on the existed mechanism,which can apply to creative design of machine.The development of computer technology,artificial intelligence(AI) and their relative technology,make the computerization of the conceptual design system of mechanisms possible,and it turned the computer-aided mechanism design system into main means of modern mechanism design.The overall scheme design of mechanism is the important stage in design process of machinery product,it deciding the marketplace competition of product to a great extent,and it is the weak link in computer-aided design at the same time.Aimed at the development demand of the stage’s automation, the subject researched the key issues of computer-aided group combination by combining the composition principle of mechanism with computer technology, and developed computer-aided innovation design system of planar linkage mechanism based on group combination,which realized the automation of scheme design on planar linkage mechanism.The subject realized computer-aided innovative design of planar linkage mechanism based on group combination,the main research contents and creative points are described as follows:1) the description of Assur group,derivative group and combinative group.According to the composition principle of mechanism,and integrated with the concept of "mechanism combination",the subject abstracted and summarized constitution of mechanism:groups and kinematic pair,and described Assur group、derivative group and combinative group by symbols which was prone to be identified by computer,and it laid a foundation for realizing the computer-aided innovative design of mechanism.Its sketch was saved in graphics file format,which also established the basis for constructing three-dimensional entity model and dynamic simulation of mechanism.2) the compatibility of group combination.By analyzing the structure of Assur group,the subject realized group combination by connecting link and kinematic pair or between kinematic pairs.This paper analyzed the rules of the compatibility of group combination and realized the automatic combination of group based on the premise that the freedom fore and after is invariability by combining group,which start from the type and quality of groups’ constituent elements(link and kinematic pair).3) the determination of the number about driving link and connection points of fixed link when group combination forming mechanism.The driving link and the fixed link are two essential kinds of components in constitution of mechanism,the selection of their type is determined by the design demand,and that the choosing and determination of the number of connection points between combinative group and them deciding the deterministic nature of the kinematic of mechanism.This paper classified the driving link and the fixed link,and studied the determination of the number about driving link and connection points of fixed link when group combination forming mechanism.The subject realized computer-aid innovative design of planar linkage mechanism based on group combination.It resolved the problems about group splitting and automatic drawing of kinematic sketch in constitution of mechanism,and it made the analysis and synthesis of kinematics and dynamics of planar linkage mechanism convenient,which not only being able to pick up the correlation between link and kinematic pair in kinematic chain, improved entire design efficiency thereby,but also a highly significant for computerization and automation of design process.